30 CFR 57.16002 - Bins, hoppers, silos, tanks, and surge piles.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Bins, hoppers, silos, tanks, and surge piles... NONMETAL MINES Materials Storage and Handling § 57.16002 Bins, hoppers, silos, tanks, and surge piles. (a) Bins, hoppers, silos, tanks, and surge piles, where loose unconsolidated materials are stored, handled...

30 CFR 56.16002 - Bins, hoppers, silos, tanks, and surge piles.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Bins, hoppers, silos, tanks, and surge piles... MINES Materials Storage and Handling § 56.16002 Bins, hoppers, silos, tanks, and surge piles. (a) Bins, hoppers, silos, tanks, and surge piles, where loose unconsolidated materials are stored, handled or...

7 CFR 58.228 - Dump hoppers, screens, mixers and conveyors.

Code of Federal Regulations, 2011 CFR

2011-01-01

... 7 Agriculture 3 2011-01-01 2011-01-01 false Dump hoppers, screens, mixers and conveyors. 58.228... Service 1 Equipment and Utensils § 58.228 Dump hoppers, screens, mixers and conveyors. The product contact surfaces of dump hoppers, screens, mixers and conveyors which are used in the process of transferring dry...

46 CFR 170.300 - Special consideration for free surface of spoil in hopper dredge hoppers.

Code of Federal Regulations, 2014 CFR

2014-10-01

... 46 Shipping 7 2014-10-01 2014-10-01 false Special consideration for free surface of spoil in hopper dredge hoppers. 170.300 Section 170.300 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) SUBDIVISION AND STABILITY STABILITY REQUIREMENTS FOR ALL INSPECTED VESSELS Free Surface § 170.300...

Flow and Jamming of Granular Materials in a Two-dimensional Hopper

NASA Astrophysics Data System (ADS)

Tang, Junyao

Flow in a hopper is both a fertile testing ground for understanding fundamental granular flow rheology and industrially highly relevant. Despite increasing research efforts in this area, a comprehensive physical theory is still lacking for both jamming and flow of granular materials in a hopper. In this work, I have designed a two dimensional (2D) hopper experiment using photoelastic particles (particles' shape: disk or ellipse), with the goal to build a bridge between macroscopic phenomenon of hopper flow and microscopic particle-scale dynamics. Through synchronized data of particle tracking and stress distributions in particles, I have shown differences between my data of the time-averaged velocity/stress profile of 2D hopper flow with previous theoretical predictions. I have also demonstrated the importance of a mechanical stable arch near the opening on controlling hopper flow rheology and suggested a heuristic phase diagram for the hopper flow/jamming transition. Another part of this thesis work is focused on studying the impact of particle shape of particles on hopper flow. By comparing particle-tracking and photoelastic data for ellipses and disks at the appropriate length scale, I have demonstrated an important role for the rotational freedom of elliptical particles in controlling flow rheology through particle tracking and stress analysis. This work has been supported by International Fine Particle Research Institute (IFPRI) .

Perturbation solutions for flow through symmetrical hoppers with inserts and asymmetrical wedge hoppers

NASA Astrophysics Data System (ADS)

Cox, G. M.; Mccue, S. W.; Thamwattana, N.; Hill, J. M.

Under certain circumstances, an industrial hopper which operates under the "funnel-flow" regime can be converted to the "mass-flow" regime with the addition of a flow-corrective insert. This paper is concerned with calculating granular flow patterns near the outlet of hoppers that incorporate a particular type of insert, the cone-in-cone insert. The flow is considered to be quasi-static, and governed by the Coulomb-Mohr yield condition together with the non-dilatant double-shearing theory. In two-dimensions, the hoppers are wedge-shaped, and as such the formulation for the wedge-in-wedge hopper also includes the case of asymmetrical hoppers. A perturbation approach, valid for high angles of internal friction, is used for both two-dimensional and axially symmetric flows, with analytic results possible for both leading order and correction terms. This perturbation scheme is compared with numerical solutions to the governing equations, and is shown to work very well for angles of internal friction in excess of 45°.

46 CFR 97.15-75 - Test of inflatable hopper gate seals on Great Lakes bulk dry cargo vessels.

Code of Federal Regulations, 2010 CFR

2010-10-01

... 46 Shipping 4 2010-10-01 2010-10-01 false Test of inflatable hopper gate seals on Great Lakes bulk... inflatable hopper gate seals on Great Lakes bulk dry cargo vessels. (a) It is the duty of the Master to ensure that the inflatable hopper gate seals installed on vessels required to meet the damage stability...

46 CFR 97.15-75 - Test of inflatable hopper gate seals on Great Lakes bulk dry cargo vessels.

Code of Federal Regulations, 2011 CFR

2011-10-01

... 46 Shipping 4 2011-10-01 2011-10-01 false Test of inflatable hopper gate seals on Great Lakes bulk... inflatable hopper gate seals on Great Lakes bulk dry cargo vessels. (a) It is the duty of the Master to ensure that the inflatable hopper gate seals installed on vessels required to meet the damage stability...

46 CFR 44.310 - Definitions.

Code of Federal Regulations, 2011 CFR

2011-10-01

... Assigning Working Freeboards to Hopper Dredges § 44.310 Definitions. Hopper dredge means a self-propelled dredge with an open hold or hopper in the hull of the dredge that receives dredged material. Working...

46 CFR 44.310 - Definitions.

Code of Federal Regulations, 2010 CFR

2010-10-01

... Assigning Working Freeboards to Hopper Dredges § 44.310 Definitions. Hopper dredge means a self-propelled dredge with an open hold or hopper in the hull of the dredge that receives dredged material. Working...

Coal storage hopper with vibrating screen agitator

DOEpatents

Daw, Charles S.; Lackey, Mack E.; Sy, Ronald L.

1984-01-01

The present invention is directed to a vibrating screen agitator in a coal storage hopper for assuring the uniform feed of coal having sufficient moisture content to effect agglomeration and bridging thereof in the coal hopper from the latter onto a conveyor mechanism. The vibrating screen agitator is provided by a plurality of transversely oriented and vertically spaced apart screens in the storage hopper with a plurality of vertically oriented rods attached to the screens. The rods are vibrated to effect the vibration of the screens and the breaking up of agglomerates in the coal which might impede the uniform flow of the coal from the hopper onto a conveyer.

Coal storage hopper with vibrating-screen agitator

DOEpatents

Daw, C.S.; Lackey, M.E.; Sy, R.L.

1982-04-27

The present invention is directed to a vibrating screen agitator in a coal storage hopper for assuring the uniform feed of coal having sufficient moisture content to effect agglomeration and bridging thereof in the coal hopper from the latter onto a conveyer mechanism. The vibrating scrren agitator is provided by a plurality of transversely oriented and vertically spaced apart screens in the storage hopper with a plurality of vertically oriented rods attached to the screens. The rods are vibrated to effect the vibration of the screens and the breaking up of agglomerates in the coal which might impede the uniform flow of the coal from the hopper onto a conveyer.

In vitro effect of fenthion on human lymphocytes

DOE Office of Scientific and Technical Information (OSTI.GOV)

Rani, M.V.U.; Rao, M.S.

1991-08-01

Fenthion is an organophosphorus insecticide which is extensively used in control of leaf hoppers, cutworms, mites on vegetable crops. It has been reported that organophosphorus pesticides cause a significant increase in sister chromatid exchanges in mammalian cell lines. A significant increase of chromosomal aberrations has been reported in rural population exposed to pesticides. Organosphosphorus pesticides malathion, diazinon, dimethoate, phosdrin and dursban induced sister chromatid exchanges in human lymphoid cells. Exchange type of aberration has been reported in fluoriculturist who were exposed to organophosphorus, organochlorine pesticides. In the present investigation an attempt has been made to evaluate the cytogenetic effect ofmore » fenthion in human lymphocyte cultures in vitro.« less

Baby leaf lettuce germplasm enhancement: developing diverse populations with resistance to bacterial leaf spot caused by Xanthomonas campestris pv. vitians

USDA-ARS?s Scientific Manuscript database

Baby leaf lettuce cultivars with resistance to bacterial leaf spot (BLS) caused by Xanthomonas campestris pv. vitians (Xcv) are needed to reduce crop losses. The objectives of this research were to assess the genetic diversity for BLS resistance in baby leaf lettuce cultivars and to select early gen...

Management of mango hopper, Idioscopus clypealis, using chemical insecticides and Neem oil.

PubMed

Adnan, S M; Uddin, M M; Alam, M J; Islam, M S; Kashem, M A; Rafii, M Y; Latif, M A

2014-01-01

An experiment was conducted in Field Laboratory, Department of Entomology at Bangladesh Agricultural University, Mymensingh, during 2013 to manage the mango hopper, Idioscopus clypealis L, using three chemical insecticides, Imidacloprid (0.3%), Endosulfan (0.5%), and Cypermethrin (0.4%), and natural Neem oil (3%) with three replications of each. All the treatments were significantly effective in managing mango hopper in comparison to the control. Imidacloprid showed the highest efficacy in percentage of reduction of hopper population (92.50 ± 9.02) at 72 hours after treatment in case of 2nd spray. It also showed the highest overall percentage of reduction (88.59 ± 8.64) of hopper population and less toxicity to natural enemies including green ant, spider, and lacewing of mango hopper. In case of biopesticide, azadirachtin based Neem oil was found effective against mango hopper as 48.35, 60.15, and 56.54% reduction after 24, 72, and 168 hours of spraying, respectively, which was comparable with Cypermethrin as there was no statistically significant difference after 168 hours of spray. Natural enemies were also higher after 1st and 2nd spray in case of Neem oil.

Management of Mango Hopper, Idioscopus clypealis, Using Chemical Insecticides and Neem Oil

PubMed Central

Adnan, S. M.; Uddin, M. M.; Alam, M. J.; Islam, M. S.; Kashem, M. A.; Rafii, M. Y.; Latif, M. A.

2014-01-01

An experiment was conducted in Field Laboratory, Department of Entomology at Bangladesh Agricultural University, Mymensingh, during 2013 to manage the mango hopper, Idioscopus clypealis L, using three chemical insecticides, Imidacloprid (0.3%), Endosulfan (0.5%), and Cypermethrin (0.4%), and natural Neem oil (3%) with three replications of each. All the treatments were significantly effective in managing mango hopper in comparison to the control. Imidacloprid showed the highest efficacy in percentage of reduction of hopper population (92.50 ± 9.02) at 72 hours after treatment in case of 2nd spray. It also showed the highest overall percentage of reduction (88.59 ± 8.64) of hopper population and less toxicity to natural enemies including green ant, spider, and lacewing of mango hopper. In case of biopesticide, azadirachtin based Neem oil was found effective against mango hopper as 48.35, 60.15, and 56.54% reduction after 24, 72, and 168 hours of spraying, respectively, which was comparable with Cypermethrin as there was no statistically significant difference after 168 hours of spray. Natural enemies were also higher after 1st and 2nd spray in case of Neem oil. PMID:25140344

Insights into the structure-function relationship of brown plant hopper resistance protein, Bph14 of rice plant: a computational structural biology approach.

PubMed

Gupta, Manoj Kumar; Vadde, Ramakrishna; Donde, Ravindra; Gouda, Gayatri; Kumar, Jitendra; Nayak, Subhashree; Jena, Mayabini; Behera, Lambodar

2018-05-02

Brown plant hopper (BPH) is one of the major destructive insect pests of rice, causing severe yield loss. Thirty-two BPH resistance genes have been identified in cultivated and wild species of rice Although, molecular mechanism of rice plant resistance against BPH studied through map-based cloning, due to non-existence of NMR/crystal structures of Bph14 protein, recognition of leucine-rich repeat (LRR) domain and its interaction with different ligands are poorly understood. Thus, in the present study, in silico approach was adopted to predict three-dimensional structure of LRR domain of Bph14 using comparative modelling approach followed by interaction study with jasmonic and salicylic acids. LRR domain along with LRR-jasmonic and salicylic acid complexes were subjected to dynamic simulation using GROMACS, individually, for energy minimisation and refinement of the structure. Final binding energy of jasmonic and salicylic acid with LRR domain was calculated using MM/PBSA. Free-energy landscape analysis revealed that overall stability of LRR domain of Bph14 is not much affected after forming complex with jasmonic and salicylic acid. MM/PBSA analysis revealed that binding affinities of LRR domain towards salicylic acid is higher as compared to jasmonic acid. Interaction study of LRR domain with salicylic acid and jasmonic acid reveals that THR987 of LRR form hydrogen bond with both complexes. Thus, THR987 plays active role in the Bph14 and phytochemical interaction for inducing resistance in rice plant against BPH. In future, Bph14 gene and phytochemicals could be used in BPH management and development of novel resistant varieties for increasing rice yield.

COKE STORAGE HOPPER LOCATED OUTSIDE THE MALLEABLE FOUNDRY SHOWING LOADING ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

COKE STORAGE HOPPER LOCATED OUTSIDE THE MALLEABLE FOUNDRY SHOWING LOADING DEVICE THAT USED A SKIP CAR TO FILL THE HOPPER FROM UNDERGROUND GRAVITY-FED STORAGE AREAS FROM INCOMING RAILROAD CARS. - Stockham Pipe & Fittings Company, 4000 Tenth Avenue North, Birmingham, Jefferson County, AL

Characterization of Lr75: a partial, broad-spectrum leaf rust resistance gene in wheat.

PubMed

Singla, Jyoti; Lüthi, Linda; Wicker, Thomas; Bansal, Urmil; Krattinger, Simon G; Keller, Beat

2017-01-01

Here, we describe a strategy to improve broad-spectrum leaf rust resistance by marker-assisted combination of two partial resistance genes. One of them represents a novel partial adult plant resistance gene, named Lr75. Leaf rust caused by the fungal pathogen Puccinia triticina is a damaging disease of wheat (Triticum aestivum L.). The combination of several, additively-acting partial disease resistance genes has been proposed as a suitable strategy to breed wheat cultivars with high levels of durable field resistance. The Swiss winter wheat cultivar 'Forno' continues to show near-immunity to leaf rust since its release in the 1980s. This resistance is conferred by the presence of at least six quantitative trait loci (QTL), one of which is associated with the morphological trait leaf tip necrosis. Here, we used a marker-informed strategy to introgress two 'Forno' QTLs into the leaf rust-susceptible Swiss winter wheat cultivar 'Arina'. The resulting backcross line 'ArinaLrFor' showed markedly increased leaf rust resistance in multiple locations over several years. One of the introgressed QTLs, QLr.sfr-1BS, is located on chromosome 1BS. We developed chromosome 1B-specific microsatellite markers by exploiting the Illumina survey sequences of wheat cv. 'Chinese Spring' and mapped QLr.sfr-1BS to a 4.3 cM interval flanked by the SSR markers gwm604 and swm271. QLr.sfr-1BS does not share a genetic location with any of the described leaf rust resistance genes present on chromosome 1B. Therefore, QLr.sfr-1BS is novel and was designated as Lr75. We conclude that marker-assisted combination of partial resistance genes is a feasible strategy to increase broad-spectrum leaf rust resistance. The identification of Lr75 adds a novel and highly useful gene to the small set of known partial, adult plant leaf rust resistance genes.

46 CFR 174.335 - Watertight doors.

Code of Federal Regulations, 2010 CFR

2010-10-01

... SPECIFIC VESSEL TYPES Hopper Dredges With Working Freeboard Assignments Design § 174.335 Watertight doors. (a) Each hopper dredge must have sliding watertight doors (Class 3) approved under § 170.270 of this... to and including the maximum amount of assumed damage. (b) Each hopper dredge must have sliding...

46 CFR 174.335 - Watertight doors.

Code of Federal Regulations, 2011 CFR

2011-10-01

... SPECIFIC VESSEL TYPES Hopper Dredges With Working Freeboard Assignments Design § 174.335 Watertight doors. (a) Each hopper dredge must have sliding watertight doors (Class 3) approved under § 170.270 of this... to and including the maximum amount of assumed damage. (b) Each hopper dredge must have sliding...

Cross-Resistance and Resistance Longevity as Induced by Bean Leaf Beetle, Cerotoma trifurcata and Soybean Looper, Pseudoplusia includens herbivory on Soybean

PubMed Central

Srinivas, P.; Danielson, Stephen D.; Smith, C. Michael; Foster, John E.

2001-01-01

Cross-resistance, and longevity of resistance, induced by the bean leaf beetle, Cerotoma trifurcata, was studied IN the soybean PI 227687 that exhibited induced response in earlier studies. Bean leaf beetle adults and soybean looper, Pseudoplusia includens, larvae were used to induce resistance and to determine beetle feeding preference. Beetles were collected from soybean fields 2 to 5 days prior to the feeding preference test. The level of cross-resistance induced by soybean looper herbivory to subsequent bean leaf beetle feeding was higher when compared to cross-resistance induced by bean leaf beetle herbivory against subsequent feeding by soybean looper. Further, herbivory by the bean leaf beetle also induced resistance against soybean looper feeding. In the longevity study, leaflets from treated plants were collected 5, 10, 12, 14, 16, 20 and 25 days after initiation of feeding. Pairwise comparisons of leaflets from plants treated by bean leaf beetle herbivory with untreated plants revealed that induced responses were highest 14 and lowest 25 days after initiation of feeding. On other sampling days, levels of induced response varied with the sampling day. PMID:15455065

7 CFR 58.212 - Hopper or dump room.

Code of Federal Regulations, 2011 CFR

2011-01-01

... 7 Agriculture 3 2011-01-01 2011-01-01 false Hopper or dump room. 58.212 Section 58.212 Agriculture Regulations of the Department of Agriculture (Continued) AGRICULTURAL MARKETING SERVICE (Standards....212 Hopper or dump room. A separate room shall be provided for the transfer of bulk dry dairy products...

Gravity flow of powder in a lunar environment. Part 2: Analysis of flow initiation

NASA Technical Reports Server (NTRS)

Pariseau, W. G.

1971-01-01

A small displacement-small strain finite element technique utilizing the constant strain triangle and incremental constitutive equations for elasticplastic (media nonhardening and obeying a Coulomb yield condition) was applied to the analysis of gravity flow initiation. This was done in a V-shaped hopper containing a powder under lunar environmental conditions. Three methods of loading were examined. Of the three, the method of computing the initial state of stress in a filled hopper prior to drawdown, by adding material to the hopper layer by layer, was the best. Results of the analysis of a typical hopper problem show that the initial state of stress, the elastic moduli, and the strength parameters have an important influence on material response subsequent to the opening of the hopper outlet.

Separate loci underlie resistance to root infection and leaf scorch during soybean sudden death syndrome.

PubMed

Kazi, S; Shultz, J; Afzal, J; Johnson, J; Njiti, V N; Lightfoot, D A

2008-05-01

Soybean [Glycine max (L.) Merr.] cultivars show differences in their resistance to both the leaf scorch and root rot of sudden death syndrome (SDS). The syndrome is caused by root colonization by Fusarium virguliforme (ex. F. solani f. sp. glycines). Root susceptibility combined with reduced leaf scorch resistance has been associated with resistance to Heterodera glycines HG Type 1.3.6.7 (race 14) of the soybean cyst nematode (SCN). In contrast, the rhg1 locus underlying resistance to Hg Type 0 was found clustered with three loci for resistance to SDS leaf scorch and one for root infection. The aims of this study were to compare the inheritance of resistance to leaf scorch and root infection in a population that segregated for resistance to SCN and to identify the underlying quantitative trait loci (QTL). "Hartwig", a cultivar partially resistant to SDS leaf scorch, F. virguliforme root infection and SCN HG Type 1.3.6.7 was crossed with the partially susceptible cultivar "Flyer". Ninety-two F5-derived recombinant inbred lines and 144 markers were used for map development. Four QTL found in earlier studies were confirmed. One contributed resistance to leaf scorch on linkage group (LG) C2 (Satt277; P = 0.004, R2 = 15%). Two on LG G underlay root infection at R8 (Satt038; P = 0.0001 R2 = 28.1%; Satt115; P = 0.003, R2 = 12.9%). The marker Satt038 was linked to rhg1 underlying resistance to SCN Hg Type 0. The fourth QTL was on LG D2 underlying resistance to root infection at R6 (Satt574; P = 0.001, R2 = 10%). That QTL was in an interval previously associated with resistance to both SDS leaf scorch and SCN Hg Type 1.3.6.7. The QTL showed repulsion linkage with resistance to SCN that may explain the relative susceptibility to SDS of some SCN resistant cultivars. One additional QTL was discovered on LG G underlying resistance to SDS leaf scorch measured by disease index (Satt130; P = 0.003, R2 = 13%). The loci and markers will provide tagged alleles with which to improve the breeding of cultivars combining resistances to SDS leaf scorch, root infection and SCN HG Type 1.3.6.7.

Adult Plant Leaf Rust Resistance Derived from Toropi Wheat is Conditioned by Lr78 and Three Minor QTL.

PubMed

Kolmer, J A; Bernardo, A; Bai, G; Hayden, M J; Chao, S

2018-02-01

Leaf rust caused by Puccinia triticina is an important disease of wheat in many regions worldwide. Durable or long-lasting leaf rust resistance has been difficult to achieve because populations of P. triticina are highly variable for virulence to race-specific resistance genes, and respond to selection by resistance genes in released wheat cultivars. The wheat cultivar Toropi, developed and grown in Brazil, was noted to have long-lasting leaf rust resistance that was effective only in adult plants. The objectives of this study were to determine the chromosome location of the leaf rust resistance genes derived from Toropi in two populations of recombinant inbred lines in a partial Thatcher wheat background. In the first population, a single gene with major effects on chromosome 5DS that mapped 2.2 centimorgans distal to IWA6289, strongly reduced leaf rust severity in all 3 years of field plot tests. This gene for adult plant leaf rust resistance was designated as Lr78. In the second population, quantitative trait loci (QTL) with small effects on chromosomes 1BL, 3BS, and 4BS were found. These QTL expressed inconsistently over 4 years of field plot tests. The adult plant leaf rust resistance derived from Toropi involved a complex combination of QTL with large and small effects.

Stripe rust and leaf rust resistance QTL mapping, epistatic interactions, and co-localization with stem rust resistance loci in spring wheat evaluated over three continents.

PubMed

Singh, A; Knox, R E; DePauw, R M; Singh, A K; Cuthbert, R D; Campbell, H L; Shorter, S; Bhavani, S

2014-11-01

In wheat, advantageous gene-rich or pleiotropic regions for stripe, leaf, and stem rust and epistatic interactions between rust resistance loci should be accounted for in plant breeding strategies. Leaf rust (Puccinia triticina Eriks.) and stripe rust (Puccinia striiformis f. tritici Eriks) contribute to major production losses in many regions worldwide. The objectives of this research were to identify and study epistatic interactions of quantitative trait loci (QTL) for stripe and leaf rust resistance in a doubled haploid (DH) population derived from the cross of Canadian wheat cultivars, AC Cadillac and Carberry. The relationship of leaf and stripe rust resistance QTL that co-located with stem rust resistance QTL previously mapped in this population was also investigated. The Carberry/AC Cadillac population was genotyped with DArT(®) and simple sequence repeat markers. The parents and population were phenotyped for stripe rust severity and infection response in field rust nurseries in Kenya (Njoro), Canada (Swift Current), and New Zealand (Lincoln); and for leaf rust severity and infection response in field nurseries in Canada (Swift Current) and New Zealand (Lincoln). AC Cadillac was a source of stripe rust resistance QTL on chromosomes 2A, 2B, 3A, 3B, 5B, and 7B; and Carberry was a source of resistance on chromosomes 2B, 4B, and 7A. AC Cadillac contributed QTL for resistance to leaf rust on chromosome 2A and Carberry contributed QTL on chromosomes 2B and 4B. Stripe rust resistance QTL co-localized with previously reported stem rust resistance QTL on 2B, 3B, and 7B, while leaf rust resistance QTL co-localized with 4B stem rust resistance QTL. Several epistatic interactions were identified both for stripe and leaf rust resistance QTL. We have identified useful combinations of genetic loci with main and epistatic effects. Multiple disease resistance regions identified on chromosomes 2A, 2B, 3B, 4B, 5B, and 7B are prime candidates for further investigation and validation of their broad resistance.

Mapping of quantitative adult plant field resistance to leaf rust and stripe rust in two European winter wheat populations reveals co-location of three QTL conferring resistance to both rust pathogens.

PubMed

Buerstmayr, Maria; Matiasch, Lydia; Mascher, Fabio; Vida, Gyula; Ittu, Marianna; Robert, Olivier; Holdgate, Sarah; Flath, Kerstin; Neumayer, Anton; Buerstmayr, Hermann

2014-09-01

We detected several, most likely novel QTL for adult plant resistance to rusts. Notably three QTL improved resistance to leaf rust and stripe rust simultaneously indicating broad spectrum resistance QTL. The rusts of wheat (Puccinia spp.) are destructive fungal wheat diseases. The deployment of resistant cultivars plays a central role in integrated rust disease management. Durability of resistance would be preferred, but is difficult to analyse. The Austrian winter wheat cultivar Capo was released in the 1989 and grown on a large acreage during more than two decades and maintained a good level of quantitative leaf rust and stripe rust resistance. Two bi-parental mapping populations: Capo × Arina and Capo × Furore were tested in multiple environments for severity of leaf rust and stripe rust at the adult plant stage in replicated field experiments. Quantitative trait loci associated with leaf rust and stripe rust severity were mapped using DArT and SSR markers. Five QTL were detected in multiple environments associated with resistance to leaf rust designated as QLr.ifa-2AL, QLr.ifa-2BL, QLr.ifa-2BS, QLr.ifa-3BS, and QLr.ifa-5BL, and five for resistance to stripe rust QYr.ifa-2AL, QYr.ifa-2BL, QYr.ifa-3AS, QYr.ifa-3BS, and QYr.ifa-5A. For all QTL apart from two (QYr.ifa-3AS, QLr.ifa-5BL) Capo contributed the resistance improving allele. The leaf rust and stripe rust resistance QTL on 2AL, 2BL and 3BS mapped to the same chromosome positions, indicating either closely linked genes or pleiotropic gene action. These three multiple disease resistance QTL (QLr.ifa-2AL/QYr.ifa-2AL, QLr.ifa.2BL/QYr.ifa-2BL, QLr.ifa-3BS/QYr.ifa.3BS) potentially contribute novel resistance sources for stripe rust and leaf rust. The long-lasting resistance of Capo apparently rests upon a combination of several genes. The described germplasm, QTL and markers are applicable for simultaneous resistance improvement against leaf rust and stripe rust.

Full-scale locomotive dynamic crash testing and correlations : C-39 type locomotive colliding with a loaded hopper car (test 7).

DOT National Transportation Integrated Search

2011-09-01

This report presents the results of a locomotive and three loaded hopper car consist traveling at 29 miles per hour colliding with a stationary consist of 35 loaded hopper cars. The details of test instrumentation, LS-DYNA finite element simulation, ...

46 CFR 174.330 - Jettisoning of spoil.

Code of Federal Regulations, 2010 CFR

2010-10-01

... PERTAINING TO SPECIFIC VESSEL TYPES Hopper Dredges With Working Freeboard Assignments Calculations § 174.330 Jettisoning of spoil. (a) When doing the calculations required by § 174.310 for a hopper dredge with bottom... calculations required by § 174.310 for a hopper dredge with a split hull, it may be assumed that the spoil is...

46 CFR 174.330 - Jettisoning of spoil.

Code of Federal Regulations, 2011 CFR

2011-10-01

... PERTAINING TO SPECIFIC VESSEL TYPES Hopper Dredges With Working Freeboard Assignments Calculations § 174.330 Jettisoning of spoil. (a) When doing the calculations required by § 174.310 for a hopper dredge with bottom... calculations required by § 174.310 for a hopper dredge with a split hull, it may be assumed that the spoil is...

Hopper Growth of Salt Crystals.

PubMed

Desarnaud, Julie; Derluyn, Hannelore; Carmeliet, Jan; Bonn, Daniel; Shahidzadeh, Noushine

2018-06-07

The growth of hopper crystals is observed for many substances, but the mechanism of their formation remains ill understood. Here we investigate their growth by performing evaporation experiments on small volumes of salt solutions. We show that sodium chloride crystals that grow very fast from a highly supersaturated solution form a peculiar form of hopper crystal consisting of a series of connected miniature versions of the original cubic crystal. The transition between cubic and such hopper growth happens at a well-defined supersaturation where the growth rate of the cubic crystal reaches a maximum (∼6.5 ± 1.8 μm/s). Above this threshold, the growth rate varies as the third power of supersaturation, showing that a new mechanism, controlled by the maximum speed of surface integration of new molecules, induces the hopper growth of cubic crystals in cascade.

Hopper Flow: Experiments and Simulation

NASA Astrophysics Data System (ADS)

Li, Zhusong; Shattuck, Mark

2013-03-01

Jamming and intermittent granular flow are important problems in industry, and the vertical hopper is a canonical example. Clogging of granular hoppers account for significant losses across many industries. We use realistic DEM simulations of gravity driven flow in a hopper to examine flow and jamming of 2D disks and compare with identical companion experiments. We use experimental data to validate simulation parameters and the form of the inter particle force law. We measure and compare flow rate, emptying times, jamming statistics, and flow fields as a function of opening angle and opening size in both experiment and simulations. Suppored by: NSF-CBET-0968013

The CC-NB-LRR-Type Rdg2a Resistance Gene Confers Immunity to the Seed-Borne Barley Leaf Stripe Pathogen in the Absence of Hypersensitive Cell Death

PubMed Central

Collins, Nicholas C.; Consonni, Gabriella; Stanca, Antonio M.; Schulze-Lefert, Paul; Valè, Giampiero

2010-01-01

Background Leaf stripe disease on barley (Hordeum vulgare) is caused by the seed-transmitted hemi-biotrophic fungus Pyrenophora graminea. Race-specific resistance to leaf stripe is controlled by two known Rdg (Resistance to Drechslera graminea) genes: the H. spontaneum-derived Rdg1a and Rdg2a, identified in H. vulgare. The aim of the present work was to isolate the Rdg2a leaf stripe resistance gene, to characterize the Rdg2a locus organization and evolution and to elucidate the histological bases of Rdg2a-based leaf stripe resistance. Principal Findings We describe here the positional cloning and functional characterization of the leaf stripe resistance gene Rdg2a. At the Rdg2a locus, three sequence-related coiled-coil, nucleotide-binding site, and leucine-rich repeat (CC-NB-LRR) encoding genes were identified. Sequence comparisons suggested that paralogs of this resistance locus evolved through recent gene duplication, and were subjected to frequent sequence exchange. Transformation of the leaf stripe susceptible cv. Golden Promise with two Rdg2a-candidates under the control of their native 5′ regulatory sequences identified a member of the CC-NB-LRR gene family that conferred resistance against the Dg2 leaf stripe isolate, against which the Rdg2a-gene is effective. Histological analysis demonstrated that Rdg2a-mediated leaf stripe resistance involves autofluorescing cells and prevents pathogen colonization in the embryos without any detectable hypersensitive cell death response, supporting a cell wall reinforcement-based resistance mechanism. Conclusions This work reports about the cloning of a resistance gene effective against a seed borne disease. We observed that Rdg2a was subjected to diversifying selection which is consistent with a model in which the R gene co-evolves with a pathogen effector(s) gene. We propose that inducible responses giving rise to physical and chemical barriers to infection in the cell walls and intercellular spaces of the barley embryo tissues represent mechanisms by which the CC-NB-LRR-encoding Rdg2a gene mediates resistance to leaf stripe in the absence of hypersensitive cell death. PMID:20844752

Genome-wide association mapping reveals novel QTL for seedling leaf rust resistance in a worldwide collection of winter wheat

USDA-ARS?s Scientific Manuscript database

Leaf rust is a major disease that causes significant wheat yield losses worldwide. Growing resistant cultivars is an effective approach to reduce disease losses. The short-lived nature of leaf rust resistance (Lr) genes necessitates a continuous search for novel sources of resistance. We performe...

New quantitative trait loci in wheat for flag leaf resistance to Stagonospora nodorum blotch.

PubMed

Francki, M G; Shankar, M; Walker, E; Loughman, R; Golzar, H; Ohm, H

2011-11-01

Stagonospora nodorum blotch (SNB) is a significant disease in some wheat-growing regions of the world. Resistance in wheat to Stagonospora nodorum is complex, whereby genes for seedling, flag leaf, and glume resistance are independent. The aims of this study were to identify alternative genes for flag leaf resistance, to compare and contrast with known quantitative trait loci (QTL) for SNB resistance, and to determine the potential role of host-specific toxins for SNB QTL. Novel QTL for flag leaf resistance were identified on chromosome 2AS inherited from winter wheat parent 'P92201D5' and chromosome 1BS from spring wheat parent 'EGA Blanco'. The chromosomal map position of markers associated with QTL on 1BS and 2AS indicated that they were unlikely to be associated with known host-toxin insensitivity loci. A QTL on chromosome 5BL inherited from EGA Blanco had highly significant association with markers fcp001 and fcp620 based on disease evaluation in 2007 and, therefore, is likely to be associated with Tsn1-ToxA insensitivity for flag leaf resistance. However, fcp001 and fcp620 were not associated with a QTL detected based on disease evaluation in 2008, indicating two linked QTL for flag leaf resistance with multiple genes residing on 5BL. This study identified novel QTL and their effects in controlling flag leaf SNB resistance.

77 FR 21797 - Hopper Mountain, Bitter Creek, and Blue Ridge National Wildlife Refuges, Ventura, Kern, San Luis...

Federal Register 2010, 2011, 2012, 2013, 2014

2012-04-11

..., and visitor and volunteer opportunities. Alternatives for Blue Ridge NWR Under Alternative B...-FF08R00000] Hopper Mountain, Bitter Creek, and Blue Ridge National Wildlife Refuges, Ventura, Kern, San Luis... Conservation Plan (CCP) and Environmental Assessment (EA) for the Hopper Mountain, Bitter Creek, and Blue Ridge...

75 FR 17430 - Hopper Mountain, Bitter Creek, and Blue Ridge National Wildlife Refuges, Kern, San Luis Obispo...

Federal Register 2010, 2011, 2012, 2013, 2014

2010-04-06

...] Hopper Mountain, Bitter Creek, and Blue Ridge National Wildlife Refuges, Kern, San Luis Obispo, Tulare... Wildlife Refuges (NWRs) located in Kern, San Luis Obispo, Tulare, and Ventura counties of California. We... developing a CCP for Hopper Mountain, Bitter Creek, and Blue Ridge NWRs in Kern, San Luis Obispo, Tulare, and...

Resistance mechanisms in Pieris taxa (Ericaceae) to Stephanitis takeyai (Hemiptera: Tingidae).

PubMed

Nair, Shakunthala; Braman, S Kristine; Knauft, D A

2012-10-01

This study examines some of the potential mechanisms of resistance in selected Pieris (Ericaceae) taxa to the Andromeda lace bug, Stephanitis takeyai Drake and Maa, based on differences in resistance to lace bug feeding, and the possible role of leaf parameters such as leaf wax, toughness, nutrient composition, and stomatal characters in plant resistance. Experiments with extracts of leaf-surface lipids revealed that Pieris leaf wax did not have a role in resistance to lace bug feeding. Leaf wax extracts from a resistant species P. phillyreifolia (Hook.) DC. applied to leaves of a susceptible cultivar P. japonica (Thunb.) D.Don ex G.Don 'Temple Bells' did not affect feeding, oviposition, or survival of S. takeyai; and neither the extracts from Temple Bells induce susceptibility in P. phillyreifolia. Leaf penetrometer measurements indicated that significantly higher force was required to puncture P. phillyreifolia leaves, which also had higher fiber, lignin, and cellulose, and lower leaf moisture contents. Ultrastructural examination of leaves of Pieris taxa revealed significant differences in the number and size of stomata. P. phillyreifolia leaves had the highest number of stomata per unit area but these were the smallest in size, whereas P. japonica (Thunb.) D.Don ex G.Don Temple Bells leaves had the fewest and largest stomata. Resistance in Pieris taxa to S. takeyai may be attributed to a combination of different factors including leaf toughness, moisture, and stomatal characters. The type of resistance may be described as antixenosis combined with antibiosis, because reduced adult survival and reproduction were observed on the taxa resistant to lace bug feeding.

Elevation (typical EBT Coal Hopper Car) with scale. 3 Bay ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

Elevation (typical EBT Coal Hopper Car) with scale. 3 Bay Steel Hopper Car with side extensions raising coal carrying capacity to 80,000 pounds. Note cars on either side lack extensions limiting their coal capacity to 70,000 pounds - East Broad Top Railroad & Coal Company, State Route 994, West of U.S. Route 522, Rockhill Furnace, Huntingdon County, PA

46 CFR 97.15-75 - Test of inflatable hopper gate seals on Great Lakes bulk dry cargo vessels.

Code of Federal Regulations, 2013 CFR

2013-10-01

... 46 Shipping 4 2013-10-01 2013-10-01 false Test of inflatable hopper gate seals on Great Lakes bulk... (CONTINUED) CARGO AND MISCELLANEOUS VESSELS OPERATIONS Tests, Drills, and Inspections § 97.15-75 Test of... ensure that the inflatable hopper gate seals installed on vessels required to meet the damage stability...

46 CFR 97.15-75 - Test of inflatable hopper gate seals on Great Lakes bulk dry cargo vessels.

Code of Federal Regulations, 2012 CFR

2012-10-01

... 46 Shipping 4 2012-10-01 2012-10-01 false Test of inflatable hopper gate seals on Great Lakes bulk... (CONTINUED) CARGO AND MISCELLANEOUS VESSELS OPERATIONS Tests, Drills, and Inspections § 97.15-75 Test of... ensure that the inflatable hopper gate seals installed on vessels required to meet the damage stability...

46 CFR 97.15-75 - Test of inflatable hopper gate seals on Great Lakes bulk dry cargo vessels.

Code of Federal Regulations, 2014 CFR

2014-10-01

... 46 Shipping 4 2014-10-01 2014-10-01 false Test of inflatable hopper gate seals on Great Lakes bulk... (CONTINUED) CARGO AND MISCELLANEOUS VESSELS OPERATIONS Tests, Drills, and Inspections § 97.15-75 Test of... ensure that the inflatable hopper gate seals installed on vessels required to meet the damage stability...

DOE Office of Scientific and Technical Information (OSTI.GOV)

Pickenheim, B.; Hansen, E.; Leishear, R.

A 10-inch READCO mixer is used for mixing the premix (45 (wt%) fly ash, 45 wt% slag, and 10 wt% portland cement) with salt solution in the Saltstone Production Facility (SPF). The Saltstone grout free falls into the grout hopper which feeds the suction line leading to the Watson SPX 100 duplex hose pump. The Watson SPX 100 pumps the grout through approximately 1500 feet of piping prior to being discharged into the Saltstone Disposal Facility (SDF) vaults. The existing grout hopper has been identified by the Saltstone Enhanced Low Activity Waste Disposal (ELAWD) project for re-design. The current nominalmore » working volume of this hopper is 12 gallons and does not permit handling an inadvertent addition of excess dry feeds. Saltstone Engineering has proposed a new hopper tank that will have a nominal working volume of 300 gallons and is agitated with a mechanical agitator. The larger volume hopper is designed to handle variability in the output of the READCO mixer and process upsets without entering set back during processing. The objectives of this task involve scaling the proposed hopper design and testing the scaled hopper for the following processing issues: (1) The effect of agitation on radar measurement. Formation of a vortex may affect the ability to accurately measure the tank level. The agitator was run at varying speeds and with varying grout viscosities to determine what parameters cause vortex formation and whether measurement accuracy is affected. (2) A dry feeds over addition. Engineering Calculating X-ESR-Z-00017 1 showed that an additional 300 pounds of dry premix added to a 300 gallon working volume would lower the water to premix ratio (W/P) from the nominal 0.60 to 0.53 based on a Salt Waste Processing Facility (SWPF) salt simulant. A grout with a W/P of 0.53 represents the upper bound of grout rheology that could be processed at the facility. A scaled amount of dry feeds will be added into the hopper to verify that this is a recoverable situation. (3) The necessity of baffles in the hopper. The preference of the facility is not to have baffles in the hopper; however, if the initial testing indicates inadequate agitation or difficulties with the radar measurement, baffles will be tested.« less

Mapping and characterization of the new adult plant leaf rust resistance gene Lr77 derived from Santa Fe winter wheat.

PubMed

Kolmer, James A; Su, Zhenqi; Bernardo, Amy; Bai, Guihua; Chao, Shiaoman

2018-07-01

A new gene for adult plant leaf rust resistance in wheat was mapped to chromosome 3BL. This gene was designated as Lr77. 'Santa Fe' is a hard red winter cultivar that has had long-lasting resistance to the leaf rust fungus, Puccinia triticina. The objective of this study was to determine the chromosome location of the adult plant leaf rust resistance in Santa Fe wheat. A partial backcross line of 'Thatcher' (Tc) wheat with adult plant leaf rust resistance derived from Santa Fe was crossed with Thatcher to develop a Thatcher//Tc*2/Santa Fe F 6 recombinant inbred line (RIL) population. The RIL population and parental lines were evaluated for segregation of leaf rust resistance in three field plot tests and in an adult plant greenhouse test. A genetic map of the RIL population was constructed using 90,000 single-nucleotide polymorphism (SNP) markers with the Illumina Infinium iSelect 90K wheat bead array. A significant quantitative trait locus for reduction of leaf rust severity in all four tests was found on chromosome 3BL that segregated as a single adult plant resistance gene. The RILs with the allele from the resistant parent for SNP marker IWB10344 had lower leaf rust severity and a moderately resistant to moderately susceptible response compared to the susceptible RILs and Thatcher. The gene derived from Santa Fe on chromosome 3BL was designated as Lr77. Kompetitive allele-specific polymerase chain reaction assay markers linked to Lr77 on 3BL should be useful for selection of wheat germplasm with this gene.

Novel sources of leaf rust resistance in winter wheat

USDA-ARS?s Scientific Manuscript database

Leaf rust is one of the most widespread diseases of wheat, causing significant yield losses. More than 70 leaf rust resistance genes have been reported, but most of them have lost their effectiveness in the southern Great Plains of the USA. Thus continuous search for new sources of resistance is e...

Characterization and mapping of LanrBo: a locus conferring anthracnose resistance in narrow-leafed lupin (Lupinus angustifolius L.).

PubMed

Fischer, Kristin; Dieterich, Regine; Nelson, Matthew N; Kamphuis, Lars G; Singh, Karam B; Rotter, Björn; Krezdorn, Nicolas; Winter, Peter; Wehling, Peter; Ruge-Wehling, Brigitte

2015-10-01

A novel and highly effective source of anthracnose resistance in narrow-leafed lupin was identified. Resistance was shown to be governed by a single dominant locus. Molecular markers have been developed, which can be used for selecting resistant genotypes in lupin breeding. A screening for anthracnose resistance of a set of plant genetic resources of narrow-leafed lupin (Lupinus angustifolius L.) identified the breeding line Bo7212 as being highly resistant to anthracnose (Colletotrichum lupini). Segregation analysis indicated that the resistance of Bo7212 is inherited by a single dominant locus. The corresponding resistance gene was given the designation LanrBo. Previously published molecular anchor markers allowed us to locate LanrBo on linkage group NLL-11 of narrow-leafed lupin. Using information from RNAseq data obtained with inoculated resistant vs. susceptible lupin entries as well as EST-sequence information from the model genome Lotus japonicus, additional SNP and EST markers linked to LanrBo were derived. A bracket of two LanrBo-flanking markers allows for precise marker-assisted selection of the novel resistance gene in narrow-leafed lupin breeding programs.

40 CFR 174.513 - Potato Leaf Roll Virus Resistance Gene (also known as orf1/orf2 gene); exemption from the...

Code of Federal Regulations, 2012 CFR

2012-07-01

... 40 Protection of Environment 25 2012-07-01 2012-07-01 false Potato Leaf Roll Virus Resistance Gene... Virus Resistance Gene (also known as orf1/orf2 gene); exemption from the requirement of a tolerance. An... protectant Potato Leaf Roll Virus Resistance Gene (also known as orf1/orf2 gene) in or on all food...

40 CFR 174.513 - Potato Leaf Roll Virus Resistance Gene (also known as orf1/orf2 gene); exemption from the...

Code of Federal Regulations, 2014 CFR

2014-07-01

... 40 Protection of Environment 24 2014-07-01 2014-07-01 false Potato Leaf Roll Virus Resistance Gene... Virus Resistance Gene (also known as orf1/orf2 gene); exemption from the requirement of a tolerance. An... protectant Potato Leaf Roll Virus Resistance Gene (also known as orf1/orf2 gene) in or on all food...

40 CFR 174.513 - Potato Leaf Roll Virus Resistance Gene (also known as orf1/orf2 gene); exemption from the...

Code of Federal Regulations, 2011 CFR

2011-07-01

... 40 Protection of Environment 24 2011-07-01 2011-07-01 false Potato Leaf Roll Virus Resistance Gene... Virus Resistance Gene (also known as orf1/orf2 gene); exemption from the requirement of a tolerance. An... protectant Potato Leaf Roll Virus Resistance Gene (also known as orf1/orf2 gene) in or on all food...

40 CFR 174.513 - Potato Leaf Roll Virus Resistance Gene (also known as orf1/orf2 gene); exemption from the...

Code of Federal Regulations, 2010 CFR

2010-07-01

... 40 Protection of Environment 23 2010-07-01 2010-07-01 false Potato Leaf Roll Virus Resistance Gene... Virus Resistance Gene (also known as orf1/orf2 gene); exemption from the requirement of a tolerance. An... protectant Potato Leaf Roll Virus Resistance Gene (also known as orf1/orf2 gene) in or on all food...

40 CFR 174.513 - Potato Leaf Roll Virus Resistance Gene (also known as orf1/orf2 gene); exemption from the...

Code of Federal Regulations, 2013 CFR

2013-07-01

... 40 Protection of Environment 25 2013-07-01 2013-07-01 false Potato Leaf Roll Virus Resistance Gene... Virus Resistance Gene (also known as orf1/orf2 gene); exemption from the requirement of a tolerance. An... protectant Potato Leaf Roll Virus Resistance Gene (also known as orf1/orf2 gene) in or on all food...

Resistance to CO2 diffusion in cuticular membranes of amphibious plants and the implication for CO2 acquisition.

PubMed

Frost-Christensen, Henning; Floto, Franz

2007-01-01

Cuticular membranes (CMs) were isolated from leaves of amphibious and submerged plants and their CO2 resistances were determined as a contribution to establish quantitatively the series of resistances met by CO2 diffusing from bulk water to the chloroplasts of submerged leaves. The isolation was performed enzymatically; permeabilities were determined and converted to resistances. The range of permeance values was 3 to 43 x 10(-6) m s(-1) corresponding to resistance values of 23 to 295 x 10(3) s m(-1), i.e. of the same order of magnitude as boundary layer resistances. The sum of boundary layer, CM, leaf cell and carboxylation resistances could be contained within the total diffusion resistance as determined from the photosynthetic CO2 affinity of the leaf. From the same species, the aerial leaf CM resistance was always higher than the aquatic leaf CM resistance. In a terrestrial plant, the CM resistance to CO2 diffusion was found lower in leaves developed submerged.

39. VIEW OF HOPPERS LOCATED AT THE BOTTOM OF COTTRELL ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

39. VIEW OF HOPPERS LOCATED AT THE BOTTOM OF COTTRELL PRECIPITATOR CHAMBERS. PARTICLES REMOVED FROM THE FLUE GAS STREAM WERE DISCHARGED INTO THE VACUUM ASH COLLECTION PIPES LOCATED BELOW THE HOPPERS. THE COTTRELL PRECIPITATORS WERE LOCATED ON THE OUTSIDE WALL OF THE EAST BOILER ROOM. REFER TO PHOTOCOPY CT-142A-15. - New York, New Haven & Hartford Railroad, Cos Cob Power Plant, Sound Shore Drive, Greenwich, Fairfield County, CT

Field performance of Populus expressing somaclonal variation in resistance to Septoria musiva

Treesearch

M. E. Ostry; K. T. Ward

2003-01-01

Over 1500 trees from two hybrid poplar clones regenerated from tissue culture and expressing somatic variation in leaf disease resistance in a laboratory leaf disk bioassay were field-tested for 5-11 years to examine their resistance to Septoria leaf spot and canker and to assess their growth characteristics compared with the source clones....

Adult plant leaf rust resistance derived from Toropi wheat is conditioned by Lr78 and three minor QTL

USDA-ARS?s Scientific Manuscript database

Brazil, was noted to have long lasting leaf rust resistance that was effective only in adult plants. The objectives of this study were to determine the chromosome location of the leaf rust resistance genes derived from Toropi in two populations of recombinant inbred lines in a partial Thatcher wheat...

Identification of QTL conferring resistance to stripe rust (Puccinia striiformis f. sp. hordei) and leaf rust (Puccinia hordei) in barley using nested association mapping (NAM)

PubMed Central

Vatter, Thomas; Maurer, Andreas; Perovic, Dragan; Kopahnke, Doris; Pillen, Klaus

2018-01-01

The biotrophic rust fungi Puccinia hordei and Puccinia striiformis are important barley pathogens with the potential to cause high yield losses through an epidemic spread. The identification of QTL conferring resistance to these pathogens is the basis for targeted breeding approaches aiming to improve stripe rust and leaf rust resistance of modern cultivars. Exploiting the allelic richness of wild barley accessions proved to be a valuable tool to broaden the genetic base of resistance of barley cultivars. In this study, SNP-based nested association mapping (NAM) was performed to map stripe rust and leaf rust resistance QTL in the barley NAM population HEB-25, comprising 1,420 lines derived from BC1S3 generation. By scoring the percentage of infected leaf area, followed by calculation of the area under the disease progress curve and the average ordinate during a two-year field trial, a large variability of resistance across and within HEB-25 families was observed. NAM based on 5,715 informative SNPs resulted in the identification of twelve and eleven robust QTL for resistance against stripe rust and leaf rust, respectively. Out of these, eight QTL for stripe rust and two QTL for leaf rust are considered novel showing no overlap with previously reported resistance QTL. Overall, resistance to both pathogens in HEB-25 is most likely due to the accumulation of numerous small effect loci. In addition, the NAM results indicate that the 25 wild donor QTL alleles present in HEB-25 strongly differ in regard to their individual effect on rust resistance. In future, the NAM concept will allow to select and combine individual wild barley alleles from different HEB parents to increase rust resistance in barley. The HEB-25 results will support to unravel the genetic basis of rust resistance in barley, and to improve resistance against stripe rust and leaf rust of modern barley cultivars. PMID:29370232

Identification of QTL conferring resistance to stripe rust (Puccinia striiformis f. sp. hordei) and leaf rust (Puccinia hordei) in barley using nested association mapping (NAM).

PubMed

Vatter, Thomas; Maurer, Andreas; Perovic, Dragan; Kopahnke, Doris; Pillen, Klaus; Ordon, Frank

2018-01-01

The biotrophic rust fungi Puccinia hordei and Puccinia striiformis are important barley pathogens with the potential to cause high yield losses through an epidemic spread. The identification of QTL conferring resistance to these pathogens is the basis for targeted breeding approaches aiming to improve stripe rust and leaf rust resistance of modern cultivars. Exploiting the allelic richness of wild barley accessions proved to be a valuable tool to broaden the genetic base of resistance of barley cultivars. In this study, SNP-based nested association mapping (NAM) was performed to map stripe rust and leaf rust resistance QTL in the barley NAM population HEB-25, comprising 1,420 lines derived from BC1S3 generation. By scoring the percentage of infected leaf area, followed by calculation of the area under the disease progress curve and the average ordinate during a two-year field trial, a large variability of resistance across and within HEB-25 families was observed. NAM based on 5,715 informative SNPs resulted in the identification of twelve and eleven robust QTL for resistance against stripe rust and leaf rust, respectively. Out of these, eight QTL for stripe rust and two QTL for leaf rust are considered novel showing no overlap with previously reported resistance QTL. Overall, resistance to both pathogens in HEB-25 is most likely due to the accumulation of numerous small effect loci. In addition, the NAM results indicate that the 25 wild donor QTL alleles present in HEB-25 strongly differ in regard to their individual effect on rust resistance. In future, the NAM concept will allow to select and combine individual wild barley alleles from different HEB parents to increase rust resistance in barley. The HEB-25 results will support to unravel the genetic basis of rust resistance in barley, and to improve resistance against stripe rust and leaf rust of modern barley cultivars.

Genome-Wide Association Mapping Reveals Novel QTL for Seedling Leaf Rust Resistance in a Worldwide Collection of Winter Wheat.

PubMed

Li, Genqiao; Xu, Xiangyang; Bai, Guihua; Carver, Brett F; Hunger, Robert; Bonman, J Michael; Kolmer, James; Dong, Hongxu

2016-11-01

Leaf rust of wheat ( L.) is a major disease that causes significant yield losses worldwide. The short-lived nature of leaf rust resistance () genes necessitates a continuous search for novel sources of resistance. We performed a genome-wide association study (GWAS) on a panel of 1596 wheat accessions. The panel was evaluated for leaf rust reaction by testing with a bulk of Eriks. () isolates collected from multiple fields of Oklahoma in 2013 and two predominant races in the fields of Oklahoma in 2015. The panel was genotyped with a set of 5011 single-nucleotide polymorphism (SNP) markers. A total of 14 quantitative trait loci (QTL) for leaf rust resistance were identified at a false discovery rate (FDR) of 0.01 using the mixed linear model (MLM). Of these, eight QTL reside in the vicinity of known genes or QTL, and more studies are needed to determine their relationship with known loci. is a new QTL to bread wheat but is close to a locus previously identified in durum wheat [ L. subsp. (Desf.) Husn.]. The other five QTL, including , , , , and , are likely novel loci for leaf rust resistance. The uneven distribution of the 14 QTL in the six subpopulations of the panel suggests that wheat breeders can enhance leaf rust resistance by selectively introgressing some of these QTL into their breeding materials. In addition, another 31 QTL were significantly associated with leaf rust resistance at a FDR of 0.05. Copyright © 2016 Crop Science Society of America.

Inheritance and bulked segregant analysis of leaf rust and stem rust resistance genes in eight durum wheat genotypes

USDA-ARS?s Scientific Manuscript database

Leaf rust, caused by Puccinia triticina (Pt) and stem rust caused by Puccinia graminis f. sp. tritici (Pgt) are important diseases of durum wheat. This study determined the inheritance and genomic locations of leaf rust resistance (Lr) genes to Pt-race BBBQJ and stem rust resistance (Sr) genes to Pg...

Pre symptomatic detection of wheat leaf rust in the susceptible cv Skalmeje and the resistant cv Esket by means of UV laser-induced fluorescence.

PubMed

Bürling, K; Hunsche, M; Noga, G

2010-01-01

In modern agriculture there is a great demand for a rapid and objective screening method for stress resistance, because so far, the resistance of new cultivars is tested in time- and money consuming field experiments. Based on fluorescence ratios, and lifetime of fluorophores measured by fluorescence spectroscopy, we have postulated that an early discrimination of susceptible and resistant wheat cultivars to the leaf rust pathogen Puccinia triticina can be accomplished. As representative for leaf rust resistant and leaf rust susceptible wheat genotypes the cultivars Esket and Skalmeje, respectively, were chosen. Plants were grown under controlled environment conditions and inoculated with the leaf rust pathogen at the second-leaf-stage by single-droplet application. Fluorescence measurements were carried out from two to four days after inoculation (dai) by using a compact fibre-optic fluorescence spectrometer with nanosecond time-resolution. Experimental results indicated that UV laser-induced spectral characteristics as well as determination of fluorescence lifetime are suited to detect leaf rust two dai. For this purpose several ratios and wavelength can be considered. In general, the tested cultivars showed distinct responses to the pathogen development. In this context the ratio F451/F687 measured three dai and mean lifetimes at 500 nm and 530 nm are suited to differentiate the resistant Esket from the susceptible Skalmeje genotypes.

Coal Handling.

DTIC Science & Technology

1981-04-01

the coal in a conical shape pile. 6 _7 7.1.2 TELESCOPING CHUTES Telescoping chutes are also fed by a conveyor . The chute has several sections that can...track hopper. Hopper belt feeders feed a conveyor then to another conveyor thru a belt scale. Onto a transfer hopper then to a stacker reclaimer. The...16.7.1 McNally Pittsburg Mfg. Corp. 16.7.2 Stephens - Adamson, Inc. 16.7.3 Heyl & Oatterson, Inc. 16.8 Telescopic Chutes 16.8.1 Midwest Conveyor Co

Small Body Hopper Mobility Concepts

NASA Technical Reports Server (NTRS)

Howe, A. Scott; Gernhardt, Michael L.; Lee, Dave E.; Crues, E. Zack; Dexter, Dan E.; Abercromby, Andrew F. J.; Chappell, Steve P.; Nguyen, Hung T.

2015-01-01

A propellant-saving hopper mobility system was studied that could help facilitate the exploration of small bodies such as Phobos for long-duration human missions. The NASA Evolvable Mars Campaign (EMC) has proposed a mission to the moons of Mars as a transitional step for eventual Mars surface exploration. While a Mars transit habitat would be parked in High-Mars Orbit (HMO), crew members would visit the surface of Phobos multiple times for up to 14 days duration (up to 50 days at a time with logistics support). This paper describes a small body surface mobility concept that is capable of transporting a small, two-person Pressurized Exploration Vehicle (PEV) cabin to various sites of interest in the low-gravity environment. Using stored kinetic energy between bounces, a propellant-saving hopper mobility system can release the energy to vector the vehicle away from the surface in a specified direction. Alternatively, the stored energy can be retained for later use while the vehicle is stationary in respect to the surface. The hopper actuation was modeled using a variety of launch velocities, and the hopper mobility was evaluated using NASA Exploration Systems Simulations (NExSyS) for transit between surface sites of interest. A hopper system with linear electromagnetic motors and mechanical spring actuators coupled with Control Moment Gyroscope (CMG) for attitude control will use renewable electrical power, resulting in a significant propellant savings.

Solid handling valve

DOEpatents

Williams, William R.

1979-01-01

The present invention is directed to a solids handling valve for use in combination with lock hoppers utilized for conveying pulverized coal to a coal gasifier. The valve comprises a fluid-actuated flow control piston disposed within a housing and provided with a tapered primary seal having a recessed seat on the housing and a radially expandable fluid-actuated secondary seal. The valve seals are highly resistive to corrosion, erosion and abrasion by the solids, liquids, and gases associated with the gasification process so as to minimize valve failure.

Effectiveness of a detached‐leaf assay as a proxy for stem inoculations in backcrossed chestnut (Castanea) blight resistance breeding populations

Treesearch

N. R. LaBonte; J.R. McKenna; K. Woeste

2016-01-01

A recently developed detached-leaf blight resistance assay has generated interest because it could reduce the amount of time needed to evaluate backcrossed hybrid trees in the American chestnut blight resistance breeding programme. We evaluated the leaf inoculation technique on a sample of advanced progeny from the Indiana state chapter American Chestnut Foundation...

Larry car for a coking oven battery

DOE Office of Scientific and Technical Information (OSTI.GOV)

Corry, D.B.

A larry car (3) for transporting a charge of pre-heated coal along the top of a battery of coke ovens, from a storage installation including a group of metering bins (1) at one or more filling stations above the battery, to a corresponding group of charge holes for the oven chamber to be charged, the car including a corresponding group of coal transfer hoppers (4) each having valved inlet and discharge apertures (5,21), a sealed connection (2) between each metering bin and transfer hopper, an inert gas reservoir (10) connectable via a valved manifold (13,14) to each transfer hopper, amore » valved connection (7,8,9) for charging the reservoir, and a valved connection (15,16,17) to permit dusty gas to be displaced into the storage bunkers, and control means for the various valved connections to maintain continuous isolation of the interior of each transfer hopper from the atmosphere, to permit dust-laden gases to escape into the storage installation, and to cause inert medium to displace coal discharged from the transfer hoppers.« less

Outflow and clogging of shape-anisotropic grains in hoppers with small apertures.

PubMed

Ashour, A; Wegner, S; Trittel, T; Börzsönyi, T; Stannarius, R

2017-01-04

Outflow of granular material through a small orifice is a fundamental process in many industrial fields, for example in silo discharge, and in everyday's life. Most experimental studies of the dynamics have been performed so far with monodisperse disks in two-dimensional (2D) hoppers or spherical grains in 3D. We investigate this process for shape-anisotropic grains in 3D hoppers and discuss the role of size and shape parameters on avalanche statistics, clogging states, and mean flow velocities. It is shown that an increasing aspect ratio of the grains leads to lower flow rates and higher clogging probabilities compared to spherical grains. On the other hand, the number of grains forming the clog is larger for elongated grains of comparable volumes, and the long axis of these blocking grains is preferentially aligned towards the center of the orifice. We find a qualitative transition in the hopper discharge behavior for aspect ratios larger than ≈6. At still higher aspect ratios >8-12, the outflowing material leaves long vertical holes in the hopper that penetrate the complete granular bed. This changes the discharge characteristics qualitatively.

Sodium chloride crystallization from thin liquid sheets, thick layers, and sessile drops in microgravity

NASA Astrophysics Data System (ADS)

Fontana, Pietro; Pettit, Donald; Cristoforetti, Samantha

2015-10-01

Crystallization from aqueous sodium chloride solutions as thin liquid sheets, 0.2-0.7 mm thick, with two free surfaces supported by a wire frame, thick liquid layers, 4-6 mm thick, with two free surfaces supported by metal frame, and hemispherical sessile drops, 20-32 mm diameter, supported by a flat polycarbonate surface or an initially flat gelatin film, were carried out under microgravity on the International Space Station (ISS). Different crystal morphologies resulted based on the fluid geometry: tabular hoppers, hopper cubes, circular [111]-oriented crystals, and dendrites. The addition of polyethylene glycol (PEG-3350) inhibited the hopper growth resulting in flat-faced surfaces. In sessile drops, 1-4 mm tabular hopper crystals formed on the free surface and moved to the fixed contact line at the support (polycarbonate or gelatin) self-assembling into a shell. Ring formation created by sessile drop evaporation to dryness was observed but with crystals 100 times larger than particles in terrestrially formed coffee rings. No hopper pyramids formed. By choosing solution geometries offered by microgravity, we found it was possible to selectively grow crystals of preferred morphologies.

Cloning and function analysis of a drought-inducible gene associated with resistance to Curvularia leaf spot in maize.

PubMed

Zhu, Jiewei; Huang, Xiuli; Liu, Tong; Gao, Shigang; Chen, Jie

2012-08-01

ZmDIP was cloned and its function against Curvularia lunata was analyzed, according to a previous finding on a drought-inducible protein in resistant maize identified through MALDI-TOF-MS/MS. The ZmDIP expression varied in roots, leaf sheaths, and young, as well as old, leaves of different maize inbred lines. The ZmDIP transcript level changed in leaves over the course of time after inoculation with C. lunata. A prokaryotic expression analysis demonstrated that the gene can regulate the salt stress tolerance of Escherichia coli. The ZmDIP transient expression in the maize leaf showed that the gene was also linked to leaf resistance against the C. lunata infection. ZmDIP-mediated ROS and ABA signaling pathways were inferred to be closely associated with maize leaf resistance to the pathogen infection.

46 CFR 174.300 - Specific applicability.

Code of Federal Regulations, 2010 CFR

2010-10-01

... PERTAINING TO SPECIFIC VESSEL TYPES Hopper Dredges With Working Freeboard Assignments § 174.300 Specific applicability. This subpart applies to each self-propelled hopper dredge for which a working freeboard...

46 CFR 174.300 - Specific applicability.

Code of Federal Regulations, 2011 CFR

2011-10-01

... PERTAINING TO SPECIFIC VESSEL TYPES Hopper Dredges With Working Freeboard Assignments § 174.300 Specific applicability. This subpart applies to each self-propelled hopper dredge for which a working freeboard...

46 CFR 44.300 - Applicability.

Code of Federal Regulations, 2011 CFR

2011-10-01

... Rules for Assigning Working Freeboards to Hopper Dredges § 44.300 Applicability. This subpart applies to each self-propelled hopper dredge— (a) For which a working freeboard assignment is desired after...

46 CFR 44.300 - Applicability.

Code of Federal Regulations, 2010 CFR

2010-10-01

... Rules for Assigning Working Freeboards to Hopper Dredges § 44.300 Applicability. This subpart applies to each self-propelled hopper dredge— (a) For which a working freeboard assignment is desired after...

Design Study for a Mars Geyser Hopper

NASA Technical Reports Server (NTRS)

Landis, Geoffrey A.; Oleson, Steven J.; McGuire, Melissa

2012-01-01

The Mars Geyser Hopper is a design reference missions (DRMs) for a Discovery-class spacecraft using Advanced Stirling Radioisotope Generator (ASRG) power source. The Geyser Hopper is a mission concept that will investigate the springtime carbon-dioxide geysers found in regions around the south pole of Mars. The Geyser Hopper design uses Phoenix heritage systems and approach, but uses a single ASRG as the power source, rather than twin solar arrays, and is designed to last over a one-year stay on the South Pole. The spacecraft will land at a target landing area near the south pole of Mars, and have the ability to "hop" after a summertime landing to reposition itself close to a geyser site, and wait through the winter until the first sunlight of spring to witness first-hand the geyser phenomenon.

Leaf Area Influence on Surface Layer in a Deciduous Forest. Part 2; Detecting Leaf Area and Surface Resistance During Transition Seasons

NASA Technical Reports Server (NTRS)

Sakai, Ricardo K.; Fitzjarrald, David R.; Moore, Kathleen E.; Sicker, John W.; Munger, Willian J.; Goulden, Michael L.; Wofsy, Steven C.

1996-01-01

Temperate deciduous forest exhibit dramatic seasonal changes in surface exchange properties following on the seasonal changes in leaf area index. The canopy resistance to water vapor transport r(sub c) decreased abruptly at leaf emergence in each year but then also continued to decrease slowly during the remaining growing season due to slowly increasing LAI. Canopy resistance and PAR-albedo (albedo from photosynthetically active radiation) began to increase about one month before leaf fall with the diminishment of CO2 gradient above the canopy as well. At this time evaporation begun to be controlled as if the canopy were leafless.

A gene encoding maize caffeoyl-CoA O-methyltransferase confers quantitative resistance to multiple pathogens.

PubMed

Yang, Qin; He, Yijian; Kabahuma, Mercy; Chaya, Timothy; Kelly, Amy; Borrego, Eli; Bian, Yang; El Kasmi, Farid; Yang, Li; Teixeira, Paulo; Kolkman, Judith; Nelson, Rebecca; Kolomiets, Michael; L Dangl, Jeffery; Wisser, Randall; Caplan, Jeffrey; Li, Xu; Lauter, Nick; Balint-Kurti, Peter

2017-09-01

Alleles that confer multiple disease resistance (MDR) are valuable in crop improvement, although the molecular mechanisms underlying their functions remain largely unknown. A quantitative trait locus, qMdr 9.02 , associated with resistance to three important foliar maize diseases-southern leaf blight, gray leaf spot and northern leaf blight-has been identified on maize chromosome 9. Through fine-mapping, association analysis, expression analysis, insertional mutagenesis and transgenic validation, we demonstrate that ZmCCoAOMT2, which encodes a caffeoyl-CoA O-methyltransferase associated with the phenylpropanoid pathway and lignin production, is the gene within qMdr 9.02 conferring quantitative resistance to both southern leaf blight and gray leaf spot. We suggest that resistance might be caused by allelic variation at the level of both gene expression and amino acid sequence, thus resulting in differences in levels of lignin and other metabolites of the phenylpropanoid pathway and regulation of programmed cell death.

Dredging Research Program: Practices and Problems Associated with Economic Loading and Overflow of Dredge Hoppers and Scows

DTIC Science & Technology

1990-10-01

Services No. EB687D020, 20 January 1987, as a part of the Dredging Research Program (DRP), managed by the WES Coastal Engineering Research Center (CERC...with the bottom. The bottom sediments are entrained with the ambient water, lifted hydraulically by the dredge pumps, and discharged into the hop - pers...in a hopper. Some of these are particle size, hopper capacity and opening area, settling velocity, flow velocity in the hop - per, inflow

Simulation of 2D Granular Hopper Flow

NASA Astrophysics Data System (ADS)

Li, Zhusong; Shattuck, Mark

2012-02-01

Jamming and intermittent granular flow are big problems in industry, and the vertical hopper is a canonical example of these difficulties. We simulate gravity driven flow and jamming of 2D disks in a vertical hopper and compare with identical companion experiments presented in this session. We measure and compare the flow rate and probability for jamming as a function of particle properties and geometry. We evaluate the ability of standard Hertz-Mindlin contact mode to quantitatively predict the experimental flow.

46 CFR 174.340 - Collision bulkhead.

Code of Federal Regulations, 2010 CFR

2010-10-01

... PERTAINING TO SPECIFIC VESSEL TYPES Hopper Dredges With Working Freeboard Assignments Design § 174.340 Collision bulkhead. Each hopper dredge must have a collision bulkhead that is located not less than 5...

46 CFR 174.340 - Collision bulkhead.

Code of Federal Regulations, 2011 CFR

2011-10-01

... PERTAINING TO SPECIFIC VESSEL TYPES Hopper Dredges With Working Freeboard Assignments Design § 174.340 Collision bulkhead. Each hopper dredge must have a collision bulkhead that is located not less than 5...

Genetics and breeding of bacterial leaf spot resistance

USDA-ARS?s Scientific Manuscript database

Bacterial leaf spot (BLS) caused by the pathogen Xanthomonas campestris pv. vitians (Xcv) is a globally important disease of whole head and baby leaf lettuce that reduces crop yield and quality. Host resistance is the most feasible method to reduce disease losses. Screening Lactuca accessions has id...

Proteomic characterization of the Rph15 barley resistance gene-mediated defence responses to leaf rust

PubMed Central

2012-01-01

Background Leaf rust, caused by the biotrophic fungal pathogen Puccinia hordei, is one of the most important foliar disease of barley (Hordeum vulgare) and represents a serious threat in many production regions of the world. The leaf rust resistance gene Rph15 is of outstanding interest for resistance breeding because it confers resistance to over 350 Puccinia hordei isolates collected from around the world. Molecular and biochemical mechanisms responsible for the Rph15 effectiveness are currently not investigated. The aim of the present work was to study the Rph15-based defence responses using a proteomic approach. Results Protein pattern changes in response to the leaf rust pathogen infection were investigated in two barley near isogenic lines (NILs), Bowman (leaf rust susceptible) and Bowman-Rph15 (leaf rust resistant), differing for the introgression of the leaf rust resistance gene Rph15. Two infection time points, 24 hours and four days post inoculation (dpi), were analysed. No statistically significant differences were identified at the early time point, while at 4 dpi eighteen protein spots were significantly up or down regulated with a fold-change equal or higher than two in response to pathogen infection. Almost all the pathogen-responsive proteins were identified in the Bowman-Rph15 resistant NIL. Protein spots were characterized by LC-MS/MS analysis and found to be involved in photosynthesis and energy metabolism, carbohydrate metabolism, protein degradation and defence. Proteomic data were complemented by transcriptional analysis of the respective genes. The identified proteins can be related to modulation of the photosynthetic apparatus components, re-direction of the metabolism to sustain defence responses and deployment of defence proteins. Conclusions The identification of leaf rust infection-modulated defence responses restricted to the resistant NIL support the hypothesis that basal defence responses of Bowman, but not the Rph15 resistance gene-based ones, are suppressed or delayed by pathogen effectors to levels below the detection power of the adopted proteomic approach. Additionally, Rph15-mediated resistance processes identified mainly resides on a modulation of primary metabolism, affecting photosyntesis and carbohydrate pool. PMID:23167439

46 CFR 174.305 - Definitions.

Code of Federal Regulations, 2010 CFR

2010-10-01

... SPECIFIC VESSEL TYPES Hopper Dredges With Working Freeboard Assignments § 174.305 Definitions. Hopper dredge has the same meaning as contained in § 44.310 of this chapter. Length has the same meaning as...

46 CFR 174.305 - Definitions.

Code of Federal Regulations, 2011 CFR

2011-10-01

... SPECIFIC VESSEL TYPES Hopper Dredges With Working Freeboard Assignments § 174.305 Definitions. Hopper dredge has the same meaning as contained in § 44.310 of this chapter. Length has the same meaning as...

Cross-genera transferability of rice and finger millet genomic SSRs to barnyard millet (Echinochloa spp.).

PubMed

Kalyana Babu, B; Sood, Salej; Kumar, Dinesh; Joshi, Anjeli; Pattanayak, A; Kant, Lakshmi; Upadhyaya, H D

2018-02-01

Barnyard millet ( Echinochloa spp.) is an important crop from nutritional point of view, nevertheless, the genetic information is very scarce. In the present investigation, rice and finger millet genomic SSRs were used for assessing cross transferability, identification of polymorphic markers, syntenic regions, genetic diversity and population structure analysis of barnyard millet genotypes. We observed 100% cross transferability for finger millet SSRs, of which 91% were polymorphic, while 71% of rice markers were cross transferable with 48% polymorphic out of them. Twenty-nine and sixteen highly polymorphic finger millet and rice SSRs yielded a mean of 4.3 and 3.38 alleles per locus in barnyard millet genotypes, respectively. The PIC values varied from 0.27 to 0.73 at an average of 0.54 for finger millet SSRs, whereas it was from 0.15 to 0.67 at an average of 0.44 for rice SSRs. High synteny was observed for markers related to panicle length, yield-related traits, spikelet fertility, plant height, root traits, leaf senescence, blast and brown plant hopper resistance. Although the rice SSRs located on chromosome 10 followed by chromosome 6 and 11 were found to be more transferable to barnyard millet, the finger millet SSRs were more polymorphic and transferable to barnyard millet genotypes. These SSR data of finger millet and rice individually as well as combined together grouped the 11 barnyard millet genotypes into 2 major clusters. The results of population structure analysis were similar to cluster analysis.

Introgression of leaf rust and stripe rust resistance from Sharon goatgrass (Aegilops sharonensis Eig) into bread wheat (Triticum aestivum L.).

PubMed

Millet, E; Manisterski, J; Ben-Yehuda, P; Distelfeld, A; Deek, J; Wan, A; Chen, X; Steffenson, B J

2014-06-01

Leaf rust and stripe rust are devastating wheat diseases, causing significant yield losses in many regions of the world. The use of resistant varieties is the most efficient way to protect wheat crops from these diseases. Sharon goatgrass (Aegilops sharonensis or AES), which is a diploid wild relative of wheat, exhibits a high frequency of leaf and stripe rust resistance. We used the resistant AES accession TH548 and induced homoeologous recombination by the ph1b allele to obtain resistant wheat recombinant lines carrying AES chromosome segments in the genetic background of the spring wheat cultivar Galil. The gametocidal effect from AES was overcome by using an "anti-gametocidal" wheat mutant. These recombinant lines were found resistant to highly virulent races of the leaf and stripe rust pathogens in Israel and the United States. Molecular DArT analysis of the different recombinant lines revealed different lengths of AES segments on wheat chromosome 6B, which indicates the location of both resistance genes.

Field evaluations of leaf spot resistance and yield in peanut genotypes in the United States and Bolivia

USDA-ARS?s Scientific Manuscript database

Field experiments were conducted in 2002-2006 to characterize yield potential and disease resistance to Cercospora arachidicola (early leaf spot) and Cercosporidium personatum (late leaf spot) in the Bolivian peanut (Arachis hypogaea) cultivar, Bayo Grande, and breeding lines developed from crosses ...

VIEW FROM CHARGING FLOOR LOOKING EAST AT COAL HOPPER, AND ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

VIEW FROM CHARGING FLOOR LOOKING EAST AT COAL HOPPER, AND PHYSICAL REMAINS OF GAS PRODUCER SYSTEM. - Pittsburgh Steel Company, Monessen Works, Open Hearth Plant, Donner Avenue, Monessen, Westmoreland County, PA

Pyramids of QTLs enhance host-plant resistance and Bt-mediated resistance to leaf-chewing insects in soybean.

PubMed

Ortega, María A; All, John N; Boerma, H Roger; Parrott, Wayne A

2016-04-01

QTL-M and QTL-E enhance soybean resistance to insects. Pyramiding these QTLs with cry1Ac increases protection against Bt-tolerant pests, presenting an opportunity to effectively deploy Bt with host-plant resistance genes. Plant resistance to leaf-chewing insects minimizes the need for insecticide applications, reducing crop production costs and pesticide concerns. In soybean [Glycine max (L.) Merr.], resistance to a broad range of leaf-chewing insects is found in PI 229358 and PI 227687. PI 229358's resistance is conferred by three quantitative trait loci (QTLs): M, G, and H. PI 227687's resistance is conferred by QTL-E. The letters indicate the soybean Linkage groups (LGs) on which the QTLs are located. This study aimed to determine if pyramiding PI 229358 and PI 227687 QTLs would enhance soybean resistance to leaf-chewing insects, and if pyramiding these QTLs with Bt (cry1Ac) enhances resistance against Bt-tolerant pests. The near-isogenic lines (NILs): Benning(ME), Benning(MGHE), and Benning(ME+cry1Ac) were developed. Benning(ME) and Benning(MGHE) were evaluated in detached-leaf and greenhouse assays with soybean looper [SBL, Chrysodeixis includens (Walker)], corn earworm [CEW, Helicoverpa zea (Boddie)], fall armyworm [FAW, Spodoptera frugiperda (J.E. Smith)], and velvetbean caterpillar [VBC, Anticarsia gemmatalis (Hübner)]; and in field-cage assays with SBL. Benning(ME+cry1Ac) was tested in detached-leaf assays against SBL, VBC, and Southern armyworm [SAW, Spodoptera eridania (Cramer)]. In the detached-leaf assay, Benning(ME) showed the strongest antibiosis against CEW, FAW, and VBC. In field-cage conditions, Benning(ME) and Benning(MGHE) suffered 61 % less defoliation than Benning. Benning(ME+cry1Ac) was more resistant than Benning(ME) and Benning (cry1Ac) against SBL and SAW. Agriculturally relevant levels of resistance in soybean can be achieved with just two loci, QTL-M and QTL-E. ME+cry1Ac could present an opportunity to protect the durability of Bt genes in elite soybean cultivars. These results should assist the development of effective pest management strategies, and sustainable deployment of Bt genes in soybean.

8. VIEW OF BATCHING HOPPER ON SERVICE FLOOR OF FURNACE ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

8. VIEW OF BATCHING HOPPER ON SERVICE FLOOR OF FURNACE AISLE IN BOP SHOP LOOKING SOUTH. - U.S. Steel Duquesne Works, Basic Oxygen Steelmaking Plant, Along Monongahela River, Duquesne, Allegheny County, PA

Looking south at the ash disposal hoppers for boilers numbers ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

Looking south at the ash disposal hoppers for boilers numbers 1 through 6. - Wheeling-Pittsburgh Steel Corporation, Allenport Works, Boiler House, Route 88 on West bank of Monongahela River, Allenport, Washington County, PA

On the computation of steady Hopper flows. II: von Mises materials in various geometries

NASA Astrophysics Data System (ADS)

Gremaud, Pierre A.; Matthews, John V.; O'Malley, Meghan

2004-11-01

Similarity solutions are constructed for the flow of granular materials through hoppers. Unlike previous work, the present approach applies to nonaxisymmetric containers. The model involves ten unknowns (stresses, velocity, and plasticity function) determined by nine nonlinear first order partial differential equations together with a quadratic algebraic constraint (yield condition). A pseudospectral discretization is applied; the resulting problem is solved with a trust region method. The important role of the hopper geometry on the flow is illustrated by several numerical experiments of industrial relevance.

Microscopic analysis of Hopper flow with ellipsoidal particles

NASA Astrophysics Data System (ADS)

Liu, Sida; Zhou, Zongyan; Zou, Ruiping; Pinson, David; Yu, Aibing

2013-06-01

Hoppers are widely used in process industries. With such widespread application, difficulties in achieving desired operational behaviors have led to extensive experimental and mathematical studies in the past decades. Particularly, the discrete element method has become one of the most important simulation tools for design and analysis. So far, most studies are on spherical particles for computational convenience. In this work, ellipsoidal particles are used as they can represent a large variation of particle shapes. Hopper flow with ellipsoidal particles is presented highlighting the effect of particle shape on the microscopic properties.

Expression of apoplast-targeted plant defensin MtDef4.2 confers resistance to leaf rust pathogen Puccinia triticina but does not affect mycorrhizal symbiosis in transgenic wheat.

PubMed

Kaur, Jagdeep; Fellers, John; Adholeya, Alok; Velivelli, Siva L S; El-Mounadi, Kaoutar; Nersesian, Natalya; Clemente, Thomas; Shah, Dilip

2017-02-01

Rust fungi of the order Pucciniales are destructive pathogens of wheat worldwide. Leaf rust caused by the obligate, biotrophic basidiomycete fungus Puccinia triticina (Pt) is an economically important disease capable of causing up to 50 % yield losses. Historically, resistant wheat cultivars have been used to control leaf rust, but genetic resistance is ephemeral and breaks down with the emergence of new virulent Pt races. There is a need to develop alternative measures for control of leaf rust in wheat. Development of transgenic wheat expressing an antifungal defensin offers a promising approach to complement the endogenous resistance genes within the wheat germplasm for durable resistance to Pt. To that end, two different wheat genotypes, Bobwhite and Xin Chun 9 were transformed with a chimeric gene encoding an apoplast-targeted antifungal plant defensin MtDEF4.2 from Medicago truncatula. Transgenic lines from four independent events were further characterized. Homozygous transgenic wheat lines expressing MtDEF4.2 displayed resistance to Pt race MCPSS relative to the non-transgenic controls in growth chamber bioassays. Histopathological analysis suggested the presence of both pre- and posthaustorial resistance to leaf rust in these transgenic lines. MtDEF4.2 did not, however, affect the root colonization of a beneficial arbuscular mycorrhizal fungus Rhizophagus irregularis. This study demonstrates that the expression of apoplast-targeted plant defensin MtDEF4.2 can provide substantial resistance to an economically important leaf rust disease in transgenic wheat without negatively impacting its symbiotic relationship with the beneficial mycorrhizal fungus.

Working Towards Disease Resistance in Peanuts Through Biotechnology

USDA-ARS?s Scientific Manuscript database

Resistant cultivars are the most desirable approach to disease control in agriculture. Early and late leaf spot are the most important foliar diseases of peanut worldwide. Significant progress for leaf spot resistance in peanut can be achieved through biotechnology. The National Peanut Research ...

Frequent occurrence of tomato leaf curl New Delhi virus in cotton leaf curl disease affected cotton in Pakistan

USDA-ARS?s Scientific Manuscript database

Cotton leaf curl disease (CLCuD) in the Indian subcontinent is associated with several distinct monopartite begomoviruses and DNA satellites. However, only a single begomovirus was associated with breakdown of resistance against CLCuD in previously resistant cotton varieties. The monopartite begomov...

Measuring and modeling the backscattering cross section of a leaf

NASA Technical Reports Server (NTRS)

Senior, T. B. A.; Sarabandi, K.; Ulaby, F. T.

1987-01-01

Leaves are a significant feature of any vegetation canopy, and for remote sensing purposes it is important to develop an effective model for predicting the scattering from a leaf. From measurements of the X band backscattering cross section of a coleus leaf in varying stages of dryness, it is shown that a uniform resistive sheet constitutes such a model for a planar leaf. The scattering is determined by the (complex) resistivity which is, in turn, entirely specified by the gravimetric moisture content of the leaf. Using an available asymptotic expression for the scattering from a rectangular resistive plate which includes, as a special case, a metallic plate whose resistivity is zero, the computed backscattering cross sections for both principal polarizations are found to be in excellent agreement with data measured for rectangular sections of leaves with different moisture contents. If the resistivity is sufficiently large, the asymptotic expressions do not differ significantly from the physical optics ones, and for naturally shaped leaves as well as rectangular sections, the physical optics approximation in conjunction with the resistive sheet model faithfully reproduces the dominant feataures of the scattering patterns under all moisture conditions.

Leaf rust of cultivated barley: pathology and control.

PubMed

Park, Robert F; Golegaonkar, Prashant G; Derevnina, Lida; Sandhu, Karanjeet S; Karaoglu, Haydar; Elmansour, Huda M; Dracatos, Peter M; Singh, Davinder

2015-01-01

Leaf rust of barley is caused by the macrocyclic, heteroecious rust pathogen Puccinia hordei, with aecia reported from selected species of the genera Ornithogalum, Leopoldia, and Dipcadi, and uredinia and telia occurring on Hordeum vulgare, H. vulgare ssp. spontaneum, Hordeum bulbosum, and Hordeum murinum, on which distinct parasitic specialization occurs. Although Puccinia hordei is sporadic in its occurrence, it is probably the most common and widely distributed rust disease of barley. Leaf rust has increased in importance in recent decades in temperate barley-growing regions, presumably because of more intensive agricultural practices. Although total crop loss does not occur, under epidemic conditions yield reductions of up to 62% have been reported in susceptible varieties. Leaf rust is primarily controlled by the use of resistant cultivars, and, to date, 21 seedling resistance genes and two adult plant resistance (APR) genes have been identified. Virulence has been detected for most seedling resistance genes but is unknown for the APR genes Rph20 and Rph23. Other potentially new sources of APR have been reported, and additivity has been described for some of these resistances. Approaches to achieving durable resistance to leaf rust in barley are discussed.

Inheritance and Bulked Segregant Analysis of Leaf Rust and Stem Rust Resistance in Durum Wheat Genotypes.

PubMed

Aoun, Meriem; Kolmer, James A; Rouse, Matthew N; Chao, Shiaoman; Bulbula, Worku Denbel; Elias, Elias M; Acevedo, Maricelis

2017-12-01

Leaf rust, caused by Puccinia triticina, and stem rust, caused by P. graminis f. sp. tritici, are important diseases of durum wheat. This study determined the inheritance and genomic locations of leaf rust resistance (Lr) genes to P. triticina race BBBQJ and stem rust resistance (Sr) genes to P. graminis f. sp. tritici race TTKSK in durum accessions. Eight leaf-rust-resistant genotypes were used to develop biparental populations. Accessions PI 192051 and PI 534304 were also resistant to P. graminis f. sp. tritici race TTKSK. The resulting progenies were phenotyped for leaf rust and stem rust response at seedling stage. The Lr and Sr genes were mapped in five populations using single-nucleotide polymorphisms and bulked segregant analysis. Five leaf-rust-resistant genotypes carried single dominant Lr genes whereas, in the remaining accessions, there was deviation from the expected segregation ratio of a single dominant Lr gene. Seven genotypes carried Lr genes different from those previously characterized in durum. The single dominant Lr genes in PI 209274, PI 244061, PI387263, and PI 313096 were mapped to chromosome arms 6BS, 2BS, 6BL, and 6BS, respectively. The Sr gene in PI 534304 mapped to 6AL and is most likely Sr13, while the Sr gene in PI 192051 could be uncharacterized in durum.

4. FLUX STORAGE HOPPERS ON THE WEIGHING FLOOR OF THE ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

4. FLUX STORAGE HOPPERS ON THE WEIGHING FLOOR OF THE FURNACE AISLE IN THE BOP SHOP LOOKING SOUTHWEST. - U.S. Steel Duquesne Works, Basic Oxygen Steelmaking Plant, Along Monongahela River, Duquesne, Allegheny County, PA

Safety control circuit for a neutronic reactor

DOEpatents

Ellsworth, Howard C.

2004-04-27

A neutronic reactor comprising an active portion containing material fissionable by neutrons of thermal energy, means to control a neutronic chain reaction within the reactor comprising a safety device and a regulating device, a safety device including means defining a vertical channel extending into the reactor from an aperture in the upper surface of the reactor, a rod containing neutron-absorbing materials slidably disposed within the channel, means for maintaining the safety rod in a withdrawn position relative to the active portion of the reactor including means for releasing said rod on actuation thereof, a hopper mounted above the active portion of the reactor having a door disposed at the bottom of the hopper opening into the vertical channel, a plurality of bodies of neutron-absorbing materials disposed within the hopper, and means responsive to the failure of the safety rod on actuation thereof to enter the active portion of the reactor for opening the door in the hopper.

6. FLUX WEIGH HOPPERS AND SCALES ON THE BATCHING FLOOR ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

6. FLUX WEIGH HOPPERS AND SCALES ON THE BATCHING FLOOR OF THE FURNACE AISLE IN THE BOP SHOP LOOKING SOUTHWEST. - U.S. Steel Duquesne Works, Basic Oxygen Steelmaking Plant, Along Monongahela River, Duquesne, Allegheny County, PA

7. NORTHWEST VIEW OF FLUX CONVEYORS FEEDING BATCH HOPPERS ON ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

7. NORTHWEST VIEW OF FLUX CONVEYORS FEEDING BATCH HOPPERS ON THE BATCHING FLOOR OF THE FURNACE AISLE IN THE BOP SHOP. - U.S. Steel Duquesne Works, Basic Oxygen Steelmaking Plant, Along Monongahela River, Duquesne, Allegheny County, PA

Genetics of leaf rust resistance in the hard red winter wheat cultivars Santa Fe and Duster

USDA-ARS?s Scientific Manuscript database

Leaf rust caused by Puccinia triticina is a common and important disease of hard red winter wheat in the Great Plains of the United States. The hard red winter wheat cultivars 'Santa Fe' and 'Duster' have had effective leaf rust resistance since their release in 2003 and 2006, respectively. Both cul...

Genetic analysis and mapping of adult plant resistance loci to leaf rust in durum wheat cultivar Bairds.

PubMed

Lan, Caixia; Basnet, Bhoja R; Singh, Ravi P; Huerta-Espino, Julio; Herrera-Foessel, Sybil A; Ren, Yong; Randhawa, Mandeep S

2017-03-01

New leaf rust adult plant resistance (APR) QTL QLr.cim - 6BL was mapped and confirmed the known pleotropic APR gene Lr46 effect on leaf rust in durum wheat line Bairds. CIMMYT-derived durum wheat line Bairds displays an adequate level of adult plant resistance (APR) to leaf rust in Mexican field environments. A recombinant inbred line (RIL) population developed from a cross of Bairds with susceptible parent Atred#1 was phenotyped for leaf rust response at Ciudad Obregon, Mexico, during 2013, 2014, 2015 and 2016 under artificially created epidemics of Puccinia triticina (Pt) race BBG/BP. The RIL population and its parents were genotyped with the 50 K diversity arrays technology (DArT) sequence system and simple sequence repeat (SSR) markers. A genetic map comprising 1150 markers was used to map the resistance loci. Four significant quantitative trait loci (QTLs) were detected on chromosomes 1BL, 2BC (centromere region), 5BL and 6BL. These QTLs, named Lr46, QLr.cim-2BC, QLr.cim-5BL and QLr.cim-6BL, respectively, explained 13.5-60.8%, 9.0-14.3%, 2.8-13.9%, and 11.6-29.4%, respectively, of leaf rust severity variation by the inclusive composite interval mapping method. All of these resistance loci were contributed by the resistant parent Bairds, except for QLr.cim-2BC, which came from susceptible parent Atred#1. Among these, the QTL on chromosome 1BL was the known pleiotropic APR gene Lr46, whereas QLr.cim-6BL, a consistently detected locus, should be a new leaf rust resistance locus in durum wheat. The mean leaf rust severity of RILs carrying all four QTLs ranged from 8.0 to 17.5%, whereas it ranged from 10.9 to 38.5% for three QTLs (Lr46 + 5BL + 6BL) derived from the resistant parent Bairds. Two RILs with four QTLs combinations can be used as sources of complex APR in durum wheat breeding.

Silicon-Mediated Resistance in a Susceptible Rice Variety to the Rice Leaf Folder, Cnaphalocrocis medinalis Guenée (Lepidoptera: Pyralidae)

PubMed Central

Han, Yongqiang; Lei, Wenbin; Wen, Lizhang; Hou, Maolin

2015-01-01

The rice leaf folder, Cnaphalocrocis medinalis (Guenée), is one of the most destructive rice pests in Asian countries. Rice varieties resistant to the rice leaf folder are generally characterized by high silicon content. In this study, silicon amendment, at 0.16 and 0.32 g Si/kg soil, enhanced resistance of a susceptible rice variety to the rice leaf folder. Silicon addition to rice plants at both the low and high rates significantly extended larval development and reduced larval survival rate and pupation rate in the rice leaf folder. When applied at the high rate, silicon amendment reduced third-instars’ weight gain and pupal weight. Altogether, intrinsic rate of increase, finite rate of increase and net reproduction rate of the rice leaf folder population were all reduced at both the low and high silicon addition rates. Although the third instars consumed more in silicon-amended treatments, C:N ratio in rice leaves was significantly increased and food conversion efficiencies were reduced due to increased silicon concentration in rice leaves. Our results indicate that reduced food quality and food conversion efficiencies resulted from silicon addition account for the enhanced resistance in the susceptible rice variety to the rice leaf folder. PMID:25837635

27. INTERIOR OF UTILITY ROOM SHOWING ELECTRICAL JUNCTION CABINET, HOPPER ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

27. INTERIOR OF UTILITY ROOM SHOWING ELECTRICAL JUNCTION CABINET, HOPPER WINDOW, OPEN DOOR TO KITCHEN NO. 2, AND METAL SINK. VIEW TO SOUTHWEST. - Bishop Creek Hydroelectric System, Plant 6, Cashbaugh-Kilpatrick House, Bishop Creek, Bishop, Inyo County, CA

4. Hopper was used to collect bark from the Chipper ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

4. Hopper was used to collect bark from the Chipper Building. Processed bark was loaded into trucks for disposal at a pit on site. - Pacific Creosoting Plant, Log Peeling Operation, 5350 Creosote Place, Northeast, Bremerton, Kitsap County, WA

A maize caffeoyl-CoA O-methyltransferase gene confers quantitative resistance to multiple pathogens

USDA-ARS?s Scientific Manuscript database

Alleles that confer multiple disease resistance (MDR) are valuable in crop improvement though molecular mechanisms underlying their functions remain largely unknown. A QTL, qMdr9.02, associated with resistance to three important foliar maize diseases, southern leaf blight (SLB), gray leaf spot (GLS)...

Using RNA-sequencing and in silico subtraction to identify resistance gene analog markers for Lr16 in wheat

USDA-ARS?s Scientific Manuscript database

Leaf rust, caused by Puccinia triticina Eriks., is one of the most widespread diseases of wheat worldwide and breeding for resistance is one of the most effective methods of control. Lr16 is a wheat leaf rust resistance gene that provides resistance at both the seedling and adult stages. Simple s...

Genome Wide Association Study of Seedling and Adult Plant Leaf Rust Resistance in Elite Spring Wheat Breeding Lines.

PubMed

Gao, Liangliang; Turner, M Kathryn; Chao, Shiaoman; Kolmer, James; Anderson, James A

2016-01-01

Leaf rust is an important disease, threatening wheat production annually. Identification of resistance genes or QTLs for effective field resistance could greatly enhance our ability to breed durably resistant varieties. We applied a genome wide association study (GWAS) approach to identify resistance genes or QTLs in 338 spring wheat breeding lines from public and private sectors that were predominately developed in the Americas. A total of 46 QTLs were identified for field and seedling traits and approximately 20-30 confer field resistance in varying degrees. The 10 QTLs accounting for the most variation in field resistance explained 26-30% of the total variation (depending on traits: percent severity, coefficient of infection or response type). Similarly, the 10 QTLs accounting for most of the variation in seedling resistance to different races explained 24-34% of the variation, after correcting for population structure. Two potentially novel QTLs (QLr.umn-1AL, QLr.umn-4AS) were identified. Identification of novel genes or QTLs and validation of previously identified genes or QTLs for seedling and especially adult plant resistance will enhance understanding of leaf rust resistance and assist breeding for resistant wheat varieties. We also developed computer programs to automate field and seedling rust phenotype data conversions. This is the first GWAS study of leaf rust resistance in elite wheat breeding lines genotyped with high density 90K SNP arrays.

Genetics of Leaf Rust Resistance in the Soft Red Winter Wheat Cultivars Coker 9663 and Pioneer 26R61

USDA-ARS?s Scientific Manuscript database

Leaf rust, caused by the fungus Puccinia triticina, is an important disease of soft red winter wheat cultivars that are grown in the southern and eastern United States. The objectives of this study were to identify the leaf rust resistance genes in two soft red winter wheat cultivars, Coker 9663 and...

Temperature and leaf wetness duration affect phenotypic expression of Rlm6-mediated resistance to Leptosphaeria maculans in Brassica napus.

PubMed

Huang, Yong-Ju; Evans, Neal; Li, Zi-Qin; Eckert, Maria; Chèvre, Anne-Marie; Renard, Michel; Fitt, Bruce D L

2006-01-01

Near-isogenic Brassica napus lines carrying/lacking resistance gene Rlm6 were used to investigate the effects of temperature and leaf wetness duration on phenotypic expression of Rlm6-mediated resistance. Leaves were inoculated with ascospores or conidia of Leptosphaeria maculans carrying the effector gene AvrLm6. Incubation period to the onset of lesion development, number of lesions and lesion diameter were assessed. Symptomless growth of L. maculans from leaf lesions to stems was investigated using a green fluorescent protein (GFP) expressing isolate carrying AvrLm6. L. maculans produced large grey lesions on Darmor (lacking Rlm6) at 5-25 degrees C and DarmorMX (carrying Rlm6) at 25 degrees C, but small dark spots and 'green islands' on DarmorMX at 5-20 degrees C. With increasing temperature/wetness duration, numbers of lesions/spots generally increased. GFP-expressing L. maculans grew from leaf lesions down leaf petioles to stems on DarmorMX at 25 degrees C but not at 15 degrees C. We conclude that temperature and leaf wetness duration affect the phenotypic expression of Rlm6-mediated resistance in leaves and subsequent L. maculans spread down petioles to produce stem cankers.

The Lr34 adult plant rust resistance gene provides seedling resistance in durum wheat without senescence.

PubMed

Rinaldo, Amy; Gilbert, Brian; Boni, Rainer; Krattinger, Simon G; Singh, Davinder; Park, Robert F; Lagudah, Evans; Ayliffe, Michael

2017-07-01

The hexaploid wheat (Triticum aestivum) adult plant resistance gene, Lr34/Yr18/Sr57/Pm38/Ltn1, provides broad-spectrum resistance to wheat leaf rust (Lr34), stripe rust (Yr18), stem rust (Sr57) and powdery mildew (Pm38) pathogens, and has remained effective in wheat crops for many decades. The partial resistance provided by this gene is only apparent in adult plants and not effective in field-grown seedlings. Lr34 also causes leaf tip necrosis (Ltn1) in mature adult plant leaves when grown under field conditions. This D genome-encoded bread wheat gene was transferred to tetraploid durum wheat (T. turgidum) cultivar Stewart by transformation. Transgenic durum lines were produced with elevated gene expression levels when compared with the endogenous hexaploid gene. Unlike nontransgenic hexaploid and durum control lines, these transgenic plants showed robust seedling resistance to pathogens causing wheat leaf rust, stripe rust and powdery mildew disease. The effectiveness of seedling resistance against each pathogen correlated with the level of transgene expression. No evidence of accelerated leaf necrosis or up-regulation of senescence gene markers was apparent in these seedlings, suggesting senescence is not required for Lr34 resistance, although leaf tip necrosis occurred in mature plant flag leaves. Several abiotic stress-response genes were up-regulated in these seedlings in the absence of rust infection as previously observed in adult plant flag leaves of hexaploid wheat. Increasing day length significantly increased Lr34 seedling resistance. These data demonstrate that expression of a highly durable, broad-spectrum adult plant resistance gene can be modified to provide seedling resistance in durum wheat. © 2016 The Authors. Plant Biotechnology Journal published by Society for Experimental Biology and The Association of Applied Biologists and John Wiley & Sons Ltd.

Inside the covered hopper car loading dock at railroad level, ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

Inside the covered hopper car loading dock at railroad level, looking east from the 1945 elevator into the 1913 elevator, control for the railroad car puller in background - Stewart Company Grain Elevator, 16 West Carson Street, Pittsburgh, Allegheny County, PA

Leaf-morphology-assisted selection for resistance to two-spotted spider mite Tetranychus urticae Koch (Acari: Tetranychidae) in carnations (Dianthus caryophyllus L).

PubMed

Seki, Kousuke

2016-10-01

The development of a cultivar resistant to the two-spotted spider mite has provided both ecological and economic benefits to the production of cut flowers. This study aimed to clarify the mechanism of resistance to mites using an inbred population of carnations. In the resistant and susceptible plants selected from an inbred population, a difference was recognised in the thickness of the abaxial palisade tissue by microscopic examination of the damaged leaf. Therefore, it was assumed that mites displayed feeding preferences within the internal leaf structure of the carnation leaf. The suitability of the host plant for mites was investigated using several cultivars selected using an index of the thickness from the abaxial leaf surface to the spongy tissue. The results suggested that the cultivar associated with a thicker abaxial tissue lowered the intrinsic rate of natural increase of the mites. The cultivars with a thicker abaxial tissue of over 120 µm showed slight damage in the field test. The ability of mites to feed on the spongy tissue during an early life stage from hatching to adult emergence was critical. It was possible to select a cultivar that is resistant to mites under a real cultivation environment by observing the internal structure of the leaf. © 2016 Society of Chemical Industry. © 2016 Society of Chemical Industry.

Cuticular permeance in relation to wax and cutin development along the growing barley (Hordeum vulgare) leaf.

PubMed

Richardson, Andrew; Wojciechowski, Tobias; Franke, Rochus; Schreiber, Lukas; Kerstiens, Gerhard; Jarvis, Mike; Fricke, Wieland

2007-05-01

The developing leaf three of barley provides an excellent model system for the direct determination of relationships between amounts of waxes and cutin and cuticular permeance. Permeance of the cuticle was assessed via the time-course of uptake of either toluidine blue or (14)C-labelled benzoic acid ([(14)C] BA) along the length of the developing leaf. Toluidine blue uptake only occurred within the region 0-25 mm from the point of leaf insertion (POLI). Resistance--the inverse of permeance--to uptake of [(14)C] BA was determined for four leaf regions and was lowest in the region 10-20 mm above POLI. At 20-30 and 50-60 mm above POLI, it increased by factors of 6 and a further 32, respectively. Above the point of emergence of leaf three from the sheath of leaf two, which was 76-80 mm above POLI, resistance was as high as at 50-60 mm above POLI. GC-FID/MS analyses of wax and cutin showed that: (1) the initial seven fold increase in cuticular resistance coincided with increase in cutin coverage and appearance of waxes; (2) the second, larger and final increase in cuticle resistance was accompanied by an increase in wax coverage, whereas cutin coverage remained unchanged; (3) cutin deposition in barley leaf epidermis occurred in parallel with cell elongation, whereas deposition of significant amounts of wax commenced as cells ceased to elongate.

Differential Expression of R-genes to Associate Leaf Spot Resistance in Cultivated Peanut

USDA-ARS?s Scientific Manuscript database

Breeding for acceptable levels of Early (ELS) or Late Leaf Spot (LLS) resistance in cultivated peanut has been elusive due to extreme variability of plant response in the field and the proper combinations of resistance (R)-genes in any particular peanut line. R-genes have been shown to be involved ...

Genome-Wide Association Mapping for Resistance to Leaf and Stripe Rust in Winter-Habit Hexaploid Wheat Landraces

PubMed Central

Kertho, Albert; Mamidi, Sujan; Bonman, J. Michael; McClean, Phillip E.; Acevedo, Maricelis

2015-01-01

Leaf rust, caused by Puccinia triticina (Pt), and stripe rust, caused by P. striiformis f. sp. tritici (Pst), are destructive foliar diseases of wheat worldwide. Breeding for disease resistance is the preferred strategy of managing both diseases. The continued emergence of new races of Pt and Pst requires a constant search for new sources of resistance. Here we report a genome-wide association analysis of 567 winter wheat (Triticum aestivum) landrace accessions using the Infinium iSelect 9K wheat SNP array to identify loci associated with seedling resistance to five races of Pt (MDCL, MFPS, THBL, TDBG, and TBDJ) and one race of Pst (PSTv-37) frequently found in the Northern Great Plains of the United States. Mixed linear models identified 65 and eight significant markers associated with leaf rust and stripe rust, respectively. Further, we identified 31 and three QTL associated with resistance to Pt and Pst, respectively. Eleven QTL, identified on chromosomes 3A, 4A, 5A, and 6D, are previously unknown for leaf rust resistance in T. aestivum. PMID:26076040

VIEW OF SEMIDISMANTLED HOPPER CAR ON THE ORE TRESTLE FACING ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

VIEW OF SEMI-DISMANTLED HOPPER CAR ON THE ORE TRESTLE FACING NORTHWEST WITH OPEN HEARTH BUILDING IN THE BACKGROUND AND THE INGOT MOLD CONDITIONING BUILDING TO THE RIGHT. - Pittsburgh Steel Company, Monessen Works, Open Hearth Plant, Donner Avenue, Monessen, Westmoreland County, PA

15. VIEW OF COAL TRESTLE LOOKING NORTHEAST. COAL DUMPED FROM ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

15. VIEW OF COAL TRESTLE LOOKING NORTHEAST. COAL DUMPED FROM HOPPER CARS COULD BE CRUSHED AND LOADED ON A CONVEYOR THAT PARALLELED THE TRACK TO THE EAST (LEFT) AND CARRIED IT TO A 1000 TON BUNKER LOCATED ON THE NORTH SIDE OF THE EAST BOILER ROOM. COAL COULD ALSO GO THROUGH THE CRUSHER AND BE DIVERTED TO THE CONVEYOR SHOWN IN THE LEFT FOREGROUND. COAL PILES FORMED UNDER THE CONVEYOR WOULD BE MOVED AND SHAPED BY BULLDOZER. A GROUND LEVEL HOPPER WAS LOCATED TO THE RIGHT OF THE SLOPING HOUSING WHICH EXTENDS FROM THE SOUTH SIDE OF THE COAL TRESTLE. THIS HOPPER FED A CONVEYOR LOCATED WITHIN THE SLOPING HOUSING. COAL DROPPED INTO THE HOPPER WOULD BE CONVEYED INTO THE CRUSHER UNDER THE TRESTLE AND THEN DIVERTED TO THE CONVEYOR WHICH LOADED THE 1000 TON BUNKER. THE COAL HANDLING SYSTEM WAS DESIGNED BY GIBBS AND HILL IN 1947. - New York, New Haven & Hartford Railroad, Cos Cob Power Plant, Sound Shore Drive, Greenwich, Fairfield County, CT

Variability of bulk density of distillers dried grains with solubles (DDGS) during gravity-driven discharge.

PubMed

Clementson, C L; Ileleji, K E

2010-07-01

Loading railcars with consistent tonnage has immense cost implications for the shipping of distillers' dried grains with soluble (DDGS) product. Therefore, this study was designed to investigate the bulk density variability of DDGS during filling of railcar hoppers. An apparatus was developed similar to a spinning riffler sampler in order to simulate the filling of railcars at an ethanol plant. There was significant difference (P<0.05) between the initial and final measures of bulk density and particle size as the hoppers were emptied in both mass and funnel flow patterns. Particle segregation that takes place during filling of hoppers contributed to the bulk density variation and was explained by particle size variation. This phenomenon is most likely the same throughout the industry and an appropriate sampling procedure should be adopted for measuring the bulk density of DDGS stored silos or transported in railcar hoppers. Copyright (c) 2010 Elsevier Ltd. All rights reserved.

Mapping of stripe rust resistance gene in an Aegilops caudate introgression line in wheat and its genetic association with leaf rust resistance.

PubMed

Toor, Puneet Inder; Kaur, Satinder; Bansal, Mitaly; Yadav, Bharat; Chhuneja, Parveen

2016-12-01

A pair of stripe rust and leaf rust resistance genes was introgressed from Aegilops caudata, a nonprogenitor diploid species with the CC genome, to cultivated wheat. Inheritance and genetic mapping of stripe rust resistance gene in backcrossrecombinant inbred line (BC-RIL) population derived from the cross of a wheat-Ae. caudata introgression line (IL) T291- 2(pau16060) with wheat cv. PBW343 is reported here. Segregation of BC-RILs for stripe rust resistance depicted a single major gene conditioning adult plant resistance (APR) with stripe rust reaction varying from TR-20MS in resistant RILs signifying the presence of some minor genes as well. Genetic association with leaf rust resistance revealed that two genes are located at a recombination distance of 13%. IL T291-2 had earlier been reported to carry introgressions on wheat chromosomes 2D, 3D, 4D, 5D, 6D and 7D. Genetic mapping indicated the introgression of stripe rust resistance gene on wheat chromosome 5DS in the region carrying leaf rust resistance gene LrAc, but as an independent introgression. Simple sequence repeat (SSR) and sequence-tagged site (STS) markers designed from the survey sequence data of 5DS enriched the target region harbouring stripe and leaf rust resistance genes. Stripe rust resistance locus, temporarily designated as YrAc, mapped at the distal most end of 5DS linked with a group of four colocated SSRs and two resistance gene analogue (RGA)-STS markers at a distance of 5.3 cM. LrAc mapped at a distance of 9.0 cM from the YrAc and at 2.8 cM from RGA-STS marker Ta5DS_2737450, YrAc and LrAc appear to be the candidate genes for marker-assisted enrichment of the wheat gene pool for rust resistance.

Mapping of leaf rust resistance genes and molecular characterization of the 2NS/2AS translocation in the wheat cultivar Jagger

USDA-ARS?s Scientific Manuscript database

Winter wheat cultivar 'Jagger' was recently found to have an alien chromosomal segment 'VPM1' that should carry Lr37, a gene conferring resistance against leaf rust caused by Puccinia triticina, and this cultivar was also reported to have the wheat gene Lr17 against leaf rust. Both Lr17 and Lr37 wer...

Development of COS-SNP and HRM markers for cost efficient and reliable haplotype-based detection of Lr14a in durum wheat (Triticum durum Desf.)

USDA-ARS?s Scientific Manuscript database

Leaf rust (Puccinia triticina Eriks. & Henn.) is a major disease affecting durum wheat production. The Lr14a leaf rust resistant gene present in the durum wheat cv. Creso and its derivative Colosseo is one of the best characterized leaf rust resistance sources presently deployed in durum wheat breed...

Expression of apoplast-targeted plant defensin MtDef4.2 confers resistance to leaf rust pathogen Puccinia triticina but does not affect mycorrhizal symbiosis in transgenic wheat

USDA-ARS?s Scientific Manuscript database

Rust diseases caused by Puccinia spp. pose a major threat to global wheat production. Puccinia triticina (Pt), an obligate basidiomycete biotroph, causes leaf rust disease which incurs yield losses of up to 50% in wheat. Historically, resistant wheat cultivars have been used to control leaf rust, bu...

Evolution of resistance and tolerance to herbivores: testing the trade-off hypothesis.

PubMed

Kariñho-Betancourt, Eunice; Núñez-Farfán, Juan

2015-01-01

Background. To cope with their natural enemies, plants rely on resistance and tolerance as defensive strategies. Evolution of these strategies among natural population can be constrained by the absence of genetic variation or because of the antagonistic genetic correlation (trade-off) between them. Also, since plant defenses are integrated by several traits, it has been suggested that trade-offs might occur between specific defense traits. Methodology/Principal Findings. We experimentally assessed (1) the presence of genetic variance in tolerance, total resistance, and leaf trichome density as specific defense trait, (2) the extent of natural selection acting on plant defenses, and (3) the relationship between total resistance and leaf trichome density with tolerance to herbivory in the annual herb Datura stramonium. Full-sib families of D. stramonium were either exposed to natural herbivores (control) or protected from them by a systemic insecticide. We detected genetic variance for leaf trichome density, and directional selection acting on this character. However, we did not detect a negative significant correlation between tolerance and total resistance, or between tolerance and leaf trichome density. We argue that low levels of leaf damage by herbivores precluded the detection of a negative genetic correlation between plant defense strategies. Conclusions/Significance. This study provides empirical evidence of the independent evolution of plant defense strategies, and a defensive role of leaf trichomes. The pattern of selection should favor individuals with high trichomes density. Also, because leaf trichome density reduces damage by herbivores and possess genetic variance in the studied population, its evolution is not constrained.

Evolution of resistance and tolerance to herbivores: testing the trade-off hypothesis

PubMed Central

Kariñho-Betancourt, Eunice

2015-01-01

Background. To cope with their natural enemies, plants rely on resistance and tolerance as defensive strategies. Evolution of these strategies among natural population can be constrained by the absence of genetic variation or because of the antagonistic genetic correlation (trade-off) between them. Also, since plant defenses are integrated by several traits, it has been suggested that trade-offs might occur between specific defense traits. Methodology/Principal Findings. We experimentally assessed (1) the presence of genetic variance in tolerance, total resistance, and leaf trichome density as specific defense trait, (2) the extent of natural selection acting on plant defenses, and (3) the relationship between total resistance and leaf trichome density with tolerance to herbivory in the annual herb Datura stramonium. Full-sib families of D. stramonium were either exposed to natural herbivores (control) or protected from them by a systemic insecticide. We detected genetic variance for leaf trichome density, and directional selection acting on this character. However, we did not detect a negative significant correlation between tolerance and total resistance, or between tolerance and leaf trichome density. We argue that low levels of leaf damage by herbivores precluded the detection of a negative genetic correlation between plant defense strategies. Conclusions/Significance. This study provides empirical evidence of the independent evolution of plant defense strategies, and a defensive role of leaf trichomes. The pattern of selection should favor individuals with high trichomes density. Also, because leaf trichome density reduces damage by herbivores and possess genetic variance in the studied population, its evolution is not constrained. PMID:25780756

Urban hopper.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Xavier, Patrick Gordon; Feddema, John Todd; Little, Charles Quentin

2010-03-01

Hopping robots provide the possibility of breaking the link between the size of a ground vehicle and the largest obstacle that it can overcome. For more than a decade, DARPA and Sandia National Laboratories have been developing small-scale hopping robot technology, first as part of purely hopping platforms and, more recently, as part of platforms that are capable of both wheeled and hopping locomotion. In this paper we introduce the Urban Hopper robot and summarize its capabilities. The advantages of hopping for overcoming certain obstacles are discussed. Several configurations of the Urban Hopper are described, as are intelligent capabilities ofmore » the system. Key challenges are discussed.« less

46 CFR 174.320 - Damage survival.

Code of Federal Regulations, 2014 CFR

2014-10-01

... 46 Shipping 7 2014-10-01 2014-10-01 false Damage survival. 174.320 Section 174.320 Shipping COAST... SPECIFIC VESSEL TYPES Hopper Dredges With Working Freeboard Assignments Calculations § 174.320 Damage survival. A hopper dredge survives assumed damage if it meets the following conditions: (a) The maximum...

46 CFR 174.320 - Damage survival.

Code of Federal Regulations, 2012 CFR

2012-10-01

... 46 Shipping 7 2012-10-01 2012-10-01 false Damage survival. 174.320 Section 174.320 Shipping COAST... SPECIFIC VESSEL TYPES Hopper Dredges With Working Freeboard Assignments Calculations § 174.320 Damage survival. A hopper dredge survives assumed damage if it meets the following conditions: (a) The maximum...

46 CFR 174.320 - Damage survival.

Code of Federal Regulations, 2013 CFR

2013-10-01

... 46 Shipping 7 2013-10-01 2013-10-01 false Damage survival. 174.320 Section 174.320 Shipping COAST... SPECIFIC VESSEL TYPES Hopper Dredges With Working Freeboard Assignments Calculations § 174.320 Damage survival. A hopper dredge survives assumed damage if it meets the following conditions: (a) The maximum...

Characterization and mapping of leaf rust resistance in four durum wheat cultivars.

PubMed

Kthiri, Dhouha; Loladze, Alexander; MacLachlan, P R; N'Diaye, Amidou; Walkowiak, Sean; Nilsen, Kirby; Dreisigacker, Susanne; Ammar, Karim; Pozniak, Curtis J

2018-01-01

Widening the genetic basis of leaf rust resistance is a primary objective of the global durum wheat breeding effort at the International Wheat and Maize Improvement Center (CIMMYT). Breeding programs in North America are following suit, especially after the emergence of new races of Puccinia triticina such as BBG/BP and BBBQD in Mexico and the United States, respectively. This study was conducted to characterize and map previously undescribed genes for leaf rust resistance in durum wheat and to develop reliable molecular markers for marker-assisted breeding. Four recombinant inbred line (RIL) mapping populations derived from the resistance sources Amria, Byblos, Geromtel_3 and Tunsyr_2, which were crossed to the susceptible line ATRED #2, were evaluated for their reaction to the Mexican race BBG/BP of P. triticina. Genetic analyses of host reactions indicated that leaf rust resistance in these genotypes was based on major seedling resistance genes. Allelism tests among resistant parents supported that Amria and Byblos carried allelic or closely linked genes. The resistance in Geromtel_3 and Tunsyr_2 also appeared to be allelic. Bulked segregant analysis using the Infinium iSelect 90K single nucleotide polymorphism (SNP) array identified two genomic regions for leaf rust resistance; one on chromosome 6BS for Geromtel_3 and Tunsyr_2 and the other on chromosome 7BL for Amria and Byblos. Polymorphic SNPs identified within these regions were converted to kompetitive allele-specific PCR (KASP) assays and used to genotype the RIL populations. KASP markers usw215 and usw218 were the closest to the resistance genes in Geromtel_3 and Tunsyr_2, while usw260 was closely linked to the resistance genes in Amria and Byblos. DNA sequences associated with these SNP markers were anchored to the wild emmer wheat (WEW) reference sequence, which identified several candidate resistance genes. The molecular markers reported herein will be useful to effectively pyramid these resistance genes with other previously marked genes into adapted, elite durum wheat genotypes.

Characterization and mapping of leaf rust resistance in four durum wheat cultivars

PubMed Central

Kthiri, Dhouha; Loladze, Alexander; MacLachlan, P. R.; N’Diaye, Amidou; Walkowiak, Sean; Nilsen, Kirby; Dreisigacker, Susanne; Ammar, Karim

2018-01-01

Widening the genetic basis of leaf rust resistance is a primary objective of the global durum wheat breeding effort at the International Wheat and Maize Improvement Center (CIMMYT). Breeding programs in North America are following suit, especially after the emergence of new races of Puccinia triticina such as BBG/BP and BBBQD in Mexico and the United States, respectively. This study was conducted to characterize and map previously undescribed genes for leaf rust resistance in durum wheat and to develop reliable molecular markers for marker-assisted breeding. Four recombinant inbred line (RIL) mapping populations derived from the resistance sources Amria, Byblos, Geromtel_3 and Tunsyr_2, which were crossed to the susceptible line ATRED #2, were evaluated for their reaction to the Mexican race BBG/BP of P. triticina. Genetic analyses of host reactions indicated that leaf rust resistance in these genotypes was based on major seedling resistance genes. Allelism tests among resistant parents supported that Amria and Byblos carried allelic or closely linked genes. The resistance in Geromtel_3 and Tunsyr_2 also appeared to be allelic. Bulked segregant analysis using the Infinium iSelect 90K single nucleotide polymorphism (SNP) array identified two genomic regions for leaf rust resistance; one on chromosome 6BS for Geromtel_3 and Tunsyr_2 and the other on chromosome 7BL for Amria and Byblos. Polymorphic SNPs identified within these regions were converted to kompetitive allele-specific PCR (KASP) assays and used to genotype the RIL populations. KASP markers usw215 and usw218 were the closest to the resistance genes in Geromtel_3 and Tunsyr_2, while usw260 was closely linked to the resistance genes in Amria and Byblos. DNA sequences associated with these SNP markers were anchored to the wild emmer wheat (WEW) reference sequence, which identified several candidate resistance genes. The molecular markers reported herein will be useful to effectively pyramid these resistance genes with other previously marked genes into adapted, elite durum wheat genotypes. PMID:29746580

Genome Wide Association Study of Seedling and Adult Plant Leaf Rust Resistance in Elite Spring Wheat Breeding Lines

PubMed Central

Gao, Liangliang; Turner, M. Kathryn; Chao, Shiaoman; Kolmer, James; Anderson, James A.

2016-01-01

Leaf rust is an important disease, threatening wheat production annually. Identification of resistance genes or QTLs for effective field resistance could greatly enhance our ability to breed durably resistant varieties. We applied a genome wide association study (GWAS) approach to identify resistance genes or QTLs in 338 spring wheat breeding lines from public and private sectors that were predominately developed in the Americas. A total of 46 QTLs were identified for field and seedling traits and approximately 20–30 confer field resistance in varying degrees. The 10 QTLs accounting for the most variation in field resistance explained 26–30% of the total variation (depending on traits: percent severity, coefficient of infection or response type). Similarly, the 10 QTLs accounting for most of the variation in seedling resistance to different races explained 24–34% of the variation, after correcting for population structure. Two potentially novel QTLs (QLr.umn-1AL, QLr.umn-4AS) were identified. Identification of novel genes or QTLs and validation of previously identified genes or QTLs for seedling and especially adult plant resistance will enhance understanding of leaf rust resistance and assist breeding for resistant wheat varieties. We also developed computer programs to automate field and seedling rust phenotype data conversions. This is the first GWAS study of leaf rust resistance in elite wheat breeding lines genotyped with high density 90K SNP arrays. PMID:26849364

Development and validation of a breeder-friendly KASPar marker for wheat leaf rust resistance locus Lr21

USDA-ARS?s Scientific Manuscript database

Development and utilization of genetic markers play a pivotal role in marker assisted breeding of wheat cultivars with pyramids of disease resistance genes. The objective of this study is to develop a closed tube, gel-free assay for high throughput genotyping of leaf rust resistance locus Lr21. Poly...

Adult plant leaf rust resistance derived from the soft red winter wheat cultivar Caldwell maps to chromosome 3BS

USDA-ARS?s Scientific Manuscript database

'Caldwell' is a U.S. soft red winter wheat that has partial, adult plant resistance to the leaf rust pathogen Puccinia triticina. A line of 'Thatcher*2/Caldwell' with adult plant resistance derived from Caldwell was crossed with 'Thatcher' to develop a population of recombinant inbred lines (RILs). ...

Lunar, Cislunar, Near/Farside Laser Retroreflectors for the Accurate: Positioning of Landers/Rovers/Hoppers/Orbiters, Commercial Georeferencing, Test of Relativistic Gravity, and Metrics of the Lunar Interior

NASA Astrophysics Data System (ADS)

Dell'Agnello, S.; Currie, D.; Ciocci, E.; Contessa, S.; Delle Monache, G.; March, R.; Martini, M.; Mondaini, C.; Porcelli, L.; Salvatori, L.; Tibuzzi, M.; Bianco, G.; Vittori, R.; Chandler, J.; Murphy, T.; Maiello, M.; Petrassi, M.; Lomastro, A.

2017-10-01

We developed next-generation lunar, cislunar, near/farside laser retroreflectors for the improved/accurate: Positioning of landers/rovers/hoppers/orbiters, commercial georeferencing, test of relativistic gravity, and metrics of the lunar interior.

46 CFR 174.310 - General.

Code of Federal Regulations, 2012 CFR

2012-10-01

... Accommodation spaces 0.95 Consumable liquid tanks 0.00 or 0.95—whichever results in the more disabling condition...: (1) The hoppers are full of seawater; (2) The permeability of flooded spaces is as provided by Table... the calculations required by this section: (1) Dredged spoil in the hopper is a homogeneous liquid...

46 CFR 174.310 - General.

Code of Federal Regulations, 2011 CFR

2011-10-01

... Accommodation spaces 0.95 Consumable liquid tanks 0.00 or 0.95—whichever results in the more disabling condition...: (1) The hoppers are full of seawater; (2) The permeability of flooded spaces is as provided by Table... the calculations required by this section: (1) Dredged spoil in the hopper is a homogeneous liquid...

46 CFR 174.310 - General.

Code of Federal Regulations, 2014 CFR

2014-10-01

... Accommodation spaces 0.95 Consumable liquid tanks 0.00 or 0.95—whichever results in the more disabling condition...: (1) The hoppers are full of seawater; (2) The permeability of flooded spaces is as provided by Table... the calculations required by this section: (1) Dredged spoil in the hopper is a homogeneous liquid...

46 CFR 174.310 - General.

Code of Federal Regulations, 2013 CFR

2013-10-01

... Accommodation spaces 0.95 Consumable liquid tanks 0.00 or 0.95—whichever results in the more disabling condition...: (1) The hoppers are full of seawater; (2) The permeability of flooded spaces is as provided by Table... the calculations required by this section: (1) Dredged spoil in the hopper is a homogeneous liquid...

46 CFR 174.310 - General.

Code of Federal Regulations, 2010 CFR

2010-10-01

... Accommodation spaces 0.95 Consumable liquid tanks 0.00 or 0.95—whichever results in the more disabling condition...: (1) The hoppers are full of seawater; (2) The permeability of flooded spaces is as provided by Table... the calculations required by this section: (1) Dredged spoil in the hopper is a homogeneous liquid...

7 CFR 58.228 - Dump hoppers, screens, mixers and conveyors.

Code of Federal Regulations, 2010 CFR

2010-01-01

... AND STANDARDS UNDER THE AGRICULTURAL MARKETING ACT OF 1946 AND THE EGG PRODUCTS INSPECTION ACT... DAIRY PRODUCTS 1 General Specifications for Dairy Plants Approved for USDA Inspection and Grading Service 1 Equipment and Utensils § 58.228 Dump hoppers, screens, mixers and conveyors. The product contact...

Genome-Wide Association Mapping of Leaf Rust Response in a Durum Wheat Worldwide Germplasm Collection.

PubMed

Aoun, Meriem; Breiland, Matthew; Kathryn Turner, M; Loladze, Alexander; Chao, Shiaoman; Xu, Steven S; Ammar, Karim; Anderson, James A; Kolmer, James A; Acevedo, Maricelis

2016-11-01

Leaf rust (caused by Erikss. []) is increasingly impacting durum wheat ( L. var. ) production with the recent appearance of races with virulence to widely grown cultivars in many durum producing areas worldwide. A highly virulent race on durum wheat was recently detected in Kansas. This race may spread to the northern Great Plains, where most of the US durum wheat is produced. The objective of this study was to identify sources of resistance to several races from the United States and Mexico at seedling stage in the greenhouse and at adult stage in field experiments. Genome-wide association study (GWAS) was used to identify single-nucleotide polymorphism (SNP) markers associated with leaf rust response in a worldwide durum wheat collection of 496 accessions. Thirteen accessions were resistant across all experiments. Association mapping revealed 88 significant SNPs associated with leaf rust response. Of these, 33 SNPs were located on chromosomes 2A and 2B, and 55 SNPs were distributed across all other chromosomes except for 1B and 7B. Twenty markers were associated with leaf rust response at seedling stage, while 68 markers were associated with leaf rust response at adult plant stage. The current study identified a total of 14 previously uncharacterized loci associated with leaf rust response in durum wheat. The discovery of these loci through association mapping (AM) is a significant step in identifying useful sources of resistance that can be used to broaden the relatively narrow leaf rust resistance spectrum in durum wheat germplasm. Copyright © 2016 Crop Science Society of America.

McGISH identification and phenotypic description of leaf rust and yellow rust resistant partial amphiploids originating from a wheat × Thinopyrum synthetic hybrid cross.

PubMed

Kruppa, Klaudia; Türkösi, Edina; Mayer, Marianna; Tóth, Viola; Vida, Gyula; Szakács, Éva; Molnár-Láng, Márta

2016-11-01

A Thinopyrum intermedium × Thinopyrum ponticum synthetic hybrid wheatgrass is an excellent source of leaf and stem rust resistance produced by N.V.Tsitsin. Wheat line Mv9kr1 was crossed with this hybrid (Agropyron glael) in Hungary in order to transfer its advantageous agronomic traits into wheat. As the wheat parent was susceptible to leaf rust, the transfer of resistance was easily recognizable in the progenies. Three different partial amphiploid lines with leaf rust resistance were selected from the wheat/Thinopyrum hybrid derivatives by multicolour genomic in situ hybridization. Chromosome counting on the partial amphiploids revealed 58 chromosomes (18 wheatgrass) in line 194, 56 (14 wheatgrass) in line 195 and 54 (12 wheatgrass) in line 196. The wheat chromosomes present in these lines were identified and the wheatgrass chromosomes were characterized by fluorescence in situ hybridization using the repetitive DNA probes Afa-family, pSc119.2 and pTa71. The 3D wheat chromosome was missing from the lines. Molecular marker analysis showed the presence of the Lr24 leaf rust resistance gene in lines 195 and 196. The morphological traits were evaluated in the field during two consecutive seasons in two different locations.

Mapping quantitative trait loci of resistance to Tomato spotted wilt virus and leaf spots in a recombinant inbred line population of peanut (Arachis hypogae L.) from SunOleic 97R and NC94022

USDA-ARS?s Scientific Manuscript database

Peanut is vulnerable to a range of diseases, such as Tomato spotted wilt virus (TSWV) and leaf spots. The most sustainable and economical solution for managing peanut diseases is development of resistance cultivars. The new breeding line NC94022, high resistance to TSWV and moderate resistance to le...

Using SNP genetic markers to elucidate the linkage of the Co-34/Phg-3 anthracnose and angular leaf spot resistance gene cluster with the Ur-14 resistance gene

USDA-ARS?s Scientific Manuscript database

The Ouro Negro common bean cultivar contains the Co-34/Phg-3 gene cluster that confers resistance to the anthracnose (ANT) and angular leaf spot (ALS) pathogens. These genes are tightly linked on chromosome 4. Ouro Negro also has the Ur-14 rust resistance gene, reportedly in the vicinity of Co- 34; ...

Physical factors affecting the mutagenicity of fly ash from a coal-fired power plant.

PubMed

Fisher, G L; Chrisp, C E; Raabe, O G

1979-05-25

The two finest, most respirable coal fly ash fractions collected from the smokestack of a power plant were more mutagenic than two coarser fractions. Mutagenicity was evaluated in the histidine-requiring bacterial strains TA 1538, TA 98, and TA 100 of Salmonella typhimurium. Ash samples collected from the hoppers of an electrostatic precipitator in the plant were not mutagenic. The mutagens in coal fly ash were resistant to x-ray or ultraviolet irradiation, possibly as a result of stabilization by fly ash surfaces. All mutagenic activity is lost with heating to 350 degrees C.

Prediction and analysis of three gene families related to leaf rust (Puccinia triticina) resistance in wheat (Triticum aestivum L.).

PubMed

Peng, Fred Y; Yang, Rong-Cai

2017-06-20

The resistance to leaf rust (Lr) caused by Puccinia triticina in wheat (Triticum aestivum L.) has been well studied over the past decades with over 70 Lr genes being mapped on different chromosomes and numerous QTLs (quantitative trait loci) being detected or mapped using DNA markers. Such resistance is often divided into race-specific and race-nonspecific resistance. The race-nonspecific resistance can be further divided into resistance to most or all races of the same pathogen and resistance to multiple pathogens. At the molecular level, these three types of resistance may cover across the whole spectrum of pathogen specificities that are controlled by genes encoding different protein families in wheat. The objective of this study is to predict and analyze genes in three such families: NBS-LRR (nucleotide-binding sites and leucine-rich repeats or NLR), START (Steroidogenic Acute Regulatory protein [STaR] related lipid-transfer) and ABC (ATP-Binding Cassette) transporter. The focus of the analysis is on the patterns of relationships between these protein-coding genes within the gene families and QTLs detected for leaf rust resistance. We predicted 526 ABC, 1117 NLR and 144 START genes in the hexaploid wheat genome through a domain analysis of wheat proteome. Of the 1809 SNPs from leaf rust resistance QTLs in seedling and adult stages of wheat, 126 SNPs were found within coding regions of these genes or their neighborhood (5 Kb upstream from transcription start site [TSS] or downstream from transcription termination site [TTS] of the genes). Forty-three of these SNPs for adult resistance and 18 SNPs for seedling resistance reside within coding or neighboring regions of the ABC genes whereas 14 SNPs for adult resistance and 29 SNPs for seedling resistance reside within coding or neighboring regions of the NLR gene. Moreover, we found 17 nonsynonymous SNPs for adult resistance and five SNPs for seedling resistance in the ABC genes, and five nonsynonymous SNPs for adult resistance and six SNPs for seedling resistance in the NLR genes. Most of these coding SNPs were predicted to alter encoded amino acids and such information may serve as a starting point towards more thorough molecular and functional characterization of the designated Lr genes. Using the primer sequences of 99 known non-SNP markers from leaf rust resistance QTLs, we found candidate genes closely linked to these markers, including Lr34 with distances to its two gene-specific markers being 1212 bases (to cssfr1) and 2189 bases (to cssfr2). This study represents a comprehensive analysis of ABC, NLR and START genes in the hexaploid wheat genome and their physical relationships with QTLs for leaf rust resistance at seedling and adult stages. Our analysis suggests that the ABC (and START) genes are more likely to be co-located with QTLs for race-nonspecific, adult resistance whereas the NLR genes are more likely to be co-located with QTLs for race-specific resistance that would be often expressed at the seedling stage. Though our analysis was hampered by inaccurate or unknown physical positions of numerous QTLs due to the incomplete assembly of the complex hexaploid wheat genome that is currently available, the observed associations between (i) QTLs for race-specific resistance and NLR genes and (ii) QTLs for nonspecific resistance and ABC genes will help discover SNP variants for leaf rust resistance at seedling and adult stages. The genes containing nonsynonymous SNPs are promising candidates that can be investigated in future studies as potential new sources of leaf rust resistance in wheat breeding.

Molecular mapping and improvement of leaf rust resistance in wheat breeding lines.

PubMed

Tsilo, Toi J; Kolmer, James A; Anderson, James A

2014-08-01

Leaf rust, caused by Puccinia triticina, is the most common and widespread disease of wheat (Triticum aestivum) worldwide. Deployment of host-plant resistance is one of the strategies to reduce losses due to leaf rust disease. The objective of this study was to map genes for adult-plant resistance to leaf rust in a recombinant inbred line (RIL) population originating from MN98550-5/MN99394-1. The mapping population of 139 RILs and five checks were evaluated in 2005, 2009, and 2010 in five environments. Natural infection occurred in the 2005 trials and trials in 2009 and 2010 were inoculated with leaf rust. Four quantitative trait loci (QTL) on chromosomes 2BS, 2DS, 7AL, and 7DS were detected. The QTL on 2BS explained up to 33.6% of the phenotypic variation in leaf rust response, whereas the QTL on 2DS, 7AL, and 7DS explained up to 15.7, 8.1, and 34.2%, respectively. Seedling infection type tests conducted with P. triticina races BBBD and SBDG confirmed that the QTL on 2BS and 2DS were Lr16 and Lr2a, respectively, and these genes were expressed in the seedling and field plot tests. The Lr2a gene mapped at the same location as Sr6. The QTL on 7DS was Lr34. The QTL on 7AL is a new QTL for leaf rust resistance. The joint effects of all four QTL explained 74% of the total phenotypic variation in leaf rust severity. Analysis of different combinations of QTL showed that the RILs containing all four or three of the QTL had the lowest average leaf rust severity in all five environments. Deployment of these QTL in combination or with other effective genes will lead to successful control of leaf rust.

Complete genome sequence of an isolate of papaya leaf distortion mosaic virus from commercialized PRSV-resistant transgenic papaya in China.

PubMed

Tuo, D; Shen, W; Yan, P; Li, Ch; Gao, L; Li, X; Li, H; Zhou, P

2013-01-01

Papaya leaf distortion mosaic virus is highly destructive to commercial papaya production. Here, the complete genome sequence was determined for an isolate of papaya leaf distortion mosaic virus, designated PLDMV-DF, infecting the commercialized papaya ringspot virus (PRSV)-resistant transgenic papaya from China. Excluding the 3'-poly (A) tail, the sequence shares high sequence identity to several PLDMV isolates from Taiwan and Japan and is phylogenetically most closely related to the isolate from Japan. Infection of PLDMV-DF in transgenic PRSV-resistant papaya may indicate emergence of this disease in genetically engineered plants. The reported sequence for this isolate may help generate bi-transgenic papaya resistant to PRSV and PLDMV.

Spissistilus festinus reovirus: a novel, unassigned species of the family Reoviridae infecting the three-cornered alfalfa hopper

USDA-ARS?s Scientific Manuscript database

A complex set of double stranded RNAs (dsRNA) were isolated from threecornered alfalfa hopper (Spissistilus festinus), a plant-feeding hemipteran insect pest. A subset of these dsRNAs constitute the genome of a novel, unassigned reovirus designated as Spissistilus festinus reovirus (SpFRV). Phylogen...

Microfluidic Bead Suspension Hopper

PubMed Central

2014-01-01

Many high-throughput analytical platforms, from next-generation DNA sequencing to drug discovery, rely on beads as carriers of molecular diversity. Microfluidic systems are ideally suited to handle and analyze such bead libraries with high precision and at minute volume scales; however, the challenge of introducing bead suspensions into devices before they sediment usually confounds microfluidic handling and analysis. We developed a bead suspension hopper that exploits sedimentation to load beads into a microfluidic droplet generator. A suspension hopper continuously delivered synthesis resin beads (17 μm diameter, 112,000 over 2.67 h) functionalized with a photolabile linker and pepstatin A into picoliter-scale droplets of an HIV-1 protease activity assay to model ultraminiaturized compound screening. Likewise, trypsinogen template DNA-coated magnetic beads (2.8 μm diameter, 176,000 over 5.5 h) were loaded into droplets of an in vitro transcription/translation system to model a protein evolution experiment. The suspension hopper should effectively remove any barriers to using suspensions as sample inputs, paving the way for microfluidic automation to replace robotic library distribution. PMID:24761972

Response to perturbations for granular flow in a hopper

NASA Astrophysics Data System (ADS)

Wambaugh, John F.; Behringer, Robert P.; Matthews, John V.; Gremaud, Pierre A.

2007-11-01

We experimentally investigate the response to perturbations of circular symmetry for dense granular flow inside a three-dimensional right-conical hopper. These experiments consist of particle tracking velocimetry for the flow at the outer boundary of the hopper. We are able to test commonly used constitutive relations and observe granular flow phenomena that we can model numerically. Unperturbed conical hopper flow has been described as a radial velocity field with no azimuthal component. Guided by numerical models based upon continuum descriptions, we find experimental evidence for secondary, azimuthal circulation in response to perturbation of the symmetry with respect to gravity by tilting. For small perturbations we can discriminate between constitutive relations, based upon the agreement between the numerical predictions they produce and our experimental results. We find that the secondary circulation can be suppressed as wall friction is varied, also in agreement with numerical predictions. For large tilt angles we observe the abrupt onset of circulation for parameters where circulation was previously suppressed. Finally, we observe that for large tilt angles the fluctuations in velocity grow, independent of the onset of circulation.

Variation in bacterial endosymbionts associated with the date palm hopper, Ommatissus lybicus populations.

PubMed

Karimi, S; Izadi, H; Askari Seyahooei, M; Bagheri, A; Khodaygan, P

2018-04-01

The date palm hopper, Ommatissus lybicus, is a key pest of the date palm, which is expected to be comprised of many allopatric populations. The current study was carried out to determine bacterial endosymbiont diversity in the different populations of this pest. Ten date palm hopper populations were collected from the main date palm growing regions in Iran and an additional four samples from Pakistan, Oman, Egypt and Tunisia for detection of primary and secondary endosymbionts using polymerase chain reaction (PCR) assay with their specific primers. The PCR products were directly sequenced and edited using SeqMan software. The consensus sequences were subjected to a BLAST similarity search. The results revealed the presence of 'Candidatus Sulcia muelleri' (primary endosymbiont) and Wolbachia, Arsenophonus and Enterobacter (secondary endosymbionts) in all populations. This assay failed to detect 'Candidatus Nasuia deltocephalinicola' and Serratia in these populations. 'Ca. S. muelleri' exhibited a 100% infection frequency in populations and Wolbachia, Arsenophonus and Enterobacter demonstrated 100, 93.04 and 97.39% infection frequencies, respectively. The infection rate of Arsenophonus and Enterobacter ranged from 75 to 100% and 62.5 to 100%, respectively, in different populations of the insect. The results demonstrated multiple infections by 'Ca. Sulcia muelleri', Wolbachia, Arsenophonus and Enterobacter in the populations and may suggest significant roles for these endosymbionts on date palm hopper population fitness. This study provides an insight to endosymbiont variation in the date palm hopper populations; however, further investigation is needed to examine how these endosymbionts may affect host fitness.

Relationship between the Al Resistance of Grasses and their Adaptation to an Infertile Habitat

PubMed Central

Poozesh, Vahid; Cruz, Pablo; Choler, Philippe; Bertoni, Georges

2007-01-01

Background and Aims Original data on Al resistance, relative growth rate and leaf traits of five European grasses as well as literature data on Al resistance, habitat preference and traits of grasses were considered to determine whether (a) Al resistance is correlated to a growth conservative strategy and (b) species occurrence could be useful to assess Al toxicity in meadows on acid soils. Methods The Al resistance of 15 species was represented by the Al activity in nutrient solution that resulted in a 50 % decrease in root length, {Al3+}50, or, for published values, in root or plant biomass. The correlations between Al resistance and acidity or nitrogen indices and the correlation between Al resistance and selected traits (relative growth rate, leaf dry matter content, specific leaf area and leaf thickness) were calculated. Principal component analysis was used for the characterization of the relationships between Al resistance and measured traits. Key Results The {Al3+}50 values of the resistant species Molinia caerulea and Sieglingia decumbens were 13 and 26 µm {Al3+}50, respectively. The known Al resistance of 15 species that were mainly of the intermediate strategy competitor–stress tolerator–ruderal (C-S-R) type and of the S type was correlated with Ellenberg's nitrogen and acidity indices. For the whole set of species, the correlation between Al resistance and traits was not significant. Conclusion The Al resistance of the C-S-R species was variable and independent of their traits. S-type species, adapted to acid soils and with traits of conservative strategy, displayed Al resistance. The large difference in Al resistance between grasses may help assess Al soil toxicity by using the abundance of grasses. PMID:17452383

Relationship between the Al resistance of grasses and their adaptation to an infertile habitat.

PubMed

Poozesh, Vahid; Cruz, Pablo; Choler, Philippe; Bertoni, Georges

2007-05-01

Original data on Al resistance, relative growth rate and leaf traits of five European grasses as well as literature data on Al resistance, habitat preference and traits of grasses were considered to determine whether (a) Al resistance is correlated to a growth conservative strategy and (b) species occurrence could be useful to assess Al toxicity in meadows on acid soils. The Al resistance of 15 species was represented by the Al activity in nutrient solution that resulted in a 50 % decrease in root length, [Al(3+)](50), or, for published values, in root or plant biomass. The correlations between Al resistance and acidity or nitrogen indices and the correlation between Al resistance and selected traits (relative growth rate, leaf dry matter content, specific leaf area and leaf thickness) were calculated. Principal component analysis was used for the characterization of the relationships between Al resistance and measured traits. The [Al(3+)](50) values of the resistant species Molinia caerulea and Sieglingia decumbens were 13 and 26 microm [Al(3+)](50), respectively. The known Al resistance of 15 species that were mainly of the intermediate strategy competitor-stress tolerator-ruderal (C-S-R) type and of the S type was correlated with Ellenberg's nitrogen and acidity indices. For the whole set of species, the correlation between Al resistance and traits was not significant. The Al resistance of the C-S-R species was variable and independent of their traits. S-type species, adapted to acid soils and with traits of conservative strategy, displayed Al resistance. The large difference in Al resistance between grasses may help assess Al soil toxicity by using the abundance of grasses.

Heritable, De Novo Resistance to Leaf Rust and Other Novel Traits in Selfed Descendants of Wheat Responding to Inoculation with Wheat Streak Mosaic Virus

PubMed Central

Seifers, Dallas L.; Haber, Steve; Martin, Terry J.; McCallum, Brent D.

2014-01-01

Stable resistance to infection with Wheat streak mosaic virus (WSMV) can be evolved de novo in selfing bread wheat lines subjected to cycles of WSMV inoculation and selection of best-performing plants or tillers. To learn whether this phenomenon might be applied to evolve resistance de novo to pathogens unrelated to WSMV, we examined the responses to leaf rust of succeeding generations of the rust- and WSMV-susceptible cultivar ‘Lakin’ following WSMV inoculation and derived rust-resistant sublines. After three cycles of the iterative protocol five plants, in contrast to all others, expressed resistance to leaf and stripe rust. A subset of descendant sublines of one of these, ‘R1’, heritably and uniformly expressed the new trait of resistance to leaf rust. Such sublines, into which no genes from a known source of resistance had been introgressed, conferred resistance to progeny of crosses with susceptible parents. The F1 populations produced from crosses between, respectively, susceptible and resistant ‘Lakin’ sublines 4-3-3 and 4-12-3 were not all uniform in their response to seedling inoculation with race TDBG. In seedling tests against TDBG and MKPS races the F2s from F1 populations that were uniformly resistant had 3∶1 ratios of resistant to susceptible individuals but the F2s from susceptible F1 progenitors were uniformly susceptible. True-breeding lines derived from resistant individuals in F2 populations were resistant to natural stripe and leaf rust inoculum in the field, while the ‘Lakin’ progenitor was susceptible. The next generation of six of the ‘Lakin’-derived lines exhibited moderate to strong de novo resistance to stem rust races TPMK, QFCS and RKQQ in seedling tests while the ‘Lakin’ progenitor was susceptible. These apparently epigenetic effects in response to virus infection may help researchers fashion a new tool that expands the range of genetic resources already available in adapted germplasm. PMID:24497941

Identification and characterization of pleiotropic and co-located resistance loci to leaf rust and stripe rust in bread wheat cultivar Sujata.

PubMed

Lan, Caixia; Zhang, Yelun; Herrera-Foessel, Sybil A; Basnet, Bhoja R; Huerta-Espino, Julio; Lagudah, Evans S; Singh, Ravi P

2015-03-01

Two new co-located resistance loci, QLr.cim - 1AS/QYr.cim - 1AS and QLr.cim - 7BL/YrSuj , in combination with Lr46 / Yr29 and Lr67/Yr46 , and a new leaf rust resistance quantitative trait loci, conferred high resistance to rusts in adult plant stage. The tall Indian bread wheat cultivar Sujata displays high and low infection types to leaf rust and stripe rust, respectively, at the seedling stage in greenhouse tests. It was also highly resistant to both rusts at adult plant stage in field trials in Mexico. The genetic basis of this resistance was investigated in a population of 148 F5 recombinant inbred lines (RILs) derived from the cross Avocet × Sujata. The parents and RIL population were characterized in field trials for resistance to leaf rust during 2011 at El Batán, and 2012 and 2013 at Ciudad Obregón, Mexico, and for stripe rust during 2011 and 2012 at Toluca, Mexico; they were also characterized three times for stripe rust at seedling stage in the greenhouse. The RILs were genotyped with diversity arrays technology and simple sequence repeat markers. The final genetic map was constructed with 673 polymorphic markers. Inclusive composite interval mapping analysis detected two new significant co-located resistance loci, QLr.cim-1AS/QYr.cim-1AS and QLr.cim-7BL/YrSuj, on chromosomes 1AS and 7BL, respectively. The chromosomal position of QLr.cim-7BL overlapped with the seedling stripe rust resistance gene, temporarily designated as YrSuj. Two previously reported pleiotropic adult plant resistance genes, Lr46/Yr29 and Lr67/Yr46, and a new leaf rust resistance quantitative trait loci derived from Avocet were also mapped in the population. The two new co-located resistance loci are expected to contribute to breeding durable rust resistance in wheat. Closely linked molecular markers can be used to transfer all four resistance loci simultaneously to modern wheat varieties.

Defense Responses in Rice Induced by Silicon Amendment against Infestation by the Leaf Folder Cnaphalocrocis medinalis

PubMed Central

Han, Yongqiang; Li, Pei; Gong, Shaolong; Yang, Lang; Wen, Lizhang; Hou, Maolin

2016-01-01

Silicon (Si) amendment to plants can confer enhanced resistance to herbivores. In the present study, the physiological and cytological mechanisms underlying the enhanced resistance of plants with Si addition were investigated for one of the most destructive rice pests in Asian countries, the rice leaf folder, Cnaphalocrocis medinalis (Guenée). Activities of defense-related enzymes, superoxide dismutase, peroxidase, catalase, phenylalanine ammonia-lyase, and polyphenol oxidase, and concentrations of malondialdehyde and soluble protein in leaves were measured in rice plants with or without leaf folder infestation and with or without Si amendment at 0.32 g Si/kg soil. Silicon amendment significantly reduced leaf folder larval survival. Silicon addition alone did not change activities of defense-related enzymes and malondialdehyde concentration in rice leaves. With leaf folder infestation, activities of the defense-related enzymes increased and malondialdehyde concentration decreased in plants amended with Si. Soluble protein content increased with Si addition when the plants were not infested, but was reduced more in the infested plants with Si amendment than in those without Si addition. Regardless of leaf folder infestation, Si amendment significantly increased leaf Si content through increases in the number and width of silica cells. Our results show that Si addition enhances rice resistance to the leaf folder through priming the feeding stress defense system, reduction in soluble protein content and cell silicification of rice leaves. PMID:27124300

The Mars Hopper: Development, Simulation and Experimental Validation of a Radioisotope Exploration Probe for the Martian Surface

DOE Office of Scientific and Technical Information (OSTI.GOV)

Nathan D. Jerred; Spencer Cooley; Robert C. O'Brien

An advanced exploration probe has been proposed by the Center for Space Nuclear Research (CSNR) to acquire detailed data from the Martian surface and subsurface, ‘hop’ large distances to multiple sites in short periods of time and perform this task repeatedly. Although several similar flying vehicles have been proposed utilizing various power sources and complex designs, e.g. solar-electric and chemical-based, the CSNR’s Mars Hopper is based on a radioisotope thermal rocket (RTR) concept. The Mars Hopper’s design relies on the high specific energies [J/kg] of radioisotopes and enhances their low specific power [W/kg] through the use of a thermal capacitancemore » material to store thermal energy over time. During operation, the RTR transfers the stored thermal energy to a flowing gas, which is then expanded through a converging-diverging nozzle, producing thrust. Between flights, the platform will have ample time to perform in-depth science at each location while the propellant tanks and thermal capacitor recharge. Recharging the propellant tanks is accomplished by sublimation freezing of the ambient CO2 atmosphere with a cryocooler, followed by heating and pressurization to yield a liquid storage state. The proposed Mars Hopper will undergo a ballistic flight, consuming the propellant in both ascent and descent, and by using multiple hopper platforms, information can be gathered on a global scale, enabling better resource resolution and providing valuable information for a possible Mars sample-return mission. The CSNR, collaborating with the Idaho National Laboratory (INL) and three universities (University of Idaho, Utah State University and Oregon State University), has identified key components and sub-systems necessary for the proposed hopper. Current project activities include the development of a lab-scale prototypic Mars Hopper and test facility, along with computational fluid dynamics (CFD)/thermal-hydraulic models to yield a better understanding of the heat transfer process and complex nature of turbulent CO2 flow. Laboratory experimentation will aid design iterations and the development of both tethered and free-flying terrestrial hoppers that utilize an electrically heated core. The knowledge base acquired from these activities will refine the Mars Hopper’s future performance and optimize the RTR core components prior to constructing the final design.« less

3D-Modeling of deformed halite hopper crystals: Object based image analysis and support vector machine, a first evaluation

NASA Astrophysics Data System (ADS)

Leitner, Christoph; Hofmann, Peter; Marschallinger, Robert

2014-05-01

Halite hopper crystals are thought to develop by displacive growth in unconsolidated mud (Gornitz & Schreiber, 1984). The Alpine Haselgebirge, but also e.g. the salt deposits of the Rhine graben (mined at the beginning of the 20th century), comprise hopper crystals with shapes of cuboids, parallelepipeds and rhombohedrons (Görgey, 1912). Obviously, they deformed under oriented stress, which had been tried to reconstruct with respect to the sedimentary layering (Leitner et al., 2013). In the present work, deformed halite hopper crystals embedded in mudrock were automated reconstructed. Object based image analysis (OBIA) has been used successfully in remote sensing for 2D images before. The present study represents the first time that the method was used for reconstruction of three dimensional geological objects. First, manually a reference (gold standard) was created by redrawing contours of the halite crystals on each HRXCT scanning slice. Then, for OBIA, the computer program eCognition was used. For the automated reconstruction a rule set was developed. Thereby, the strength of OBIA was to recognize all objects similar to halite hopper crystals and in particular to eliminate cracks. In a second step, all the objects unsuitable for a structural deformation analysis were dismissed using a support vector machine (SVM) (clusters, polyhalite-coated crystals and spherical halites) The SVM simultaneously drastically reduced the number of halites. From 184 OBIA-objects 67 well shaped remained, which comes close to the number of pre-selected 52 objects. To assess the accuracy of the automated reconstruction, the result before and after SVM was compared to the reference, i.e. the gold standard. State-of the art per-scene statistics were extended to a per-object statistics. Görgey R (1912) Zur Kenntnis der Kalisalzlager von Wittelsheim im Ober-Elsaß. Tschermaks Mineral Petrogr Mitt 31:339-468 Gornitz VM, Schreiber BC (1981) Displacive halite hoppers from the dead sea: Some implications for ancient evaporite deposits. J of Sediment Petrol 51:787-794. doi: 10.1306/212F7DAB-2B24-11D7-8648000102C1865D Leitner C, Neubauer F, Marschallinger R, Genser J, Bernroider M (2013) Origin of deformed halite hopper crystals, pseudomorphic anhydrite cubes and polyhalite in Alpine evaporates (Austria, Germany). Int J Earth Sc 102, pp 813-829, doi: 10.1007/s00531-012-0836-6

Assessing Quantitative Resistance against Leptosphaeria maculans (Phoma Stem Canker) in Brassica napus (Oilseed Rape) in Young Plants

PubMed Central

Huang, Yong-Ju; Qi, Aiming; King, Graham J.; Fitt, Bruce D. L.

2014-01-01

Quantitative resistance against Leptosphaeria maculans in Brassica napus is difficult to assess in young plants due to the long period of symptomless growth of the pathogen from the appearance of leaf lesions to the appearance of canker symptoms on the stem. By using doubled haploid (DH) lines A30 (susceptible) and C119 (with quantitative resistance), quantitative resistance against L. maculans was assessed in young plants in controlled environments at two stages: stage 1, growth of the pathogen along leaf veins/petioles towards the stem by leaf lamina inoculation; stage 2, growth in stem tissues to produce stem canker symptoms by leaf petiole inoculation. Two types of inoculum (ascospores; conidia) and three assessment methods (extent of visible necrosis; symptomless pathogen growth visualised using the GFP reporter gene; amount of pathogen DNA quantified by PCR) were used. In stage 1 assessments, significant differences were observed between lines A30 and C119 in area of leaf lesions, distance grown along veins/petioles assessed by visible necrosis or by viewing GFP and amount of L. maculans DNA in leaf petioles. In stage 2 assessments, significant differences were observed between lines A30 and C119 in severity of stem canker and amount of L. maculans DNA in stem tissues. GFP-labelled L. maculans spread more quickly from the stem cortex to the stem pith in A30 than in C119. Stem canker symptoms were produced more rapidly by using ascospore inoculum than by using conidial inoculum. These results suggest that quantitative resistance against L. maculans in B. napus can be assessed in young plants in controlled conditions. Development of methods to phenotype quantitative resistance against plant pathogens in young plants in controlled environments will help identification of stable quantitative resistance for control of crop diseases. PMID:24454767

Cytogenetic analysis and mapping of leaf rust resistance in Aegilops speltoides Tausch derived bread wheat line Selection2427 carrying putative gametocidal gene(s).

PubMed

Niranjana, M; Vinod; Sharma, J B; Mallick, Niharika; Tomar, S M S; Jha, S K

2017-12-01

Leaf rust (Puccinia triticina) is a major biotic stress affecting wheat yields worldwide. Host-plant resistance is the best method for controlling leaf rust. Aegilops speltoides is a good source of resistance against wheat rusts. To date, five Lr genes, Lr28, Lr35, Lr36, Lr47, and Lr51, have been transferred from Ae. speltoides to bread wheat. In Selection2427, a bread wheat introgresed line with Ae. speltoides as the donor parent, a dominant gene for leaf rust resistance was mapped to the long arm of chromosome 3B (LrS2427). None of the Lr genes introgressed from Ae. speltoides have been mapped to chromosome 3B. Since none of the designated seedling leaf rust resistance genes have been located on chromosome 3B, LrS2427 seems to be a novel gene. Selection2427 showed a unique property typical of gametocidal genes, that when crossed to other bread wheat cultivars, the F 1 showed partial pollen sterility and poor seed setting, whilst Selection2427 showed reasonable male and female fertility. Accidental co-transfer of gametocidal genes with LrS2427 may have occurred in Selection2427. Though LrS2427 did not show any segregation distortion and assorted independently of putative gametocidal gene(s), its utilization will be difficult due to the selfish behavior of gametocidal genes.

75 FR 62560 - Exemption and Equivalent Arrangements Under the International Convention on Load Lines, 1966, as...

Federal Register 2010, 2011, 2012, 2013, 2014

2010-10-12

... equivalent arrangements, as permitted by the ICLL and U.S. regulations, regarding hatch covers for hopper... Guard issued formal notification to the IMO of equivalent arrangements for hatch covers for certain... arrangements for hatch covers for certain manned, self-propelled open hopper dredges on November 12, 2009. We...

49 CFR 231.4 - Fixed-end low-side gondola and low-side hopper cars.

Code of Federal Regulations, 2013 CFR

2013-10-01

... cars. 231.4 Section 231.4 Transportation Other Regulations Relating to Transportation (Continued... Fixed-end low-side gondola and low-side hopper cars. (Cars with sides 36 inches or less above the floor are low-side cars.) (a) Hand brakes—(1) Number. Same as specified for “Box and other house cars” (see...

49 CFR 231.4 - Fixed-end low-side gondola and low-side hopper cars.

Code of Federal Regulations, 2014 CFR

2014-10-01

... cars. 231.4 Section 231.4 Transportation Other Regulations Relating to Transportation (Continued... Fixed-end low-side gondola and low-side hopper cars. (Cars with sides 36 inches or less above the floor are low-side cars.) (a) Hand brakes—(1) Number. Same as specified for “Box and other house cars” (see...

46 CFR 172.110 - Survival conditions.

Code of Federal Regulations, 2010 CFR

2010-10-01

... flooding: (c) A hopper barge must not heel or trim beyond the angle at which— (1) The deck edge is first... section. (d) A hopper barge must not heel beyond the angle at which the deck edge is first submerged by... section, each tank barge must not heel beyond the angle at which— (1) The deck edge is first submerged; or...

46 CFR 172.110 - Survival conditions.

Code of Federal Regulations, 2011 CFR

2011-10-01

... flooding: (c) A hopper barge must not heel or trim beyond the angle at which— (1) The deck edge is first... section. (d) A hopper barge must not heel beyond the angle at which the deck edge is first submerged by... section, each tank barge must not heel beyond the angle at which— (1) The deck edge is first submerged; or...

Preliminary evaluation of feeder and lint slide moisture addition on ginning, fiber quality, and textile processing of western cotton

USDA-ARS?s Scientific Manuscript database

The objective of this study was to evaluate the effects of moisture addition at the gin stand feeder conditioning hopper and/or the battery condenser slide on gin performance and Western cotton fiber quality and textile processing. The test treatments included no moisture addition, feeder hopper hum...

Unjamming a granular hopper by vibration

NASA Astrophysics Data System (ADS)

Janda, A.; Maza, D.; Garcimartín, A.; Kolb, E.; Lanuza, J.; Clément, E.

2009-07-01

We present an experimental study of the outflow of a hopper continuously vibrated by a piezoelectric device. Outpouring of grains can be achieved for apertures much below the usual jamming limit observed for non-vibrated hoppers. Granular flow persists down to the physical limit of one grain diameter, a limit reached for a finite vibration amplitude. For the smaller orifices, we observe an intermittent regime characterized by alternated periods of flow and blockage. Vibrations do not significantly modify the flow rates both in the continuous and the intermittent regime. The analysis of the statistical features of the flowing regime shows that the flow time significantly increases with the vibration amplitude. However, at low vibration amplitude and small orifice sizes, the jamming time distribution displays an anomalous statistics.

Excised leaf method for high volume evaluation of sorghum germplasm for resistance against Colletotrichum sublineolum

USDA-ARS?s Scientific Manuscript database

Foliar phase of anthracnose, caused by Colletotrichum sublineolum is the most important leaf disease of sorghum. Due to the hyper-variable nature of the fungus, continuous evaluation of sorghum germplasm to identify new sources of resistance is imperative. Field and greenhouse evaluations for anth...

Genetic diversity in Gossypium hirsutum L. for cotton leaf curl disease in association with agronomic and fiber traits

USDA-ARS?s Scientific Manuscript database

Information of genetic diversity in germplasm for cotton leaf curl disease (CLCuD) resistance/susceptibility and economic characters is essential before starting a breeding program to development germplasm with disease resistance. In this study, 17 conventional cotton (Gossypium hirsutum L.) genoty...

Cercospora leaf spot: monitoring and managing fungicide resistance in populations of Cercospora beticola in Michigan

USDA-ARS?s Scientific Manuscript database

Cercospora leaf spot (CLS, Cercospora beticola) is the most serious foliar disease of sugarbeet in Michigan and Ontario.Management of CLS depends on timely fungicide applications, disease forecasting prediction models and the use of CLS resistant sugar beet varieties. Fungicides have a dominant role...

Increasing leaf longevity and disease resistance by altering salicylic acid catabolism

DOEpatents

Gan, Susheng; Zhang, Kewei

2018-01-23

The present invention relates to a transgenic plant having an altered level of salicylic acid 3-hydroxylase ("S3H") protein, compared to that of a non-transgenic plant, where the transgenic plant displays an altered leaf senescence phenotype, relative to a non-transgenic plant. The present invention relates to a mutant plant comprising an inactivated gene encoding S3H protein, where the mutant plant displays a premature or precocious leaf senescence phenotype, relative to a non-mutant plant. The present invention also relates to methods for promoting premature or precocious leaf senescence in a plant, delaying leaf senescence in a plant, and making a mutant plant having a decreased level of S3H protein compared to that of a non-mutant plant, where the mutant plant displays a premature or precocious leaf senescence phenotype relative to a non-mutant plant. The present invention also relates to inducing or promoting pathogen resistance in plants.

Linking Xylem Hydraulic Conductivity and Vulnerability to the Leaf Economics Spectrum—A Cross-Species Study of 39 Evergreen and Deciduous Broadleaved Subtropical Tree Species

PubMed Central

Kröber, Wenzel; Zhang, Shouren; Ehmig, Merten; Bruelheide, Helge

2014-01-01

While the fundamental trade-off in leaf traits related to carbon capture as described by the leaf economics spectrum is well-established among plant species, the relationship of the leaf economics spectrum to stem hydraulics is much less known. Since carbon capture and transpiration are coupled, a close connection between leaf traits and stem hydraulics should be expected. We thus asked whether xylem traits that describe drought tolerance and vulnerability to cavitation are linked to particular leaf traits. We assessed xylem vulnerability, using the pressure sleeve technique, and anatomical xylem characteristics in 39 subtropical tree species grown under common garden conditions in the BEF-China experiment and tested for correlations with traits related to the leaf economics spectrum as well as to stomatal control, including maximum stomatal conductance, vapor pressure deficit at maximum stomatal conductance and vapor pressure deficit at which stomatal conductance is down-regulated. Our results revealed that specific xylem hydraulic conductivity and cavitation resistance were closely linked to traits represented in the leaf economic spectrum, in particular to leaf nitrogen concentration, as well as to log leaf area and leaf carbon to nitrogen ratio but not to any parameter of stomatal conductance. The study highlights the potential use of well-known leaf traits from the leaf economics spectrum to predict plant species' drought resistance. PMID:25423316

Linking xylem hydraulic conductivity and vulnerability to the leaf economics spectrum--a cross-species study of 39 evergreen and deciduous broadleaved subtropical tree species.

PubMed

Kröber, Wenzel; Zhang, Shouren; Ehmig, Merten; Bruelheide, Helge

2014-01-01

While the fundamental trade-off in leaf traits related to carbon capture as described by the leaf economics spectrum is well-established among plant species, the relationship of the leaf economics spectrum to stem hydraulics is much less known. Since carbon capture and transpiration are coupled, a close connection between leaf traits and stem hydraulics should be expected. We thus asked whether xylem traits that describe drought tolerance and vulnerability to cavitation are linked to particular leaf traits. We assessed xylem vulnerability, using the pressure sleeve technique, and anatomical xylem characteristics in 39 subtropical tree species grown under common garden conditions in the BEF-China experiment and tested for correlations with traits related to the leaf economics spectrum as well as to stomatal control, including maximum stomatal conductance, vapor pressure deficit at maximum stomatal conductance and vapor pressure deficit at which stomatal conductance is down-regulated. Our results revealed that specific xylem hydraulic conductivity and cavitation resistance were closely linked to traits represented in the leaf economic spectrum, in particular to leaf nitrogen concentration, as well as to log leaf area and leaf carbon to nitrogen ratio but not to any parameter of stomatal conductance. The study highlights the potential use of well-known leaf traits from the leaf economics spectrum to predict plant species' drought resistance.

Unraveling the Effects of Plant Hydraulics on Stomatal Closure during Water Stress in Walnut

PubMed Central

Cochard, Hervé; Coll, Lluis; Le Roux, Xavier; Améglio, Thierry

2002-01-01

The objectives of the study were to identify the relevant hydraulic parameters associated with stomatal regulation during water stress and to test the hypothesis of a stomatal control of xylem embolism in walnut (Juglans regia × nigra) trees. The hydraulic characteristics of the sap pathway were experimentally altered with different methods to alter plant transpiration (Eplant) and stomatal conductance (gs). Potted trees were exposed to a soil water depletion to alter soil water potential (Ψsoil), soil resistance (Rsoil), and root hydraulic resistances (Rroot). Soil temperature was changed to alter Rroot alone. Embolism was created in the trunk to increase shoot resistance (Rshoot). Stomata closed in response to these stresses with the effect of maintaining the water pressure in the leaf rachis xylem (Prachis) above −1.4 MPa and the leaf water potential (Ψleaf) above −1.6 MPa. The same dependence of Eplant and gs on Prachis or Ψleaf was always observed. This suggested that stomata were not responding to changes in Ψsoil, Rsoil, Rroot, or Rshoot per se but rather to their impact on Prachis and/or Ψleaf. Leaf rachis was the most vulnerable organ, with a threshold Prachis for embolism induction of −1.4 MPa. The minimum Ψleaf values corresponded to leaf turgor loss point. This suggested that stomata are responding to leaf water status as determined by transpiration rate and plant hydraulics and that Prachis might be the physiological parameter regulated by stomatal closure during water stress, which would have the effect of preventing extensive developments of cavitation during water stress. PMID:11788773

49 CFR 231.2 - Hopper cars and high-side gondolas with fixed ends.

Code of Federal Regulations, 2014 CFR

2014-10-01

... 49 Transportation 4 2014-10-01 2014-10-01 false Hopper cars and high-side gondolas with fixed ends... cars and high-side gondolas with fixed ends. (Cars with sides more than 36 inches above the floor are high-side cars.) (a) Hand brakes—(1) Number. Same as specified for “Box and other house cars” (see...

49 CFR 231.2 - Hopper cars and high-side gondolas with fixed ends.

Code of Federal Regulations, 2012 CFR

2012-10-01

... 49 Transportation 4 2012-10-01 2012-10-01 false Hopper cars and high-side gondolas with fixed ends... cars and high-side gondolas with fixed ends. (Cars with sides more than 36 inches above the floor are high-side cars.) (a) Hand brakes—(1) Number. Same as specified for “Box and other house cars” (see...

49 CFR 231.2 - Hopper cars and high-side gondolas with fixed ends.

Code of Federal Regulations, 2013 CFR

2013-10-01

... 49 Transportation 4 2013-10-01 2013-10-01 false Hopper cars and high-side gondolas with fixed ends... cars and high-side gondolas with fixed ends. (Cars with sides more than 36 inches above the floor are high-side cars.) (a) Hand brakes—(1) Number. Same as specified for “Box and other house cars” (see...

A Mission Concept: Re-Entry Hopper-Aero-Space-Craft System on-Mars (REARM-Mars)

NASA Technical Reports Server (NTRS)

Davoodi, Faranak

2013-01-01

Future missions to Mars that would need a sophisticated lander, hopper, or rover could benefit from the REARM Architecture. The mission concept REARM Architecture is designed to provide unprecedented capabilities for future Mars exploration missions, including human exploration and possible sample-return missions, as a reusable lander, ascend/descend vehicle, refuelable hopper, multiple-location sample-return collector, laboratory, and a cargo system for assets and humans. These could all be possible by adding just a single customized Re-Entry-Hopper-Aero-Space-Craft System, called REARM-spacecraft, and a docking station at the Martian orbit, called REARM-dock. REARM could dramatically decrease the time and the expense required to launch new exploratory missions on Mars by making them less dependent on Earth and by reusing the assets already designed, built, and sent to Mars. REARM would introduce a new class of Mars exploration missions, which could explore much larger expanses of Mars in a much faster fashion and with much more sophisticated lab instruments. The proposed REARM architecture consists of the following subsystems: REARM-dock, REARM-spacecraft, sky-crane, secure-attached-compartment, sample-return container, agile rover, scalable orbital lab, and on-the-road robotic handymen.

Food powders flowability characterization: theory, methods, and applications.

PubMed

Juliano, Pablo; Barbosa-Cánovas, Gustavo V

2010-01-01

Characterization of food powders flowability is required for predicting powder flow from hoppers in small-scale systems such as vending machines or at the industrial scale from storage silos or bins dispensing into powder mixing systems or packaging machines. This review covers conventional and new methods used to measure flowability in food powders. The method developed by Jenike (1964) for determining hopper outlet diameter and hopper angle has become a standard for the design of bins and is regarded as a standard method to characterize flowability. Moreover, there are a number of shear cells that can be used to determine failure properties defined by Jenike's theory. Other classic methods (compression, angle of repose) and nonconventional methods (Hall flowmeter, Johanson Indicizer, Hosokawa powder tester, tensile strength tester, powder rheometer), used mainly for the characterization of food powder cohesiveness, are described. The effect of some factors preventing flow, such as water content, temperature, time consolidation, particle composition and size distribution, is summarized for the characterization of specific food powders with conventional and other methods. Whereas time-consuming standard methods established for hopper design provide flow properties, there is yet little comparative evidence demonstrating that other rapid methods may provide similar flow prediction.

Investigation of the effect of wall friction on the flow rate in 2D and 3D Granular Flow

NASA Astrophysics Data System (ADS)

Carballo-Ramirez, Brenda; Pleau, Mollie; Easwar, Nalini; Birwa, Sumit; Shah, Neil; Tewari, Shubha

We have measured the mass flow rate of spherical steel spheres under gravity in vertical, straight-walled 2 and 3-dimensional hoppers, where the flow velocity is controlled by the opening size. Our measurements focus on the role of friction and its placement along the walls of the hopper. In the 2D case, an increase in the coefficient of static friction from μ = 0.2 to 0.6 is seen to decrease the flow rate significantly. We have changed the placement of frictional boundaries/regions from the front and back walls of the 2D hopper to the side walls and floor to investigate the relative importance of the different regions in determining the flow rate. Fits to the Beverloo equation show significant departure from the expected exponent of 1.5 in the case of 2D flow. In contrast, 3D flow rates do not show much dependence on wall friction and its placement. We compare the experimental data to numerical simulations of gravity driven hopper granular flow with varying frictional walls constructed using LAMMPS*. *http://lammps.sandia.gov Supported by NSF MRSEC DMR 0820506.

Intercropping for Management of Insect Pests of Castor, Ricinus communis, in the Semi—Arid Tropics of India

PubMed Central

Srinivasa Rao, M.; Venkateswarlu, B.

2012-01-01

Intercropping is one of the important cultural practices in pest management and is based on the principle of reducing insect pests by increasing the diversity of an ecosystem. On—farm experiments were conducted in villages of semi—arid tropical (SAT) India to identify the appropriate combination of castor (Ricinus communis L.) (Malpighiales: Euphorbiaceae) and intercropping in relation to pest incidence. The diversity created by introducing cluster bean, cowpea, black gram, or groundnut as intercrops in castor (1:2 ratio proportions) resulted in reduction of incidence of insect pests, namely semilooper (Achaea janata L.), leaf hopper (Empoasca flavescens Fabricius), and shoot and capsule borer (Conogethes punctiferalis Guenee). A buildup of natural enemies (Microplitis, coccinellids, and spiders) of the major pests of castor was also observed in these intercropping systems and resulted in the reduction of insect pests. Further, these systems were more efficient agronomically and economically, and were thus more profitable than a castor monocrop. PMID:22934569

Red leaf lettuce breeding line with resistance to corky root, 06-810

USDA-ARS?s Scientific Manuscript database

The Agricultural Research Service, United States Department of Agriculture (USDA) announces the release of a breeding line of red leaf lettuce (Lactuca sativa L.), 06-810. The line may be suitable for commercial production, and is suitable for use as a source of resistance to corky root disease in t...

The genetics of leaf flecking in maize and its relationship to plant defense and disease resistance

USDA-ARS?s Scientific Manuscript database

Physiological/genetic leaf spotting, or flecking, is a mild lesion phenotype observed on the leaves of several commonly used maize inbred lines and has been anecdotally linked to enhanced broad-spectrum disease resistance. Flecking was assessed in the maize nested association mapping (NAM) populati...

Continuous pressure letdown system

DOEpatents

Sprouse, Kenneth M.; Matthews, David R.; Langowski, Terry

2010-06-08

A continuous pressure letdown system connected to a hopper decreases a pressure of a 2-phase (gas and solid) dusty gas stream flowing through the system. The system includes a discharge line for receiving the dusty gas from the hopper, a valve, a cascade nozzle assembly positioned downstream of the discharge line, a purge ring, an inert gas supply connected to the purge ring, an inert gas throttle, and a filter. The valve connects the hopper to the discharge line and controls introduction of the dusty gas stream into the discharge line. The purge ring is connected between the discharge line and the cascade nozzle assembly. The inert gas throttle controls a flow rate of an inert gas into the cascade nozzle assembly. The filter is connected downstream of the cascade nozzle assembly.

Development of transgenic finger millet (Eleusine coracana (L.) Gaertn.) resistant to leaf blast disease.

PubMed

Ignacimuthu, S; Ceasar, S Antony

2012-03-01

Finger millet plants conferring resistance to leaf blast disease have been developed by inserting a rice chitinase (chi11) gene through Agrobacterium-mediated transformation. Plasmid pHyg-Chi.11 harbouring the rice chitinase gene under the control of maize ubiquitin promoter was introduced into finger millet using Agrobacterium strain LBA4404 (pSB1). Transformed plants were selected and regenerated on hygromycin-supplemented medium. Transient expression of transgene was confirmed by GUS histochemical staining. The incorporation of rice chitinase gene in R0 and R1 progenies was confirmed by PCR and Southern blot analyses. Expression of chitinase gene in finger millet was confirmed by Western blot analysis with a barley chitinase antibody. A leaf blast assay was also performed by challenging the transgenic plants with spores of Pyricularia grisea. The frequency of transient expression was 16.3% to 19.3%. Stable frequency was 3.5% to 3.9%. Southern blot analysis confirmed the integration of 3.1 kb chitinase gene. Western blot analysis detected the presence of 35 kDa chitinase enzyme. Chitinase activity ranged from 19.4 to 24.8. In segregation analysis, the transgenic R1 lines produced three resistant and one sensitive for hygromycin, confirming the normal Mendelian pattern of transgene segregation. Transgenic plants showed high level of resistance to leaf blast disease compared to control plants. This is the first study reporting the introduction of rice chitinase gene into finger millet for leaf blast resistance.

Host Plant Resistance and Insect Pest Management in Chickpea

USDA-ARS?s Scientific Manuscript database

Nearly 60 insect species feed on chickpea worldwide, of which cutworms (black cutworm - Agrotis ipsilon and turnip moth - Agrotis segetum), leaf feeding caterpillars (leaf caterpillar - Spodoptera exigua and hairy caterpillar - Spilarctia oblique), leaf miners (Liriomyza cicerina), aphids (Aphis cr...

30. HULETT NO. 2 IN MOTION; OPERATOR HAS JUST DUMPED ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

30. HULETT NO. 2 IN MOTION; OPERATOR HAS JUST DUMPED A GRAB BUCKET OF ORE INTO THE RECEIVING HOPPER AND IS READY TO RETURN FOR ANOTHER LOAD. A ROUND TRIP FROM THE BOAT TO THE HOPPER AND BACK CAN BE MADE IN 50 SECONDS. - Pennsylvania Railway Ore Dock, Lake Erie at Whiskey Island, approximately 1.5 miles west of Public Square, Cleveland, Cuyahoga County, OH

The inheritance of resistance to bacterial leaf spot of lettuce caused by Xanthomonas campestris pv. vitians in three lettuce cultivars

USDA-ARS?s Scientific Manuscript database

Lettuce yields can be reduced by the disease bacterial leaf spot (BLS) caused by the pathogen Xanthomonas campestris pv. vitians (Xcv) and host resistance is the most feasible method to reduce disease losses. The cultivars La Brillante, Pavane, and Little Gem express an incompatible host-pathogen in...

MU06-857, a Green Leaf Lettuce Breeding Line with Resistance to Leafminer and Lettuce Mosaic Virus.

USDA-ARS?s Scientific Manuscript database

The Agricultural Research Service, United States Department of Agriculture announces the release of a breeding line of green leaf lettuce (Lactuca sativa L.) with resistance to leafminers (Liriomyza langei Frick) and lettuce mosaic. The line MU06-857 is similar to cultivar ‘Lolla Rossa’ (‘Lollo Ros...

Field evaluation of leaf blight-resistant plant introductions of Brassica Juncea and Brassica Rapa and elucidation of inheritance of resistance

USDA-ARS?s Scientific Manuscript database

Brassica leafy greens (Brassica juncea and Brassica rapa) represent one of the most economically important vegetable crop groups in the southeastern United States. In the last 10 years, numerous occurrences of a leaf blight disease on these leafy vegetables have been reported in several states. One ...

Detection of gene expression changes in Capsicum annuum L. leaf foliar blight caused by Phytophthora capsici Leon. using qRT-PCR and leaf discs

USDA-ARS?s Scientific Manuscript database

Phytophthora capsici is responsible for multiple disease syndromes of Capsicum annuum but the resistance mechanism is still unknown. Evaluating gene expression during foliar blight can be used to identify expression patterns associated with resistance in Capsicum species. This study reports a direct...

Competition studies of QoI resistant and sensitive Cercospora sojina isolates the causal agent of frogeye leaf spot

USDA-ARS?s Scientific Manuscript database

Frogeye leaf spot (FLS), caused by Cercospora sojina, is a yearly foliar disease in Tennessee and causes substantial economic losses if not properly managed. Quinone outside inhibitor (QoI) fungicides are often used to manage FLS, but C. sojina isolates have developed resistance to this class of fun...

Association analysis and identification of SNP markers for Stemphylium leaf spot (Stemphylium botryosum f. sp. spinacia) resistance in spinach (Spinacia oleracea)

USDA-ARS?s Scientific Manuscript database

Stemphylium leaf spot, caused by Stemphylium botryosum f. sp. spinacia is an important disease in spinach. Use of genetic resistance is an efficient, economic and environment-friendly method to control this disease. The objective of this research was to conduct association analysis and identify SNP ...

Identification of Teosinte (Zea mays ssp. parviglumis) alleles for resistance to southern leaf blight in near isogenic maize lines

USDA-ARS?s Scientific Manuscript database

Southern Leaf Blight [(SLB), causal agent Cochliobolus heterostrophus race O] is an important fungal disease of maize in the United States. Teosinte (Zea mays ssp. parviglumis), the wild progenitor of maize, offers a novel source of resistance alleles that may have been lost during domestication. T...

Identification of alleles conferring resistance to gray leaf spot in maize derived from its wild progenitor species teosinte (Zea mays ssp. parviglumis)

USDA-ARS?s Scientific Manuscript database

Gray Leaf Spot [(GLS), causal agent Cercospora zeae-maydis and Cercospora zeina] is an important maize disease in the United States. Current control methods for GLS include using resistant cultivars, crop rotation, chemical applications, and conventional tillage to reduce inoculum levels. Teosinte ...

Somaclonal variation in hybrid poplars for resistance to Septoria leaf spot

Treesearch

M.E. Ostry; D. D. Skilling

1987-01-01

Tissue culture techniques have been used to obtain hybrid poplars with putative resistance to leaf spot caused by Septoria musiva from clones previously susceptible to the disease. Stem internode explants were used to obtain proliferating callus cultures. Adventitious bud formation and shoot proliferation were then induced. Elongated shoots were excised and rooted in a...

Association analysis of bacterial leaf spot resistance and SNP markers derived from expressed sequence tags (ESTs) in lettuce (Lactuca sativa L.)

USDA-ARS?s Scientific Manuscript database

Bacterial leaf spot of lettuce, caused by Xanthomonas campestris pv. vitians, is a devastating disease of lettuce worldwide. Since there are no chemicals available for effective control of the disease, host-plant resistance is highly desirable to protect lettuce production. A total of 179 lettuce ge...

The Mars Hopper: a radioisotope powered, impulse driven, long-range, long-lived mobile platform for exploration of Mars

DOE Office of Scientific and Technical Information (OSTI.GOV)

Steven D. Howe; Robert C. O'Brien; William Taitano

Planetary exploration mission requirements are becoming more demanding. Due to the increasing cost, the missions that provide mobile platforms that can acquire data at multiple locations are becoming more attractive. Wheeled vehicles such as the MER rovers have proven extremely capable but have very limited range and cannot traverse rugged terrain. Flying vehicles such as balloons and airplanes have been proposed but are problematic due to the very thin atmospheric pressure and the strong, dusty winds present on Mars. The Center for Space Nuclear Research has designed an instrumented platform that can acquire detailed data at hundreds of locations duringmore » its lifetime - a Mars Hopper. The Mars Hopper concept utilizes energy from radioisotopic decay in a manner different from any existing radioisotopic power sources—as a thermal capacitor. By accumulating the heat from radioisotopic decay for long periods, the power of the source can be dramatically increased for short periods. The platform will be able to "hop" from one location to the next every 5-7 days with a separation of 5-10 km per hop. Preliminary designs show a platform that weighs around 52 kgs unfueled which is the condition at deployment. Consequently, several platforms may be deployed on a single launch from Earth. With sufficient lifetime, the entire surface of Mars can be mapped in detail by a couple dozen platforms. In addition, Hoppers can collect samples from all over the planet, including gorges, mountains and crevasses, and deliver them to a central location for eventual pick-up by a Mars Sample Return mission. The status of the Mars Hopper development project at the CSNR is discussed.« less

Fine mapping of a quantitative resistance gene for gray leaf spot of maize (Zea mays L.) derived from teosinte (Z. mays ssp. parviglumis).

PubMed

Zhang, Xinye; Yang, Qin; Rucker, Elizabeth; Thomason, Wade; Balint-Kurti, Peter

2017-06-01

In this study we mapped the QTL Qgls8 for gray leaf spot (GLS) resistance in maize to a ~130 kb region on chromosome 8 including five predicted genes. In previous work, using near isogenic line (NIL) populations in which segments of the teosinte (Zea mays ssp. parviglumis) genome had been introgressed into the background of the maize line B73, we had identified a QTL on chromosome 8, here called Qgls8, for gray leaf spot (GLS) resistance. We identified alternate teosinte alleles at this QTL, one conferring increased GLS resistance and one increased susceptibility relative to the B73 allele. Using segregating populations derived from NIL parents carrying these contrasting alleles, we were able to delimit the QTL region to a ~130 kb (based on the B73 genome) which encompassed five predicted genes.

Scientific exploration of low-gravity planetary bodies using the Highland Terrain Hopper

NASA Astrophysics Data System (ADS)

Mège, D.; Grygorczuk, J.; Gurgurewicz, J.; Wiśniewski, Ł.; Rickman, H.; Banaszkiewicz, M.; Kuciński, T.; Skocki, K.

2013-09-01

Field geoscientists need to collect three-dimensional data in order characterise the lithologic succession and structure of terrains, recontruct their evolution, and eventually reveal the history of a portion of the planet. This is achieved by walking up and down mountains and valleys, interpreting geological and geophysical traverses, and reading measures made at station located at key sites on mountain peaks or rocky promontories. These activities have been denied to conventional planetary exploration rovers because engineering constraints for landing are strong, especially in terms of allowed terrain roughness and slopes. The Highland Terrain Hopper, a new, light and robust locomotion system, addresses the challenge of accessing most areas on low-gravity planetary body for performing scientific observations and measurements, alone or as part of a hopper commando. Examples of geological applications on Mars and the Moon are given.

Anatomical variation of mesophyll conductance under potassium deficiency has a vital role in determining leaf photosynthesis.

PubMed

Lu, Zhifeng; Lu, Jianwei; Pan, Yonghui; Lu, Piaopiao; Li, Xiaokun; Cong, Rihuan; Ren, Tao

2016-11-01

Leaves exposed to potassium (K) deficiency usually present decreased mesophyll conductance (g m ) and photosynthesis (A). The relative contributions of leaf anatomical traits in determining g m have been quantified; however, anatomical variabilities related to low g m under K starvation remain imperfectly known. A one-dimensional model was used to quantify anatomical controls of the entire CO 2 diffusion pathway resistance within a leaf on two Brassica napus L. cultivars in response to K deficiency. Leaf photosynthesis of both cultivars was significantly decreased under K deficiency in parallel with down-regulated g m . The mesophyll conductance limitation contributed to more than one-half of A decline. The decreased internal air space in K-starved leaves was associated with the increase of gas-phase resistance. Potassium deficiency reduced liquid-phase conductance by decreasing the exposed surface area of chloroplasts per unit leaf area (S c /S), and enlarging the resistance of the cytoplasm that can be interpreted by the increasing distance of chloroplast from cell wall, and between adjacent chloroplasts. Additionally, the discrepancies of A between two cultivars were in part because of g m variations, ascribing to an altered S c /S. These results emphasize the important role of K on the regulation of g m by enhancing S c /S and reducing cytoplasm resistance. © 2016 John Wiley & Sons Ltd.

Detection of food-borne bacteria in ready to eat betel leaf sold at local markets in Mymensingh.

PubMed

Haque, Md Mazedul; Sarker, Md Atiqur Rahman; Rifa, Rafia Afroze; Islam, Md Ariful; Khatun, Mst Minara

2017-09-01

The present study was undertaken to determine bacterial load as well as characterize bacterial flora of ready to eat (RTE) betel leaf sold at local markets in Mymensingh city. A total of 25 RTE betel leaf samples were collected from five local markets such as Kamal-Ranjit (KR) market, Shesh more, Kewatkhali, Jobber more, and Ganginar par. Total viable count of bacteria in betel leaf (log 10 mean colony forming unit±standard deviation/ml) was 7.58±0.04 for KR market, 7.72±0.06 for Shesh more, 7.62±0.04 for Kewatkhali, 7.40±0.03 for Jobber more, and 7.60±0.06 for Ganginar par. A total of 98 bacterial isolates belong to five genera ( Escherichia coli , Salmonella spp., Vibrio spp., Bacillus spp., and Staphylococcus spp.) were identified. The prevalence of E. coli was 17.34%, Salmonella spp. was 25.51%, Vibrio spp. was 19.39%, Bacillus spp. was 18.37%, and Staphylococcus spp. was 19.39%. Antibiotic sensitivity test showed that all isolates were sensitive to two antibiotics such as ciprofloxacin and gentamicin. Four isolates ( E. coli , Salmonella spp., Vibrio spp., and Staphylococcus spp.) were resistant to two antibiotics (ampicillin and cephalexin). Antibiogram profile of bacterial isolates of betel leaf suggests that they were multidrug resistance. Data of this study indicate that betel leaf sold at local market harbors multidrug resistance food-borne bacteria which might cause public health hazards if these antibiotic resistant transfer to human through food chain.

Detection of food-borne bacteria in ready to eat betel leaf sold at local markets in Mymensingh

PubMed Central

Haque, Md. Mazedul; Sarker, Md. Atiqur Rahman; Rifa, Rafia Afroze; Islam, Md. Ariful; Khatun, Mst. Minara

2017-01-01

Aim: The present study was undertaken to determine bacterial load as well as characterize bacterial flora of ready to eat (RTE) betel leaf sold at local markets in Mymensingh city. Materials and Methods: A total of 25 RTE betel leaf samples were collected from five local markets such as Kamal-Ranjit (KR) market, Shesh more, Kewatkhali, Jobber more, and Ganginar par. Results: Total viable count of bacteria in betel leaf (log10 mean colony forming unit±standard deviation/ml) was 7.58±0.04 for KR market, 7.72±0.06 for Shesh more, 7.62±0.04 for Kewatkhali, 7.40±0.03 for Jobber more, and 7.60±0.06 for Ganginar par. A total of 98 bacterial isolates belong to five genera (Escherichia coli, Salmonella spp., Vibrio spp., Bacillus spp., and Staphylococcus spp.) were identified. The prevalence of E. coli was 17.34%, Salmonella spp. was 25.51%, Vibrio spp. was 19.39%, Bacillus spp. was 18.37%, and Staphylococcus spp. was 19.39%. Antibiotic sensitivity test showed that all isolates were sensitive to two antibiotics such as ciprofloxacin and gentamicin. Four isolates (E. coli, Salmonella spp., Vibrio spp., and Staphylococcus spp.) were resistant to two antibiotics (ampicillin and cephalexin). Antibiogram profile of bacterial isolates of betel leaf suggests that they were multidrug resistance. Conclusion: Data of this study indicate that betel leaf sold at local market harbors multidrug resistance food-borne bacteria which might cause public health hazards if these antibiotic resistant transfer to human through food chain. PMID:29062191

Microscopic and Molecular Characterization of the Prehaustorial Resistance against Wheat Leaf Rust (Puccinia triticina) in Einkorn (Triticum monococcum)

PubMed Central

Serfling, Albrecht; Templer, Sven E.; Winter, Peter; Ordon, Frank

2016-01-01

Puccinia triticina f. sp. tritici (Eriks.), the causal agent of leaf rust, causes substantial yield losses in wheat production. In wheat many major leaf rust resistance genes have been overcome by virulent races. In contrast, the prehaustorial resistance (phr) against wheat leaf rust detected in the diploid wheat Einkorn (Triticum monoccocum var. monococcum) accession PI272560 confers race-independent resistance against isolates virulent on accessions harboring resistance genes located on the A-genome of Triticum aestivum. Phr in PI272560 leads to abortion of fungal development during the formation of haustorial mother cells and to increased hydrogen peroxide concentration in comparison to the susceptible accession 36554 (Triticum boeoticum ssp. thaoudar var. reuteri). Increased peroxidase and endochitinase activity was detected in PI272560 within 6 h after inoculation (hai). Comparative transcriptome profiling using Massive Analysis of cDNA Ends (MACE) in infected and non-infected leaves detected 14220 differentially expressed tags in PI272560 and 15472 in accession 36554. Of these 2908 and 3004, respectively, could be assigned to Gene Ontology (GO) categories of which 463 were detected in both accessions and 311 were differentially expressed between the accessions. In accordance with the concept of non-host resistance in PI272560, genes with similarity to peroxidases, chitinases, β-1,3-glucanases and other pathogenesis-related genes were up-regulated within the first 8 hai, whereas up-regulation of such genes was delayed in 36554. Moreover, a Phosphoribulokinase gene contributing to non-host resistance in rice against stripe rust was exclusively expressed in the resistant accession PI272560. Gene expression underpinned physiological and phenotypic observations at the site of infection and are in accordance with the concept of non-host resistance. PMID:27881987

1913 Richardson Scales in 1913 head house, looking east. The ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

1913 Richardson Scales in 1913 head house, looking east. The balance beam on the right side of the photograph is for the west hopper scale. To the left and right are two discharge charges from the hopper scales. On the left is an auger that fills the bins. In the background is the grain cleaner. - Stewart Company Grain Elevator, 16 West Carson Street, Pittsburgh, Allegheny County, PA

Rotary bulk solids divider

DOEpatents

Maronde, Carl P.; Killmeyer, Jr., Richard P.

1992-01-01

An apparatus for the disbursement of a bulk solid sample comprising, a gravity hopper having a top open end and a bottom discharge end, a feeder positioned beneath the gravity hopper so as to receive a bulk solid sample flowing from the bottom discharge end, and a conveyor receiving the bulk solid sample from the feeder and rotating on an axis that allows the bulk solid sample to disperse the sample to a collection station.

ROTARY BULK SOLIDS DIVIDER

DOEpatents

Maronde, Carl P.; Killmeyer JR., Richard P.

1992-03-03

An apparatus for the disbursement of a bulk solid sample comprising, a gravity hopper having a top open end and a bottom discharge end, a feeder positioned beneath the gravity hopper so as to receive a bulk solid sample flowing from the bottom discharge end, and a conveyor receiving the bulk solid sample from the feeder and rotating on an axis that allows the bulk solid sample to disperse the sample to a collection station.

Development of the Variable Atmosphere Testing Facility for Blow-Down Analysis of the Mars Hopper Prototype

DOE Office of Scientific and Technical Information (OSTI.GOV)

Nathan D. Jerred; Robert C. O'Brien; Steven D. Howe

Recent developments at the Center for Space Nuclear Research (CSNR) on a Martian exploration probe have lead to the assembly of a multi-functional variable atmosphere testing facility (VATF). The VATF has been assembled to perform transient blow-down analysis of a radioisotope thermal rocket (RTR) concept that has been proposed for the Mars Hopper; a long-lived, long-ranged mobile platform for the Martian surface. This study discusses the current state of the VATF as well as recent blow-down testing performed on a laboratory-scale prototype of the Mars Hopper. The VATF allows for the simulation of Mars ambient conditions within the pressure vesselmore » as well as to safely perform blow-down tests through the prototype using CO2 gas; the proposed propellant for the Mars Hopper. Empirical data gathered will lead to a better understanding of CO2 behavior and will provide validation of simulation models. Additionally, the potential of the VATF to test varying propulsion system designs has been recognized. In addition to being able to simulate varying atmospheres and blow-down gases for the RTR, it can be fitted to perform high temperature hydrogen testing of fuel elements for nuclear thermal propulsion.« less

Coconut leaf bioactivity toward generalist maize insect pests

USDA-ARS?s Scientific Manuscript database

Tropical plants are often more resistant to insects than temperate plants due to evolution of robust defenses to cope with a more constant insect threat. Coconut (Cocos nucifera L.) has very few chewing leaf feeding insect pests and was tested against two omnivorous leaf feeding caterpillar species,...

Early detection of crop injury from herbicide glyphosate by leaf biochemical parameter inversion

USDA-ARS?s Scientific Manuscript database

Early detection of crop injury from glyphosate is of significant importance in crop management. In this paper, we attempt to detect glyphosate-induced crop injury by PROSPECT (leaf optical PROperty SPECTra model) inversion through leaf hyperspectral reflectance measurements for non-Glyphosate-Resist...

Hydraulic resistance components of mature apple trees on rootstocks of different vigours.

PubMed

Cohen, Shabtai; Naor, Amos; Bennink, John; Grava, Avraham; Tyree, Melvin

2007-01-01

Dwarfing of fruit trees is often achieved through the use of dwarfing rootstocks. Dwarf trees are characterized by sustained reductions in vegetative growth during the lifetime of the tree. The dwarfing mechanism is not well understood, but it has been hypothesized that hydraulic properties of the rootstock and the graft union are involved. It is hypothesized here that leaf- or stem-specific resistance of at least one hydraulic component of the water transport system would be negatively correlated with rootstock 'vigour', and this could be useful for selection of rootstocks. Hydraulic resistance (R) of fully grown apple trees on a variety of rootstocks of different 'vigours' was measured. Most measurements were with the evaporative flux (EF) method, where water uptake measured with sap flow sensors was related to the pressure gradient from soil (taken as pre-dawn leaf) and midday root (taken as covered root-sucker), stem (from covered leaf), and exposed and shaded leaf water potentials (Psi(l)). R of trees on dwarfing M9 rootstock was compared with that of more vigorous MM106 and MM111 rootstocks in Israel and Vermont, USA. In Israel, M9 consistently had higher leaf-specific hydraulic resistance (R(l)) in the soil to scion stem pathway, but this difference was only significant for one summer. R was larger in M9 between the root and stem, implicating the graft union as the site of increased resistance. In Vermont, R(l) of 9- and 10-year-old trees on six rootstocks of various vigours was not consistently related to vigour, and stem-specific resistance (R(s)) increased with increasing vigour. High pressure flow meter (HPFM) measurements gave a lower R than the EF method in all but one case, perhaps indicating a significant amount of xylem dysfunction in these trees, and demonstrated the increased resistivity of stem sections that included dwarf graft unions as compared with non-graft stem sections. It is concluded that stem- and leaf-specific R are not consistently positively correlated with dwarfing, although the increased resistivity of the graft union in dwarfing rootstocks may influence the transport of water and other elements across the graft union, and therefore be involved in the dwarfing mechanism.

Measurement of leaf hydraulic conductance and stomatal conductance and their responses to irradiance and dehydration using the Evaporative Flux Method (EFM).

PubMed

Sack, Lawren; Scoffoni, Christine

2012-12-31

Water is a key resource, and the plant water transport system sets limits on maximum growth and drought tolerance. When plants open their stomata to achieve a high stomatal conductance (gs) to capture CO2 for photosynthesis, water is lost by transpiration(1,2). Water evaporating from the airspaces is replaced from cell walls, in turn drawing water from the xylem of leaf veins, in turn drawing from xylem in the stems and roots. As water is pulled through the system, it experiences hydraulic resistance, creating tension throughout the system and a low leaf water potential (Ψ(leaf)). The leaf itself is a critical bottleneck in the whole plant system, accounting for on average 30% of the plant hydraulic resistance(3). Leaf hydraulic conductance (K(leaf) = 1/ leaf hydraulic resistance) is the ratio of the water flow rate to the water potential gradient across the leaf, and summarizes the behavior of a complex system: water moves through the petiole and through several orders of veins, exits into the bundle sheath and passes through or around mesophyll cells before evaporating into the airspace and being transpired from the stomata. K(leaf) is of strong interest as an important physiological trait to compare species, quantifying the effectiveness of the leaf structure and physiology for water transport, and a key variable to investigate for its relationship to variation in structure (e.g., in leaf venation architecture) and its impacts on photosynthetic gas exchange. Further, K(leaf) responds strongly to the internal and external leaf environment(3). K(leaf) can increase dramatically with irradiance apparently due to changes in the expression and activation of aquaporins, the proteins involved in water transport through membranes(4), and K(leaf) declines strongly during drought, due to cavitation and/or collapse of xylem conduits, and/or loss of permeability in the extra-xylem tissues due to mesophyll and bundle sheath cell shrinkage or aquaporin deactivation(5-10). Because K(leaf) can constrain gs and photosynthetic rate across species in well watered conditions and during drought, and thus limit whole-plant performance they may possibly determine species distributions especially as droughts increase in frequency and severity(11-14). We present a simple method for simultaneous determination of K(leaf) and gs on excised leaves. A transpiring leaf is connected by its petiole to tubing running to a water source on a balance. The loss of water from the balance is recorded to calculate the flow rate through the leaf. When steady state transpiration (E, mmol • m(-2) • s(-1)) is reached, gs is determined by dividing by vapor pressure deficit, and K(leaf) by dividing by the water potential driving force determined using a pressure chamber (K(leaf)= E /- Δψ(leaf), MPa)(15). This method can be used to assess K(leaf) responses to different irradiances and the vulnerability of K(leaf) to dehydration(14,16,17).

Genotyping-by-sequencing to re-map QTL for type II Fusarium head blight and leaf rust resistance in a wheat-tall wheatgrass introgression recombinant inbred population

USDA-ARS?s Scientific Manuscript database

Fusarium graminaerum (Fusarium head blight; FHB) and Puccinia recondita Roberge ex Desmaz. f. sp. tritici Eriks. & E. Henn (leaf rust; LR) are two major fungal pathogens threatening the wheat crop; consequently identifying resistance genes from various sources is always of importance to wheat breede...

High-density genetic map using whole-genome re-sequencing for fine mapping and candidate gene discovery for disease resistance in peanut

USDA-ARS?s Scientific Manuscript database

High-density genetic linkage maps are essential for fine mapping QTLs controlling disease resistance traits, such as early leaf spot (ELS), late leaf spot (LLS), and Tomato spotted wilt virus (TSWV). With completion of the genome sequences of two diploid ancestors of cultivated peanut, we could use ...

Multiple begomoviruses found associated with cotton leaf curl disease in Pakistan in early 1990 are back in cultivated cotton

USDA-ARS?s Scientific Manuscript database

The first epidemic of cotton leaf curl disease (CLCuD) in the early 1990’s on the Indian subcontinent was associated with several distinct begomoviruses along with a disease-specific betasatellite. Resistant cotton varieties were introduced in the late 1990’s, but resistance was broken in early 2000...

Fitness and competition studies of QoI resistant and sensitive Cercospora sojina isolates, the causal agent of frogeye leaf spot

USDA-ARS?s Scientific Manuscript database

Frogeye leaf spot (FLS), caused by Cercospora sojina, is a yearly foliar disease of soybean in Tennessee and causes substantial economic losses if not properly managed. Quinone outside inhibitor (QoI) fungicides are often used to manage FLS, but C. sojina isolates have developed resistance to this c...

Effects of hirami lemon, Citrus depressa Hayata, leaf meal in diets on the immune response and disease resistance of juvenile barramundi, Lates calcarifer (bloch), against Aeromonas hydrophila.

PubMed

Shiu, Ya-Li; Lin, Hsueh-Li; Chi, Chia-Chun; Yeh, Shinn-Pyng; Liu, Chun-Hung

2016-08-01

The present study was conducted to evaluate the dietary supplementation of leaf meal from Citrus depressa Hayata on the growth, innate immune response, and disease resistance of juvenile barramundi, Lates calcarifer. Four diets were formulated to contain 0% (control), 1% (C1), 3% (C3), and 5% (C5) leaf meal, respectively. During a 56 d feeding trial, fish survival, growth performance, and feed efficiency were not significantly different among all groups. For immune response, respiratory burst, superoxide dismutase and lysozyme activities were not significantly different among all groups. However, fish fed the C5 diet for 56 d had significantly higher phagocytic activity. Also, fish fed C3 and C5 diets had significantly higher Mx gene expressions in spleens and head kidneys with nerve necrosis virus injections after 24 h. Disease resistance against Aeromonas hydrophila was increased by the C5 diet. In this study, barramundi fed on a diet containing 5% C. depressa Hayata leaf meal had significantly better innate immune response and disease resistance against A. hydrophila. Copyright © 2016 Elsevier Ltd. All rights reserved.

Tracing QTLs for Leaf Blast Resistance and Agronomic Performance of Finger Millet (Eleusine coracana (L.) Gaertn.) Genotypes through Association Mapping and in silico Comparative Genomics Analyses.

PubMed

Ramakrishnan, M; Antony Ceasar, S; Duraipandiyan, V; Vinod, K K; Kalpana, Krishnan; Al-Dhabi, N A; Ignacimuthu, S

2016-01-01

Finger millet is one of the small millets with high nutritive value. This crop is vulnerable to blast disease caused by Pyricularia grisea, which occurs annually during rainy and winter seasons. Leaf blast occurs at early crop stage and is highly damaging. Mapping of resistance genes and other quantitative trait loci (QTLs) for agronomic performance can be of great use for improving finger millet genotypes. Evaluation of one hundred and twenty-eight finger millet genotypes in natural field conditions revealed that leaf blast caused severe setback on agronomic performance for susceptible genotypes, most significant traits being plant height and root length. Plant height was reduced under disease severity while root length was increased. Among the genotypes, IE4795 showed superior response in terms of both disease resistance and better agronomic performance. A total of seven unambiguous QTLs were found to be associated with various agronomic traits including leaf blast resistance by association mapping analysis. The markers, UGEP101 and UGEP95, were strongly associated with blast resistance. UGEP98 was associated with tiller number and UGEP9 was associated with root length and seed yield. Cross species validation of markers revealed that 12 candidate genes were associated with 8 QTLs in the genomes of grass species such as rice, foxtail millet, maize, Brachypodium stacei, B. distachyon, Panicum hallii and switchgrass. Several candidate genes were found proximal to orthologous sequences of the identified QTLs such as 1,4-β-glucanase for leaf blast resistance, cytokinin dehydrogenase (CKX) for tiller production, calmodulin (CaM) binding protein for seed yield and pectin methylesterase inhibitor (PMEI) for root growth and development. Most of these QTLs and their putatively associated candidate genes are reported for first time in finger millet. On validation, these novel QTLs may be utilized in future for marker assisted breeding for the development of fungal resistant and high yielding varieties of finger millet.

Tracing QTLs for Leaf Blast Resistance and Agronomic Performance of Finger Millet (Eleusine coracana (L.) Gaertn.) Genotypes through Association Mapping and in silico Comparative Genomics Analyses

PubMed Central

Ramakrishnan, M.; Antony Ceasar, S.; Duraipandiyan, V.; Vinod, K. K.; Kalpana, Krishnan; Al-Dhabi, N. A.; Ignacimuthu, S.

2016-01-01

Finger millet is one of the small millets with high nutritive value. This crop is vulnerable to blast disease caused by Pyricularia grisea, which occurs annually during rainy and winter seasons. Leaf blast occurs at early crop stage and is highly damaging. Mapping of resistance genes and other quantitative trait loci (QTLs) for agronomic performance can be of great use for improving finger millet genotypes. Evaluation of one hundred and twenty-eight finger millet genotypes in natural field conditions revealed that leaf blast caused severe setback on agronomic performance for susceptible genotypes, most significant traits being plant height and root length. Plant height was reduced under disease severity while root length was increased. Among the genotypes, IE4795 showed superior response in terms of both disease resistance and better agronomic performance. A total of seven unambiguous QTLs were found to be associated with various agronomic traits including leaf blast resistance by association mapping analysis. The markers, UGEP101 and UGEP95, were strongly associated with blast resistance. UGEP98 was associated with tiller number and UGEP9 was associated with root length and seed yield. Cross species validation of markers revealed that 12 candidate genes were associated with 8 QTLs in the genomes of grass species such as rice, foxtail millet, maize, Brachypodium stacei, B. distachyon, Panicum hallii and switchgrass. Several candidate genes were found proximal to orthologous sequences of the identified QTLs such as 1,4-β-glucanase for leaf blast resistance, cytokinin dehydrogenase (CKX) for tiller production, calmodulin (CaM) binding protein for seed yield and pectin methylesterase inhibitor (PMEI) for root growth and development. Most of these QTLs and their putatively associated candidate genes are reported for first time in finger millet. On validation, these novel QTLs may be utilized in future for marker assisted breeding for the development of fungal resistant and high yielding varieties of finger millet. PMID:27415007

Mapping of Leaf Rust Resistance Genes and Molecular Characterization of the 2NS/2AS Translocation in the Wheat Cultivar Jagger.

PubMed

Xue, Shulin; Kolmer, James A; Wang, Shuwen; Yan, Liuling

2018-05-31

Winter wheat cultivar 'Jagger' was recently found to have an alien chromosomal segment 2NS that has Lr37 , a gene conferring resistance against leaf rust caused by Puccinia triticina The objective of this study was to map and characterize the gene(s) for seedling leaf rust resistance in Jagger. The recombinant inbred line (RIL) population of Jagger × '2174' was inoculated with leaf rust pathogen THBJG and BBBDB, and evaluated for infection type (IT) response. A major quantitative trait locus (QTL) for THBJG and BBBDB was coincidently mapped to chromosome arm 2AS, and the QTL accounted for 56.6-66.2% of total phenotypic variation in infection type (IT) response to THBJG, and 72.1-86.9% to BBBDB. The causal gene for resistance to these rust races was mapped to the 2NS segment in Jagger. The 2NS segment was located in a region of approximately 27.8 Mb starting from the telomere of chromosome arm 2AS, based on the sequences of the A genome in tetraploid wheat. The Lr17a gene on chromosome arm 2AS was delimited to 3.1 Mb in the genomic region, which was orthologous to the 2NS segment. Therefore, the Lr37 gene in the 2NS segment can be pyramided with other effective resistance genes, rather than Lr17a in wheat, to improve resistance to rust diseases. Copyright © 2018 Xue et al.

Characterisation of glufosinate resistance mechanisms in Eleusine indica.

PubMed

Jalaludin, Adam; Yu, Qin; Zoellner, Peter; Beffa, Roland; Powles, Stephen B

2017-06-01

An Eleusine indica population has evolved resistance to glufosinate, a major post-emergence herbicide of global agriculture. This population was analysed for target-site (glutamine synthetase) and non-target-site (glufosinate uptake, translocation and metabolism) resistance mechanisms. Glutamine synthetase (GS) activity extracted from susceptible (S) and resistant (R*) plants was equally sensitive to glufosinate inhibition, with IC 50 values of 0.85 mm and 0.99 mm, respectively. The extractable GS activity was also similar in S and R* samples. Foliar uptake of [ 14 C]-glufosinate did not differ in S and R* plants, nor did glufosinate net uptake in leaf discs. Translocation of [ 14 C]-glufosinate into untreated shoots and roots was also similar in both populations, with 44% to 47% of the herbicide translocated out from the treated leaf 24 h after treatment. The HPLC and LC-MS analysis of glufosinate metabolism revealed no major metabolites in S or R* leaf tissue. Glufosinate resistance in this resistant population is not due to an insensitive GS, or increased activity, or altered glufosinate uptake and translocation, or enhanced glufosinate metabolism. Thus, target-site resistance is likely excluded and the exact resistance mechanism(s) remain to be determined. © 2017 Society of Chemical Industry. © 2017 Society of Chemical Industry.

Common bean varieties demonstrate differential physiological and metabolic responses to the pathogenic fungus Sclerotinia sclerotiorum.

PubMed

Robison, Faith M; Turner, Marie F; Jahn, Courtney E; Schwartz, Howard F; Prenni, Jessica E; Brick, Mark A; Heuberger, Adam L

2018-02-24

Plant physiology and metabolism are important components of a plant response to microbial pathogens. Physiological resistance of common bean (Phaseolus vulgaris L.) to the fungal pathogen Sclerotinia sclerotiorum has been established, but the mechanisms of resistance are largely unknown. Here, the physiological and metabolic responses of bean varieties that differ in physiological resistance to S. sclerotiorum are investigated. Upon infection, the resistant bean variety A195 had a unique physiological response that included reduced photosynthesis and maintaining a higher leaf surface pH during infection. Leaf metabolomics was performed on healthy tissue adjacent to the necrotic lesion at 16, 24, and 48 hr post inoculation, and 144 metabolites were detected that varied between A195 and Sacramento following infection. The metabolites that varied in leaves included amines/amino acids, organic acids, phytoalexins, and ureides. The metabolic pathways associated with resistance included amine metabolism, uriede-based nitrogen remobilization, antioxidant production, and bean-specific phytoalexin production. A second experiment was conducted in stems of 13 bean genotypes with varying resistance. Stem resistance was associated with phytoalexin production, but unlike leaf metabolism, lipid changes were associated with susceptibility. Taken together, the data supports a multifaceted, physiometabolic response of common bean to S. sclerotiorum that mediates resistance. © 2018 John Wiley & Sons Ltd.

Low NO.sub.x burner system

DOEpatents

Kitto, Jr., John B.; Kleisley, Roger J.; LaRue, Albert D.; Latham, Chris E.; Laursen, Thomas A.

1993-01-01

A low NO.sub.x burner system for a furnace having spaced apart front and rear walls, comprises a double row of cell burners on each of the front and rear walls. Each cell burner is either of the inverted type with a secondary air nozzle spaced vertically below a coal nozzle, or the non-inverted type where the coal nozzle is below the secondary air port. The inverted and non-inverted cells alternate or are provided in other specified patterns at least in the lower row of cells. A small percentage of the total air can be also provided through the hopper or hopper throat forming the bottom of the furnace, or through the boiler hopper side walls. A shallow angle impeller design also advances the purpose of the invention which is to reduce CO and H.sub.2 S admissions while maintaining low NO.sub.x generation.

Calculational note for the radiological and toxicological effects of a UO{sub 3} release from the T-hopper storage pad

DOE Office of Scientific and Technical Information (OSTI.GOV)

Goldberg, H.J.

1998-06-18

UO{sub 3} powder is stored at the T-hopper storage area associated with the 2714-U building in the 200 west area. The T-hopper containers and 13 drums containing this material are used to store the powder on pads immediately north of the building. An interim safety basis document (WHC,1996) was issued in 1996 for the UO{sub 3} powder storage area. In this document the isotope {sup 99}Tc was not included in the source term used to calculate the radiological consequences of a postulated release of the powder. A calculations note (HNF, 1998) was issued to remedy that deficiency. The present documentmore » is a revision to that document to reflect updated data concerning the solubility of UO{sub 3} in simulated lung fluid and to utilize more realistic powder release fractions.« less

Some exact velocity profiles for granular flow in converging hoppers

NASA Astrophysics Data System (ADS)

Cox, Grant M.; Hill, James M.

2005-01-01

Gravity flow of granular materials through hoppers occurs in many industrial processes. For an ideal cohesionless granular material, which satisfies the Coulomb-Mohr yield condition, the number of known analytical solutions is limited. However, for the special case of the angle of internal friction δ equal to ninety degrees, there exist exact parametric solutions for the governing coupled ordinary differential equations for both two-dimensional wedges and three-dimensional cones, both of which involve two arbitrary constants of integration. These solutions are the only known analytical solutions of this generality. Here, we utilize the double-shearing theory of granular materials to determine the velocity field corresponding to these exact parametric solutions for the two problems of gravity flow through converging wedge and conical hoppers. An independent numerical solution for other angles of internal friction is shown to coincide with the analytical solution.

Resistance of cabbage (Brassica oleracea capitata group) crops to Mamestra brassicae.

PubMed

Cartea, M E; Francisco, M; Lema, M; Soengas, P; Velasco, P

2010-10-01

Twenty-one cabbage (Brassica oleracea capitata group) varieties, including 16 local varieties and five commercial hybrids, were screened for resistance to the moth Mamestra brassicae L. under natural and artificial conditions in northwestern Spain. Resistance was assessed as the proportion of damaged plants and damaged leaves, leaf feeding injury, and number of larvae present. Correlation coefficients among damage traits showed that a visual scale (general appearance rating) should be a useful indicator of resistance. Most local varieties were highly susceptible to M. brassicae, whereas the commercial hybrids tested were resistant in terms of head foliage consumption and number of larvae per plant. Performance of varieties was similar under natural and artificial infestation although some of them performed differently at each year. Three local varieties (MBG-BRS0057, MBG-BRS0074, and MBG-BRS0452) were highly susceptible at both natural and artificial infestation conditions being MBG-BRS0074 the most damaged variety. Two local varieties (MBG-BRS0402 and MBG-BRS0535) and commercial hybrids were identified as resistant or moderately resistant to M. brassicae. Among them, 'Corazón de Buey' and 'Cabeza negra' were the most resistant and produced compact heads. These varieties could be useful sources of resistance to obtain resistant varieties to M. brassicae or as donors of resistance to other Brassica crops. The possible role of leaf traits, head compactness, and leaf glucosinolate content in relation to M. brassicae resistance is discussed.

[Relationship between leaf anatomical structure and heat resistance of 15 Rhododendron cultivars].

PubMed

Shen, Hui Fei; Zhao, Bing; Xu, Jing Jing

2016-12-01

In this study, 17 anatomical structure indexes of 15 Rhododendron cultivars were mea-sured by scanning electron microscope (SEM). Leaf anatomical structure indexes were screened via coefficient of variation, analysis of correlation and hierarchical cluster analysis, and comprehensive evaluation on heat resistance for each cultivar was conducted by the subordinate function. The results showed that the leaves of Rhododendron cultivars were typical bifacial leaf and the epidermal anticlinal walls showed slightly sinuate. The stomata only distributed in the lower epidermis and the shape was ruleless. The anatomical structure indexes all reached a significant level difference among 15 cultivars (P<0.01), except for lower epidermis thickness (P<0.05). Thickness of lamina corneum, stomatal density, stomatal width, the thickness palisade tissue and looseness of leaf spongy tissue were the main factors related to the hardness, while other indexes, such as stomatal length, stoma aperture, stomatal opening, length and thickness of upper epidermis, length and thickness of lower epidermis, thickness of spongy tissue, the ratio of the palisade tissue to spongy tissue, tightness of leaf palisade tissue, leaf thickness and media thickness didn't show much effect on heat resistance. There were some differences among 15 cultivars in heat resistance, and the order was Rhododendron 'Song Jiang Da Tao Hong' > Rhododendron 'Zhuang Yuan Hong' > Rhododendron 'Lv Se Guang Hui' > Rhododendron 'Fen Zhen Zhu' > Rhododendron 'Wai Guo Hong' > Rhododendron 'Lan Yin' > Rhododendron 'Bi Zhi' >Rhododendron 'Da He Zhi Chun' > Rhododendron 'Guo Qi Hong' > Rhododendron 'Yu Ling Long' > Rhododendron 'Hong Shan Hu' > Rhododendron 'Ning Bo Hong' > Rhododendron 'Tao Ban Zhu Sha' > Rhododendron 'Ai Ding Bao' > Rhododendron 'Liu Qiu Hong'. According to the heat hardiness, the cultivars could be divided into 4 groups: R. 'Song Jiang Da Tao Hong', R. 'Zhuang Yuan Hong' and R. 'Lv Se Guang Hui' with high heat resistance, R. 'Fen Zhen Zhu', R. 'Wai Guo Hong', R. 'Lan Yin', R. 'Bi Zhi', R. 'Da He Zhi Chun', R. 'Guo Qi Hong' and R. 'Yu Ling Long' with medium heat resistance, R. 'Hong Shan Hu', R. 'Ning Bo Hong', R. 'Tao Ban Zhu Sha' and R. 'Ai Ding Bao' with lower heat resistance, R. 'Liu Qiu Hong' without heat resistance. However, the accurate heat hardiness evaluation of Rhododendron still needs to consider other factors, including morphological structure, physiological and biochemical indicators and genetic factor of heat resistance, the harmfulness of Rhododendron, and the recovery state after being injured by high temperature.

Granular flows: fundamentals and applications

NASA Astrophysics Data System (ADS)

Cleary, Paul W.

DEM allows the prediction of complex industrial and geophysical particle flows. The importance of particle shape is demonstrated through a series of simple examples. Shape controls resistance to shear, the magnitude of collision stress, dilation and the angle of repose. We use a periodic flow of a bed of particles to demonstrate the different states of granular matter, the generation of dilute granular flow when granular temperature is high and the flow dependent nature of the granular thermodynamic boundary conditions. A series of industrial case studies examines how DEM can be used to understand and improve processes such as separation, mixing, grinding, excavation, hopper discharge, metering and conveyor interchange. Finally, an example of landslide motion over real topography is presented.

High-resolution mapping reveals linkage between genes in common bean cultivar Ouro Negro conferring resistance to the rust, anthracnose, and angular leaf spot diseases

USDA-ARS?s Scientific Manuscript database

Rust, Anthracnose, and angular leaf spot are major diseases of common bean in the world and most particularly in the Americas and Africa, which are the largest common bean production regions of the world. The Mesoamerican black-seeded cultivar Ouro Negro is unusual in that it has resistance to all t...

RNA-Seq analysis of resistant and susceptible sub-tropical maize lines reveals a role for kauralexins in resistance to grey leaf spot disease, caused by Cercospora zeina

USDA-ARS?s Scientific Manuscript database

Cercospora zeina is a foliar pathogen responsible for maize grey leaf spot in southern Africa that negatively impacts maize production. Plants use a variety of chemical and structural mechanisms to defend themselves against invading pathogens such as C. zeina, including the production of secondary m...

Fine mapping of a quantitative resistance gene for gray leaf spot of maize (Zea mays L.) derived from teosinte (Z. mays ssp. parviglumis)

USDA-ARS?s Scientific Manuscript database

In previous work, using near isogenic line (NIL) populations in which segments of the tesosinte (Zea mays ssp. parviglumis) genome had been introgressed into the background of the maize line B73, we had identified a QTL on chromosome 8, here called Qgls8, for gray leaf spot resistance. We identified...

QTL-seq approach identified genomic regions and diagnostic markers for rust and late leaf spot resistance in groundnut (Arachis hypogaea L.)

USDA-ARS?s Scientific Manuscript database

Rust and late leaf spot (LLS) are the two major foliar fungal diseases in groundnut, and their co-occurrence leads to yield loss up to 50–70% in addition to the deterioration of fodder quality. To identify candidate genomic regions controlling rust and LLS resistance, we deployed whole genome re-seq...

Factors Influencing Expression of Antixenosis in Soybean to Anticarsia gemmatalis and Spodoptera frugiperda (Lepidoptera: Noctuidae).

PubMed

Boiça Júnior, Arlindo Leal; De Souza, Bruno Henrique Sardinha; Costa, Eduardo Neves; Ribeiro, Zulene Antonio; Stout, Michael Joseph

2015-02-01

This study aimed to evaluate some factors that influence the expression of antixenosis in soybean genotypes against Anticarsia gemmatalis Hübner and Spodoptera frugiperda (J. E. Smith) (Lepidoptera: Noctuidae). Free-choice and no-choice feeding assays were performed with the resistant soybean genotype IAC 100 and the susceptible genotype BRSGO 8360 using A. gemmatalis and S. frugiperda larvae. The following factors that may affect expression of resistance were evaluated: one larva versus two larvae per leaf disc; use of larvae without prior feeding suspension versus larvae starved for 3 h prior to the assay; leaf discs versus entire leaflets; upper part versus lower part of the plant; and, vegetative versus reproductive growth stages. The level of resistance exhibited by the genotype IAC 100 was high enough to not be obscured by the effects of all factors assayed in the present study upon the feeding preference of A. gemmatalis and S. frugiperda larvae. However, our results demonstrate the importance of knowing the optimal conditions for conducting an assay for evaluating resistance of genotypes for specialist and generalist insect species. Utilization of two larvae of A. gemmatalis per leaf disc, not starved before the assays, with leaf discs from the upper part of plants at the reproductive growth stage provided better discrimination of differences in antixenosis expression in soybean genotypes. For S. frugiperda, use of one larva per leaf disc, not starved before the assays, with leaf discs from the lower part of plants at the reproductive growth stage gave more satisfactory results for feeding preference tests. © The Authors 2015. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

Pyramided rice lines harbouring Allium sativum (asal) and Galanthus nivalis (gna) lectin genes impart enhanced resistance against major sap-sucking pests.

PubMed

Bharathi, Y; Vijaya Kumar, S; Pasalu, I C; Balachandran, S M; Reddy, V D; Rao, K V

2011-03-20

We have developed transgene pyramided rice lines, endowed with enhanced resistance to major sap-sucking insects, through sexual crosses made between two stable transgenic rice lines containing Allium sativum (asal) and Galanthus nivalis (gna) lectin genes. Presence and expression of asal and gna genes in pyramided lines were confirmed by PCR and western blot analyses. Segregation analysis of F₂ progenies disclosed digenic (9:3:3:1) inheritance of the transgenes. Homozygous F₃ plants carrying asal and gna genes were identified employing genetic and molecular methods besides insect bioassays. Pyramided lines, infested with brown planthopper (BPH), green leafhopper (GLH) and whitebacked planthopper (WBPH), proved more effective in reducing insect survival, fecundity, feeding ability besides delayed development of insects as compared to the parental transgenics. Under infested conditions, pyramided lines were found superior to the parental transgenics in their seed yield potential. This study represents first report on pyramiding of two lectin genes into rice exhibiting enhanced resistance against major sucking pests. The pyramided lines appear promising and might serve as a novel genetic resource in rice breeding aimed at durable and broad based resistance against hoppers. Copyright © 2011 Elsevier B.V. All rights reserved.

Regulation and acclimation of leaf gas exchange in a piñon-juniper woodland exposed to three different precipitation regimes.

PubMed

Limousin, Jean-Marc; Bickford, Christopher P; Dickman, Lee T; Pangle, Robert E; Hudson, Patrick J; Boutz, Amanda L; Gehres, Nathan; Osuna, Jessica L; Pockman, William T; McDowell, Nate G

2013-10-01

Leaf gas-exchange regulation plays a central role in the ability of trees to survive drought, but forecasting the future response of gas exchange to prolonged drought is hampered by our lack of knowledge regarding potential acclimation. To investigate whether leaf gas-exchange rates and sensitivity to drought acclimate to precipitation regimes, we measured the seasonal variations of leaf gas exchange in a mature piñon-juniper Pinus edulis-Juniperus monosperma woodland after 3 years of precipitation manipulation. We compared trees receiving ambient precipitation with those in an irrigated treatment (+30% of ambient precipitation) and a partial rainfall exclusion (-45%). Treatments significantly affected leaf water potential, stomatal conductance and photosynthesis for both isohydric piñon and anisohydric juniper. Leaf gas exchange acclimated to the precipitation regimes in both species. Maximum gas-exchange rates under well-watered conditions, leaf-specific hydraulic conductance and leaf water potential at zero photosynthetic assimilation all decreased with decreasing precipitation. Despite their distinct drought resistance and stomatal regulation strategies, both species experienced hydraulic limitation on leaf gas exchange when precipitation decreased, leading to an intraspecific trade-off between maximum photosynthetic assimilation and resistance of photosynthesis to drought. This response will be most detrimental to the carbon balance of piñon under predicted increases in aridity in the southwestern USA. © 2013 John Wiley & Sons Ltd.

Summer Freezing Resistance: A Critical Filter for Plant Community Assemblies in Mediterranean High Mountains

PubMed Central

Pescador, David S.; Sierra-Almeida, Ángela; Torres, Pablo J.; Escudero, Adrián

2016-01-01

Assessing freezing community response and whether freezing resistance is related to other functional traits is essential for understanding alpine community assemblages, particularly in Mediterranean environments where plants are exposed to freezing temperatures and summer droughts. Thus, we characterized the leaf freezing resistance of 42 plant species in 38 plots at Sierra de Guadarrama (Spain) by measuring their ice nucleation temperature, freezing point (FP), and low-temperature damage (LT50), as well as determining their freezing resistance mechanisms (i.e., tolerance or avoidance). The community response to freezing was estimated for each plot as community weighted means (CWMs) and functional diversity (FD), and we assessed their relative importance with altitude. We established the relationships between freezing resistance, growth forms, and four key plant functional traits (i.e., plant height, specific leaf area, leaf dry matter content (LDMC), and seed mass). There was a wide range of freezing resistance responses and more than in other alpine habitats. At the community level, the CWMs of FP and LT50 responded negatively to altitude, whereas the FD of both traits increased with altitude. The proportion of freezing-tolerant species also increased with altitude. The ranges of FP and LT50 varied among growth forms, and only leaf dry matter content was negatively correlated with freezing-resistance traits. Summer freezing events represent important abiotic filters for assemblies of Mediterranean high mountain communities, as suggested by the CWMs. However, a concomitant summer drought constraint may also explain the high freezing resistance of species that thrive in these areas and the lower FD of freezing resistance traits at lower altitudes. Leaves with high dry matter contents may maintain turgor at lower water potential and enhance drought tolerance in parallel to freezing resistance. This adaptation to drought seems to be a general prerequisite for plants found in xeric mountains. PMID:26941761

Recessive Resistance Derived from Tomato cv. Tyking-Limits Drastically the Spread of Tomato Yellow Leaf Curl Virus

PubMed Central

Pereira-Carvalho, Rita C.; Díaz-Pendón, Juan A.; Fonseca, Maria Esther N.; Boiteux, Leonardo S.; Fernández-Muñoz, Rafael; Moriones, Enrique; Resende, Renato O.

2015-01-01

The tomato yellow leaf curl disease (TYLCD) causes severe damage to tomato (Solanum lycopersicum L.) crops throughout tropical and subtropical regions of the world. TYLCD is associated with a complex of single-stranded circular DNA plant viruses of the genus Begomovirus (family Geminiviridae) transmitted by the whitefy Bemisia tabaci Gennadius (Hemiptera: Aleyrodidae). The tomato inbred line TX 468-RG is a source of monogenic recessive resistance to begomoviruses derived from the hybrid cv. Tyking F1. A detailed analysis of this germplasm source against tomato yellow leaf curl virus-Israel (TYLCV-IL), a widespread TYLCD-associated virus, showed a significant restriction to systemic virus accumulation even under continuous virus supply. The resistance was effective in limiting the onset of TYLCV-IL in tomato, as significantly lower primary spread of the virus occurred in resistant plants. Also, even if a limited number of resistant plants could result infected, they were less efficient virus sources for secondary spread owing to the impaired TYLCV-IL accumulation. Therefore, the incorporation of this resistance into breeding programs might help TYLCD management by drastically limiting TYLCV-IL spread. PMID:26008699

The genetic basis of flecking and its relationship to disease resistance in the IBM maize mapping population.

PubMed

Vontimitta, Vijay; Olukolu, Bode A; Penning, Bryan W; Johal, Gurmukh; Balint-Kurti, P J

2015-11-01

In this paper, we determine the genetic architecture controlling leaf flecking in maize and investigate its relationship to disease resistance and the defense response. Flecking is defined as a mild, often environmentally dependent lesion phenotype observed on the leaves of several commonly used maize inbred lines. Anecdotal evidence suggests a link between flecking and enhanced broad-spectrum disease resistance. Neither the genetic basis underlying flecking nor its possible relationship to disease resistance has been systematically evaluated. The commonly used maize inbred Mo17 has a mild flecking phenotype. The IBM-advanced intercross mapping population, derived from a cross between Mo17 and another commonly used inbred B73, has been used for mapping a number of traits in maize including several related to disease resistance. In this study, flecking was assessed in the IBM population over 6 environments. Several quantitative trait loci for flecking were identified, with the strongest one located on chromosome 6. Low but moderately significant correlations were observed between stronger flecking and higher disease resistance with respect to two diseases, southern leaf blight and northern leaf blight and between stronger flecking and a stronger defense response.

National Waterways Study. Waterway Science and Technology.

DTIC Science & Technology

1981-08-01

Revetments 278 VII-A Split Hull Type Trailing Suction Hopper Dredge 304 VII-B Drag Heads 306 VII-C Overflow Systems 307 VII-D Trailing Suction Hopper... head reversals are possible. Poor approach conditions currently exist at some locks which could have been mitigated if modern, improved design...of ti,.c that a navigable pass section can be used. Navigation dams must be designed to pass high flows and floods with minor swell head and without in

Granular material flow in two-dimensional hoppers

DOE Office of Scientific and Technical Information (OSTI.GOV)

Brennen, C.; Pearce, J.C.

To aid in improving the transport of granular media for industrial purposes, the California Institute of Technology presents a comparison of experimental data with analytical results for the flow of dry granular media (such as coal) through a two-dimensional or wedge-shaped hopper. The analytical solution, which is based on the constitutive postulates (suggested by A.W. Jenike and R.T. Shield) of intergrain Coulomb friction and isotropy, produces results that are in good agreement with the experimental measurements.

Effects of wall friction on flow in a quasi-2D hopper

NASA Astrophysics Data System (ADS)

Shah, Neil; Birwa, Sumit; Carballo-Ramirez, Brenda; Pleau, Mollie; Easwar, Nalini; Tewari, Shubha

Our experiments on the gravity-driven flow of spherical particles in a vertical hopper examine how the flow rate varies with opening size and wall friction. We report here on a model simulation using LAMMPS of the experimental geometry, a quasi-2D hopper. Keeping inter-particle friction fixed, the coefficient of friction at the walls is varied from 0.0 to 0.9 for a range of opening sizes. Our simulations find a steady rate of flow at each wall friction and outlet size. The Janssen effect attributes the constant rate of flow of a granular column to the column height independence of the pressure at the base, since the weight of the grains is borne in part by friction at the walls. However, we observe a constant flow regime even in the absence of wall friction, suggesting that wall friction may not be a necessary condition for pressure saturation. The observed velocities of particles near the opening are used to extrapolate their starting positions had they been in free fall. In contrast to scaling predictions, our data suggest that the height of this free-fall arch does not vary with opening size for higher frictional coefficients. We analyze the velocity traces of particles to see the range over which contact interactions remain collisional as they approach the hopper outlet.

Plant morphological characteristics and resistance to simulated trampling

NASA Astrophysics Data System (ADS)

Sun, Dan; Liddle, Michael J.

1993-07-01

The relationship between responses of plants to trampling and their morphological characteristics was studied in a glasshouse experiment. Thirteen species with four different growth forms were used in this experiment. They were five tussock species. Chloris gayana, Eragrostis tenuifolia, Lolium perenne, Panicum maximum, and Sporobolus elongatus; three prostate grasses, Axonopus compressus, Cynodon dactylon, and Trifolium repens, two herbaceous species, Daucus glochidiatus and Hypochoeris radicata; and three woody species, Acacia macradenia, Acrotriche aggregata, and Sida rhombifolia. These species were subjected to three levels of simulated trampling. For each species, measurements were taken of aboveground biomass, root biomass, leaf length, leaf width, leaf thickness, leaf number, broken leaf number and plant height. Overall, these measurements were greatest in the control plants, moderate in the level of light trampling, and the lowest in the level of heavy trampling. Biomass was used as a basis of the assessment of plant resistance to trampling. Three tussock species, Eragrostis tenuifolia, Lolium perenne, and Sporobolus elongatus had a high resistance. Woody and erect herbaceous plants were more intolerant to trampling. There appear to be two processes involved in the reduction of the plant parameters: direct physical damage with portions of the plants detached, and physiological changes, which slow down vegetative growth rates. Plant height was found to be the most sensitive indicator of trampling damage.

Oreochromis mossambicus diet supplementation with Psidium guajava leaf extracts enhance growth, immune, antioxidant response and resistance to Aeromonas hydrophila.

PubMed

Gobi, Narayanan; Ramya, Chinnu; Vaseeharan, Baskaralingam; Malaikozhundan, Balasubramanian; Vijayakumar, Sekar; Murugan, Kadarkarai; Benelli, Giovanni

2016-11-01

In this research, we focused on the efficacy of aqueous and ethanol leaf extracts of Psidium guajava L. (guava) based experimental diets on the growth, immune, antioxidant and disease resistance of tilapia, Oreochromis mossambicus following challenge with Aeromonas hydrophila. The experimental diets were prepared by mixing powdered (1, 5 and 10 mg/g) aqueous and ethanol extract of guava leaf with commercial diet. The growth (FW, FCR and SGR), non-specific cellular immune (myeloperoxidase activity, reactive oxygen activity and reactive nitrogen activity) humoral immune (complement activity, antiprotease, alkaline phosphatase activity and lysozyme activity) and antioxidant enzyme responses (SOD, GPX, and CAT) were examined after 30 days of post-feeding. A significant enhancement in the biochemical and immunological parameters of fish were observed fed with experimental diets compared to control. The dietary supplementation of P. guajava leaf extract powder for 30 days significantly reduced the mortality and increased the disease resistance of O. mossambicus following challenge with A. hydrophila at 50 μl (1 × 10 7  cells ml -1 ) compared to control after post-infection. The results suggest that the guava leaf extract could be used as a promising feed additive in aquaculture. Copyright © 2016 Elsevier Ltd. All rights reserved.

Transcriptomic and Proteomic Analyses of Resistant Host Responses in Arachis diogoi Challenged with Late Leaf Spot Pathogen, Phaeoisariopsis personata

PubMed Central

Kumar, Dilip; Kirti, Pulugurtha Bharadwaja

2015-01-01

Late leaf spot is a serious disease of peanut caused by the imperfect fungus, Phaeoisariopsis personata. Wild diploid species, Arachis diogoi. is reported to be highly resistant to this disease and asymptomatic. The objective of this study is to investigate the molecular responses of the wild peanut challenged with the late leaf spot pathogen using cDNA-AFLP and 2D proteomic study. A total of 233 reliable, differentially expressed genes were identified in Arachis diogoi. About one third of the TDFs exhibit no significant similarity with the known sequences in the data bases. Expressed sequence tag data showed that the characterized genes are involved in conferring resistance in the wild peanut to the pathogen challenge. Several genes for proteins involved in cell wall strengthening, hypersensitive cell death and resistance related proteins have been identified. Genes identified for other proteins appear to function in metabolism, signal transduction and defence. Nineteen TDFs based on the homology analysis of genes associated with defence, signal transduction and metabolism were further validated by quantitative real time PCR (qRT-PCR) analyses in resistant wild species in comparison with a susceptible peanut genotype in time course experiments. The proteins corresponding to six TDFs were differentially expressed at protein level also. Differentially expressed TDFs and proteins in wild peanut indicate its defence mechanism upon pathogen challenge and provide initial breakthrough of genes possibly involved in recognition events and early signalling responses to combat the pathogen through subsequent development of resistivity. This is the first attempt to elucidate the molecular basis of the response of the resistant genotype to the late leaf spot pathogen, and its defence mechanism. PMID:25646800

Variation between Ethiopian and North American barley varieties (Hordeum vulgare) in response to Russian wheat aphid (Diuraphis noxia) populations.

PubMed

Araya, Alemu; Belay, Tesfay; Hussein, Temam

2014-03-15

The Russian wheat aphid, Diuraphis noxia (Mordvilko) (Hemiptera: Aphididae), causes severe damage to barley, Hordeum vulgare L. (Poales: Poaceae), in the highlands of Ethiopia. Little information is available on the control of this pest in Ethiopia. An experiment aimed at evaluating the resistance of barley varieties from the USA to D. noxia populations and determining biotypic variation between Ethiopian and North American D. noxia populations was conducted. The D. noxia-resistant barley varieties Burton and RWA-1758 from the USA, the resistant barley line 3296-15 from Ethiopia, and a local Ethiopian susceptible variety were included in a randomized design in a greenhouse under natural light conditions. There were highly significant differences (P < 0.001) in the mean D. noxia population, leaf chlorosis, leaf rolling, plant stunting, number of tillers per plant, and the percentage of infested tillers per plant between the resistant and susceptible varieties. The aphid population per tiller was lower on the resistant barley plants than on the susceptible plants. Severe plant damage was observed on the local barley variety, while the least damage was observed on Burton, followed by RWA-1758. Burton and RWA-1758 were therefore highly resistant and moderately resistant, respectively, to the northern Ethiopian D. noxia populations, indicating similarities in biotypes between the United States and northern Ethiopian D. noxia populations. The damage to variety 3296-15 was greater than to Burton and RWA-1758. Leaf chlorosis scores and leaf rolling scores for variety 3296-15 upon treatment with the north Ethiopian D. noxia population indicate likely biotypic variation between D. noxia populations of northern and central Ethiopia. This is an open access paper. We use the Creative Commons Attribution 3.0 license that permits unrestricted use, provided that the paper is properly attributed.

Design, Fabrication, and Analysis of a Hybrid FIBER Composite Monoleaf Spring Using Carbon and E-Glass Fibers for Automotive Suspension Applications

NASA Astrophysics Data System (ADS)

Sureshkumar, M.; Tamilselvam, P.; Kumaravelan, R.; Dharmalingam, R.

2014-03-01

The leaf spring is an important component that provides suspension and plays a vital role in automotive applications. As a vehicle travels, a tremendous force, mostly in terms of a fatigue load, is applied to the leaf spring assembly, particularly to the eye point of the rear axle. In a vehicle with rear-wheel drive, the leaf spring is subject to twisting forces that are opposite in direction and magnitude during the acceleration of drive wheels. A multileaf spring provides an additional strength, but lacks the flexibility and increases the overall weight of the vehicle. Considering the loading conditions, the availability of space in a vehicle, and geometrical considerations, a composite monoleaf spring is designed. In due consideration of the tensile behavior, fatigue resistance, chipping resistance, and base part resistance, a hybrid laminated spring is constructed for the purpose. The present study focuses on an analysis and behavior of a monoleaf spring made of hybrid composite materials, i.e., carbon and E-glass fibers. It is observed that the natural frequency of a hybrid composite leaf spring is twice the frequency of a conventional leaf spring, particularly in the vertical direction, which means that the occurrences of resonance will be less. Also, it is observed that the stress produced in it is lower than that in a conventional leaf spring. The hybrid composite monoleaf spring proved to have better impact and tensile behavior than a steel one.

Regulating low-NOx and high-burnout deep-air-staging combustion under real-furnace conditions in a 600 MWe down-fired supercritical boiler by strengthening the staged-air effect.

PubMed

Kuang, Min; Wang, Zhihua; Zhu, Yanqun; Ling, Zhongqian; Li, Zhengqi

2014-10-21

A 600 MW(e) down-fired pulverized-coal supercritical boiler, which was equipped with a deep-air-staging combustion system for reducing the particularly high NOx emissions, suffered from the well-accepted contradiction between low NOx emissions and high carbon in fly ash, in addition to excessively high gas temperatures in the hopper that jeopardized the boiler's safe operations. Previous results uncovered that under low-NOx conditions, strengthening the staged-air effect by decreasing the staged-air angle and simultaneously increasing the staged-air damper opening alleviated the aforementioned problems to some extent. To establish low-NOx and high-burnout circumstances and control the aforementioned hopper temperatures, a further staged-air retrofit with horizontally redirecting staged air through an enlarged staged-air slot area was performed to greatly strengthen the staged-air effect. Full-load industrial-size measurements were performed to confirm the availability of this retrofit. The present data were compared with those published results before the retrofit. High NOx emissions, low carbon in fly ah, and high hopper temperatures (i.e., levels of 1036 mg/m(3) at 6% O2, 3.72%, and about 1300 °C, respectively) appeared under the original conditions with the staged-air angle of 45° and without overfire air (OFA) application. Applying OFA and reducing the angle to 20° achieved an apparent NOx reduction and a moderate hopper temperature decrease while a sharp increase in carbon in fly ash (i.e., levels of 878 mg/m(3) at 6% O2, about 1200 °C, and 9.81%, respectively). Fortunately, the present staged-air retrofit was confirmed to be applicable in regulating low-NOx, high-burnout, and low hopper temperature circumstances (i.e., levels of 867 mg/m(3) at 6% O2, 5.40%, and about 1100 °C, respectively).

Regulation of leaf hydraulics: from molecular to whole plant levels.

PubMed

Prado, Karine; Maurel, Christophe

2013-01-01

The water status of plant leaves is dependent on both stomatal regulation and water supply from the vasculature to inner tissues. The present review addresses the multiple physiological and mechanistic facets of the latter process. Inner leaf tissues contribute to at least a third of the whole resistance to water flow within the plant. Physiological studies indicated that leaf hydraulic conductance (K leaf) is highly dependent on the anatomy, development and age of the leaf and can vary rapidly in response to physiological or environmental factors such as leaf hydration, light, temperature, or nutrient supply. Differences in venation pattern provide a basis for variations in K leaf during development and between species. On a short time (hour) scale, the hydraulic resistance of the vessels can be influenced by transpiration-induced cavitations, wall collapses, and changes in xylem sap composition. The extravascular compartment includes all living tissues (xylem parenchyma, bundle sheath, and mesophyll) that transport water from xylem vessels to substomatal chambers. Pharmacological inhibition and reverse genetics studies have shown that this compartment involves water channel proteins called aquaporins (AQPs) that facilitate water transport across cell membranes. In many plant species, AQPs are present in all leaf tissues with a preferential expression in the vascular bundles. The various mechanisms that allow adjustment of K leaf to specific environmental conditions include transcriptional regulation of AQPs and changes in their abundance, trafficking, and intrinsic activity. Finally, the hydraulics of inner leaf tissues can have a strong impact on the dynamic responses of leaf water potential and stomata, and as a consequence on plant carbon economy and leaf expansion growth. The manipulation of these functions could help optimize the entire plant performance and its adaptation to extreme conditions over short and long time scales.

Leaf hydraulic architecture correlates with regeneration irradiance in tropical rainforest trees

Treesearch

Lawren Sack; Melvin T. Tyree; N. Michele Holbrook; N. Michele Holbrook

2005-01-01

The leaf hydraulic conductance (Kleaf)s a major determinant of plant water transport capacity. Here, we measured Kleaf, and its basis in the resistances of leaf components, for fully illuminated leaves of five tree species that regenerate in deep shade, and five that regenerate in gaps or clearings, in Panamanian lowland tropical rainforest. We also determined...

Transcriptomics reveals multiple resistance mechanisms against cotton leaf curl disease in a naturally immune cotton species, Gossypium arboreum

USDA-ARS?s Scientific Manuscript database

Cotton is an economically important crop affected by a number of abiotic and biotic stresses. Cotton leaf curl disease (CLCuD) is caused by virus in the genus Begomovirus (family Geminiviridae), collectively called cotton leaf curl viruses (CLCuVs). It is one of the most devastating virual diseases ...

Resistance to Septoria Leaf Spot in Eastern Cottonwood

Treesearch

D. T. Cooper; T. H. Filer

1976-01-01

Septoria leaf spot, which is caused by Septoria musiva Peck, is a potentially serious dis ease of eastern cottonwood (Populus deltoides) in nuseries and plantations in the lower Miss issippi Valley. Lesions reduce photosynthetic area of leaves and cause premature leaf fall; the fungus also causes cankers on the stem (l). During late summer 1975. incidence of Septoria...

An eQTL Analysis of Partial Resistance to Puccinia hordei in Barley

PubMed Central

Chen, Xinwei; Hackett, Christine A.; Niks, Rients E.; Hedley, Peter E.; Booth, Clare; Druka, Arnis; Marcel, Thierry C.; Vels, Anton; Bayer, Micha; Milne, Iain; Morris, Jenny; Ramsay, Luke; Marshall, David; Cardle, Linda; Waugh, Robbie

2010-01-01

Background Genetic resistance to barley leaf rust caused by Puccinia hordei involves both R genes and quantitative trait loci. The R genes provide higher but less durable resistance than the quantitative trait loci. Consequently, exploring quantitative or partial resistance has become a favorable alternative for controlling disease. Four quantitative trait loci for partial resistance to leaf rust have been identified in the doubled haploid Steptoe (St)/Morex (Mx) mapping population. Further investigations are required to study the molecular mechanisms underpinning partial resistance and ultimately identify the causal genes. Methodology/Principal Findings We explored partial resistance to barley leaf rust using a genetical genomics approach. We recorded RNA transcript abundance corresponding to each probe on a 15K Agilent custom barley microarray in seedlings from St and Mx and 144 doubled haploid lines of the St/Mx population. A total of 1154 and 1037 genes were, respectively, identified as being P. hordei-responsive among the St and Mx and differentially expressed between P. hordei-infected St and Mx. Normalized ratios from 72 distant-pair hybridisations were used to map the genetic determinants of variation in transcript abundance by expression quantitative trait locus (eQTL) mapping generating 15685 eQTL from 9557 genes. Correlation analysis identified 128 genes that were correlated with resistance, of which 89 had eQTL co-locating with the phenotypic quantitative trait loci (pQTL). Transcript abundance in the parents and conservation of synteny with rice allowed us to prioritise six genes as candidates for Rphq11, the pQTL of largest effect, and highlight one, a phospholipid hydroperoxide glutathione peroxidase (HvPHGPx) for detailed analysis. Conclusions/Significance The eQTL approach yielded information that led to the identification of strong candidate genes underlying pQTL for resistance to leaf rust in barley and on the general pathogen response pathway. The dataset will facilitate a systems appraisal of this host-pathogen interaction and, potentially, for other traits measured in this population. PMID:20066049

Effect of Two-Way Air-Sea Coupling in High and Low Wind Speed Regimes

DTIC Science & Technology

2010-09-01

testing determined, however, that using a separate dynamical framework for the ocean model produced better results, primarily because it allowed for a...author address: Sue Chen, Naval Research Lab- oratory, 7 Grace Hopper Ave., Stop 2, Monterey, CA 93943-5502. E-mail: sue.chen@nrlmry.navy.mil 1 COAMPS is...ORGANIZATION NAME(S) AND ADDRESS(ES) Naval Research Laboratory,7 Grace Hopper Ave., Stop 2,Monterey, CA ,93943-5502 8. PERFORMING ORGANIZATION REPORT NUMBER 9

Analysis of a Radioisotope Thermal Rocket Engine

NASA Technical Reports Server (NTRS)

Machado-Rodriguez, Jonathan P.; Landis, Geoffrey A.

2017-01-01

The Triton Hopper is a concept for a vehicle to explore the surface of Neptunes moon Triton, which uses a radioisotope heated rocket engine and in-situ propellant acquisition. The initial Triton Hopper conceptual design stores pressurized Nitrogen in a spherical tank to be used as the propellant. The aim of the research was to investigate the benefits of storing propellant at ambient temperature and heating it through a thermal block during engine operation, as opposed to storing gas at a high temperature.

Mesoionic pyrido[1,2-a]pyrimidinones: Discovery of triflumezopyrim as a potent hopper insecticide1.

PubMed

Zhang, Wenming; Holyoke, Caleb W; Pahutski, Thomas F; Lahm, George P; Barry, James D; Cordova, Daniel; Leighty, Robert M; Singh, Vineet; Vicent, Daniel R; Tong, My-Hanh T; Hughes, Kenneth A; McCann, Stephen F; Henry, Yewande T; Xu, Ming; Briddell, Twyla A

2017-01-01

A novel class of mesoionic pyrido[1,2-a]pyrimidinones has been discovered with exceptional insecticidal activity controlling a number of insect species. In this communication, we report the part of the optimization program which led to the discovery of triflumezopyrim as a highly potent insecticide controlling various hopper species. Our efforts in discovery, synthesis, structure-activity relationship elucidation, and biological activity evaluation are also presented. Copyright © 2016 Elsevier Ltd. All rights reserved.

Hydraulics and gas exchange recover more rapidly from severe drought stress in small pot-grown grapevines than in field-grown plants.

PubMed

Romero, Pascual; Botía, Pablo; Keller, Markus

2017-09-01

Modifications of plant hydraulics and shoot resistances (R shoot ) induced by water withholding followed by rewatering, and their relationships with plant water status, leaf gas exchange and water use efficiency at the leaf level, were investigated in pot-grown and field-grown, own-rooted Syrah grapevines in an arid climate. Water stress induced anisohydric behavior, gradually reducing stomatal conductance (g s ) and leaf photosynthesis (A) in response to decreasing midday stem water potential (Ψ s ). Water stress also rapidly increased intrinsic water-use efficiency (A/g s ); this effect persisted for many days after rewatering. Whole-plant (K plant ), canopy (K canopy ), shoot (K shoot ) and leaf (K leaf ) hydraulic conductances decreased during water stress, in tune with the gradual decrease in Ψ s , leaf gas exchange and whole plant water use. Water-stressed vines also had a lower Ψ gradient between stem and leaf (ΔΨ l ), which was correlated with lower leaf transpiration rate (E). E and ΔΨ l increased with increasing vapour pressure deficit (VPD) in non-stressed control vines but not in stressed vines. Perfusion of xylem-mobile dye showed that water flow to petioles and leaves was substantially reduced or even stopped under moderate and severe drought stress. Leaf blade hydraulic resistance accounted for most of the total shoot resistance. However, hydraulic conductance of the whole root system (K root ) was not significantly reduced until water stress became very severe in pot-grown vines. Significant correlations between K plant , K canopy and Ψ s , K canopy and leaf gas exchange, K leaf and Ψ s , and K leaf and A support a link between water supply, leaf water status and gas exchange. Upon re-watering, Ψ s recovered faster than gas exchange and leaf-shoot hydraulics. A gradual recovery of hydraulic functionality of plant organs was also observed, the leaves being the last to recover after rewatering. In pot-grown vines, K canopy recovered rather quickly following restoration of Ψ s , although gas exchange recovery did not directly depend on recovery of K canopy . In field-grown vines, recovery of water status, gas exchange and hydraulic functionality was slower than in pot-grown plants, and low g s after rewatering was related to sustained decreased K plant , K canopy and K shoot and lower water transport to leaves. These results suggest that caution should be exercised when scaling up conclusions from experiments with small pot-grown plants to field conditions. Copyright © 2017 Elsevier GmbH. All rights reserved.

Categories and inheritance of resistance to Nilaparvata lugens (Hemiptera: Delphacidae) in mutants of indica rice 'IR64'.

PubMed

Sangha, Jatinder Singh; Chen, Yolanda H; Palchamy, Kadirvel; Jahn, Gary C; Maheswaran, M; Adalla, Candida B; Leung, Hei

2008-04-01

Varietal mutants can be useful for developing durable resistance, understanding categories of resistance, and identifying candidate genes involved in defense responses. We used mutants of rice 'IR64' to isolate new sources of resistance to the planthopper Nilaparvata lugens (Stål) (Hemiptera: Delphacidae). We compared two mutants that showed a gain and loss of resistance to N. lugens, to determine the categories of resistance to this pest. Under choice tests, female planthoppers avoided settling and laid fewer eggs on the resistant mutant 'D518' than on the susceptible mutant D1131, susceptible check 'TN1', and wild-type IR64, indicating that antixenosis was the resistance category. Similarly, under no-choice conditions, planthoppers laid 29% fewer eggs in D518 than in IR64, but they oviposited more in 'D1131' and TN1. Honeydew excretion was greater on D1131 seedlings but slightly lower on D518 than on IR64. Nymphal survival and adult female weight did not differ among rice cultivars. D518 showed higher tolerance of N. lugens infestations than IR64. Genetic analysis of the F1, F2, and F3 populations derived from D518 x IR64 revealed that resistance in D518 is dominant and controlled by a single gene. Despite the variation in resistance to N. lugens, both mutants and IR64 performed similarly in the field. The mutant D518 is a new source of durable resistance to N. lugens, mainly due to enhanced antixenosis to female hoppers for settling and oviposition.

Thin Layer Chromatography-Bioautography and Gas Chromatography-Mass Spectrometry of Antimicrobial Leaf Extracts from Philippine Piper betle L. against Multidrug-Resistant Bacteria.

PubMed

Valle, Demetrio L; Puzon, Juliana Janet M; Cabrera, Esperanza C; Rivera, Windell L

2016-01-01

This study isolated and identified the antimicrobial compounds of Philippine Piper betle L. leaf ethanol extracts by thin layer chromatography- (TLC-) bioautography and gas chromatography-mass spectrometry (GC-MS). Initially, TLC separation of the leaf ethanol extracts provided a maximum of eight compounds with R f values of 0.92, 0.86, 0.76, 0.53, 0.40, 0.25, 0.13, and 0.013, best visualized when inspected under UV 366 nm. Agar-overlay bioautography of the isolated compounds demonstrated two spots with R f values of 0.86 and 0.13 showing inhibitory activities against two Gram-positive multidrug-resistant (MDR) bacteria, namely, methicillin-resistant Staphylococcus aureus and vancomycin-resistant Enterococcus. The compound with an R f value of 0.86 also possessed inhibitory activity against Gram-negative MDR bacteria, namely, carbapenem-resistant Enterobacteriaceae-Klebsiella pneumoniae and metallo-β-lactamase-producing Acinetobacter baumannii. GC-MS was performed to identify the semivolatile and volatile compounds present in the leaf ethanol extracts. Six compounds were identified, four of which are new compounds that have not been mentioned in the medical literature. The chemical compounds isolated include ethyl diazoacetate, tris(trifluoromethyl)phosphine, heptafluorobutyrate, 3-fluoro-2-propynenitrite, 4-(2-propenyl)phenol, and eugenol. The results of this study could lead to the development of novel therapeutic agents capable of dealing with specific diseases that either have weakened reaction or are currently not responsive to existing drugs.

Thin Layer Chromatography-Bioautography and Gas Chromatography-Mass Spectrometry of Antimicrobial Leaf Extracts from Philippine Piper betle L. against Multidrug-Resistant Bacteria

PubMed Central

Valle, Demetrio L.; Puzon, Juliana Janet M.; Cabrera, Esperanza C.

2016-01-01

This study isolated and identified the antimicrobial compounds of Philippine Piper betle L. leaf ethanol extracts by thin layer chromatography- (TLC-) bioautography and gas chromatography-mass spectrometry (GC-MS). Initially, TLC separation of the leaf ethanol extracts provided a maximum of eight compounds with R f values of 0.92, 0.86, 0.76, 0.53, 0.40, 0.25, 0.13, and 0.013, best visualized when inspected under UV 366 nm. Agar-overlay bioautography of the isolated compounds demonstrated two spots with R f values of 0.86 and 0.13 showing inhibitory activities against two Gram-positive multidrug-resistant (MDR) bacteria, namely, methicillin-resistant Staphylococcus aureus and vancomycin-resistant Enterococcus. The compound with an R f value of 0.86 also possessed inhibitory activity against Gram-negative MDR bacteria, namely, carbapenem-resistant Enterobacteriaceae-Klebsiella pneumoniae and metallo-β-lactamase-producing Acinetobacter baumannii. GC-MS was performed to identify the semivolatile and volatile compounds present in the leaf ethanol extracts. Six compounds were identified, four of which are new compounds that have not been mentioned in the medical literature. The chemical compounds isolated include ethyl diazoacetate, tris(trifluoromethyl)phosphine, heptafluorobutyrate, 3-fluoro-2-propynenitrite, 4-(2-propenyl)phenol, and eugenol. The results of this study could lead to the development of novel therapeutic agents capable of dealing with specific diseases that either have weakened reaction or are currently not responsive to existing drugs. PMID:27478476

Simultaneous Transfer of Leaf Rust and Powdery Mildew Resistance Genes from Hexaploid Triticale Cultivar Sorento into Bread Wheat

PubMed Central

Li, Feng; Li, Yinghui; Cao, Lirong; Liu, Peiyuan; Geng, Miaomiao; Zhang, Qiang; Qiu, Lina; Sun, Qixin; Xie, Chaojie

2018-01-01

Wheat powdery mildew, caused by Blumeria graminis f. sp. tritici, and wheat leaf rust, caused by Puccinia triticina Eriks, are two important diseases that severely threaten wheat production. Sorento, a hexaploid triticale cultivar from Poland, shows high resistance to the wheat powdery mildew isolate E09 and the leaf rust isolate PHT in Beijing, China. To introduce resistance genes into common wheat, Sorento was crossed with wheat line Xuezao, which is susceptible to both diseases, and the F1 hybrids were then backcrossed with Xuezao as the recurrent male parent. By marker analysis, we demonstrate that the long arm of the 2R (2RL) chromosome confers resistance to both the leaf rust and powdery mildew isolates at adult-plant and seedling stages, while the long arm of 4R (4RL) confers resistance only to powdery mildew at both stages. The chromosomal composition of BC2F3 plants containing 2R or 2RL and 4R or 4RL in the form of substitution and translocation were confirmed by GISH (genomic in situ hybridization) and FISH (fluorescence in situ hybridization). Monosomic and disomic substitutions of a wheat chromosome with chromosome 2R or 4R, as well as one 4RS-4DL/4DS-4RL reciprocal translocation homozigote and one 2RL-1DL translocation hemizigote, were recovered. Such germplasms are of great value in wheat improvement. PMID:29459877

Simultaneous Transfer of Leaf Rust and Powdery Mildew Resistance Genes from Hexaploid Triticale Cultivar Sorento into Bread Wheat.

PubMed

Li, Feng; Li, Yinghui; Cao, Lirong; Liu, Peiyuan; Geng, Miaomiao; Zhang, Qiang; Qiu, Lina; Sun, Qixin; Xie, Chaojie

2018-01-01

Wheat powdery mildew, caused by Blumeria graminis f. sp. tritici , and wheat leaf rust, caused by Puccinia triticina Eriks, are two important diseases that severely threaten wheat production. Sorento, a hexaploid triticale cultivar from Poland, shows high resistance to the wheat powdery mildew isolate E09 and the leaf rust isolate PHT in Beijing, China. To introduce resistance genes into common wheat, Sorento was crossed with wheat line Xuezao, which is susceptible to both diseases, and the F 1 hybrids were then backcrossed with Xuezao as the recurrent male parent. By marker analysis, we demonstrate that the long arm of the 2R (2RL) chromosome confers resistance to both the leaf rust and powdery mildew isolates at adult-plant and seedling stages, while the long arm of 4R (4RL) confers resistance only to powdery mildew at both stages. The chromosomal composition of BC 2 F 3 plants containing 2R or 2RL and 4R or 4RL in the form of substitution and translocation were confirmed by GISH (genomic in situ hybridization) and FISH (fluorescence in situ hybridization). Monosomic and disomic substitutions of a wheat chromosome with chromosome 2R or 4R, as well as one 4RS-4DL/4DS-4RL reciprocal translocation homozigote and one 2RL-1DL translocation hemizigote, were recovered. Such germplasms are of great value in wheat improvement.

Anatomical basis of variation in mesophyll resistance in eastern Australian sclerophylls: news of a long and winding path

PubMed Central

Tosens, Tiina

2012-01-01

In sclerophylls, photosynthesis is particularly strongly limited by mesophyll diffusion resistance from substomatal cavities to chloroplasts (r m), but the controls on diffusion limits by integral leaf variables such as leaf thickness, density, and dry mass per unit area and by the individual steps along the diffusion pathway are imperfectly understood. To gain insight into the determinants of r m in leaves with varying structure, the full CO2 physical diffusion pathway was analysed in 32 Australian species sampled from sites contrasting in soil nutrients and rainfall, and having leaf structures from mesophytic to strongly sclerophyllous. r m was estimated based on combined measurements of gas exchange and chlorophyll fluorescence. In addition, r m was modelled on the basis of detailed anatomical measurements to separate the importance of different serial resistances affecting CO2 diffusion into chloroplasts. The strongest sources of variation in r m were S c/S, the exposed surface area of chloroplasts per unit leaf area, and mesophyll cell wall thickness, t cw. The strong correlation of r m with t cw could not be explained by cell wall thickness alone, and most likely arose from a further effect of cell wall porosity. The CO2 drawdown from intercellular spaces to chloroplasts was positively correlated with t cw, suggesting enhanced diffusional limitations in leaves with thicker cell walls. Leaf thickness and density were poorly correlated with S c/S, indicating that widely varying combinations of leaf anatomical traits occur at given values of leaf integrated traits, and suggesting that detailed anatomical studies are needed to predict r m for any given species. PMID:22888123

Leaf hydraulics II: vascularized tissues.

PubMed

Rockwell, Fulton E; Holbrook, N Michele; Stroock, Abraham D

2014-01-07

Current models of leaf hydration employ an Ohm's law analogy of the leaf as an ideal capacitor, neglecting the resistance to flow between cells, or treat the leaf as a plane sheet with a source of water at fixed potential filling the mid-plane, neglecting the discrete placement of veins as well as their resistance. We develop a model of leaf hydration that considers the average conductance of the vascular network to a representative areole (region bounded by the vascular network), and represent the volume of tissue within the areole as a poroelastic composite of cells and air spaces. Solutions to the 3D flow problem are found by numerical simulation, and these results are then compared to 1D models with exact solutions for a range of leaf geometries, based on a survey of temperate woody plants. We then show that the hydration times given by these solutions are well approximated by a sum of the ideal capacitor and plane sheet times, representing the time for transport through the vasculature and tissue respectively. We then develop scaling factors relating this approximate solution to the 3D model, and examine the dependence of these scaling factors on leaf geometry. Finally, we apply a similar strategy to reduce the dimensions of the steady state problem, in the context of peristomatal transpiration, and consider the relation of transpirational gradients to equilibrium leaf water potential measurements. © 2013 Published by Elsevier Ltd. All rights reserved.

Fabrication of Artificial Leaf to Develop Fluid Pump Driven by Surface Tension and Evaporation

NASA Astrophysics Data System (ADS)

Lee, Minki; Lim, Hosub; Lee, Jinkee

2017-11-01

Plants transport water from roots to leaves via xylem through transpiration, which is an evaporation process that occurs at the leaves. During transpiration, negative pressure can be generated by the porous structure of mesophyll cells in the leaves. Here, an artificial leaf mimicking structure using hydrogel, which has a nanoporous structure is fabricated. The cryogel method is used to develop a hierarchy structure on the nano- and microscale in the hydrogel media that is similar to the mesophyll cells and veins of a leaf, respectively. The theoretical model is analyzed to calculate the flow resistance in the artificial leaf, and compare the model with the experimental results. The experiment involves connecting a glass capillary tube at the bottom of the artificial leaf to observe the fluid velocity in the glass capillary tube generated by the negative pressure. The use of silicone oil as fluid instead of water to increase the flow resistance enables the measurement of negative pressure. The negative pressure of the artificial leaf is affected by several variables (e.g., pore size, wettability of the structure). Finally, by decreasing the pore size and increasing the wettability, the maximum negative pressure of the artificial leaf, -7.9 kPa is obtained.

The durable wheat disease resistance gene Lr34 confers common rust and northern corn leaf blight resistance in maize.

PubMed

Sucher, Justine; Boni, Rainer; Yang, Ping; Rogowsky, Peter; Büchner, Heike; Kastner, Christine; Kumlehn, Jochen; Krattinger, Simon G; Keller, Beat

2017-04-01

Maize (corn) is one of the most widely grown cereal crops globally. Fungal diseases of maize cause significant economic damage by reducing maize yields and by increasing input costs for disease management. The most sustainable control of maize diseases is through the release and planting of maize cultivars with durable disease resistance. The wheat gene Lr34 provides durable and partial field resistance against multiple fungal diseases of wheat, including three wheat rust pathogens and wheat powdery mildew. Because of its unique qualities, Lr34 became a cornerstone in many wheat disease resistance programmes. The Lr34 resistance is encoded by a rare variant of an ATP-binding cassette (ABC) transporter that evolved after wheat domestication. An Lr34-like disease resistance phenotype has not been reported in other cereal species, including maize. Here, we transformed the Lr34 resistance gene into the maize hybrid Hi-II. Lr34-expressing maize plants showed increased resistance against the biotrophic fungal disease common rust and the hemi-biotrophic disease northern corn leaf blight. Furthermore, the Lr34-expressing maize plants developed a late leaf tip necrosis phenotype, without negative impact on plant growth. With this and previous reports, it could be shown that Lr34 is effective against various biotrophic and hemi-biotrophic diseases that collectively parasitize all major cereal crop species. © 2016 The Authors. Plant Biotechnology Journal published by Society for Experimental Biology and The Association of Applied Biologists and John Wiley & Sons Ltd.

The role of preliminary magazine training in acquisition of the autoshaped key peck1

PubMed Central

Davol, G. H.; Steinhauer, G. D.; Lee, A.

1977-01-01

A series of experiments tested the hypothesis that initial key pecks in the autoshaping procedure are generalized pecks at the illuminated grain hopper. Experiment I found that autoshaping readily occurred when the chamber was continuously illuminated by a house-light. In Experiment II, pigeons given magazine training and autoshaping with an unlighted grain hopper failed to autoshape in 200 trials. Acquisition of autoshaped key pecking was retarded in Experiment III when stimulus control by the magazine light was reduced. In the fourth study, pigeons were given magazine training with either a red or white magazine light and then given autoshaping with concurrently presented red and white keys. For all pigeons in this experiment, the first key peck occurred on the key of the same color as that pigeon's magazine light. The results of these experiments were interpreted as supporting an account of autoshaping that identifies initial key pecks as arising due to generalization of pecking at the lighted grain hopper to pecking at the lighted key. PMID:16812027

Short-term response of subadult white sturgeon to hopper dredge disposal operations

USGS Publications Warehouse

Parsley, Michael J.; Popoff, Nicholas D.; Romine, Jason G.

2011-01-01

The effect of dredged-material disposal operations on the behavior of seven white sturgeon Acipenser transmontanus (50–101 cm fork length) was examined by analysis of the movements and depth use of these fish before, during, and after a series of hopper dredge disposal operations in the lower Columbia River. Analyses of fish locations showed that 12 flow-lane disposal operations within a 24-h period had minimal effect on subadult white sturgeon behavior; six of the seven fish showed slight attraction to the disposal area during disposals, and one fish increased its distance from the disposal area. The core area for all fish combined shifted toward the disposal area during disposals. In the 24 h after completion of the disposal operations the fish core areas shifted back toward those areas occupied before the disposals. The rates of movement, depths used, and diel movement patterns of the white sturgeon showed little change over all periods, suggesting that natural behaviors were not altered during and immediately after hopper dredge disposal operations.

Study of composition change and agglomeration of flue gas cleaning residue from a fluidized bed waste incinerator.

PubMed

Lievens, P; Verbinnen, B; Bollaert, P; Alderweireldt, N; Mertens, G; Elsen, J; Vandecasteele, C

2011-10-01

Blocking of the collection hoppers of the baghouse filters in a fluidized bed incinerator for co-incineration of high calorific industrial solid waste and sludge was observed. The composition of the flue gas cleaning residue (FGCR), both from a blocked hopper and from a normal hopper, was investigated by (differential) thermogravimetric analysis, quantitative X-ray powder diffraction and wet chemical analysis. The lower elemental carbon concentration and the higher calcium carbonate concentration of the agglomerated sample was the result of oxidation of carbon and subsequent reaction of CO2 with CaO. The evolved heat causes a temperature increase, with the decomposition of CaOHCl as a consequence. The formation of calcite and calcium chloride and the evolution of heat caused agglomeration of the FGCR. Activated lignite coke was replaced by another adsorption agent with less carbon, so the auto-ignition temperature increased; since then no further block formation has occurred.

Phenol contents, oxidase activities, and the resistance of coffee to the leaf miner Leucoptera coffeella.

PubMed

Ramiro, Daniel Alves; Guerreiro-Filho, Oliveiro; Mazzafera, Paulo

2006-09-01

We examined the role of phenolic compounds, and the enzymes peroxidase and polyphenol oxidase, in the expression of resistance of coffee plants to Leucoptera coffeella (Lepidoptera: Lyonetiidae). The concentrations of total soluble phenols and chlorogenic acid (5-caffeoylquinic acid), and the activities of the oxidative enzymes peroxidase (POD) and polyphenol oxidase (PPO), were estimated in leaves of Coffea arabica, C. racemosa, and progenies of crosses between these species, which have different levels of resistance, before and after attack by this insect. The results indicate that phenols do not play a central role in resistance to the coffee leaf miner. Differences were detected between the parental species in terms of total soluble phenol concentrations and activities of the oxidative enzymes. However, resistant and susceptible hybrid plants did not differ in any of these characteristics. Significant induction of chlorogenic acid and PPO was only found in C. racemosa, the parental donator of the resistance genes against L. coffeella. High-performance liquid chromatography (HPLC) analysis also showed qualitative similarity between hybrids and the susceptible C. arabica. These results suggest that the phenolic content and activities of POD and PPO in response to the attack by the leaf miner may not be a strong evidence of their participation in direct defensive mechanisms.

Engineered disease resistance in cotton using RNA-interference to knock down cotton leaf curl kokhran virus-Burewala and cotton leaf curl Multan betasatellite

USDA-ARS?s Scientific Manuscript database

Cotton Leaf Curl virus Disease (CLCuD) has caused enormous losses in cotton (Gossypium hirsutum) production in Pakistan. RNA interference (RNAi) is an emerging technique that could knock out CLCuD by targeting different regions of the pathogen genome that are important for replication, transcription...

Mapping Late Leaf Spot Resistance in Peanut (Arachis hypogaea) Using QTL-seq Reveals Markers for Marker-Assisted Selection.

PubMed

Clevenger, Josh; Chu, Ye; Chavarro, Carolina; Botton, Stephanie; Culbreath, Albert; Isleib, Thomas G; Holbrook, C C; Ozias-Akins, Peggy

2018-01-01

Late leaf spot (LLS; Cercosporidium personatum ) is a major fungal disease of cultivated peanut ( Arachis hypogaea ). A recombinant inbred line population segregating for quantitative field resistance was used to identify quantitative trait loci (QTL) using QTL-seq. High rates of false positive SNP calls using established methods in this allotetraploid crop obscured significant QTLs. To resolve this problem, robust parental SNPs were first identified using polyploid-specific SNP identification pipelines, leading to discovery of significant QTLs for LLS resistance. These QTLs were confirmed over 4 years of field data. Selection with markers linked to these QTLs resulted in a significant increase in resistance, showing that these markers can be immediately applied in breeding programs. This study demonstrates that QTL-seq can be used to rapidly identify QTLs controlling highly quantitative traits in polyploid crops with complex genomes. Markers identified can then be deployed in breeding programs, increasing the efficiency of selection using molecular tools. Key Message: Field resistance to late leaf spot is a quantitative trait controlled by many QTLs. Using polyploid-specific methods, QTL-seq is faster and more cost effective than QTL mapping.

Mapping Late Leaf Spot Resistance in Peanut (Arachis hypogaea) Using QTL-seq Reveals Markers for Marker-Assisted Selection

PubMed Central

Clevenger, Josh; Chu, Ye; Chavarro, Carolina; Botton, Stephanie; Culbreath, Albert; Isleib, Thomas G.; Holbrook, C. C.; Ozias-Akins, Peggy

2018-01-01

Late leaf spot (LLS; Cercosporidium personatum) is a major fungal disease of cultivated peanut (Arachis hypogaea). A recombinant inbred line population segregating for quantitative field resistance was used to identify quantitative trait loci (QTL) using QTL-seq. High rates of false positive SNP calls using established methods in this allotetraploid crop obscured significant QTLs. To resolve this problem, robust parental SNPs were first identified using polyploid-specific SNP identification pipelines, leading to discovery of significant QTLs for LLS resistance. These QTLs were confirmed over 4 years of field data. Selection with markers linked to these QTLs resulted in a significant increase in resistance, showing that these markers can be immediately applied in breeding programs. This study demonstrates that QTL-seq can be used to rapidly identify QTLs controlling highly quantitative traits in polyploid crops with complex genomes. Markers identified can then be deployed in breeding programs, increasing the efficiency of selection using molecular tools. Key Message: Field resistance to late leaf spot is a quantitative trait controlled by many QTLs. Using polyploid-specific methods, QTL-seq is faster and more cost effective than QTL mapping. PMID:29459876

An Improved Method for Measuring Quantitative Resistance to the Wheat Pathogen Zymoseptoria tritici Using High-Throughput Automated Image Analysis.

PubMed

Stewart, Ethan L; Hagerty, Christina H; Mikaberidze, Alexey; Mundt, Christopher C; Zhong, Ziming; McDonald, Bruce A

2016-07-01

Zymoseptoria tritici causes Septoria tritici blotch (STB) on wheat. An improved method of quantifying STB symptoms was developed based on automated analysis of diseased leaf images made using a flatbed scanner. Naturally infected leaves (n = 949) sampled from fungicide-treated field plots comprising 39 wheat cultivars grown in Switzerland and 9 recombinant inbred lines (RIL) grown in Oregon were included in these analyses. Measures of quantitative resistance were percent leaf area covered by lesions, pycnidia size and gray value, and pycnidia density per leaf and lesion. These measures were obtained automatically with a batch-processing macro utilizing the image-processing software ImageJ. All phenotypes in both locations showed a continuous distribution, as expected for a quantitative trait. The trait distributions at both sites were largely overlapping even though the field and host environments were quite different. Cultivars and RILs could be assigned to two or more statistically different groups for each measured phenotype. Traditional visual assessments of field resistance were highly correlated with quantitative resistance measures based on image analysis for the Oregon RILs. These results show that automated image analysis provides a promising tool for assessing quantitative resistance to Z. tritici under field conditions.

Effects of Changing Stomatal Width in A Red Pine Forest on Soil Water Content, Leaf Water Potential, Bole Diameter, and Growth

PubMed Central

Turner, Neil C.; Waggoner, Paul E.

1968-01-01

Spraying a 16 meter tall stand of red pine (Pinus resinosa Ait.) with 10−3 m phenylmercuric acetate in early June and again in mid-July resulted in the water use between June 1 and October 25 being reduced by almost 10%. It was demonstrated that this was caused by an increase in the leaf resistance with partial stomatal closure, which reduced absolute water potential in the needles by 1 to 3 bars in the middle of the day. Smaller demands were made upon the reserves of water in the bole of the tree as shown by the smaller bole contraction in the treated trees. Although needle length and dry weight were unaffected by the spray, radial growth was reduced by approximately 32%. The dependence of leaf resistance on light intensity is shown, and its independence from leaf water potential discussed. PMID:16656870

Moringa Oleifera aqueous leaf extract down-regulates nuclear factor-kappaB and increases cytotoxic effect of chemotherapy in pancreatic cancer cells

PubMed Central

2013-01-01

Background Fewer than 6% patients with adenocarcinoma of the pancreas live up to five years after diagnosis. Chemotherapy is currently the standard treatment, however, these tumors often develop drug resistance over time. Agents for increasing the cytotoxic effects of chemotherapy or reducing the cancer cells’ chemo-resistance to the drugs are required to improve treatment outcome. Nuclear factor kappa B (NF-kB), a pro-inflammatory transcription factor, reportedly plays a significant role in the resistance of pancreatic cancer cells to apoptosis-based chemotherapy. This study investigated the effect of aqueous Moringa Oleifera leaf extract on cultured human pancreatic cancer cells - Panc-1, p34, and COLO 357, and whether it can potentiates the effect of cisplatin chemotherapy on these cells. Methods The effect of Moringa Oleifera leaf extract alone and in combination with cisplatin on the survival of cultured human pancreatic cancer cells was evaluated by XTT-based colorimetric assay. The distribution of Panc-1 cells in the cell cycle following treatment with Moringa leaf extract was evaluated by flow cytometry, and evaluations of protein levels were via immunoblotting. Data of cell survival following combined treatments were analyzed with Calcusyn software. Results Moringa Oleifera leaf extract inhibited the growth of all pancreatic cell lines tested. This effect was significant in all cells following exposure to ≥0.75 mg/ml of the extract. Exposure of Panc-1 cells to Moringa leaf extract induced an elevation in the sub-G1 cell population of the cell-cycle, and reduced the expression of p65, p-IkBα and IkBα proteins in crude cell extracts. Lastly, Moringa Oleifera leaf extract synergistically enhanced the cytotoxic effect of cisplatin on Panc-1 cells. Conclusion Moringa Oleifera leaf extract inhibits the growth of pancreatic cancer cells, the cells NF-κB signaling pathway, and increases the efficacy of chemotherapy in human pancreatic cancer cells. PMID:23957955

Moringa Oleifera aqueous leaf extract down-regulates nuclear factor-kappaB and increases cytotoxic effect of chemotherapy in pancreatic cancer cells.

PubMed

Berkovich, Liron; Earon, Gideon; Ron, Ilan; Rimmon, Adam; Vexler, Akiva; Lev-Ari, Shahar

2013-08-19

Fewer than 6% patients with adenocarcinoma of the pancreas live up to five years after diagnosis. Chemotherapy is currently the standard treatment, however, these tumors often develop drug resistance over time. Agents for increasing the cytotoxic effects of chemotherapy or reducing the cancer cells' chemo-resistance to the drugs are required to improve treatment outcome. Nuclear factor kappa B (NF-kB), a pro-inflammatory transcription factor, reportedly plays a significant role in the resistance of pancreatic cancer cells to apoptosis-based chemotherapy. This study investigated the effect of aqueous Moringa Oleifera leaf extract on cultured human pancreatic cancer cells - Panc-1, p34, and COLO 357, and whether it can potentiates the effect of cisplatin chemotherapy on these cells. The effect of Moringa Oleifera leaf extract alone and in combination with cisplatin on the survival of cultured human pancreatic cancer cells was evaluated by XTT-based colorimetric assay. The distribution of Panc-1 cells in the cell cycle following treatment with Moringa leaf extract was evaluated by flow cytometry, and evaluations of protein levels were via immunoblotting. Data of cell survival following combined treatments were analyzed with Calcusyn software. Moringa Oleifera leaf extract inhibited the growth of all pancreatic cell lines tested. This effect was significant in all cells following exposure to ≥0.75 mg/ml of the extract. Exposure of Panc-1 cells to Moringa leaf extract induced an elevation in the sub-G1 cell population of the cell-cycle, and reduced the expression of p65, p-IkBα and IkBα proteins in crude cell extracts. Lastly, Moringa Oleifera leaf extract synergistically enhanced the cytotoxic effect of cisplatin on Panc-1 cells. Moringa Oleifera leaf extract inhibits the growth of pancreatic cancer cells, the cells NF-κB signaling pathway, and increases the efficacy of chemotherapy in human pancreatic cancer cells.

Prospecting sugarcane resistance to Sugarcane yellow leaf virus by genome-wide association.

PubMed

Debibakas, S; Rocher, S; Garsmeur, O; Toubi, L; Roques, D; D'Hont, A; Hoarau, J-Y; Daugrois, J H

2014-08-01

Using GWAS approaches, we detected independent resistant markers in sugarcane towards a vectored virus disease. Based on comparative genomics, several candidate genes potentially involved in virus/aphid/plant interactions were pinpointed. Yellow leaf of sugarcane is an emerging viral disease whose causal agent is a Polerovirus, the Sugarcane yellow leaf virus (SCYLV) transmitted by aphids. To identify quantitative trait loci controlling resistance to yellow leaf which are of direct relevance for breeding, we undertook a genome-wide association study (GWAS) on a sugarcane cultivar panel (n = 189) representative of current breeding germplasm. This panel was fingerprinted with 3,949 polymorphic markers (DArT and AFLP). The panel was phenotyped for SCYLV infection in leaves and stalks in two trials for two crop cycles, under natural disease pressure prevalent in Guadeloupe. Mixed linear models including co-factors representing population structure fixed effects and pairwise kinship random effects provided an efficient control of the risk of inflated type-I error at a genome-wide level. Six independent markers were significantly detected in association with SCYLV resistance phenotype. These markers explained individually between 9 and 14 % of the disease variation of the cultivar panel. Their frequency in the panel was relatively low (8-20 %). Among them, two markers were detected repeatedly across the GWAS exercises based on the different disease resistance parameters. These two markers could be blasted on Sorghum bicolor genome and candidate genes potentially involved in plant-aphid or plant-virus interactions were localized in the vicinity of sorghum homologs of sugarcane markers. Our results illustrate the potential of GWAS approaches to prospect among sugarcane germplasm for accessions likely bearing resistance alleles of significant effect useful in breeding programs.

Antioxidant activity and induction of mechanisms of resistance to stresses related to the inoculation with Azospirillum brasilense.

PubMed

Fukami, Josiane; Ollero, Francisco Javier; de la Osa, Clara; Valderrama-Fernández, Rocio; Nogueira, Marco Antonio; Megías, Manuel; Hungria, Mariangela

2018-06-07

We investigated the effects of Azospirillum brasilense strains Ab-V5 and Ab-V6 in the induction of mechanisms of systemic acquired resistance (SAR) and induced system resistance (ISR) on maize (Zea mays L.) plants. Under normal growth conditions, the treatments consisted of the standard inoculation of cells at sowing, and leaf spray of cells or their metabolites at the V2.5 growth stage; under saline stress (170 mM NaCl), the treatment consisted of standard single and co-inoculation of A. brasilense and Rhizobium tropici. The main compounds in the Azospirillum metabolites were identified as indole-3-acetic acid (IAA) and salicylic acid (SA). Under normal conditions, A. brasilense cells applied at sowing or by leaf spray increased the activities of catalase (CAT), superoxide dismutase (SOD), and malondialdehyde (MDA) in leaves, and of ascorbate peroxidase (APX) in roots; however, interestingly, in general the highest activities were observed by leaf spray of metabolites. Under normal conditions, the highest levels of salicylic acid (SA) and jasmonic acid (JA) were achieved in leaves by leaf spray of metabolites, of SA in roots by leaf spray of cells, and of JA in roots by standard inoculation and leaf spray of metabolites. Under saline stress, plant protection occurred via SA and abscisic acid (ABA), but not JA. In general, inoculation resulted in further increases in SA in leaves and roots, and ABA in leaves. We hypothesize that A. brasilense confers protection to maize plants by simultaneous induction of JA and SA pathways, and, under saline stressing conditions, by SA and ABA pathways.

Stem hydraulic traits and leaf water-stress tolerance are co-ordinated with the leaf phenology of angiosperm trees in an Asian tropical dry karst forest

PubMed Central

Fu, Pei-Li; Jiang, Yan-Juan; Wang, Ai-Ying; Brodribb, Tim J.; Zhang, Jiao-Lin; Zhu, Shi-Dan; Cao, Kun-Fang

2012-01-01

Background and Aims The co-occurring of evergreen and deciduous angiosperm trees in Asian tropical dry forests on karst substrates suggests the existence of different water-use strategies among species. In this study it is hypothesized that the co-occurring evergreen and deciduous trees differ in stem hydraulic traits and leaf water relationships, and there will be correlated evolution in drought tolerance between leaves and stems. Methods A comparison was made of stem hydraulic conductivity, vulnerability curves, wood anatomy, leaf life span, leaf pressure–volume characteristics and photosynthetic capacity of six evergreen and six deciduous tree species co-occurring in a tropical dry karst forest in south-west China. The correlated evolution of leaf and stem traits was examined using both traditional and phylogenetic independent contrasts correlations. Key Results It was found that the deciduous trees had higher stem hydraulic efficiency, greater hydraulically weighted vessel diameter (Dh) and higher mass-based photosynthetic rate (Am); while the evergreen species had greater xylem-cavitation resistance, lower leaf turgor-loss point water potential (π0) and higher bulk modulus of elasticity. There were evolutionary correlations between leaf life span and stem hydraulic efficiency, Am, and dry season π0. Xylem-cavitation resistance was evolutionarily correlated with stem hydraulic efficiency, Dh, as well as dry season π0. Both wood density and leaf density were closely correlated with leaf water-stress tolerance and Am. Conclusions The results reveal the clear distinctions in stem hydraulic traits and leaf water-stress tolerance between the co-occurring evergreen and deciduous angiosperm trees in an Asian dry karst forest. A novel pattern was demonstrated linking leaf longevity with stem hydraulic efficiency and leaf water-stress tolerance. The results show the correlated evolution in drought tolerance between stems and leaves. PMID:22585930

Uncovering leaf rust responsive miRNAs in wheat (Triticum aestivum L.) using high-throughput sequencing and prediction of their targets through degradome analysis.

PubMed

Kumar, Dhananjay; Dutta, Summi; Singh, Dharmendra; Prabhu, Kumble Vinod; Kumar, Manish; Mukhopadhyay, Kunal

2017-01-01

Deep sequencing identified 497 conserved and 559 novel miRNAs in wheat, while degradome analysis revealed 701 targets genes. QRT-PCR demonstrated differential expression of miRNAs during stages of leaf rust progression. Bread wheat (Triticum aestivum L.) is an important cereal food crop feeding 30 % of the world population. Major threat to wheat production is the rust epidemics. This study was targeted towards identification and functional characterizations of micro(mi)RNAs and their target genes in wheat in response to leaf rust ingression. High-throughput sequencing was used for transcriptome-wide identification of miRNAs and their expression profiling in retort to leaf rust using mock and pathogen-inoculated resistant and susceptible near-isogenic wheat plants. A total of 1056 mature miRNAs were identified, of which 497 miRNAs were conserved and 559 miRNAs were novel. The pathogen-inoculated resistant plants manifested more miRNAs compared with the pathogen infected susceptible plants. The miRNA counts increased in susceptible isoline due to leaf rust, conversely, the counts decreased in the resistant isoline in response to pathogenesis illustrating precise spatial tuning of miRNAs during compatible and incompatible interaction. Stem-loop quantitative real-time PCR was used to profile 10 highly differentially expressed miRNAs obtained from high-throughput sequencing data. The spatio-temporal profiling validated the differential expression of miRNAs between the isolines as well as in retort to pathogen infection. Degradome analysis provided 701 predicted target genes associated with defense response, signal transduction, development, metabolism, and transcriptional regulation. The obtained results indicate that wheat isolines employ diverse arrays of miRNAs that modulate their target genes during compatible and incompatible interaction. Our findings contribute to increase knowledge on roles of microRNA in wheat-leaf rust interactions and could help in rust resistance breeding programs.

Influence of Cadmium on Water Relations, Stomatal Resistance, and Abscisic Acid Content in Expanding Bean Leaves 1

PubMed Central

Poschenrieder, Charlotte; Gunsé, Benet; Barceló, Juan

1989-01-01

Ten day old bush bean plants (Phaseolus vulgaris L. cv Contender) were used to analyze the effects of 3 micromolar Cd on the time courses of expansion growth, dry weight, leaf water relations, stomatal resistance, and abscisic acid (ABA) levels in roots and leaves. Control and Cd-treated plants were grown for 144 hours in nutrient solution. Samples were taken at 24 hour intervals. At the 96 and 144 hour harvests, additional measurements were made on excised leaves which were allowed to dry for 2 hours. From the 48 hour harvest, Cd-treated plants showed lower leaf relative water contents and higher stomatal resistances than controls. At the same time, root and leaf expansion growth, but not dry weight, was significantly reduced. The turgor potentials of leaves from Cd-treated plants were nonsignificantly higher than those of control leaves. A significant increase (almost 400%) of the leaf ABA concentration was detected after 120 hours exposure to Cd. But Cd was found to inhibit ABA accumulation during drying of excised leaves. It is concluded that Cd-induced decrease of expansion growth is not due to turgor decrease. The possible mechanisms of Cd-induced stomatal closure are discussed. PMID:16666937

Indirect selection for resistance to ear rot and leaf diseases in maize lines using biplots.

PubMed

Pereira, G S; Camargos, R B; Balestre, M; Von Pinho, R G; C Melo, W M

2015-09-21

Leaf disease and ear rot have caused reductions in maize yield in Brazil and other producer countries. Therefore, the aims of this study were to analyze the association between husked ear yield and the severity of maize white spot, gray leaf spot, helminthosporium, and ear rot caused by Fusarium verticillioides and Diplodia maydis using biplots in a mixed-model approach. The responses of 238 lines introduced to Brazil and four controls were evaluated using an incomplete block design with three replicates in two locations: Lavras and Uberlândia, Minas Gerais, Brazil. Two experiments were conducted in each location, one with F. verticillioides and the other with D. maydis. The mixed models elucidated the relationship between yield, leaf disease, and ear disease. Significant genotype x environment and genotype x pathogen interactions were observed. In conclusion, husked ear yield is more associated with ear rot than with the leaf diseases evaluated, justifying the indirect selection for resistance to kernel rot in maize-F. verticillioides and maize-D. maydis pathosystems by yield evaluation.

Mapping of SnTox3-Snn3 as a major determinant of field susceptibility to Septoria nodorum leaf blotch in the SHA3/CBRD x Naxos population

USDA-ARS?s Scientific Manuscript database

Parastagonospora nodorum is a necrotrophic pathogen of wheat, causing Septoria nodorum blotch (SNB) affecting both the leaf and glume. P. nodorum is the major leaf blotch pathogen on spring wheat in Norway. Resistance to the disease is quantitative, but several host-specific interactions between nec...

Molecular Cytogenetic Characterization of two Triticum-Secale-Thinopyrum Trigeneric Hybrids Exhibiting Superior Resistance to Fusarium Head Blight, Leaf Rust, and Stem Rust Race Ug99.

PubMed

Dai, Yi; Duan, Yamei; Liu, Huiping; Chi, Dawn; Cao, Wenguang; Xue, Allen; Gao, Yong; Fedak, George; Chen, Jianmin

2017-01-01

Fusarium head blight (FHB), leaf rust, and stem rust are the most destructive fungal diseases in current world wheat production. The diploid wheatgrass, Thinopyrum elongatum (Host) Dewey (2 n = 2 x = 14, EE) is an excellent source of disease resistance genes. Two new Triticum-Secale-Thinopyrum trigeneric hybrids were derived from a cross between a hexaploid triticale (X Triticosecale Wittmack, 2 n = 6 x = 42, AABBRR) and a hexaploid Triticum trititrigia (2 n = 6 x = 42, AABBEE), were produced and analyzed using genomic in situ hybridization and molecular markers. The results indicated that line RE21 contained 14 A-chromosomes, 14 B-chromosomes, three pairs of R-chromosomes (4R, 6R, and 7R), and four pairs of E-chromosomes (1E, 2E, 3E, and 5E) for a total chromosome number of 2 n = 42. Line RE62 contained 14 A-chromosomes, 14 B-chromosomes, six pairs of R-chromosomes, and one pair of translocation chromosomes between chromosome 5R and 5E, for a total chromosome number of 2 n = 42. At the seedling and adult growth stages under greenhouse conditions, line RE21 showed high levels of resistance to FHB, leaf rust, and stem rust race Ug99, and line RE62 was highly resistant to leaf rust and stem rust race Ug99. These two lines (RE21 and RE62) display superior disease resistance characteristics and have the potential to be utilized as valuable germplasm sources for future wheat improvement.

Gravity flow rate of solids through orifices and pipes

NASA Technical Reports Server (NTRS)

Gardner, J. F.; Smith, J. E.; Hobday, J. M.

1977-01-01

Lock-hopper systems are the most common means for feeding solids to and from coal conversion reactor vessels. The rate at which crushed solids flow by gravity through the vertical pipes and valves in lock-hopper systems affects the size of pipes and valves needed to meet the solids-handling requirements of the coal conversion process. Methods used to predict flow rates are described and compared with experimental data. Preliminary indications are that solids-handling systems for coal conversion processes are over-designed by a factor of 2 or 3.

A single-nucleotide polymorphism that accounts for allelic variation in the Lr34 gene and leaf rust reaction in hard winter wheat.

PubMed

Cao, Shuanghe; Carver, Brett F; Zhu, Xinkai; Fang, Tilin; Chen, Yihua; Hunger, Robert M; Yan, Liuling

2010-07-01

Leaf rust, caused by Puccinia triticina Eriks, is one of the most common and persistent wheat diseases in the US Great Plains. We report that the Lr34 gene was mapped in the center of a QTL for leaf rust reaction and explained 18-35% of the total phenotypic variation in disease severity of adult plants in a Jagger x 2174 population of recombinant inbred lines (RILs) field-tested for 3 years. The sequence of the complete Lr34 gene was determined for the susceptible Jagger allele and for the resistant 2174 allele. The two alleles had exactly the same sequence as the resistant allele reported previously in Chinese Spring at three polymorphic sites in intron 4, exon 11, and exon 12. A G/T polymorphism was found in exon 22, where a premature stop codon was found in the susceptible Jagger allele (Lr34E22s), confirming a previous report, due to a point mutation compared with the resistant 2174 allele (Lr34E22r). We have experimentally demonstrated a tight association between the point mutation at exon 22 of Lr34 and leaf rust susceptibility in a segregating biparental population. A PCR marker was developed to distinguish between the Lr34E22r and Lr34E22s alleles. A survey of 33 local hard winter wheat cultivars indicated that 7 cultivars carry the Lr34E22s allele and 26 cultivars carry the Lr34E22r allele. This study significantly improves our genetic understanding of allelic variation in the Lr34 gene and provides a functional molecular tool to improve leaf rust resistance in a major US wheat gene pool.

LOGIC CIRCUIT

DOEpatents

Strong, G.H.; Faught, M.L.

1963-12-24

A device for safety rod counting in a nuclear reactor is described. A Wheatstone bridge circuit is adapted to prevent de-energizing the hopper coils of a ball backup system if safety rods, sufficient in total control effect, properly enter the reactor core to effect shut down. A plurality of resistances form one arm of the bridge, each resistance being associated with a particular safety rod and weighted in value according to the control effect of the particular safety rod. Switching means are used to switch each of the resistances in and out of the bridge circuit responsive to the presence of a particular safety rod in its effective position in the reactor core and responsive to the attainment of a predetermined velocity by a particular safety rod enroute to its effective position. The bridge is unbalanced in one direction during normal reactor operation prior to the generation of a scram signal and the switching means and resistances are adapted to unbalance the bridge in the opposite direction if the safety rods produce a predetermined amount of control effect in response to the scram signal. The bridge unbalance reversal is then utilized to prevent the actuation of the ball backup system, or, conversely, a failure of the safety rods to produce the predetermined effect produces no unbalance reversal and the ball backup system is actuated. (AEC)

Leaf transpiration efficiency of some drought-resistant maize lines

USDA-ARS?s Scientific Manuscript database

Field measurements of leaf gas exchange in maize often indicate stomatal conductances higher than required to provide substomatal carbon dioxide concentrations saturating to photosynthesis. Thus maize leaves often operate at lower transpiration efficiency (TE) than potentially achievable for specie...

Moisture Resistant Finishes for Airplane Woods

NASA Technical Reports Server (NTRS)

Dunlap, M E

1921-01-01

This report describes briefly a series of experiments made at the Forest Products Laboratory, Madison, Wisconsin, to determine the comparative moisture resistance of linseed oil, impregnation treatments, condensation varnishes, oil varnishes, enamels, cellulose varnishes, rubber, electroplated and sprayed metal coatings, and metal-leaf coatings when applied to wood. All coatings except rubber and electroplated metal coatings, which were not developed sufficiently to make them practical, admitted moisture in varying degrees. The most effective and most practical coating was found to be that of aluminum leaf.

Effects of ammonium sulfate aerosols on vegetation—II. Mode of entry and responses of vegetation

NASA Astrophysics Data System (ADS)

Gmur, Nicholas F.; Evans, Lance S.; Cunningham, Elizabeth A.

These experiments were designed to provide information on the rates of aerosol deposition, mode of entry, and effects of deposition of submicrometer ammonium sulfate aerosols on foliage of Phaseolus vulgaris L. A deposition velocity of 3.2 × 10 3cms-1 was constant during 3-week exposures of plants to aerosol concentrations of 26mg m -3 (i.e. about two orders of magnitude above ambient episode concentrations). Mean deposition rate on foliage was 4.1 × 10 -11 μg cm -2s -1. Visible injury symptoms included leaf chlorosis, necrosis and loss of turgor. Chlorosis was most frequent near leaf margins causing epinasty and near major veins. Internal injury occurred initially in spongy mesophyll cells. Eventually abaxial epidermal and palisade parenchyma cells were injured. These results suggest that submicrometer aerosols enter abaxial stomata and affect more internal cells before affecting leaf surface cells. Exposure to aerosols decreased both abaxial and adaxial leaf resistances markedly. Although visible injury to foliage occurred, no changes in dry mass of roots and shoots or leaf area occurred. These results suggest that for the plant developmental stage studied, while leaf resistances decreased and cellular injury occurred in foliage, these factors were not significantly related to plant growth and development.

Transcriptome Profiling of Buffalograss Challenged with the Leaf Spot Pathogen Curvularia inaequalis.

PubMed

Amaradasa, Bimal S; Amundsen, Keenan

2016-01-01

Buffalograss (Bouteloua dactyloides) is a low maintenance U. S. native turfgrass species with exceptional drought, heat, and cold tolerance. Leaf spot caused by Curvularia inaequalis negatively impacts buffalograss visual quality. Two leaf spot susceptible and two resistant buffalograss lines were challenged with C. inaequalis. Samples were collected from treated and untreated leaves when susceptible lines showed symptoms. Transcriptome sequencing was done and differentially expressed genes were identified. Approximately 27 million raw sequencing reads were produced per sample. More than 86% of the sequencing reads mapped to an existing buffalograss reference transcriptome. De novo assembly of unmapped reads was merged with the existing reference to produce a more complete transcriptome. There were 461 differentially expressed transcripts between the resistant and susceptible lines when challenged with the pathogen and 1552 in its absence. Previously characterized defense-related genes were identified among the differentially expressed transcripts. Twenty one resistant line transcripts were similar to genes regulating pattern triggered immunity and 20 transcripts were similar to genes regulating effector triggered immunity. There were also nine up-regulated transcripts in resistance lines which showed potential to initiate systemic acquired resistance (SAR) and three transcripts encoding pathogenesis-related proteins which are downstream products of SAR. This is the first study characterizing changes in the buffalograss transcriptome when challenged with C. inaequalis.

Association between QTLs and morphological traits toward sheath blight resistance in rice (Oryza sativa L.)

PubMed Central

Hossain, Md Kamal; Jena, Kshirod Kumar; Bhuiyan, Md Atiqur Rahman; Wickneswari, Ratnam

2016-01-01

Sheath blight is considered the most significant disease of rice and causes enormous yield losses over the world. Breeding for resistant varieties is the only viable option to combat the disease efficiently. Seventeen diverged rice genotypes along with 17 QTL-linked SSR markers were evaluated under greenhouse conditions. Pearson’s correlation showed only the flag leaf angle had a significant correlation with sheath blight resistance under greenhouse screening. Multivariate analysis based on UPGMA clustering and principal component analysis (PCA) indicated that the flag leaf angle, flag leaf length, and plant compactness were significantly associated with the following SSR marker alleles: RM209 (116,130), RM202 (176), RM224 (126), RM257 (156), RM426 (175), and RM6971 (196), which are linked to the SB QTLs: QRlh11, qSBR11-3, qSBR11-1, qSBR9-1, qShB3-2, and qSB-9. A Mantel test suggested a weak relationship between the observed phenotypes and allelic variation patterns, implying the independent nature of morphological and molecular variations. Teqing and Tetep were found to be the most resistant cultivars. IR65482-4-136-2-2, MR219-4, and MR264 showed improved resistance potentials. These results suggest that the morphological traits and QTLs which have been found to associate with sheath blight resistance are a good choice to enhance resistance through pyramiding either 2 QTLs or QTLs and traits in susceptible rice cultivars. PMID:27795687

Freezing resistance in Patagonian woody shrubs: the role of cell wall elasticity and stem vessel size.

PubMed

Zhang, Yong-Jiang; Bucci, Sandra J; Arias, Nadia S; Scholz, Fabian G; Hao, Guang-You; Cao, Kun-Fang; Goldstein, Guillermo

2016-08-01

Freezing resistance through avoidance or tolerance of extracellular ice nucleation is important for plant survival in habitats with frequent subzero temperatures. However, the role of cell walls in leaf freezing resistance and the coordination between leaf and stem physiological processes under subzero temperatures are not well understood. We studied leaf and stem responses to freezing temperatures, leaf and stem supercooling, leaf bulk elastic modulus and stem xylem vessel size of six Patagonian shrub species from two sites (plateau and low elevation sites) with different elevation and minimum temperatures. Ice seeding was initiated in the stem and quickly spread to leaves, but two species from the plateau site had barriers against rapid spread of ice. Shrubs with xylem vessels smaller in diameter had greater stem supercooling capacity, i.e., ice nucleated at lower subzero temperatures. Only one species with the lowest ice nucleation temperature among all species studied exhibited freezing avoidance by substantial supercooling, while the rest were able to tolerate extracellular freezing from -11.3 to -20 °C. Leaves of species with more rigid cell walls (higher bulk elastic modulus) could survive freezing to lower subzero temperatures, suggesting that rigid cell walls potentially reduce the degree of physical injury to cell membranes during the extracellular freezing and/or thaw processes. In conclusion, our results reveal the temporal-spatial ice spreading pattern (from stem to leaves) in Patagonian shrubs, and indicate the role of xylem vessel size in determining supercooling capacity and the role of cell wall elasticity in determining leaf tolerance of extracellular ice formation. © The Author 2016. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

Distributor means for charging particulate material into receptacles

DOEpatents

Greaves, Melvin J.

1977-06-14

Disclosed are receptacles, such as shaft furnaces illustrated by a blast furnace and an upright oil shale retort, embodying rotatable charge distributor means for distributing particulate charge material in the furnace, which charge distributor means can provide a high uniformity of distribution of various sizes of particles and also can provide and maintain a stock line of desired contour and heighth in the receptacle. The distributor means includes a hopper having rigidly fixed to it a plurality of downwardly extending chutes with lower discharge portions that discharge in concentric circular zones at the stock line. The distributor means includes a segmented portion at the juncture of the hopper and the chutes that divides the charge material discharged into the hopper in proportion to the area of the circular zone at the stock line that is fed by the chute. The distributor means embodies means for providing mass flow of the particulate charge material through the chutes to the stock line and for avoiding segregation between larger and smaller particles of charge material deposited at the stock line.

Credit BG. This view looks northwest (290°) in the mixer ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

Credit BG. This view looks northwest (290°) in the mixer room at the 30-gallon Baker-Perkins model 121/2 PVM mixer and its associated equipment. The hopper in the left background feeds ingredients to the mixing pot when the hopper is mounted on the mixer frame; the hoist overhead is used to mount the hopper. The mixing pot is in its lowered position beneath the mixer blades. The pot is normally raised and secured to the upper half of the mixer, and a vacuum is applied during mixing operations to prevent the entrainment of air bubbles in the mix. A second mixing pot appears in the right background, and a pot vacuum lid appears in the extreme right foreground. The equipment on the palette in the left foreground is not related to the mixer. Note the explosion-proof fluorescent lighting fixtures suspended from the ceiling. The floor has an electrically conductive coating to dissipate static electrical charges - Jet Propulsion Laboratory Edwards Facility, Mixer & Casting Building, Edwards Air Force Base, Boron, Kern County, CA

Introgression of genes for cotton leaf curl virus resistance and increased fiber strength from Gossypium stocksii into upland cotton (G. hirsutum).

PubMed

Nazeer, W; Ahmad, S; Mahmood, K; Tipu, A L; Mahmood, A; Zhou, B

2014-02-21

Cotton leaf curl virus disease is a major hurdle for successful cotton production in Pakistan. There has been considerable economic loss due to this disease during the last decade. It would be desirable to have cotton varieties resistant to this disease. We explored the possibility of transferring virus resistant genes from the wild species Gossypium stocksii into MNH-786, a cultivar of G. hirsutum. Hybridization was done under field condition at the Cotton Research Station, Multan, during 2010-11. Boll shedding was controlled by application of exogenous hormones. F1 seeds were treated with 0.03% colchicine solution for 6 h and germinated. Cytological observations at peak squaring/flowering stage showed that these plants were hexaploid, having 2n = 6x = 78 chromosomes. The F1 plants showed intermediate expression for leaf size, leaf area, petiole length, bracteole number and size, bracteole area, bracteole dentation, flower size, pedicel size, and petal number and size. Moreover it possessed high fiber strength of 54.4 g/tex, which is 54% greater than that of the check variety, i.e. MNH-786 (G. hirsutum). The F1 population did not show any symptom of CLCuVD in the field, tested by grafting with CLCuVD susceptible rootstock (var. S12). We conclude that it is possible to transfer CLCuVD resistance and high fiber strength from G. stocksii to G. hirsutum.

Acylsucrose-Producing Tomato Plants Forces Bemisia tabaci to Shift Its Preferred Settling and Feeding Site

PubMed Central

Rodríguez-López, Maria Jose; Garzo, Elisa; Bonani, Jean Patrick; Fernández-Muñoz, Rafael; Moriones, Enrique; Fereres, Alberto

2012-01-01

Background The whitefly Bemisia tabaci (Genn.) causes dramatic damage to plants by transmitting yield-limiting virus diseases. Previous studies proved that the tomato breeding line ABL 14-8 was resistant to B. tabaci, the vector of tomato yellow leaf curl disease (TYLCD). This resistance is based on the presence of type IV glandular trichomes and acylsucrose production. These trichomes deter settling and probing of B. tabaci in ABL 14-8, which reduces primary and secondary spread of TYLCD. Methodology/Principal Findings Whitefly settlement preference was evaluated on the adaxial and abaxial leaf surfaces of nearly-isogenic tomato lines with and without B. tabaci-resistance traits, ‘ABL 14-8 and Moneymaker’ respectively, under non-choice and free-choice conditions. In addition, the Electrical Penetration Graph technique was used to study probing and feeding activities of B. tabaci on the adaxial and abaxial leaf surfaces of the same genotypes. B. tabaci preferred to settle on the abaxial than on the adaxial surface of ‘Moneymaker’ leaves, whereas no such preference was observed on ABL 14-8 tomato plants at the ten-leaf growth stage. Furthermore, B. tabaci preferred to feed on the abaxial than on the adaxial leaf surface of ‘Moneymarker’ susceptible tomato plants as shown by a higher number of sustained phloem feeding ingestion events and a shorter time to reach the phloem. However, B. tabaci standard probing and feeding behavior patterns were altered in ABL 14-8 plants and whiteflies were unable to feed from the phloem and spent more time in non-probing activities when exposed to the abaxial leaf surface. Conclusions/Significance The distorted behavior of B. tabaci on ABL 14-8 protects tomato plants from the transmission of phloem-restricted viruses such as Tomato yellow leaf curl virus (TYLCV), and forces whiteflies to feed on the adaxial side of leaves where they feed less efficiently and become more vulnerable to natural enemies. PMID:22427950

Response of Russian wheat aphid resistance in wheat and barley to four Diuraphis (Hemiptera: Aphididae) species.

PubMed

Puterka, Gary J; Scott, J Nicholson; Brown, Michael J; Hammon, R W

2013-04-01

Three Diuraphis species, Diuraphis frequens (Walker), Diuraphis mexicana (McVicar Baker), and Diuraphis tritici (Gillette), were known to exist in the United States before the 1986 appearance of the Russian wheat aphid, Diuraphis noxia Kurdjumov. The Russian wheat aphid soon became a significant pest of wheat although other endemic Diuraphis species were known to infest wheat. Wheat and barley entries resistant and susceptible to Russian wheat aphid biotype 2 were evaluated against all four Diuraphis species to determine their host interrelationships. Leaf chlorosis, leaf roll, leaf number, plant height, and infestation levels were assessed 21 d after the plants were infested by aphids in a no-choice caged environment. D. mexicana was unable to survive on wheat by 21 d after infestation and effects on the plant damage variables were negligible. D. frequens survived at low levels on resistant and susceptible plant entries and had a low impact on plant damage and growth. Russian wheat aphid biotype 2 and D. tritici were damaged most wheat and barley lines except the Russian wheat aphid biotype 2-resistant wheat lines containing genes from Dn7, STARS 2414-11, and CI2401; and resistant barley containing genes from STARS 9577B and 9301B. Russian wheat aphid biotype 2 and D. tritici reduced the growth of resistant plants by 25-50% and susceptible entries by 65-75%. Reductions at this level are typical under no-choice studies but resistant cultivars do not have these reductions under field conditions. The Russian wheat aphid biotype 2 resistant wheat lines would be effective in managing both wheat pest species.

Plasticity of vulnerability to leaf hydraulic dysfunction during acclimation to drought in grapevines: an osmotic-mediated process.

PubMed

Martorell, Sebastian; Medrano, Hipolito; Tomàs, Magdalena; Escalona, José M; Flexas, Jaume; Diaz-Espejo, Antonio

2015-03-01

Previous studies have reported correlation of leaf hydraulic vulnerability with pressure-volume parameters related to cell turgor. This link has been explained on the basis of the effects of turgor on connectivity among cells and tissue structural integrity, which affect leaf water transport. In this study, we tested the hypothesis that osmotic adjustment to water stress would shift the leaf vulnerability curve toward more negative water potential (Ψ leaf ) by increasing turgor at low Ψ leaf . We measured leaf hydraulic conductance (K leaf ), K leaf vulnerability [50 and 80% loss of K leaf (P50 and P80 ); |Ψ leaf | at 50 and 80% loss of K leaf , respectively), bulk leaf water relations, leaf gas exchange and sap flow in two Vitis vinifera cultivars (Tempranillo and Grenache), under two water treatments. We found that P50 , P80 and maximum K leaf decreased seasonally by more than 20% in both cultivars and watering treatments. However, K leaf at 2 MPa increased threefold, while osmotic potential at full turgor and turgor loss point decreased. Our results indicate that leaf resistance to hydraulic dysfunction is seasonally plastic, and this plasticity may be mediated by osmotic adjustment. © 2014 Scandinavian Plant Physiology Society.

Bacterial Leaf Spot of Lettuce: Request for Samples

USDA-ARS?s Scientific Manuscript database

Bacterial leaf spot of lettuce caused by by Xanthomonas campestris pv. vitians has been affecting coastal California crops for many years and has become a chronic problem. Differences in pathogen genotypes have been demonstrated and correlated to disease responses on resistant and susceptible cultiv...

Leaf Morphological Characters Can Be a Factor for Intra-Varietal Preference of Whitefly Bemisia tabaci (Hemiptera: Aleyrodidae) among Eggplant Varieties.

PubMed

Hasanuzzaman, Abu Tayeb Mohammad; Islam, Md Nazrul; Zhang, Yi; Zhang, Chen-Yang; Liu, Tong-Xian

2016-01-01

The sweetpotato whitefly, Bemisia tabaci (Hemiptera: Aleyrodidae) MEAM1, is considered a serious pest of horticultural and many other crops. While eggplant (Solanum melongena) is one of the most favored host plants, the whiteflies exhibit preferences among different varieties. We hypothesized that certain morphological leaf characteristics of different varieties, like leaf trichome density, trichome length, leaf lamina thickness and leaf color, may affect whitefly landing, feeding and oviposition. In this study, we investigated the variation in leaf morphological characters among selected eggplant varieties and evaluated the effect of these leaf characteristics in rendering eggplant varieties either susceptible or resistant to B. tabaci. We evaluated eight eggplant varieties in choice feeding tests, and we found that the varieties JinSheng Zilongchangqie (JSZ) and H149 were the highly preferred varieties with the highest numbers of whitefly adults and eggs. Significantly lower numbers of whitefly adult eggs were found on the resistant variety Tuo Lu Bamu (TLB). The varieties JinGuangbo Luqie (JGL), JinGuangbo Ziquanqie (JGZ), DaYang Ziguanqie (DYZ), QinXing Ziguanqie (QXZ), and QinXing Niuxinqie (QXN) were moderately favored by B. tabaci. Leaf trichome density, trichome length and leaf lamina thickness were positively correlated with numbers of whitefly adults and eggs. B. tabaci was less attracted to the leaves that reflect long and middle wavelength light (higher R and G values) than to the bright green leaves (medium G value), but the short wavelength light (higher B value) had no significant effect on whitefly preference. The degree of hue had a positive effect, and saturation and brightness had a negative effect on whitefly attraction.

Regulation of leaf hydraulics: from molecular to whole plant levels

PubMed Central

Prado, Karine; Maurel, Christophe

2013-01-01

The water status of plant leaves is dependent on both stomatal regulation and water supply from the vasculature to inner tissues. The present review addresses the multiple physiological and mechanistic facets of the latter process. Inner leaf tissues contribute to at least a third of the whole resistance to water flow within the plant. Physiological studies indicated that leaf hydraulic conductance (Kleaf) is highly dependent on the anatomy, development and age of the leaf and can vary rapidly in response to physiological or environmental factors such as leaf hydration, light, temperature, or nutrient supply. Differences in venation pattern provide a basis for variations in Kleaf during development and between species. On a short time (hour) scale, the hydraulic resistance of the vessels can be influenced by transpiration-induced cavitations, wall collapses, and changes in xylem sap composition. The extravascular compartment includes all living tissues (xylem parenchyma, bundle sheath, and mesophyll) that transport water from xylem vessels to substomatal chambers. Pharmacological inhibition and reverse genetics studies have shown that this compartment involves water channel proteins called aquaporins (AQPs) that facilitate water transport across cell membranes. In many plant species, AQPs are present in all leaf tissues with a preferential expression in the vascular bundles. The various mechanisms that allow adjustment of Kleaf to specific environmental conditions include transcriptional regulation of AQPs and changes in their abundance, trafficking, and intrinsic activity. Finally, the hydraulics of inner leaf tissues can have a strong impact on the dynamic responses of leaf water potential and stomata, and as a consequence on plant carbon economy and leaf expansion growth. The manipulation of these functions could help optimize the entire plant performance and its adaptation to extreme conditions over short and long time scales. PMID:23874349

On the Resistance to Transpiration of the Sites of Evaporation within the Leaf 1

PubMed Central

Farquhar, Graham D.; Raschke, Klaus

1978-01-01

The rates of transpiration from the upper and lower surfaces of leaves of Gossypium hirsutum, Xanthium strumarium, and Zea mays were compared with the rates at which helium diffused across those leaves. There was no evidence for effects of CO2 concentration or rate of evaporation on the resistance to water loss from the evaporating surface (“resistance of the mesophyll wall to transpiration”) and no evidence for any significant wall resistance in turgid tissues. The possible existence of a wall resistance was also tested in leaves of Commelina communis and Tulipa gesneriana whose epidermis could be easily peeled. Only when an epidermis was removed from a leaf, evaporation from the mesophyll tissue declined. We conclude that under conditions relevant to studies of stomatal behavior, the water vapor pressure at the sites of evaporation is equal to the saturation vapor pressure. PMID:16660404

The potential of biomonitoring of air quality using leaf characteristics of white willow (Salix alba L.).

PubMed

Wuytack, Tatiana; Verheyen, Kris; Wuyts, Karen; Kardel, Fatemeh; Adriaenssens, Sandy; Samson, Roeland

2010-12-01

In this study, we assess the potential of white willow (Salix alba L.) as bioindicator for monitoring of air quality. Therefore, shoot biomass, specific leaf area, stomatal density, stomatal pore surface, and stomatal resistance were assessed from leaves of stem cuttings. The stem cuttings were introduced in two regions in Belgium with a relatively high and a relatively low level of air pollution, i.e., Antwerp city and Zoersel, respectively. In each of these regions, nine sampling points were selected. At each sampling point, three stem cuttings of white willow were planted in potting soil. Shoot biomass and specific leaf area were not significantly different between Antwerp city and Zoersel. Microclimatic differences between the sampling points may have been more important to plant growth than differences in air quality. However, stomatal pore surface and stomatal resistance of white willow were significantly different between Zoersel and Antwerp city. Stomatal pore surface was 20% lower in Antwerp city due to a significant reduction in both stomatal length (-11%) and stomatal width (-14%). Stomatal resistance at the adaxial leaf surface was 17% higher in Antwerp city because of the reduction in stomatal pore surface. Based on these results, we conclude that stomatal characteristics of white willow are potentially useful indicators for air quality.

Screening of melon genotypes for resistance to vegetable leafminer and your phenotypic correlations with colorimetry.

PubMed

Oliveira, Frederico I C DE; Fiege, Leonardo B C; Celin, Elaine F; Innecco, Renato; Nunes, Glauber H S; Aragão, Fernando A S DE

2017-01-01

Melon is one of the most important vegetable crops in the world. With short cycle in a system of phased planting, phytosanitary control is compromised, and a great volume of agricultural chemicals is used to control vegetable leafminer. Genetic control is an ideal alternative to avoid the damage caused by this insect. Thus, the aim of this study was to evaluate Cucumis accessions in regard to resistance to leafminer and correlate the variables analyzed. Fifty-four accessions and four commercial hybrids of melon were tested. The study was divided into two experiments: with and with no choice. The following characteristics were evaluated: with choice, in field - subjective score based on the infestation and the number of mines per leaf; and with no choice, in cage - number of mines per leaf, chlorophyll content, and leaf colorimetry. The results showed variability among the accessions and some genotypes showed favorable results for resistance in both experiments. There was correlation between the two variables in the experiment in the field. The accessions CNPH 11-282, CNPH 06-1047, and CNPH 11-1077 are the most recommended for future breeding programs with aim on introgression of resistance to vegetable leafminer in melon.

Identification of Quantitative Trait Loci Conditioning the Main Biomass Yield Components and Resistance to Melampsora spp. in Salix viminalis × Salix schwerinii Hybrids

PubMed Central

Sulima, Paweł; Przyborowski, Jerzy A.; Kuszewska, Anna; Załuski, Dariusz; Jędryczka, Małgorzata; Irzykowski, Witold

2017-01-01

The biomass of Salix viminalis is the most highly valued source of green energy, followed by S. schwerinii, S. dasyclados and other species. Significant variability in productivity and leaf rust resistance are noted both within and among willow species, which creates new opportunities for improving willow yield parameters through selection of desirable recombinants supported with molecular markers. The aim of this study was to identify quantitative trait loci (QTLs) linked with biomass yield-related traits and the resistance/susceptibility of Salix mapping population to leaf rust. The experimental material comprised a mapping population developed based on S. viminalis × S. schwerinii hybrids. Phenotyping was performed on plants grown in a field experiment that had a balanced incomplete block design with 10 replications. Based on a genetic map, 11 QTLs were identified for plant height, 9 for shoot diameter, 3 for number of shoots and 11 for resistance/susceptibility to leaf rust. The QTLs identified in our study explained 3%–16% of variability in the analyzed traits. Our findings make significant contributions to the development of willow breeding programs and research into shrubby willow crops grown for energy. PMID:28327519

Two years at Meridiani Planum: Results from the opportunity rover

USGS Publications Warehouse

Squyres, S. W.; Knoll, A.H.; Arvidson, R. E.; Clark, B. C.; Grotzinger, J.P.; Jolliff, B.L.; McLennan, S.M.; Tosca, N.; Bell, J.F.; Calvin, W.M.; Farrand, W. H.; Glotch, T.D.; Golombek, M.P.; Herkenhoff, K. E.; Johnson, J. R.; Klingelhofer, G.; McSween, H.Y.; Yen, A. S.

2006-01-01

The Mars Exploration Rover Opportunity has spent more than 2 years exploring Meridiani Planum, traveling ???8 kilometers and detecting features that reveal ancient environmental conditions. These include well-developed festoon (trough) cross-lamination formed in flowing liquid water, strata with smaller and more abundant hematite-rich concretions than those seen previously, possible relict "hopper crystals" that might reflect the formation of halite, thick weathering rinds on rock surfaces, resistant fracture fills, and networks of polygonal fractures likely caused by dehydration of sulfate salts. Chemical variations with depth show that the siliciclastic fraction of outcrop rock has undergone substantial chemical alteration from a precursor basaltic composition. Observations from microscopic to orbital scales indicate that ancient Meridiani once had abundant acidic groundwater, arid and oxidizing surface conditions, and occasional liquid flow on the surface.

The Hopper System: How the Largest XE6 in the World Went From Requirements to Reality.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Antypas, Katie; Butler, Tina; Carter, Jonathan

This paper will discuss the entire process of acquiring and deploying Hopper from the first vendor market surveys to providing 3.8 million hours of production cycles per day for NERSC users. Installing the latest system at NERSC has been both a logistical and technical adventure. Balancing compute requirements with power, cooling, and space limitations drove the initial choice and configuration of the XE6, and a number of first-of- a-kind features implemented in collaboration with Cray have resulted in a high performance, usable, and reliable system.

Thermal Performance Benchmarking: Annual Report

DOE Office of Scientific and Technical Information (OSTI.GOV)

Feng, Xuhui

In FY16, the thermal performance of the 2014 Honda Accord Hybrid power electronics thermal management systems were benchmarked. Both experiments and numerical simulation were utilized to thoroughly study the thermal resistances and temperature distribution in the power module. Experimental results obtained from the water-ethylene glycol tests provided the junction-to-liquid thermal resistance. The finite element analysis (FEA) and computational fluid dynamics (CFD) models were found to yield a good match with experimental results. Both experimental and modeling results demonstrate that the passive stack is the dominant thermal resistance for both the motor and power electronics systems. The 2014 Accord power electronicsmore » systems yield steady-state thermal resistance values around 42- 50 mm to the 2nd power K/W, depending on the flow rates. At a typical flow rate of 10 liters per minute, the thermal resistance of the Accord system was found to be about 44 percent lower than that of the 2012 Nissan LEAF system that was benchmarked in FY15. The main reason for the difference is that the Accord power module used a metalized-ceramic substrate and eliminated the thermal interface material layers. FEA models were developed to study the transient performance of 2012 Nissan LEAF, 2014 Accord, and two other systems that feature conventional power module designs. The simulation results indicate that the 2012 LEAF power module has lowest thermal impedance at a time scale less than one second. This is probably due to moving low thermally conductive materials further away from the heat source and enhancing the heat spreading effect from the copper-molybdenum plate close to the insulated gate bipolar transistors. When approaching steady state, the Honda system shows lower thermal impedance. Measurement results of the thermal resistance of the 2015 BMW i3 power electronic system indicate that the i3 insulated gate bipolar transistor module has significantly lower junction-to-liquid thermal resistance as compared to the other systems. At a flow rate of 12 liters per minute, the thermal resistance of the i3 systems is only 30 percent of the Accord system and 15 percent of the LEAF system.« less

The role of nitric oxide in basal and induced resistance in relation with hydrogen peroxide and antioxidant enzymes.

PubMed

Keshavarz-Tohid, Vahid; Taheri, Parissa; Taghavi, Seyed Mohsen; Tarighi, Saeed

2016-07-20

Nitric oxide (NO) is one of the main signal molecules, which is involved in plant growth and development and can change regular physiological activity in biotic and abiotic stresses. In this study, the role of NO in induced resistance with Pseudomonas fluorescent (CHA0) and basal resistance against Rhizoctonia solani in bean plant was investigated. Our results revealed that P. fluorescent and R. solani can increase NO production at 6h post inoculation (hpi). Also, using the NO donor S-nitroso-N-acetyl D-penicillamine (SNAP) led to increase NO and bean plant resistance against R. solani. Utilizing the NO scavenger, 2-(4-carboxyphenyl)-4,4,5,5-tetramethy-limidazoline-1-oxyl-3-oxide (cPTIO), not only decreased basal resistance but also reduced induced resistance. In continue, the activity of antioxidant enzymes was studied in the former treatments. SNAP, CHA0 and R. solani increased the activity of peroxidase (POX), catalase (CAT) and ascorbate peroxidase (APX) at 6, 12 and 24h post inoculation (hpi). In contrast, using cPTIO and R. solani simultaneously (cPTIO+R) showed reduction in activity of POX and APX at 6 hpi. The cPTIO+R treatment increased POX, APX and CAT activity at 12 and 24 hpi. Hydrogen peroxide (H 2 O 2 ) monitoring in the leaf discs clarified that SNAP can increase H 2 O 2 production like CHA0 and R. solani. On the other hand, SNAP increased the resistance level of leaf discs against R. solani. Treating the leaf discs with cPTIO led to decrease resistance against the pathogen. These leaf discs showed reduction in H 2 O 2 production at 6 hpi and suddenly enhanced H 2 O 2 generation was observed at 24hpi. This study showed that CHA0 can increase NO level in bean plants. NO induced H 2 O 2 generation and regulated redox state of the host plant. This interaction resulted in significant defense against the pathogen. Copyright © 2016 Elsevier GmbH. All rights reserved.

Evaluation of fall armyworm resistance in maize germplasm lines using visual leaf injury rating and predator survey

USDA-ARS?s Scientific Manuscript database

After examining ear-colonizing pest resistance, 20 maize lines from the USDA-ARS germplasm enhancement of Maize (GEM) Program were evaluated for whorl-feeding fall armyworm (FAW) (Spodoptera frugiperda) resistance using four maize inbred lines as the resistant and susceptible controls. Both FAW inju...

Water stress-induced modifications of leaf hydraulic architecture in sunflower: co-ordination with gas exchange.

PubMed

Nardini, Andrea; Salleo, Sebastiano

2005-12-01

The hydraulic architecture, water relationships, and gas exchange of leaves of sunflower plants, grown under different levels of water stress, were measured. Plants were either irrigated with tap water (controls) or with PEG600 solutions with osmotic potential of -0.4 and -0.8 MPa (PEG04 and PEG08 plants, respectively). Mature leaves were measured for hydraulic resistance (R(leaf)) before and after making several cuts across minor veins, thus getting the hydraulic resistance of the venation system (R(venation)). R(leaf) was nearly the same in controls and PEG04 plants but it was reduced by about 30% in PEG08 plants. On the contrary, R(venation) was lowest in controls and increased in PEG04 and PEG08 plants as a likely result of reduction in the diameter of the veins' conduits. As a consequence, the contribution of R(venation) to the overall R(leaf) markedly increased from controls to PEG08 plants. Leaf conductance to water vapour (g(L)) was highest in controls and significantly lower in PEG04 and PEG08 plants. Moreover, g(L) was correlated to R(venation) and to leaf water potential (psi(leaf)) with highly significant linear relationships. It is concluded that water stress has an important effect on the hydraulic construction of leaves. This, in turn, might prove to be a crucial factor in plant-water relationships and gas exchange under water stress conditions.

Effects of Cottonwood Leaf Beetle (Coleoptera: Chrysomelidae) Larval Defoliation, Clone, and Season on Populus Foliar Phagostimulants

Treesearch

David R. Coyle; Joel D. McMillin; Richard B. Hall; Elwood R. Hart

2003-01-01

Abstract: The cottonwood leaf beetle, Chrysomela scripta F., is a serious defoliator of plantation Populus in the United States. Current control methods include biorational and synthetic chemicals as well as selecting Populus clones resistant or tolerant to C. scripta...

Lr67/Yr46 confers adult plant resistance to stem rust and powdery mildew in wheat.

PubMed

Herrera-Foessel, Sybil A; Singh, Ravi P; Lillemo, Morten; Huerta-Espino, Julio; Bhavani, Sridhar; Singh, Sukhwinder; Lan, Caixia; Calvo-Salazar, Violeta; Lagudah, Evans S

2014-04-01

We demonstrate that Lr67/Yr46 has pleiotropic effect on stem rust and powdery mildew resistance and is associated with leaf tip necrosis. Genes are designated as Sr55, Pm46 and Ltn3 , respectively. Wheat (Triticum aestivum) accession RL6077, known to carry the pleiotropic slow rusting leaf and yellow rust resistance genes Lr67/Yr46 in Thatcher background, displayed significantly lower stem rust (P. graminis tritici; Pgt) and powdery mildew (Blumeria graminis tritici; Bgt) severities in Kenya and in Norway, respectively, compared to its recurrent parent Thatcher. We investigated the resistance of RL6077 to stem rust and powdery mildew using Avocet × RL6077 F6 recombinant inbred lines (RILs) derived from two photoperiod-insensitive F3 families segregating for Lr67/Yr46. Greenhouse seedling tests were conducted with Mexican Pgt race RTR. Field evaluations were conducted under artificially initiated stem rust epidemics with Pgt races RTR and TTKST (Ug99 + Sr24) at Ciudad Obregon (Mexico) and Njoro (Kenya) during 2010-2011; and under natural powdery mildew epiphytotic in Norway at Ås and Hamar during 2011 and 2012. In Mexico, a mean reduction of 41 % on stem rust severity was obtained for RILs carrying Lr67/Yr46, compared to RILs that lacked the gene, whereas in Kenya the difference was smaller (16 %) but significant. In Norway, leaf tip necrosis was associated with Lr67/Yr46 and RILs carrying Lr67/Yr46 showed a 20 % reduction in mean powdery mildew severity at both sites across the 2 years of evaluation. Our study demonstrates that Lr67/Yr46 confers partial resistance to stem rust and powdery mildew and is associated with leaf tip necrosis. The corresponding pleiotropic, or tightly linked, genes, designated as Sr55, Pm46, and Ltn3, can be utilized to provide broad-spectrum durable disease resistance in wheat.

Lr41, Lr39, and a leaf rust resistance gene from Aegilops cylindrica may be allelic and are located on wheat chromosome 2DS.

PubMed

Singh, Sukhwinder; Franks, C D; Huang, L; Brown-Guedira, G L; Marshall, D S; Gill, B S; Fritz, A

2004-02-01

The leaf rust resistance gene Lr41 in wheat germplasm KS90WGRC10 and a resistance gene in wheat breeding line WX93D246-R-1 were transferred to Triticum aestivum from Aegilops tauschii and Ae. cylindrica, respectively. The leaf rust resistance gene in WX93D246-R-1 was located on wheat chromosome 2D by monosomic analysis. Molecular marker analysis of F(2) plants from non-critical crosses determined that this gene is 11.2 cM distal to marker Xgwm210 on the short arm of 2D. No susceptible plants were detected in a population of 300 F(2) plants from a cross between WX93D246-R-1 and TA 4186 ( Lr39), suggesting that the gene in WX93D246-R-1 is the same as, or closely linked to, Lr39. In addition, no susceptible plants were detected in a population of 180 F(2) plants from the cross between KS90WGRC10 and WX93D246-R-1. The resistance gene in KS90WGRC10, Lr41, was previously reported to be located on wheat chromosome 1D. In this study, no genetic association was found between Lr41 and 51 markers located on chromosome 1D. A population of 110 F(3 )lines from a cross between KS90WGRC10 and TAM 107 was evaluated with polymorphic SSR markers from chromosome 2D and marker Xgdm35 was found to be 1.9 cM proximal to Lr41. When evaluated with diverse isolates of Puccinia triticina, similar reactions were observed on WX93D246-R-1, KS90WGRC10, and TA 4186. The results of mapping, allelism, and race specificity test indicate that these germplasms likely have the same gene for resistance to leaf rust.

Breeding for cotton leaf curl disease (CLCuD) resistance

USDA-ARS?s Scientific Manuscript database

Cotton leaf curl disease (CLCuD) is caused by a whitefly (Bemisia tabaci) transmitted geminivirus. It is a major disease of cotton in Africa and South Asia, and has spread to other countries through ornamental plants. It can potentially devastate U.S. cotton where commercial varieties have no resi...

Leaf protein and mineral concentrations across the "miracle tree" genus Moringa

USDA-ARS?s Scientific Manuscript database

The moringa tree Moringa oleifera is a fast-growing, drought-resistant tree cultivated across the lowland dry tropics worldwide for its nutritious leaves. Despite its nutritious reputation, there has been no systematic survey of the variation in leaf nutritional quality across M. oleifera grown worl...

Association Mapping of Leaf Rust Response in Durum Wheat

USDA-ARS?s Scientific Manuscript database

Resistance to leaf rust (Puccinia triticina Eriks.) is a main objective for durum wheat (Triticum durum Desf.) breeding.Association mapping on germplasm collections is now being used as an additional approach for the discovery and validation of major genes/QTLs. In this study, a collection of 164 el...

Diverse mechanisms of plant resistance to cauliflower mosaic virus revealed by leaf skeleton hybridization.

PubMed

Melcher, U; Brannan, C M; Gardner, C O; Essenberg, R C

1992-01-01

Plants not hosts for cauliflower mosaic virus (CaMV) may prevent systemic CaMV infection by interfering with dissemination of infection through the plant or by preventing viral replication and maturation. Leaf skeleton hybridization allows distinction between these two barriers. The technique assesses the spatial distribution of CaMV in an inoculated leaf by hybridization of a skeleton of the leaf with a CaMV DNA probe. Leaves or leaflets of soybean, cucumber, peanut, tomato, lettuce, spinach, pepper, onion, wheat, maize and barley, inoculated with CaMV DNA or CaMV virions were processed for leaf skeleton hybridization either immediately after inoculation or two weeks thereafter. Autoradiographic images of soybean and cucumber skeletons had many dark spots suggesting that CaMV DNA replication and local spread had occurred. Images of onion leaf skeletons prepared two weeks after inoculation with CaMV DNA had fewer spots. To test whether these spots resulted from CaMV replication, DNA was extracted from inoculated onion leaves and analyzed by electrophoresis, blotting and hybridization. Molecules recovered two weeks after inoculation resembled those inoculated, indicating absence of replication. For the other species, we found no evidence of local spread of CaMV infections. Thus, many plant species resist systemic CaMV infection by preventing replication or local spread of CaMV, while others solely prevent systemic movement of infection.

Defensive changes in maize leaves induced by feeding of Mediterranean corn borer larvae.

PubMed

Santiago, Rogelio; Cao, Ana; Butrón, Ana; López-Malvar, Ana; Rodríguez, Víctor M; Sandoya, Germán V; Malvar, Rosa A

2017-02-15

Plants can respond to insect attack via defense mechanisms that reduce insect performance. In this study, we examined the effects of several treatments applied to two maize genotypes (one resistant, one susceptible) on the subsequent growth and survival of Sesamia nonagrioides Lef. (Mediterranean corn borer, MCB) larvae. The treatments were infestation with MCB larvae, application of MCB regurgitant upon wounding, wounding alone, or exposure to methyl jasmonate, and they were applied at the V6-V8 stage of maize development. We also monitored changes in the concentrations of compounds known to be involved in constitutive resistance, such as cell wall-bound hydroxycinnamates and benzoxazinoids. In both maize genotypes, the leaves of plants pre-infested with MCB larvae were less suitable for larval development than those from untreated plants. Application of MCB regurgitant upon wounding, and wounding itself, resulted in leaf tissues becoming less suitable for larval growth than those of pre-infested plants, suggesting that there could be herbivore-associated effector molecules that suppress some wounding responses. A single application of MCB regurgitant did not seem to mimic feeding by MCB larvae, although the results suggested that regurgitant deposited during feeding may have enhanced ferulates and diferulates synthesis in infested vs. control plants. Jasmonic acid may play a role in mediating the maize response to MCB attack, but it did not trigger hydroxycinnamate accumulation in the leaves to a level comparable to that induced by larval leaf feeding. The EP39 maize genotype showed an increase in leaf cell wall strength by increasing hemicellulose cross-linking in response to MCB attack, while induced defenses in the EP42 plants appeared to reflect a broader array of resistance mechanisms. The results indicated that leaf feeding by MCB larvae can increase leaf antibiosis against MCB in two maize genotypes with contrasting levels of resistance against this borer. Also, the larval regurgitant played a positive role in eliciting a defense response. We determined the effects of the plant response on larval growth, and detected defense compounds related to borer resistance.

Confirmation and mechanism of glyphosate resistance in tall windmill grass (Chloris elata) from Brazil.

PubMed

Brunharo, Caio Acg; Patterson, Eric L; Carrijo, Daniela R; de Melo, Marcel Sc; Nicolai, Marcelo; Gaines, Todd A; Nissen, Scott J; Christoffoleti, Pedro J

2016-09-01

Overreliance on glyphosate as a single tool for weed management in agricultural systems in Brazil has selected glyphosate-resistant populations of tall windmill grass (Chloris elata Desv.). Two C. elata populations, one glyphosate resistant (GR) and one glyphosate susceptible (GS), were studied in detail for a dose-response experiment and for resistance mechanism. The dose causing 50% reduction in dry weight was 620 g a.e. ha(-1) for GR and 114 g ha(-1) for GS, resulting in an R/S ratio of 5.4. GS had significantly higher maximum (14) C-glyphosate absorption into the treated leaf (51.3%) than GR (39.5%), a difference of 11.8% in maximum absorption. GR also retained more (14) C-glyphosate in the treated leaf (74%) than GS (51%), and GR translocated less glyphosate (27%) to other plant parts (stems, roots and root exudation) than GS (36%). There were no mutations at the Pro106 codon in the gene encoding 5-enolpyruvylshikimate-3-phosphate synthase (EPSPS). There was no difference in EPSPS genomic copy number or EPSPS transcription between GS and GR populations. Based on these data, reduced glyphosate absorption and increased glyphosate retention in the treated leaf contribute to glyphosate resistance in this C. elata population from Brazil. © 2015 Society of Chemical Industry. © 2015 Society of Chemical Industry.

Intracellular Ca(2+) and K(+) concentration in Brassica oleracea leaf induces differential expression of transporter and stress-related genes.

PubMed

Lee, Jeongyeo; Kim, Jungeun; Choi, Jae-Pil; Lee, MiYe; Kim, Min Keun; Lee, Young Han; Hur, Yoonkang; Nou, Ill-Sup; Park, Sang Un; Min, Sung Ran; Kim, HyeRan

2016-03-09

One of the most important members of the genus Brassica, cabbage, requires a relatively high level of calcium for normal growth (Plant Cell Environ 7: 397-405, 1984; Plant Physiol 60: 854-856, 1977). Localized Ca(2+) deficiency in cabbage leaves causes tip-burn, bringing about serious economic losses (Euphytica 9:203-208, 1960; Ann Bot 43:363-372, 1979; Sci Hortic 14:131-138, 1981). Although it has been known that the occurrence of tip-burn is related to Ca(2+) deficiency, there is limited information on the underlying mechanisms of tip-burn or the relationship between Ca(2+) and tip-burn incidence. To obtain more information on the genetic control of tip-burn symptoms, we focused on the identification of genes differentially expressed in response to increasing intracellular Ca(2+) and K(+) concentrations in B. oleracea lines derived from tip-burn susceptible, tip-burn resistant cabbages (B. oleracea var. capitata), and kale (B. oleracea var. acephala). We compared the levels of major macronutrient cations, including Ca(2+) and K(+), in three leaf segments, the leaf apex (LA), middle of leaf (LM), and leaf base (LB), of tip-burn susceptible, tip-burn resistant cabbages, and kale. Ca(2+) and K(+) concentrations were highest in kale, followed by tip-burn resistant and then tip-burn susceptible cabbages. These cations generally accumulated to a greater extent in the LB than in the LA. Transcriptome analysis identified 58,096 loci as putative non-redundant genes in the three leaf segments of the three B. oleracea lines and showed significant changes in expression of 27,876 loci based on Ca(2+) and K(+) levels. Among these, 1844 loci were identified as tip-burn related phenotype-specific genes. Tip-burn resistant cabbage and kale-specific genes were largely related to stress and transport activity based on GO annotation. Tip-burn resistant cabbage and kale plants showed phenotypes clearly indicative of heat-shock, freezing, and drought stress tolerance compared to tip-burn susceptible cabbages, demonstrating a correlation between intracellular Ca(2+) and K(+) concentrations and tolerance of abiotic stress with differential gene expression. We selected 165 genes that were up- or down-regulated in response to increasing Ca(2+) and K(+) concentrations in the three leaf segments of the three plant lines. Gene ontology enrichment analysis indicated that these genes participated in regulatory metabolic processes or stress responses. Our results indicate that the genes involved in regulatory metabolic processes or stress responses were differentially expressed in response to increasing Ca(2+) and K(+) concentrations in the B. oleracea leaf. Our transcriptome data and the genes identified may serve as a starting point for understanding the mechanisms underlying essential macronutrient deficiencies in plants, as well as the features of tip-burn in cabbage and other Brassica species.

Genome-wide identification and characterization of NB-ARC resistant genes in wheat (Triticum aestivum L.) and their expression during leaf rust infection.

PubMed

Chandra, Saket; Kazmi, Andaleeb Z; Ahmed, Zainab; Roychowdhury, Gargi; Kumari, Veena; Kumar, Manish; Mukhopadhyay, Kunal

2017-07-01

NB-ARC domain-containing resistance genes from the wheat genome were identified, characterized and localized on chromosome arms that displayed differential yet positive response during incompatible and compatible leaf rust interactions. Wheat (Triticum aestivum L.) is an important cereal crop; however, its production is affected severely by numerous diseases including rusts. An efficient, cost-effective and ecologically viable approach to control pathogens is through host resistance. In wheat, high numbers of resistance loci are present but only few have been identified and cloned. A comprehensive analysis of the NB-ARC-containing genes in complete wheat genome was accomplished in this study. Complete NB-ARC encoding genes were mined from the Ensembl Plants database to predict 604 NB-ARC containing sequences using the HMM approach. Genome-wide analysis of orthologous clusters in the NB-ARC-containing sequences of wheat and other members of the Poaceae family revealed maximum homology with Oryza sativa indica and Brachypodium distachyon. The identification of overlap between orthologous clusters enabled the elucidation of the function and evolution of resistance proteins. The distributions of the NB-ARC domain-containing sequences were found to be balanced among the three wheat sub-genomes. Wheat chromosome arms 4AL and 7BL had the most NB-ARC domain-containing contigs. The spatio-temporal expression profiling studies exemplified the positive role of these genes in resistant and susceptible wheat plants during incompatible and compatible interaction in response to the leaf rust pathogen Puccinia triticina. Two NB-ARC domain-containing sequences were modelled in silico, cloned and sequenced to analyze their fine structures. The data obtained in this study will augment isolation, characterization and application NB-ARC resistance genes in marker-assisted selection based breeding programs for improving rust resistance in wheat.

Resistance mechanisms and their difference between the root and leaf of Microsorum pteropus - A novel potential aquatic cadmium hyperaccumulator.

PubMed

Lan, Xin-Yu; Yang, Bin; Yan, Yun-Yun; Li, Xin-Yuan; Xu, Fu-Liu

2018-03-01

Microsorum pteropus (M. pteropus), an aquatic Polypodiaceae fern, was identified as a novel potential cadmium (Cd) hyperaccumulator in our previous study. This study reveals the Cd-resistance mechanisms and their difference between the root and leaf of M. pteropus based on analyses of photosynthesis, antioxidant systems and gene expression. A high level of Cd at 500μM was used to treat the samples to test the effects of this compound. Superoxide dismutase (SOD), peroxidase (POD), malondialdehyde (MDA) and flavonoids were used as indicators for antioxidant system changes. Five chlorophyll fluorescent parameters including the maximal photochemical efficiency of photosystem II (F v /F m ), effective quantum yield of photosystem II (Y(II)), photochemical quenching (qP), nonphotochemical quenching (qN) and electron transport rate (ETR) were measured to determine the photosynthetic changes. RNA-sequencing analysis was used to study the changes in gene expression. The results showed that after exposure to high levels of Cd, the concentrations of enzymatic oxidants (SOD and POD) were significantly increased, while the MDA levels were significantly decreased. There were no significant changes for the chlorophyll fluorescent parameters during Cd stress, which indicates that M. pteropus is highly effective at protecting itself. Certain functional genes, including photosystem genes and secondary metabolites, had significantly altered levels of expression. Different Cd-resistance mechanisms were found between the root and leaf tissues of M. pteropus. The root tissues of M. pteropus resist Cd damage using antioxidants, while its leaf tissues mainly protect themselves using photosystem self-protection. Copyright © 2017 Elsevier B.V. All rights reserved.

FaRXf1: a locus conferring resistance to angular leaf spot caused by Xanthomonas fragariae in octoploid strawberry.

PubMed

Roach, Jack A; Verma, Sujeet; Peres, Natalia A; Jamieson, Andrew R; van de Weg, W Eric; Bink, Marco C A M; Bassil, Nahla V; Lee, Seonghee; Whitaker, Vance M

2016-06-01

Angular leaf spot is a devastating bacterial disease of strawberry. Resistance from two wild accessions is highly heritable and controlled by a major locus on linkage group 6D. Angular leaf spot caused by Xanthomonas fragariae is the only major bacterial disease of cultivated strawberry (Fragaria ×ananassa). While this disease may cause reductions of up to 8 % of marketable yield in Florida winter annual production, no resistant cultivars have been commercialized. Wild accessions US4808 and US4809 were previously identified as resistant to the four genetic clades of X. fragariae, and introgression of the trait into commercial quality perennial-type germplasm was initiated. Previous reports indicated high heritability for the trait but proposed both single-locus and multi-locus inheritance models. The objective of this study was to determine the mode of inheritance of resistance, to identify causal loci, and to begin introgression of resistance into Florida-adapted germplasm. Resistance was observed in two years of field trials with inoculated plants that assayed four full-sib families descended from US4808 to US4809. Resistance segregated 1:1 in all families indicating control by a dominant allele at a single locus. Using a selective genotyping approach with the IStraw90 Axiom(®) SNP array and pedigree-based QTL detection, a single major-effect QTL was identified in two full-sib families, one descended from each resistant accession. High-resolution melt curve analysis validated the presence of the QTL in separate populations. The QTL was delimited to the 33.1-33.6 Mbp (F. vesca vesca v1.1 reference) and 34.8-35.3 Mbp (F. vesca bracteata v2.0 reference) regions of linkage group 6D for both resistance sources and was designated FaRXf1. Characterization of this locus will facilitate marker-assisted selection toward the development of resistant cultivars.

The content of phenolic compounds in leaf tissues of Aesculus glabra and Aesculus parviflora walt.

PubMed

Oszmiański, Jan; Kolniak-Ostek, Joanna; Biernat, Agata

2015-01-28

In plants, flavonoids play an important role in biological processes. They are involved in UV-scavenging, fertility and disease resistance. Therefore, in this study, we attempted to quantify and characterize phenolic compounds in Aesculus parviflora Walt. leaves and Aesculus glabra leaves partly suffering from attack by a leaf mining insect (C. ohridella). A total of 28 phenolic compounds belonging to the hydroxycinnamic acid, flavan-3-ols and flavonol groups were identified and quantified in Aesculus parviflora and A. glabra leaf extracts. Significantly decreased concentrations of some phenolic compounds, especially of flavan-3-ols, were observed in infected leaves compared to the non-infected ones. Additionally, a higher content of polymeric procyanidins in leaves of Aesculus parviflora than in Aesculus glabra may explain their greater resistance to C. ohridella insects.

Specificity of a Rust Resistance Suppressor on 7DL in the Spring Wheat Cultivar Canthatch.

PubMed

Talajoor, Mina; Jin, Yue; Wan, Anmin; Chen, Xianming; Bhavani, Sridhar; Tabe, Linda; Lagudah, Evans; Huang, Li

2015-04-01

The spring wheat 'Canthatch' has been shown to suppress stem rust resistance genes in the background due to the presence of a suppressor gene located on the long arm of chromosome 7D. However, it is unclear whether the suppressor also suppresses resistance genes against leaf rust and stripe rust. In this study, we investigated the specificity of the resistance suppression. To determine whether the suppression is genome origin specific, chromosome location specific, or rust species or race specific, we introduced 11 known rust resistance genes into the Canthatch background, including resistance to leaf, stripe, or stem rusts, originating from A, B, or D genomes and located on different chromosome homologous groups. F1 plants of each cross were tested with the corresponding rust race, and the infection types were scored and compared with the parents. Our results show that the Canthatch 7DL suppressor only suppressed stem rust resistance genes derived from either the A or B genome, and the pattern of the suppression is gene specific and independent of chromosomal location.

Identification of Functional Single-Nucleotide Polymorphisms Affecting Leaf Hair Number in Brassica rapa.

PubMed

Zhang, Wenting; Mirlohi, Shirin; Li, Xiaorong; He, Yuke

2018-06-01

Leaf traits affect plant agronomic performance; for example, leaf hair number provides a morphological indicator of drought and insect resistance. Brassica rapa crops have diverse phenotypes, and many B. rapa single-nucleotide polymorphisms (SNPs) have been identified and used as molecular markers for plant breeding. However, which SNPs are functional for leaf hair traits and, therefore, effective for breeding purposes remains unknown. Here, we identify a set of SNPs in the B. rapa ssp. pekinenesis candidate gene BrpHAIRY LEAVES1 ( BrpHL1 ) and a number of SNPs of BrpHL1 in a natural population of 210 B. rapa accessions that have hairy, margin-only hairy, and hairless leaves. BrpHL1 genes and their orthologs and paralogs have many SNPs. By intensive mutagenesis and genetic transformation, we selected the functional SNPs for leaf hairs by the exclusion of nonfunctional SNPs and the orthologous and paralogous genes. The residue tryptophan-92 of BrpHL1a was essential for direct interaction with GLABROUS3 and, thus, necessary for the formation of leaf hairs. The accessions with the functional SNP leading to substitution of the tryptophan-92 residue had hairless leaves. The orthologous BrcHL1b from B. rapa ssp. chinensis regulates hair formation on leaf margins rather than leaf surfaces. The selected SNP for the hairy phenotype could be adopted as a molecular marker for insect resistance in Brassica spp. crops. Moreover, the procedures optimized here can be used to explain the molecular mechanisms of natural variation and to facilitate the molecular breeding of many crops. © 2018 American Society of Plant Biologists. All rights reserved.

Leaf structural traits of tropical woody species resistant to cement dust.

PubMed

Siqueira-Silva, Advanio Inácio; Pereira, Eduardo Gusmão; Modolo, Luzia Valentina; Paiva, Elder Antonio Sousa

2016-08-01

Cement industries located nearby limestone outcrops in Brazil have contributed to the coating of cement dust over native plant species. However, little is known about the extent of the response of tropical woody plants to such environmental pollutant particularly during the first stages of plant development and establishment. This work focused on the investigation of possible alterations in leaf structural and ultrastructural traits of 5-month-old Guazuma ulmifolia Lam. (Malvaceae), 6-month-old Myracrodruon urundeuva Allemão (Anacardiaceae), and 9-month-old Trichilia hirta L. (Meliaceae) challenged superficially with cement dust during new leaf development. Leaf surface of plants, the soil or both (leaf plus soil), were treated (or not) for 60 days, under controlled conditions, with cement dust at 2.5 or 5.0 mg cm(-2). After exposure, no significant structural changes were observed in plant leaves. Also, no plant death was recorded by the end of the experiment. There was also some evidence of localized leaf necrosis in G. ulmifolia and T. hirta, leaf curling in M. urundeuva and T. hirta, and bulges formation on epidermal surface of T. hirta, after cement dust contact with plant shoots. All species studied exhibited stomata obliteration while T. hirta, in particular, presented early leaf abscission, changes in cellular relief, and organization and content of midrib cells. No significant ultrastructural alterations were detected under the experimental conditions studied. Indeed, mesophyll cells presented plastids with intact membrane systems. The high plant survival rates, together with mild morphoanatomic traits alterations in leaves, indicate that G. ulmifolia is more resistant to cement dust pollutant, followed by M. urundeuva and T. hirta. Thus, the three plant species are promising for being used to revegetate areas impacted by cement industries activities.

Ecohydrology of the wetland-forestland interface: hydrophobicity in leaf litter and its potential effect on surface evaporation

NASA Astrophysics Data System (ADS)

Probert, Samantha; Kettridge, Nicholas; Devito, Kevin; Hurley, Alexander

2017-04-01

Riparian wetlands represent an important ecotone at the interface of peatlands and forests within the Western Boreal Plain of Canada. Water storage and negative feedbacks to evaporation in these systems is crucial for the conservation and redistribution of water during dry periods and providing ecosystem resilience to disturbance. Litter cover can alter the relative importance of the physical processes that drive soil evaporation. Negative feedbacks to drying are created as the hydrophysical properties of the litter and soil override atmospheric controls on evaporation in dry conditions, subsequently dampening the effects of external forcings on the wetland moisture balance. In this study, water repellency in leaf litter has been shown to significantly correlate with surface-atmosphere interactions, whereby severely hydrophobic leaf litter is linked to the highest surface resistances to evaporation, and therefore lowest instantaneous evaporation. Decreasing moisture is associated with increasing hydrophobicity, which may reduce the evaporative flux further as the dry hydrophobic litter creates a hydrological disconnect between soil moisture and the atmosphere. In contrast, hydrophilic litter layers exhibited higher litter moistures, which is associated with reduced resistances to evaporation and enhanced evaporative fluxes. Water repellency of the litter layer has a greater control on evaporation than the presence or absence of litter itself. Litter removal had no significant effect on instantaneous evaporation or surface resistance to evaporation except under the highest evaporation conditions, where litter layers produced higher resistance values than bare peat soils. However, litter removal modified the dominant physical controls on evaporation: moisture loss in plots with leaf litter was driven by leaf and soil hydrophysical properties. Contrastingly, bare peat soils following litter removal exhibited cooler, wetter surfaces and were more strongly correlated to atmospheric controls. The interaction between evaporation, hydrophobicity and moisture of the soil surface, or litter, presents a potentially significant negative feedback to drying across wetland-forestland interfaces.

Maize Domestication and Anti-Herbivore Defences: Leaf-Specific Dynamics during Early Ontogeny of Maize and Its Wild Ancestors

PubMed Central

Maag, Daniel; Erb, Matthias; Bernal, Julio S.; Wolfender, Jean-Luc; Turlings, Ted C. J.; Glauser, Gaétan

2015-01-01

As a consequence of artificial selection for specific traits, crop plants underwent considerable genotypic and phenotypic changes during the process of domestication. These changes may have led to reduced resistance in the cultivated plant due to shifts in resource allocation from defensive traits to increased growth rates and yield. Modern maize (Zea mays ssp. mays) was domesticated from its ancestor Balsas teosinte (Z. mays ssp. parviglumis) approximately 9000 years ago. Although maize displays a high genetic overlap with its direct ancestor and other annual teosintes, several studies show that maize and its ancestors differ in their resistance phenotypes with teosintes being less susceptible to herbivore damage. However, the underlying mechanisms are poorly understood. Here we addressed the question to what extent maize domestication has affected two crucial chemical and one physical defence traits and whether differences in their expression may explain the differences in herbivore resistance levels. The ontogenetic trajectories of 1,4-benzoxazin-3-ones, maysin and leaf toughness were monitored for different leaf types across several maize cultivars and teosinte accessions during early vegetative growth stages. We found significant quantitative and qualitative differences in 1,4-benzoxazin-3-one accumulation in an initial pairwise comparison, but we did not find consistent differences between wild and cultivated genotypes during a more thorough examination employing several cultivars/accessions. Yet, 1,4-benzoxazin-3-one levels tended to decline more rapidly with plant age in the modern maize cultivars. Foliar maysin levels and leaf toughness increased with plant age in a leaf-specific manner, but were also unaffected by domestication. Based on our findings we suggest that defence traits other than the ones that were investigated are responsible for the observed differences in herbivore resistance between teosinte and maize. Furthermore, our results indicate that single pairwise comparisons may lead to false conclusions regarding the effects of domestication on defensive and possibly other traits. PMID:26267478

Evidence from Amazonian forests is consistent with isohydric control of leaf water potential.

PubMed

Fisher, Rosie A; Williams, Mathew; Do Vale, Raquel Lobo; Da Costa, Antonio Lola; Meir, Patrick

2006-02-01

Climate modelling studies predict that the rain forests of the Eastern Amazon basin are likely to experience reductions in rainfall of up to 50% over the next 50-100 years. Efforts to predict the effects of changing climate, especially drought stress, on forest gas exchange are currently limited by uncertainty about the mechanism that controls stomatal closure in response to low soil moisture. At a through-fall exclusion experiment in Eastern Amazonia where water was experimentally excluded from the soil, we tested the hypothesis that plants are isohydric, that is, when water is scarce, the stomata act to prevent leaf water potential from dropping below a critical threshold level. We made diurnal measurements of leaf water potential (psi 1), stomatal conductance (g(s)), sap flow and stem water potential (psi stem) in the wet and dry seasons. We compared the data with the predictions of the soil-plant-atmosphere (SPA) model, which embeds the isohydric hypothesis within its stomatal conductance algorithm. The model inputs for meteorology, leaf area index (LAI), soil water potential and soil-to-leaf hydraulic resistance (R) were altered between seasons in accordance with measured values. No optimization parameters were used to adjust the model. This 'mechanistic' model of stomatal function was able to explain the individual tree-level seasonal changes in water relations (r2 = 0.85, 0.90 and 0.58 for psi 1, sap flow and g(s), respectively). The model indicated that the measured increase in R was the dominant cause of restricted water use during the dry season, resulting in a modelled restriction of sap flow four times greater than that caused by reduced soil water potential. Higher resistance during the dry season resulted from an increase in below-ground resistance (including root and soil-to-root resistance) to water flow.

Cytotoxicity and apoptosis induced by alfalfa (Medicago sativa) leaf extracts in sensitive and multidrug-resistant tumor cells.

PubMed

Gatouillat, Grégory; Magid, Abdulmagid Alabdul; Bertin, Eric; Okiemy-Akeli, Marie-Genevieve; Morjani, Hamid; Lavaud, Catherine; Madoulet, Claudie

2014-01-01

Alfalfa (Medicago sativa) has been used to cure a wide variety of ailments. However, only a few studies have reported its anticancer effects. In this study, extracts were obtained from alfalfa leaves and their cytotoxic effects were assessed on several sensitive and multidrug-resistant tumor cells lines. Using the mouse leukaemia P388 cell line and its doxorubicin-resistant counterpart (P388/DOX), we showed that the inhibition of cell growth induced by alfalfa leaf extracts was mediated through the induction of apoptosis, as evidenced by DNA fragmentation analysis. The execution of programmed cell death was achieved via the activation of caspase-3, leading to PARP cleavage. Fractionation of toluene extract (To-1), the most active extract obtained from crude extract, led to the identification of 3 terpene derivatives and 5 flavonoids. Among them, (-)-medicarpin, (-)-melilotocarpan E, millepurpan, tricin, and chrysoeriol showed cytotoxic effects in P388 as well as P388/DOX cells. These results demonstrate that alfalfa leaf extract may have interesting potential in cancer chemoprevention and therapy.

Identification of novel powdery mildew resistance sources in wheat

USDA-ARS?s Scientific Manuscript database

Powdery mildew is a globally dominating disease of wheat with a high occurrence frequency, and genetic resistance plays an important role in managing this devastating disease. The objectives of this study were to evaluate leaf rust resistance and the underlying genes of breeding lines in the USA, a...

Characterization of partial resistance to black spot disease of Rosa spp.

USDA-ARS?s Scientific Manuscript database

Black spot disease (BSD) is one of the most serious diseases of garden roses. Both complete (vertical) resistance and partial (horizontal) resistance have been identified in 16 rose genotypes using two laboratory assays, the detached leaf assay (DLA) and the whole plant inoculation (WPI) approaches...

High-resolution mapping reveals linkage between genes in common bean cultivar Ouro Negro conferring resistance to the rust, anthracnose, and angular leaf spot diseases.

PubMed

Valentini, Giseli; Gonçalves-Vidigal, Maria Celeste; Hurtado-Gonzales, Oscar P; de Lima Castro, Sandra Aparecida; Cregan, Perry B; Song, Qijian; Pastor-Corrales, Marcial A

2017-08-01

Co-segregation analysis and high-throughput genotyping using SNP, SSR, and KASP markers demonstrated genetic linkage between Ur-14 and Co-3 4 /Phg-3 loci conferring resistance to the rust, anthracnose and angular leaf spot diseases of common bean. Rust, anthracnose, and angular leaf spot are major diseases of common bean in the Americas and Africa. The cultivar Ouro Negro has the Ur-14 gene that confers broad spectrum resistance to rust and the gene cluster Co-3 4 /Phg-3 containing two tightly linked genes conferring resistance to anthracnose and angular leaf spot, respectively. We used co-segregation analysis and high-throughput genotyping of 179 F 2:3 families from the Rudá (susceptible) × Ouro Negro (resistant) cross-phenotyped separately with races of the rust and anthracnose pathogens. The results confirmed that Ur-14 and Co-3 4 /Phg-3 cluster in Ouro Negro conferred resistance to rust and anthracnose, respectively, and that Ur-14 and the Co-3 4 /Phg-3 cluster were closely linked. Genotyping the F 2:3 families, first with 5398 SNPs on the Illumina BeadChip BARCBEAN6K_3 and with 15 SSR, and eight KASP markers, specifically designed for the candidate region containing Ur-14 and Co-3 4 /Phg-3, permitted the creation of a high-resolution genetic linkage map which revealed that Ur-14 was positioned at 2.2 cM from Co-3 4 /Phg-3 on the short arm of chromosome Pv04 of the common bean genome. Five flanking SSR markers were tightly linked at 0.1 and 0.2 cM from Ur-14, and two flanking KASP markers were tightly linked at 0.1 and 0.3 cM from Co-3 4 /Phg-3. Many other SSR, SNP, and KASP markers were also linked to these genes. These markers will be useful for the development of common bean cultivars combining the important Ur-14 and Co-3 4 /Phg-3 genes conferring resistance to three of the most destructive diseases of common bean.

Fluidized bed heat exchanger with water cooled air distributor and dust hopper

DOEpatents

Jukkola, Walfred W.; Leon, Albert M.; Van Dyk, Jr., Garritt C.; McCoy, Daniel E.; Fisher, Barry L.; Saiers, Timothy L.; Karstetter, Marlin E.

1981-11-24

A fluidized bed heat exchanger is provided in which air is passed through a bed of particulate material containing fuel. A steam-water natural circulation system is provided for heat exchange and the housing of the heat exchanger has a water-wall type construction. Vertical in-bed heat exchange tubes are provided and the air distributor is water-cooled. A water-cooled dust hopper is provided in the housing to collect particulates from the combustion gases and separate the combustion zone from a volume within said housing in which convection heat exchange tubes are provided to extract heat from the exiting combustion gases.

Methods and sorbents for utilizing a hot-side electrostatic precipitator for removal of mercury from combustion gases

DOEpatents

Nelson, Sidney [Hudson, OH

2011-02-15

Methods are provided for reducing emission of mercury from a gas stream by treating the gas with carbonaceous mercury sorbent particles to reduce the mercury content of the gas; collecting the carbonaceous mercury sorbent particles on collection plates of a hot-side ESP; periodically rapping the collection plates to release a substantial portion of the collected carbonaceous mercury sorbent particles into hoppers; and periodically emptying the hoppers, wherein such rapping and emptying are done at rates such that less than 70% of mercury adsorbed onto the mercury sorbent desorbs from the collected mercury sorbent into the gas stream.

Credit PSR. The interior of the grinder room appears as ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

Credit PSR. The interior of the grinder room appears as seen looking southeast (148°), showing the remaining grinder equipment in the building. Note the blow-out wall in the background, and the water sprinkler head positioned over the hopper. The hopper top is connected to the dust receiver in the adjacent room. The blow-out wall is constructed to relieve pressure easily should an explosion occur, thus minimizing damage to the rest of the building structure. The floor has a conductive coating which dissipates static electrical charges that might otherwise cause fires - Jet Propulsion Laboratory Edwards Facility, Oxidizer Grinder Building, Edwards Air Force Base, Boron, Kern County, CA

Stagnation, circulation, and erosion of granular materials through belt conveyor sluice gate

NASA Astrophysics Data System (ADS)

Pohlman, Nicholas; Moralda, Michael; Dunne, Ryan

2013-11-01

Control of flow rates in conversion reactors for discrete materials like biomass can be achieved in belt conveyors through a combination of belt speed, hopper size, and aperture opening. As material is extracted from the bottom of the storage hopper, other material cannot achieve plug flow and therefore is restricted from exiting through a sluice-gate type opening. The excess material moves vertically from the opening causing a pile up and recirculation back along the free surface of the hopper. Experimental results obtained through high speed imaging show the position of the stagnation point as well as the rate of circulation is dependent on the mass flow rate achieved and instantaneous fill level. The movement of material into the plug flow along the belt allows verification of deposition models on erodible beds rather than rigid surfaces with artificial roughness of glued particles. Similarly, the pile-up at the exit influences the efficiency of the transport affecting the narrow energy return on investment of biomass resources. The laboratory-scale behavior can therefore be translated into industrial performance metrics for increased operational efficiency. This work is supported by the NSF REU Site Operation E-Tank under award number 1156789.

Stationary bubble formation and cavity collapse in wedge-shaped hoppers

PubMed Central

Yagisawa, Yui; Then, Hui Zee; Okumura, Ko

2016-01-01

The hourglass is one of the apparatuses familiar to everyone, but reveals intriguing behaviors peculiar to granular materials, and many issues are remained to be explored. In this study, we examined the dynamics of falling sand in a special form of hourglass, i.e., a wedge-shaped hopper, when a suspended granular layer is stabilized to a certain degree. As a result, we found remarkably different dynamic regimes of bubbling and cavity. In the bubbling regime, bubbles of nearly equal size are created in the sand at a regular time interval. In the cavity regime, a cavity grows as sand beads fall before a sudden collapse of the cavity. Bubbling found here is quite visible to a level never discussed in the physics literature and the cavity regime is a novel phase, which is neither continuous, intermittent nor completely blocked phase. We elucidate the physical conditions necessary for the bubbling and cavity regimes and develop simple theories for the regimes to successfully explain the observed phenomena by considering the stability of a suspended granular layer and clogging of granular flow at the outlet of the hopper. The bubbling and cavity regimes could be useful for mixing a fluid with granular materials. PMID:27138747

Structure of jammed configurations and their relation to unjamming times

NASA Astrophysics Data System (ADS)

Birwa, Sumit Kumar; Merrigan, Carl; Chakraborty, Bulbul; Tewari, Shubha

The distribution of the times for the cessation of flow of grains falling under gravity in a vertical hopper is known to be exponential. Recent experiments have shown, however, that the time lapse between avalanches follows a power-law distribution when the hopper is unjammed using periodic vertical vibrations. The reasons for this distribution of the unjamming times, which indicates the time needed for an applied continuous perturbation to induce another avalanche, are not well understood. We report on a numerical simulation of granular hopper flow using LAMMPS in which we seek to understand the origin and scope of this behavior. We find that cessation of flow is related to the formation of a stable arch that spans the system. However, the actual structure of the jammed configuration varies and is closely related to the unjamming time. We find that the symmetry of the arches is an important parameter in determining the strength of the jammed configurations. Using different force thresholds, we have characterized the contact networks around the arches which provides stability to the packed structure and analyzed the strength of various jammed configurations. Supported by NSF Grant DMR1409093 and DGE1068620.

RNAi-mediated resistance against Cotton leaf curl disease in elite Indian cotton (Gossypium hirsutum) cultivar Narasimha.

PubMed

Khatoon, Sameena; Kumar, Abhinav; Sarin, Neera B; Khan, Jawaid A

2016-08-01

Cotton leaf curl disease (CLCuD) is caused by several distinct begomovirus species in association with disease-specific betasatellite essential for induction of disease symptoms. CLCuD is a serious threat for the cultivation of cotton (Gossypium sp.) and several species in the family Malvaceae. In this study, RNAi-based approach was applied to generate transgenic cotton (Gossypium hirsutum) plants resistant to Cotton leaf curl Rajasthan virus (CLCuRV). An intron hairpin (ihp) RNAi construct capable of expressing dsRNA homologous to the intergenic region (IR) of CLCuRV was designed and developed. Following Agrobacterium tumefaciens-mediated transformation of cotton (G. hirsutum cv. Narasimha) plants with the designed ihpRNAi construct, a total of 9 independent lines of transformed cotton were obtained. The presence of the potential stretch of IR in the transformed cotton was confirmed by PCR coupled with Southern hybridization. Upon inoculation with viruliferous whiteflies, the transgenic plants showed high degree of resistance. None of them displayed any CLCuD symptoms even after 90 days post inoculation. The transformed cotton plants showed the presence of siRNAs. The present study demonstrated that ihp dsRNA-mediated resistance strategy of RNAi is an effective means to combat the CLCuD infection in cotton.

Stability of tetraconazole-resistant isolates of Cercospora beticola after exposure to different temperature and time treatments

USDA-ARS?s Scientific Manuscript database

Cercospora leaf spot caused by Cercospora beticola is the major foliar disease effecting sugar beet (Beta vulgaris L.) production in North Dakota and Minnesota. The sterol demethylation inhibitor (DMI) fungicide tetraconazole is widely-used to manage Cercospora leaf spot. However, there has been an ...

Mining cotton germplasm resources to fight Cotton Leaf Curl Virus

USDA-ARS?s Scientific Manuscript database

CLCuV (Cotton Leaf Curl Virus) is a major threat to cotton production in Pakistan and parts of India and has been reported in cotton producing countries in Africa, as well as China and Uzbekistan. Identifying sources of resistance to CLCuV helps not only countries such as Pakistan where the virus is...

QTLs for resistance to the leaf rust Puccinia brachypodii in the model grass Brachypodium distachyon

USDA-ARS?s Scientific Manuscript database

The wild grass Brachypodium distachyon is a useful new model for temperate cereals, but its potential to study the interactions with pathogens remains underexploited. Leaf rust is one of the major fungal diseases affecting cereals, and recently the host status of Brachypodium to Puccinia rusts was i...

Oxidative stress: A link between drought and aflatoxin contamination in maize

USDA-ARS?s Scientific Manuscript database

Host resistance to diseases, such as early leaf spot (ELS), late leaf spot (LLS) and Tomato spotted wilt virus (TSWV), is critical for increasing the yield and reducing the cost for peanut farmers. With the completion of the genome sequences of two diploid ancestors of cultivated peanut, we could ge...

Unravel the genetic basis of Sugarcane Yellow Leaf Virus (SCYLV) resistance in Saccharum spp. hybrid

USDA-ARS?s Scientific Manuscript database

Sugarcane (Saccharum Spp.) produces 80% of the world’s table sugar along with several other byproducts. The production of sugarcane is vulnerable due to infestation of sugarcane yellow leaf virus (SCYLV) worldwide. A genetic mapping study was conducted using an F1 segregating population derived from...

Mapping of quantitative trait loci for resistance to fall armyworm and southwestern corn borer leaf-feeding damage in maize.

USDA-ARS?s Scientific Manuscript database

Fall armyworm (FAW), Spodoptera frugiperda (J. E. Smith), and southwestern corn borer (SWCB), Diatraea grandiosella Dyar are damaging insect pests of maize resulting in significant yield and economic losses. A previous study identified quantitative trait loci (QTL) that contribute to reduced leaf-fe...

Glyphosate and fungicide effects on Cercospora leaf spot in four glyphosate-resistant sugar beet (Beta vulgaris) varieties

USDA-ARS?s Scientific Manuscript database

Glyphosate has been shown to reduce foliar diseases in soybean and wheat. In fact, currently there is a patent application for a synergistic combination of glyphosate and a fungicide for disease management. Cercospora leaf spot (Cercospora beticola) is one of the most significant foliar disease prob...

Coordination of leaf and stem water transport properties in tropical forest trees

Treesearch

Frederick C. Meinzer; David R. Woodruff; Jean-Christophe Domec; Guillermo Goldstein; Paula I. Campanello; Genoveva M. Gatti; Randol Villalobos-Vega

2008-01-01

Stomatal regulation of transpiration constrains leaf water potential (ψ l) within species-specific ranges that presumably avoid excessive tension and embolism in the stem xylem upstream. However, the hydraulic resistance of leaves can be highly variable over short time scales, uncoupling tension in the xylem of leaves from that in the...

Evaluating an Arachis hypogaea x Arachis diogoi interspecific hybrid derived population for multiple disease resistance

USDA-ARS?s Scientific Manuscript database

The peanut (Arachis hypogaea L.) crop in North Carolina is subject to yield and quality loss from a number of diseases including Cylindrocladium black rot (CBR) caused by Cylindrocladium parasiticum, early leaf spot (ELS) caused by Cercospora arachidicola, late leaf spot (LLS) caused by Cercosporidi...

RNA-Sequencing of Cercospora beticola DMI-sensitive and -resistant isolates after treatment with tetraconazole identifies common and contrasting pathway induction

USDA-ARS?s Scientific Manuscript database

Cercospora beticola causes Cercospora leaf spot of sugarbeet. Cercospora leaf spot management measures often include application of the sterol demethylation inhibitor (DMI) class of fungicides. The reliance on DMIs and the consequent selection pressures imposed by their widespread use has led to th...

Trypsin inhibitors from Capsicum baccatum var. pendulum leaves involved in Pepper yellow mosaic virus resistance.

PubMed

Moulin, M M; Rodrigues, R; Ribeiro, S F F; Gonçalves, L S A; Bento, C S; Sudré, C P; Vasconcelos, I M; Gomes, V M

2014-11-07

Several plant organs contain proteinase inhibitors, which are produced during normal plant development or are induced upon pathogen attack to suppress the enzymatic activity of phytopathogenic microorganisms. In this study, we examined the presence of proteinase inhibitors, specifically trypsin inhibitors, in the leaf extract of Capsicum baccatum var. pendulum inoculated with PepYMV (Pepper yellow mosaic virus). Leaf extract from plants with the accession number UENF 1624, which is resistant to PepYMV, was collected at 7 different times (0, 24, 48, 72, 96, 120, and 144 h). Seedlings inoculated with PepYMV and control seedlings were grown in a growth chamber. Protein extract from leaf samples was partially purified by reversed-phase chromatography using a C2/C18 column. Residual trypsin activity was assayed to detect inhibitors followed by Tricine-SDS-PAGE analysis to determine the N-terminal peptide sequence. Based on trypsin inhibitor assays, trypsin inhibitors are likely constitutively synthesized in C. baccatum var. pendulum leaf tissue. These inhibitors are likely a defense mechanism for the C. baccatum var. pendulum- PepYMV pathosystem.

A transgenic approach to control hemipteran insects by expressing insecticidal genes under phloem-specific promoters.

PubMed

Javaid, Shaista; Amin, Imran; Jander, Georg; Mukhtar, Zahid; Saeed, Nasir A; Mansoor, Shahid

2016-10-06

The first generation transgenic crops used strong constitutive promoters for transgene expression. However, tissue-specific expression is desirable for more precise targeting of transgenes. Moreover, piercing/sucking insects, which are generally resistant to insecticidal Bacillus thuringiensis (Bt) proteins, have emerged as a major pests since the introduction of transgenic crops expressing these toxins. Phloem-specific promoters isolated from Banana bunchy top virus (BBTV) were used for the expression of two insecticidal proteins, Hadronyche versuta (Blue Mountains funnel-web spider) neurotoxin (Hvt) and onion leaf lectin, in tobacco (Nicotiana tabacum). Here we demonstrate that transgenic plants expressing Hvt alone or in combination with onion leaf lectin are resistant to Phenacoccus solenopsis (cotton mealybug), Myzus persicae (green peach aphids) and Bemisia tabaci (silver leaf whitefly). The expression of both proteins under different phloem-specific promoters resulted in close to 100% mortality and provided more rapid protection than Hvt alone. Our results suggest the employment of the Hvt and onion leaf lectin transgenic constructs at the commercial level will reduce the use of chemical pesticides for control of hemipteran insect pests.

Theoretical and experimental errors for in situ measurements of plant water potential.

PubMed

Shackel, K A

1984-07-01

Errors in psychrometrically determined values of leaf water potential caused by tissue resistance to water vapor exchange and by lack of thermal equilibrium were evaluated using commercial in situ psychrometers (Wescor Inc., Logan, UT) on leaves of Tradescantia virginiana (L.). Theoretical errors in the dewpoint method of operation for these sensors were demonstrated. After correction for these errors, in situ measurements of leaf water potential indicated substantial errors caused by tissue resistance to water vapor exchange (4 to 6% reduction in apparent water potential per second of cooling time used) resulting from humidity depletions in the psychrometer chamber during the Peltier condensation process. These errors were avoided by use of a modified procedure for dewpoint measurement. Large changes in apparent water potential were caused by leaf and psychrometer exposure to moderate levels of irradiance. These changes were correlated with relatively small shifts in psychrometer zero offsets (-0.6 to -1.0 megapascals per microvolt), indicating substantial errors caused by nonisothermal conditions between the leaf and the psychrometer. Explicit correction for these errors is not possible with the current psychrometer design.

Theoretical and Experimental Errors for In Situ Measurements of Plant Water Potential 1

PubMed Central

Shackel, Kenneth A.

1984-01-01

Errors in psychrometrically determined values of leaf water potential caused by tissue resistance to water vapor exchange and by lack of thermal equilibrium were evaluated using commercial in situ psychrometers (Wescor Inc., Logan, UT) on leaves of Tradescantia virginiana (L.). Theoretical errors in the dewpoint method of operation for these sensors were demonstrated. After correction for these errors, in situ measurements of leaf water potential indicated substantial errors caused by tissue resistance to water vapor exchange (4 to 6% reduction in apparent water potential per second of cooling time used) resulting from humidity depletions in the psychrometer chamber during the Peltier condensation process. These errors were avoided by use of a modified procedure for dewpoint measurement. Large changes in apparent water potential were caused by leaf and psychrometer exposure to moderate levels of irradiance. These changes were correlated with relatively small shifts in psychrometer zero offsets (−0.6 to −1.0 megapascals per microvolt), indicating substantial errors caused by nonisothermal conditions between the leaf and the psychrometer. Explicit correction for these errors is not possible with the current psychrometer design. PMID:16663701

Association of tomato leaf curl Gujarat virus and tomato leaf curl Bangladesh betasatellite on papaya showing typical leaf curl symptoms in North India.

PubMed

Varun, Priyanka; Saxena, Sangeeta

2018-05-01

Papaya leaf curl is an economically important disease occurring in papaya growing tropical and subtropical areas. Papaya leaf curl virus, a begomovirus, is the main causative agent for the disease, but many other begomoviruses as well as betasatellites have also been reported on papaya leaf curl disease. Rapidly evolving host range of begomoviruses is a major issue for developing successful resistance strategies against begomoviral infection considering their expanding host range and mixed infection. In our study, we have identified the presence of begomovirus and associated satellite molecule on papaya showing severe leaf curl symptoms in Lucknow, India. Analysis of complete DNA-A component of this isolate (MG757245) revealed the highest similarity (91%) with tomato leaf curl Gujarat virus (ToLCuGuV), while sequence data of betasatellite (MG478451) showed maximum (89%) identity with tomato leaf curl Bangladesh betasatellite (ToLCuBB). This is the first report on identification of ToLCuGuV and ToLCuBB coinfecting papaya plants in Lucknow, Uttar Pradesh (India).

In vitro antimicrobial activity of Combretum molle (Combretaceae) against Staphylococcus aureus and Streptococcus agalactiae isolated from crossbred dairy cows with clinical mastitis.

PubMed

Regassa, Fekadu; Araya, Mengistu

2012-08-01

Following the rapidly expanding dairy enterprise, mastitis has remained the most economically damaging disease. The objective of this study was mainly to investigate the in vitro antibacterial activities of ethanol extracts of Combretum molle (R.Br.Ex.G.Don) Engl & Diels (Combretaceae) against antibiotic-resistant and susceptible Staphylococcus aureus and Streptococcus agalactiae isolated from clinical cases of bovine mastitis using agar disc diffusion method. The leaf and bark extracts showed antibacterial activity against S. aureus at concentrations of 3 mg/ml while the stem and seed extract did not show any bioactivity. Although both leaf and bark extracts were handled in the same manner, the antibacterial activity of the bark extract against the bacterial strains had declined gradually to a lower level as time advanced after extraction. The leaf extract had sustained bioactivity for longer duration. The susceptibility of the bacteria to the leaf extract is not obviously different between S. aureus and S. agalactiae. Also, there was no difference in susceptibility to the leaf extract between the antibiotic-resistant and antibiotic-sensitive bacteria. Further phytochemical and in vivo efficacy and safety studies are required to evaluate the therapeutic value of the plant against bovine mastitis.

Lettuce breeding

USDA-ARS?s Scientific Manuscript database

In the 2016-2017 period, major efforts targeted resistance to lettuce drop caused by Sclerotinia species, Verticillium wilt, Fusarium wilt, bacterial leaf spot, corky root, downy mildew, drought tolerance, lettuce aphid, tipburn, shelf-life of salad-cut lettuce, and multiple disease resistance. Resi...

Novel potato plants with enhanced cadmium resistance and antioxidative defence generated after in vitro cell line selection.

PubMed

Ashrafzadeh, Seyedardalan; Leung, David W M

2017-01-01

It is of interest to apply plant tissue culture to generate plants resistant to toxic effects of cadmium (Cd) on plant growth. Callus cultures were initiated from leaf explants of micropropagated potato plantlets (Solanum tuberosum L., cv. Iwa) for in vitro selection comprising 18 different Cd treatments varying in Cd exposure timing and duration. Plantlets regenerated from two different lines of Cd-selected calli, L9 and L11, were found to exhibit enhanced resistance to 218 μM Cd compared to control (source plantlets for leaf explants used to initiate callus cultures for Cd resistance). In response to 218 μM Cd, L11 plantlets had lower levels of lipid peroxidation and hydrogen peroxide than control and L9 plantlets. In addition, antioxidative enzyme activities in L11 were generally higher than control. L11 also had a higher level of proline than control.

SP-LL-37, human antimicrobial peptide, enhances disease resistance in transgenic rice.

PubMed

Lee, In Hye; Jung, Yu-Jin; Cho, Yong Gu; Nou, Ill Sup; Huq, Md Amdadul; Nogoy, Franz Marielle; Kang, Kwon-Kyoo

2017-01-01

Human LL-37 is a multifunctional antimicrobial peptide of cathelicidin family. It has been shown in recent studies that it can serve as a host's defense against influenza A virus. We now demonstrate in this study how signal peptide LL-37 (SP-LL-37) can be used in rice resistance against bacterial leaf blight and blast. We synthesized LL-37 peptide and subcloned in a recombinant pPZP vector with pGD1 as promoter. SP-LL-37 was introduced into rice plants by Agrobacterium mediated transformation. Stable expression of SP-LL-37 in transgenic rice plants was confirmed by RT-PCR and ELISA analyses. Subcellular localization of SP-LL-37-GFP fusion protein showed evidently in intercellular space. Our data on testing for resistance to bacterial leaf blight and blast revealed that the transgenic lines are highly resistant compared to its wildtype. Our results suggest that LL-37 can be further explored to improve wide-spectrum resistance to biotic stress in rice.

Glyphosate inhibits rust diseases in glyphosate-resistant wheat and soybean.

PubMed

Feng, Paul C C; Baley, G James; Clinton, William P; Bunkers, Greg J; Alibhai, Murtaza F; Paulitz, Timothy C; Kidwell, Kimberlee K

2005-11-29

Glyphosate is a broad-spectrum herbicide used for the control of weeds in glyphosate-resistant crops. Glyphosate inhibits 5-enolpyruvyl shikimate 3-phosphate synthase, a key enzyme in the synthesis of aromatic amino acids in plants, fungi, and bacteria. Studies with glyphosate-resistant wheat have shown that glyphosate provided both preventive and curative activities against Puccinia striiformis f. sp. tritici and Puccinia triticina, which cause stripe and leaf rusts, respectively, in wheat. Growth-chamber studies demonstrated wheat rust control at multiple plant growth stages with a glyphosate spray dose typically recommended for weed control. Rust control was absent in formulation controls without glyphosate, dependent on systemic glyphosate concentrations in leaf tissues, and not mediated through induction of four common systemic acquired resistance genes. A field test with endemic stripe rust inoculum confirmed the activities of glyphosate pre- and postinfestation. Preliminary greenhouse studies also demonstrated that application of glyphosate in glyphosate-resistant soybeans suppressed Asian soybean rust, caused by Phakopsora pachyrhizi.

Identification of quantitative trait Loci for resistance to southern leaf blight and days to anthesis in a maize recombinant inbred line population.

PubMed

Balint-Kurti, P J; Krakowsky, M D; Jines, M P; Robertson, L A; Molnár, T L; Goodman, M M; Holl, J B

2006-10-01

ABSTRACT A recombinant inbred line population derived from a cross between the maize lines NC300 (resistant) and B104 (susceptible) was evaluated for resistance to southern leaf blight (SLB) disease caused by Cochliobolus heterostrophus race O and for days to anthesis in four environments (Clayton, NC, and Tifton, GA, in both 2004 and 2005). Entry mean and average genetic correlations between disease ratings in different environments were high (0.78 to 0.89 and 0.9, respectively) and the overall entry mean heritability for SLB resistance was 0.89. When weighted mean disease ratings were fitted to a model using multiple interval mapping, seven potential quantitative trait loci (QTL) were identified, the two strongest being on chromosomes 3 (bin 3.04) and 9 (bin 9.03-9.04). These QTL explained a combined 80% of the phenotypic variation for SLB resistance. Some time-point-specific SLB resistance QTL were also identified. There was no significant correlation between disease resistance and days to anthesis. Six putative QTL for time to anthesis were identified, none of which coincided with any SLB resistance QTL.

Removal of nutrient limitations in forest gaps enhances growth rate and resistance to cavitation in subtropical canopy tree species differing in shade tolerance.

PubMed

Villagra, Mariana; Campanello, Paula I; Montti, Lia; Goldstein, Guillermo

2013-03-01

A 4-year fertilization experiment with nitrogen (N) and phosphorus (P) was carried out in natural gaps of a subtropical forest in northeastern Argentina. Saplings of six dominant canopy species differing in shade tolerance were grown in five control and five N + P fertilized gaps. Hydraulic architectural traits such as wood density, the leaf area to sapwood area ratio (LA : SA), vulnerability to cavitation (P50) and specific and leaf-specific hydraulic conductivity were measured, as well as the relative growth rate, specific leaf area (SLA) and percentage of leaf damage by insect herbivores. Plant growth rates and resistance to drought-induced embolisms increased when nutrient limitations were removed. On average, the P50 of control plants was -1.1 MPa, while the P50 of fertilized plants was -1.6 MPa. Wood density and LA : SA decreased with N + P additions. A trade-off between vulnerability to cavitation and efficiency of water transport was not observed. The relative growth rate was positively related to the total leaf surface area per plant and negatively related to LA : SA, while P50 was positively related to SLA across species and treatments. Plants with higher growth rates and higher total leaf area in fertilized plots were able to avoid hydraulic dysfunction by becoming less vulnerable to cavitation (more negative P50). Two high-light-requiring species exhibited relatively low growth rates due to heavy herbivore damage. Contrary to expectations, shade-tolerant plants with relatively high resistance to hydraulic dysfunction and reduced herbivory damage were able to grow faster. These results suggest that during the initial phase of sapling establishment in gaps, species that were less vulnerable to cavitation and exhibited reduced herbivory damage had faster realized growth rates than less shade-tolerant species with higher potential growth rates. Finally, functional relationships between hydraulic traits and growth rate across species and treatments were maintained regardless of soil nutrient status.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Moreno, Gilberto; Bennion, Kevin; King, Charles

Thermal management strategies for automotive power electronic systems have evolved over time to reduce system cost and to improve reliability and thermal performance. In this study, we characterized the power electronic thermal management systems of two electric-drive vehicles--the 2012 Nissan LEAF and 2014 Honda Accord Hybrid. Tests were conducted to measure the insulated-gate bipolar transistor-to-coolant thermal resistances for both steady-state and transient conditions at various coolant flow rates. Water-ethylene glycol at a temperature of 65 degrees C was used as the coolant for these experiments. Computational fluid dynamics and finite element analysis models of the vehicle's power electronics thermal managementmore » system were then created and validated using experimentally obtained results. Results indicate that the Accord module provides lower steady-state thermal resistance as compared with the LEAF module. However, the LEAF design may provide improved performance in transient conditions and may have cost benefits.« less

[Cold resistance of four evergreen broad-leaved tree species].

PubMed

Wang, Na; Wang, Kui Ling; Liu, Qing Hua; Liu, Qing Chao

2016-10-01

The leaves of four evergreen plants, i.e., Fatsia japonica, Nerium indicum, Mahonia bealei and Acer cinnamomifolium were used as the experimental materials. By measuring the changes of in vitro leaf in soluble sugar, soluble protein, free proline, POD activity, chlorophyll content and relative electrolytic conductivity under aritificial simulated low temperature, combining the measurements of SPAD, leaf surface features and anatomical changes in organizational structure in the process of natural wintering, the cold resistance of four evergreen tree species was evaluated comprehensively. The results showed that in the process of artificial low temperature stress, the chlorophyll content of the leaves of four evergreen species decreased, the content of soluble protein pea-ked at -20 ℃, and the soluble sugar, free proline, POD activity and relative electrolytic conductivity showed an overall upward trend. The semilethal temperatures of four species were -8.0, -13.4, -19.4 and -14.8 ℃, respectively. During the winter, the leaf SPAD of the four species changed markedly, reflecting that the change of relative chlorophyll content was related to the change of temperature. Meanwhile, the leaf thickness, cutin layer thickness, stockade tissue thickness and tightness of four species increased and the plasmolysis occurred thereafter. Also the content of starch grains and calcium oxalate cluster crystal increased. The typical stomatal pits and the intensive non-glandular trichome within the pits of N. indicum and the sclerenchyma of M. Bealei could improve the cold resistance of plants to some extent. In addition, the phenomena like the breakage of wax layer in leaf surface, the fracture of epidermal hair and the deformation of palisade tissue indicated that plants were damaged to a certain extent by low temperature.

In vitro antimalarial activity of medicinal plant extracts against Plasmodium falciparum.

PubMed

Bagavan, Asokan; Rahuman, Abdul Abdul; Kaushik, Naveen Kumar; Sahal, Dinkar

2011-01-01

Malaria is a major global public health problem, and the alarming spread of drug resistance and limited number of effective drugs now available underline how important it is to discover new antimalarial compounds. In the present study, ten plants were extracted with ethyl acetate and methanol and tested for their antimalarial activity against chloroquine (CQ)-sensitive (3D7) and CQ-resistant (Dd2 and INDO) strains of Plasmodium falciparum in culture using the fluorescence-based SYBR Green assay. Plant extracts showed moderate to good antiparasitic effects. Promising antiplasmodial activity was found in the extracts from two plants, Phyllanthus emblica leaf 50% inhibitory concentration (IC₅₀) 3D7: 7.25 μg/mL (ethyl acetate extract), 3.125 μg/mL (methanol extract), and Syzygium aromaticum flower bud, IC₅₀ 3D7:13 μg/mL, (ethyl acetate extract) and 6.25 μg/mL (methanol extract). Moderate activity (30-75 μg/mL) was found in the ethyl acetate and methanol extracts of Abrus precatorius (seed) and Gloriosa superba (leaf); leaf ethyl acetate extracts of Annona squamosa and flower of Musa paradisiaca. The above mentioned plant extracts were also found to be active against CQ-resistant strains (Dd2 and INDO). Cytotoxicity study with P. emblica leaf and S. aromaticum flower bud, extracts showed good therapeutic indices. These results demonstrate that leaf ethyl acetate and methanol extracts of P. emblica and flower bud extract of S. aromaticum may serve as antimalarial agents even in their crude form. The isolation of compounds from P. emblica and S. aromaticum seems to be of special interest for further antimalarial studies.

A specialist root herbivore reduces plant resistance and uses an induced plant volatile to aggregate in a density dependent manner

USDA-ARS?s Scientific Manuscript database

1. Leaf-herbivore attack often triggers induced resistance in plants. However, certain specialist herbivores can also take advantage of the induced metabolic changes. In some cases, they even manipulate plant resistance, leading to a phenomenon called induced susceptibility. Compared to above-ground...

Transgenic American chestnuts show enhanced blight resistance and transmit the trait to T1 progeny.

PubMed

Newhouse, Andrew E; Polin-McGuigan, Linda D; Baier, Kathleen A; Valletta, Kristia E R; Rottmann, William H; Tschaplinski, Timothy J; Maynard, Charles A; Powell, William A

2014-11-01

American chestnut (Castanea dentata) is a classic example of a native keystone species that was nearly eradicated by an introduced fungal pathogen. This report describes progress made toward producing a fully American chestnut tree with enhanced resistance to the blight fungus (Cryphonectria parasitica). The transgenic American chestnut 'Darling4,' produced through an Agrobacterium co-transformation procedure to express a wheat oxalate oxidase gene driven by the VspB vascular promoter, shows enhanced blight resistance at a level intermediate between susceptible American chestnut and resistant Chinese chestnut (Castanea mollissima). Enhanced resistance was identified first with a leaf-inoculation assay using young chestnuts grown indoors, and confirmed with traditional stem inoculations on 3- and 4-year-old field-grown trees. Pollen from 'Darling4' and other events was used to produce transgenic T1 seedlings, which also expressed the enhanced resistance trait in leaf assays. Outcrossed transgenic seedlings have several advantages over tissue-cultured plantlets, including increased genetic diversity and faster initial growth. This represents a major step toward the restoration of the majestic American chestnut. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

Tolerance and resistance of invasive and native Eupatorium species to generalist herbivore insects

NASA Astrophysics Data System (ADS)

Wang, Rui-Fang; Feng, Yu-Long

2016-11-01

Invasive plants are exotic species that escape control by native specialist enemies. However, exotic plants may still be attacked by locally occurring generalist enemies, which can influence the dynamics of biological invasions. If invasive plants have greater defensive (resistance and tolerance) capabilities than indigenous plants, they may experience less damage from native herbivores. In the present study, we tested this prediction using the invasive plant Eupatorium adenophorum and two native congeners under simulated defoliation and generalist herbivore insect (Helicoverpa armigera and Spodoptera litura) treatments. E. adenophorum was less susceptible and compensated more quickly to damages in biomass production from both treatments compared to its two congeners, exhibiting greater herbivore tolerance. This strong tolerance to damage was associated with greater resource allocation to aboveground structures, leading to a higher leaf area ratio and a lower root: crown mass ratio than those of its native congeners. E. adenophorum also displayed a higher resistance index (which integrates acid detergent fiber, nitrogen content, carbon/nitrogen ratio, leaf mass per area, toughness, and trichome density) than its two congeners. Thus, H. armigera and S. litura performed poorly on E. adenophorum, with less leaf damage, a lengthened insect developmental duration, and decreased pupating: molting ratios compared to those of the native congeners. Strong tolerance and resistance traits may facilitate the successful invasion of E. adenophorum in China and may decrease the efficacy of leaf-feeding biocontrol agents. Our results highlight both the need for further research on defensive traits and their role in the invasiveness and biological control of exotic plants, and suggest that biocontrol of E. adenophorum in China would require damage to the plant far in excess of current levels.

The Role of Bundle Sheath Extensions and Life Form in Stomatal Responses to Leaf Water Status1[W][OA

PubMed Central

Buckley, Thomas N.; Sack, Lawren; Gilbert, Matthew E.

2011-01-01

Bundle sheath extensions (BSEs) are key features of leaf structure with currently little-understood functions. To test the hypothesis that BSEs reduce the hydraulic resistance from the bundle sheath to the epidermis (rbe) and thereby accelerate hydropassive stomatal movements, we compared stomatal responses with reduced humidity and leaf excision among 20 species with heterobaric or homobaric leaves and herbaceous or woody life forms. We hypothesized that low rbe due to the presence of BSEs would increase the rate of stomatal opening (V) during transient wrong-way responses, but more so during wrong-way responses to excision (Ve) than humidity (Vh), thus increasing the ratio of Ve to Vh. We predicted the same trends for herbaceous relative to woody species given greater hydraulic resistance in woody species. We found that Ve, Vh, and their ratio were 2.3 to 4.4 times greater in heterobaric than homobaric leaves and 2.0 to 3.1 times greater in herbaceous than woody species. To assess possible causes for these differences, we simulated these experiments in a dynamic compartment/resistance model, which predicted larger Ve and Ve/Vh in leaves with smaller rbe. These results support the hypothesis that BSEs reduce rbe. Comparison of our data and simulations suggested that rbe is approximately 4 to 16 times larger in homobaric than heterobaric leaves. Our study provides new evidence that variations in the distribution of hydraulic resistance within the leaf and plant are central to understanding dynamic stomatal responses to water status and their ecological correlates and that BSEs play several key roles in the functional ecology of heterobaric leaves. PMID:21459977

A hairy-leaf gene, BLANKET LEAF, of wild Oryza nivara increases photosynthetic water use efficiency in rice.

PubMed

Hamaoka, Norimitsu; Yasui, Hideshi; Yamagata, Yoshiyuki; Inoue, Yoko; Furuya, Naruto; Araki, Takuya; Ueno, Osamu; Yoshimura, Atsushi

2017-12-01

High water use efficiency is essential to water-saving cropping. Morphological traits that affect photosynthetic water use efficiency are not well known. We examined whether leaf hairiness improves photosynthetic water use efficiency in rice. A chromosome segment introgression line (IL-hairy) of wild Oryza nivara (Acc. IRGC105715) with the genetic background of Oryza sativa cultivar 'IR24' had high leaf pubescence (hair). The leaf hairs developed along small vascular bundles. Linkage analysis in BC 5 F 2 and F 3 populations showed that the trait was governed by a single gene, designated BLANKET LEAF (BKL), on chromosome 6. IL-hairy plants had a warmer leaf surface in sunlight, probably due to increased boundary layer resistance. They had a lower transpiration rate under moderate and high light intensities, resulting in higher photosynthetic water use efficiency. Introgression of BKL on chromosome 6 from O. nivara improved photosynthetic water use efficiency in the genetic background of IR24.

RNA interference-based resistance in transgenic tomato plants against Tomato yellow leaf curl virus-Oman (TYLCV-OM) and its associated betasatellite.

PubMed

Ammara, Um e; Mansoor, Shahid; Saeed, Muhammad; Amin, Imran; Briddon, Rob W; Al-Sadi, Abdullah Mohammed

2015-03-04

Tomato yellow leaf curl virus (TYLCV), a monopartite begomovirus (family Geminiviridae) is responsible for heavy yield losses for tomato production around the globe. In Oman at least five distinct begomoviruses cause disease in tomato, including TYLCV. Unusually, TYLCV infections in Oman are sometimes associated with a betasatellite (Tomato leaf curl betasatellite [ToLCB]; a symptom modulating satellite). RNA interference (RNAi) can be used to develop resistance against begomoviruses at either the transcriptional or post-transcriptional levels. A hairpin RNAi (hpRNAi) construct to express double-stranded RNA homologous to sequences of the intergenic region, coat protein gene, V2 gene and replication-associated gene of Tomato yellow leaf curl virus-Oman (TYLCV-OM) was produced. Initially, transient expression of the hpRNAi construct at the site of virus inoculation was shown to reduce the number of plants developing symptoms when inoculated with either TYLCV-OM or TYLCV-OM with ToLCB-OM to Nicotiana benthamiana or tomato. Solanum lycopersicum L. cv. Pusa Ruby was transformed with the hpRNAi construct and nine confirmed transgenic lines were obtained and challenged with TYLCV-OM and ToLCB-OM by Agrobacterium-mediated inoculation. For all but one line, for which all plants remained symptomless, inoculation with TYLCV-OM led to a proportion (≤25%) of tomato plants developing symptoms of infection. For inoculation with TYLCV-OM and ToLCB-OM all lines showed a proportion of plants (≤45%) symptomatic. However, for all infected transgenic plants the symptoms were milder and virus titre in plants was lower than in infected non-transgenic tomato plants. These results show that RNAi can be used to develop resistance against geminiviruses in tomato. The resistance in this case is not immunity but does reduce the severity of infections and virus titer. Also, the betasatellite may compromise resistance, increasing the proportion of plants which ultimately show symptoms.

Acclimation to short-term low temperatures in two Eucalyptus globulus clones with contrasting drought resistance.

PubMed

Costa E Silva, F; Shvaleva, A; Broetto, F; Ortuño, M F; Rodrigues, M L; Almeida, M H; Chaves, M M; Pereira, J S

2009-01-01

We tested the hypothesis that Eucalyptus globulus Labill. genotypes that are more resistant to dry environments might also exhibit higher cold tolerances than drought-sensitive plants. The effect of low temperatures was evaluated in acclimated and unacclimated ramets of a drought-resistant clone (CN5) and a drought-sensitive clone (ST51) of E. globulus. We studied the plants' response via leaf gas exchanges, leaf water and osmotic potentials, concentrations of soluble sugars, several antioxidant enzymes and leaf electrolyte leakage. Progressively lowering air temperatures (from 24/16 to 10/-2 degrees C, day/night) led to acclimation of both clones. Acclimated ramets exhibited higher photosynthetic rates, stomatal conductances and lower membrane relative injuries when compared to unacclimated ramets. Moreover, low temperatures led to significant increases of soluble sugars and antioxidant enzymes activity (glutathione reductase, ascorbate peroxidase and superoxide dismutases) of both clones in comparison to plants grown at control temperature (24/16 degrees C). On the other hand, none of the clones, either acclimated or not, exhibited signs of photoinhibition under low temperatures and moderate light. The main differences in the responses to low temperatures between the two clones resulted mainly from differences in carbon metabolism, including a higher accumulation of soluble sugars in the drought-resistant clone CN5 as well as a higher capacity for osmotic regulation, as compared to the drought-sensitive clone ST51. Although membrane injury data suggested that both clones had the same inherent freezing tolerance before and after cold acclimation, the results also support the hypothesis that the drought-resistant clone had a greater cold tolerance at intermediate levels of acclimation than the drought-sensitive clone. A higher capacity to acclimate in a short period can allow a clone to maintain an undamaged leaf surface area along sudden frost events, increasing growth capacity. Moreover, it can enhance survival chances in frost-prone sites expanding the plantation range with more adaptive clones.

Characterization of expressed resistance gene analogs (RGAs) from peanut expressed sequence tags (ESTs)

USDA-ARS?s Scientific Manuscript database

Cultivated peanut (Arachis hypogaea L.) is one of the most important food legume crops grown worldwide, and is a major source for edible oil and protein. However, due to low genetic variation, peanut is very vulnerable to a variety of pathogens, such as early leaf spot, late leaf spot, rust and Toma...

Comparative analysis highlights variable genome content of wheat rusts and divergence of the mating loci

USDA-ARS?s Scientific Manuscript database

Wheat is grown around the world and has been plagued by three rust fungi for centuries. Leaf rust, stripe rust, and stem rust each cause significant damage and can adapt quickly to overcome resistance that is present in wheat cultivars. Using advanced DNA sequencing technology, the genomes of leaf ...

Population structure and the rapid increase of QoI fungicide resistance in frogeye leaf spot (Cercospora sojina) from Tennessee

USDA-ARS?s Scientific Manuscript database

Frogeye leaf spot (FLS), caused by Cercospora sojina, causes significant damage to soybean in the US. In this study, C. sojina isolates collected from Jackson and Milan, TN in 2015 and historical isolates collected before 2015 were included. Fifty novel single nucleotide polymorphism (SNP) markers, ...

Biological Control of Septoria Leaf Spot Disease of Hybrid Poplar in the Field

Treesearch

Laszlo Gyenis; Neil A. Anderson; Michael E. Ostry

2003-01-01

Biological control of Septoria leaf spot of hrhrid poplars was investigated using disease-suppressive Streptomyces strains. Field experiments were conducted in 1998 and 1999 on potted trees placed in a hybrid poplar plantation near Rosemount, MN, and on field-planted trees in 1998 at St. Paul. At both locations, one resistant and three susceptible...

Interactive influence of leaf age, light intensity, and girdling on green ash foliar chemistry and emerald ash borer development

Treesearch

Yigen Chen; Therese M. Poland

2009-01-01

Biotic and abiotic environmental factors affect plant nutritional quality and defensive compounds that confer plant resistance to herbivory. Influence of leaf age, light availability, and girdling on foliar nutrition and defense of green ash (Fraxinus pennsylvanica Marsh) was examined in this study. Longevity of the emerald ash borer, ...

Characterization of the common bean host and Pseudocercospora griseola the causative agent of angular leaf spot disease in Tanzania

USDA-ARS?s Scientific Manuscript database

Angular leaf spot (ALS) caused by the fungus Pseudocercospora griseola is one of the most important diseases of common bean in Tanzania. Breeding for resistance to this disease is complicated by the variable nature of the pathogen. In Tanzania no thorough analysis of the variability of this pathogen...

Green leaf lettuce breeding lines with resistance to corky root, 06-831 and 06-833.

USDA-ARS?s Scientific Manuscript database

The Agricultural Research Service, United States Department of Agriculture (USDA) announces the release of two breeding lines of green leaf lettuce (Lactuca sativa L.). The lines 06-831 and 06-833 look similar to ‘Waldmann’s Green’ and related cultivars. The lines may be suitable for commercial pro...

Variation in Septoria musiva and Implications for Disease Resistance Screening

Treesearch

K.T. Ward; M.E. Ostry

2005-01-01

A set of isolates of Septoria musiva differed in aggressiveness in hybrid poplar leaf disk and stem assays and culture growth in vitro. Clone x isolate interactions were observed in one of the stem assay experiments, but not in the leaf disk assay experiments. Random amplified polymorphic DNA (RAPD) analyses were performed using 52 isolates of

Carbon Costs of Constitutive and Expressed Resistance to a Non-Native Pathogen in Limber Pine.

PubMed

Vogan, Patrick J; Schoettle, Anna W

2016-01-01

Increasing the frequency of resistance to the non-native fungus Cronartium ribicola (causative agent of white pine blister rust, WPBR) in limber pine populations is a primary management objective to sustain high-elevation forest communities. However, it is not known to what extent genetic disease resistance is costly to plant growth or carbon economy. In this study, we measured growth and leaf-level physiology in (1) seedling families from seed trees that have previously been inferred to carry or not carry Cr4, the dominant R gene allele conferring complete, gene-for-gene resistance to WPBR in limber pine, and (2) populations that were and were not infected with C. ribicola. We found that, in the absence of C. ribicola exposure, there was no significant difference in carbon relations between families born from seed trees that harbor the resistance allele compared to those that lack it, either to plant growth and phenology or leaf-level photosynthetic traits. However, post-infection with C. ribicola, growth was significantly reduced in inoculation survivors expressing complete resistance compared to uninoculated seedlings. Furthermore, inoculation survivors exhibited significant increases in a suite of traits including photosynthetic rate, respiration rate, leaf N, and stomatal conductance and a decrease in photosynthetic water-use efficiency. The lack of constitutive carbon costs associated with Cr4 resistance in non-stressed limber pine is consistent with a previous report that the R gene allele is not under selection in the absence of C. ribicola and suggests that host resistance may not bear a constitutive cost in pathosystems that have not coevolved. However, under challenge by C. ribicola, complete resistance to WPBR in limber pine has a significant cost to plant growth, though enhanced carbon acquisition post-infection may offset this somewhat. These costs and effects on performance further complicate predictions of this species' response in warmer future climates in the presence of WPBR.

Carbon Costs of Constitutive and Expressed Resistance to a Non-Native Pathogen in Limber Pine

PubMed Central

2016-01-01

Increasing the frequency of resistance to the non-native fungus Cronartium ribicola (causative agent of white pine blister rust, WPBR) in limber pine populations is a primary management objective to sustain high-elevation forest communities. However, it is not known to what extent genetic disease resistance is costly to plant growth or carbon economy. In this study, we measured growth and leaf-level physiology in (1) seedling families from seed trees that have previously been inferred to carry or not carry Cr4, the dominant R gene allele conferring complete, gene-for-gene resistance to WPBR in limber pine, and (2) populations that were and were not infected with C. ribicola. We found that, in the absence of C. ribicola exposure, there was no significant difference in carbon relations between families born from seed trees that harbor the resistance allele compared to those that lack it, either to plant growth and phenology or leaf-level photosynthetic traits. However, post-infection with C. ribicola, growth was significantly reduced in inoculation survivors expressing complete resistance compared to uninoculated seedlings. Furthermore, inoculation survivors exhibited significant increases in a suite of traits including photosynthetic rate, respiration rate, leaf N, and stomatal conductance and a decrease in photosynthetic water-use efficiency. The lack of constitutive carbon costs associated with Cr4 resistance in non-stressed limber pine is consistent with a previous report that the R gene allele is not under selection in the absence of C. ribicola and suggests that host resistance may not bear a constitutive cost in pathosystems that have not coevolved. However, under challenge by C. ribicola, complete resistance to WPBR in limber pine has a significant cost to plant growth, though enhanced carbon acquisition post-infection may offset this somewhat. These costs and effects on performance further complicate predictions of this species’ response in warmer future climates in the presence of WPBR. PMID:27706249

Molecular Mapping of High Resistance to Bacterial Leaf Spot in Lettuce PI 358001-1.

PubMed

Wang, Yunwen; Lu, Huangjun; Hu, Jinguo

2016-11-01

Lettuce (Lactuca sativa L.) is a diploid (2n = 18) with a genome size of 2,600 Mbp, and belongs to the family Compositae. Bacterial leaf spot (BLS), caused by Xanthomonas campestris pv. vitians, is a major disease of lettuce worldwide. Leaf lettuce PI 358001-1 has been characterized as an accession highly resistant to BLS and has white seed. In order to understand inheritance of the high resistance in this germplasm line, an F 3 population consisting of 163 families was developed from the cross PI 358001-1 × 'Tall Guzmaine' (a susceptible Romaine lettuce variety with black seed). The segregation ratio of reaction to disease by seedling inoculation with X. campestris pv. vitians L7 strain in the F 3 families was shown to be 32:82:48 homozygous resistant/heterozygous/homozygous susceptible, fitting to 1:2:1 (n = 162, χ 2 = 3.19, P = 0.20). The segregation ratio of seed color by checking F 2 plants was 122:41 black/white, fitting to 3:1 (n = 163, χ 2 = 0.002, P = 0.96). The results indicated that both BLS resistance and seed color were inherited as a dominant gene mode. A genetic linkage map based on 124 randomly selected F 2 plants was developed to enable molecular mapping of the BLS resistance and the seed color trait. In total, 199 markers, comprising 176 amplified fragment length polymorphisms, 16 simple-sequence repeats, 5 resistant gene candidate markers, and 2 cleaved amplified polymorphic sequences (CAPS) markers were assigned to six linkage groups. The dominant resistance gene to BLS (Xcvr) was mapped on linkage group 2 and the gene locus y for seed color was identified on linkage group 5. Due to the nature of a single gene inheritance, the high-resistance gene should be readily transferred to adapted lettuce cultivars to battle against the devastating disease of lettuce.

Leaf oxygen and Carbon Isotopic Signatures Reflect Drought Resistance and Water Use Efficiency in the C4 Grass, Setaria viridis

NASA Astrophysics Data System (ADS)

Ellsworth, P.; Cousins, A. B.

2014-12-01

Low water availability is a major constraint in crop production, especially as agriculture is pushed to marginal lands. Therefore, improving drought resistance such as increasing water use efficiency (WUE) through plant breeding is needed to expand the range of soil water availability adequate for food production. With the goal of finding the genomic basis for WUE in C4 grasses, Setaria viridis makes an ideal model species because of its small size, short lifespan, and sequenced genome. Also it is part of the panicoid grass clade, which is one of the most important clades for food and biofuel production. In plant breeding programs, large numbers of genotypes must be quickly screened for drought resistance traits, but there is no well-defined method of screening for WUE in C4 grasses. However, bulk leaf oxygen (Δ18OBL) and carbon (δ13C) isotopic signatures have shown potential as recorders of transpiration rate (E) and stomatal conductance (gs), and combined with biomass production potentially serve as a measure of WUE. Values of Δ18OBL record differences in transpiration rate because leaf water becomes more enriched as transpiration rate decreases, and leaf tissue records the isotopic composition of leaf water in which it is synthesized. Additionally, in C4 plants δ13C values decrease as gs decreases but the change in δ13C in response to gs may not be adequate to tease apart differences in WUE. In this study, we grew S. viridis plants under well-watered and water-limited conditions to determine if Δ18OBL and δ13C could be used as proxies for E and gs, and be used to screen S. viridis for differences in WUE in breeding programs. The Δ18OBL and δ13C were significantly different between well-watered and water-limited plants and correlated with each other and with E, gs, and instantaneous water use efficiency (Anet/gs). Therefore, Δ18OBL and δ13C can be useful proxies to screen genotypes for drought resistance by recording differences in E, gs, and WUE. Measuring Δ18OBL and δ13C are relatively simple and quick, requiring the collection of a single leaf sample from each genotype instead of making laborious gas exchange measurements of E and gs.

Mapping Quantitative Field Resistance Against Apple Scab in a 'Fiesta' x 'Discovery' Progeny.

PubMed

Liebhard, R; Koller, B; Patocchi, A; Kellerhals, M; Pfammatter, W; Jermini, M; Gessler, C

2003-04-01

ABSTRACT Breeding of resistant apple cultivars (Malus x domestica) as a disease management strategy relies on the knowledge and understanding of the underlying genetics. The availability of molecular markers and genetic linkage maps enables the detection and the analysis of major resistance genes as well as of quantitative trait loci (QTL) contributing to the resistance of a genotype. Such a genetic linkage map was constructed, based on a segregating population of the cross between apple cvs. Fiesta (syn. Red Pippin) and Discovery. The progeny was observed for 3 years at three different sites in Switzerland and field resistance against apple scab (Venturia inaequalis) was assessed. Only a weak correlation was detected between leaf scab and fruit scab. A QTL analysis was performed, based on the genetic linkage map consisting of 804 molecular markers and covering all 17 chromosomes of apple. With the maximum likelihood-based interval mapping method, eight genomic regions were identified, six conferring resistance against leaf scab and two conferring fruit scab resistance. Although cv. Discovery showed a much stronger resistance against scab in the field, most QTL identified were attributed to the more susceptible parent 'Fiesta'. This indicated a high degree of homozygosity at the scab resistance loci in 'Discovery', preventing their detection in the progeny due to the lack of segregation.

Developing disease resistance in CP-Cultivars

USDA-ARS?s Scientific Manuscript database

Disease resistance is an important selection criterion in the Canal Point (CP) Sugarcane Cultivar Development Program. Ratoon stunt (RSD, caused by Leifsonia xyli subsp. Xyli Evtsuhenko et al.), leaf scald (caused by Xanthomonas albilineans Ashby, Dowson), mosaic (caused by Sugarcane mosaic virus st...

2,4-D resistance in wild radish: reduced herbicide translocation via inhibition of cellular transport

PubMed Central

Goggin, Danica E.; Cawthray, Gregory R.; Powles, Stephen B.

2016-01-01

Resistance to auxinic herbicides is increasing in a range of dicotyledonous weed species, but in most cases the biochemical mechanism of resistance is unknown. Using 14C-labelled herbicide, the mechanism of resistance to 2,4-dichlorophenoxyacetic acid (2,4-D) in two wild radish (Raphanus raphanistrum L.) populations was identified as an inability to translocate 2,4-D out of the treated leaf. Although 2,4-D was metabolized in wild radish, and in a different manner to the well-characterized crop species wheat and bean, there was no difference in metabolism between the susceptible and resistant populations. Reduced translocation of 2,4-D in the latter was also not due to sequestration of the herbicide, or to reduced uptake by the leaf epidermis or mesophyll cells. Application of auxin efflux or ABCB transporter inhibitors to 2,4-D-susceptible plants caused a mimicking of the reduced-translocation resistance phenotype, suggesting that 2,4-D resistance in the populations under investigation could be due to an alteration in the activity of a plasma membrane ABCB-type auxin transporter responsible for facilitating long-distance transport of 2,4-D. PMID:26994475

Carbonized-leaf Membrane with Anisotropic Surfaces for Sodium-ion Battery.

PubMed

Li, Hongbian; Shen, Fei; Luo, Wei; Dai, Jiaqi; Han, Xiaogang; Chen, Yanan; Yao, Yonggang; Zhu, Hongli; Fu, Kun; Hitz, Emily; Hu, Liangbing

2016-01-27

A simple one-step thermal pyrolysis route has been developed to prepare carbon membrane from a natural leaf. The carbonized leaf membrane possesses anisotropic surfaces and internal hierarchical porosity, exhibiting a high specific capacity of 360 mAh/g and a high initial Coulombic efficiency of 74.8% as a binder-free, current-collector-free anode for rechargeable sodium ion batteries. Moreover, large-area carbon membranes with low contact resistance are fabricated by simply stacking and carbonizing leaves, a promising strategy toward large-scale sodium-ion battery developments.

In situ field measurement of leaf water potential using thermocouple psychrometers.

PubMed

Savage, M J; Wiebe, H H; Cass, A

1983-11-01

Thermocouple psychrometers are the only instruments which can measure the in situ water potential of intact leaves, and which can possibly be used to monitor leaf water potential. Unfortunately, their usefulness is limited by a number of difficulties, among them fluctuating temperatures and temperature gradients within the psychrometer, sealing of the psychrometer chamber to the leaf, shading of the leaf by the psychrometer, and resistance to water vapor diffusion by the cuticle when the stomates are closed. Using Citrus jambhiri, we have tested several psychrometer design and operational modifications and showed that in situ psychrometric measurements compared favorably with simultaneous Scholander pressure chamber measurements on neighboring leaves when the latter were corrected for the osmotic potential.

Comparative drought-resistance of seedlings of 28 species of co-occurring tropical woody plants.

PubMed

Engelbrecht, Bettina M J; Kursar, Thomas A

2003-08-01

Quantifying plant drought resistance is important for understanding plant species' association to microhabitats with different soil moisture availability and their distribution along rainfall gradients, as well as for understanding the role of underlying morphological and physiological mechanisms. The effect of dry season drought on survival and leaf-area change of first year seedlings of 28 species of co-occurring woody tropical plants was experimentally quantified in the understory of a tropical moist forest. The seedlings were subjected to a drought or an irrigation treatment in the forest for 22 weeks during the dry season. Drought decreased survival and growth (assessed as leaf-area change) in almost all of the species. Both survival and leaf-area change in the dry treatment ranged fairly evenly from 0% to about 100% of that in the irrigated treatment. In 43% of the species the difference between treatments in survival was not significant even after 22 weeks. In contrast, only three species showed no significant effect of drought on leaf-area change. The effects of drought on species' survival and growth were not correlated with each other, reflecting different strategies in response to drought. Seedling size at the onset of the dry season had no significant effect on species' drought response. Our study is the first to comparatively assess seedling drought resistance in the habitat for a large number of tropical species, and underlines the importance of drought for plant population dynamics in tropical forests.

Molecular interactions between tomato and the leaf mold pathogen Cladosporium fulvum.

PubMed

Rivas, Susana; Thomas, Colwyn M

2005-01-01

The interaction between tomato and the leaf mold pathogen Cladosporium fulvum is controlled in a gene-for-gene manner. This interaction has provided useful insights to the molecular basis of recognition specificity in plant disease resistance (R) proteins, disease resistance (R) gene evolution, R-protein mediated signaling, and cellular responses to pathogen attack. Tomato Cf genes encode type I membrane-associated receptor-like proteins (RLPs) comprised predominantly of extracellular leucine-rich repeats (eLRRs) and which are anchored in the plasma membrane. Cf proteins recognize fungal avirulence (Avr) peptides secreted into the leaf apoplast during infection. A direct interaction of Cf proteins with their cognate Avr proteins has not been demonstrated and the molecular mechanism of Avr protein perception is not known. Following ligand perception Cf proteins trigger a hypersensitive response (HR) and the arrest of pathogen development. Cf proteins lack an obvious signaling domain, suggesting that defense response activation is mediated through interactions with other partners. Avr protein perception results in the rapid accumulation of active oxygen species (AOS), changes in cellular ion fluxes, activation of protein kinase cascades, changes in gene expression and, possibly, targeted protein degradation. Here we review our current understanding of Cf-mediated responses in resistance to C. fulvum.

Using functional traits to assess the resistance of subalpine grassland to trampling by mountain biking and hiking.

PubMed

Pickering, Catherine Marina; Barros, Agustina

2015-12-01

Functional traits reflect plant responses to disturbance, including from visitor impacts. The impacts of mountain biking and hiking on functional composition were compared using a common experimental protocol in a subalpine grassland in the Australian Alps. The overlapping cover of all species was recorded two weeks after different intensities of hiking (200 and 500 passes) and mountain biking (none, 25, 75, 200 and 500 passes). Species' functional trait data were combined with their relative cover to calculate community trait weighted means for plant height, leaf area, percentage leaf dry matter content and Specific Leaf Area (SLA). Species such as Poa fawcettiae with larger leaves and SLA but lower dry weight content of leaves were more resistant to use, with differences between bikers and hikers only apparent at the highest levels of use tested. This differs from some vegetation communities in Europe where plants with smaller leaves were more resistant to hiking. More research using functional traits may account for differences in species responses to trampling. Managers of conservation areas used for hiking and biking need to minimise off trail use by both user groups. Copyright © 2015 Elsevier Ltd. All rights reserved.

Concerted action of two avirulent spore effectors activates Reaction to Puccinia graminis 1 (Rpg1)-mediated cereal stem rust resistance

USDA-ARS?s Scientific Manuscript database

The barley stem rust resistance gene Reaction to Puccinia graminis 1 (Rpg1), encoding a receptor-like kinase, confers durable resistance to the stem rust pathogen Puccinia graminis f. sp. tritici. The fungal urediniospores form adhesion structures with the leaf epidermal cells within 1 h of inocula...

Host resistance to Botrytis bunch rot in Vitis spp. and its correlation with Botrytis leaf spot

USDA-ARS?s Scientific Manuscript database

Botrytis cinerea, the causal agent of Botrytis bunch rot, is the number one postharvest disease of fresh grapes in the U.S. Fungicide applications are used to manage the disease, but resistant isolates are common and postharvest losses occur annually. Host resistance is needed for long-term manageme...

De Novo Assembled Wheat Transcriptomes Delineate Differentially Expressed Host Genes in Response to Leaf Rust Infection.

PubMed

Chandra, Saket; Singh, Dharmendra; Pathak, Jyoti; Kumari, Supriya; Kumar, Manish; Poddar, Raju; Balyan, Harindra Singh; Gupta, Puspendra Kumar; Prabhu, Kumble Vinod; Mukhopadhyay, Kunal

2016-01-01

Pathogens like Puccinia triticina, the causal organism for leaf rust, extensively damages wheat production. The interaction at molecular level between wheat and the pathogen is complex and less explored. The pathogen induced response was characterized using mock- or pathogen inoculated near-isogenic wheat lines (with or without seedling leaf rust resistance gene Lr28). Four Serial Analysis of Gene Expression libraries were prepared from mock- and pathogen inoculated plants and were subjected to Sequencing by Oligonucleotide Ligation and Detection, which generated a total of 165,767,777 reads, each 35 bases long. The reads were processed and multiple k-mers were attempted for de novo transcript assembly; 22 k-mers showed the best results. Altogether 21,345 contigs were generated and functionally characterized by gene ontology annotation, mining for transcription factors and resistance genes. Expression analysis among the four libraries showed extensive alterations in the transcriptome in response to pathogen infection, reflecting reorganizations in major biological processes and metabolic pathways. Role of auxin in determining pathogenesis in susceptible and resistant lines were imperative. The qPCR expression study of four LRR-RLK (Leucine-rich repeat receptor-like protein kinases) genes showed higher expression at 24 hrs after inoculation with pathogen. In summary, the conceptual model of induced resistance in wheat contributes insights on defense responses and imparts knowledge of Puccinia triticina-induced defense transcripts in wheat plants.

De Novo Assembled Wheat Transcriptomes Delineate Differentially Expressed Host Genes in Response to Leaf Rust Infection

PubMed Central

Pathak, Jyoti; Kumari, Supriya; Kumar, Manish; Poddar, Raju; Balyan, Harindra Singh; Gupta, Puspendra Kumar; Prabhu, Kumble Vinod; Mukhopadhyay, Kunal

2016-01-01

Pathogens like Puccinia triticina, the causal organism for leaf rust, extensively damages wheat production. The interaction at molecular level between wheat and the pathogen is complex and less explored. The pathogen induced response was characterized using mock- or pathogen inoculated near-isogenic wheat lines (with or without seedling leaf rust resistance gene Lr28). Four Serial Analysis of Gene Expression libraries were prepared from mock- and pathogen inoculated plants and were subjected to Sequencing by Oligonucleotide Ligation and Detection, which generated a total of 165,767,777 reads, each 35 bases long. The reads were processed and multiple k-mers were attempted for de novo transcript assembly; 22 k-mers showed the best results. Altogether 21,345 contigs were generated and functionally characterized by gene ontology annotation, mining for transcription factors and resistance genes. Expression analysis among the four libraries showed extensive alterations in the transcriptome in response to pathogen infection, reflecting reorganizations in major biological processes and metabolic pathways. Role of auxin in determining pathogenesis in susceptible and resistant lines were imperative. The qPCR expression study of four LRR-RLK (Leucine-rich repeat receptor-like protein kinases) genes showed higher expression at 24 hrs after inoculation with pathogen. In summary, the conceptual model of induced resistance in wheat contributes insights on defense responses and imparts knowledge of Puccinia triticina-induced defense transcripts in wheat plants. PMID:26840746

Increased lodging resistance in long-culm, low-lignin gh2 rice for improved feed and bioenergy production

PubMed Central

Ookawa, Taiichiro; Inoue, Kazuya; Matsuoka, Makoto; Ebitani, Takeshi; Takarada, Takeshi; Yamamoto, Toshio; Ueda, Tadamasa; Yokoyama, Tadashi; Sugiyama, Chisato; Nakaba, Satoshi; Funada, Ryo; Kato, Hiroshi; Kanekatsu, Motoki; Toyota, Koki; Motobayashi, Takashi; Vazirzanjani, Mehran; Tojo, Seishu; Hirasawa, Tadashi

2014-01-01

Lignin modification has been a breeding target for the improvements of forage digestibility and energy yields in forage and bioenergy crops, but decreased lignin levels are often accompanied by reduced lodging resistance. The rice mutant gold hull and internode2 (gh2) has been identified to be lignin deficient. GH2 has been mapped to the short arm of chromosome 2 and encodes cinnamyl-alcohol dehydrogenase (CAD). We developed a long-culm variety, ‘Leaf Star’, with superior lodging resistance and a gh phenotype similar to one of its parents, ‘Chugoku 117’. The gh loci in Leaf Star and Chugoku 117 were localized to the same region of chromosome 2 as the gh2 mutant. Leaf Star had culms with low lignin concentrations due to a natural mutation in OsCAD2 that was not present in Chugoku 117. However, this variety had high culm strength due to its strong, thick culms. Additionally, this variety had a thick layer of cortical fiber tissue with well-developed secondary cell walls. Our results suggest that rice can be improved for forage and bioenergy production by combining superior lodging resistance, which can be obtained by introducing thick and stiff culm traits, with low lignin concentrations, which can be obtained using the gh2 variety. PMID:25298209

Energy efficient continuous flow ash lockhopper

NASA Technical Reports Server (NTRS)

Collins, Earl R., Jr. (Inventor); Suitor, Jerry W. (Inventor); Dubis, David (Inventor)

1989-01-01

The invention relates to an energy efficient continuous flow ash lockhopper, or other lockhopper for reactor product or byproduct. The invention includes an ash hopper at the outlet of a high temperature, high pressure reactor vessel containing heated high pressure gas, a fluidics control chamber having an input port connected to the ash hopper's output port and an output port connected to the input port of a pressure letdown means, and a control fluid supply for regulating the pressure in the control chamber to be equal to or greater than the internal gas pressure of the reactor vessel, whereby the reactor gas is contained while ash is permitted to continuously flow from the ash hopper's output port, impelled by gravity. The main novelty resides in the use of a control chamber to so control pressure under the lockhopper that gases will not exit from the reactor vessel, and to also regulate the ash flow rate. There is also novelty in the design of the ash lockhopper shown in two figures. The novelty there is the use of annular passages of progressively greater diameter, and rotating the center parts on a shaft, with the center part of each slightly offset from adjacent ones to better assure ash flow through the opening.

Discharge flow of a granular media from a silo: effect of the packing fraction and of the hopper angle

NASA Astrophysics Data System (ADS)

Benyamine, Mebirika; Aussillous, Pascale; Dalloz-Dubrujeaud, Blanche

2017-06-01

Silos are widely used in the industry. While empirical predictions of the flow rate, based on scaling laws, have existed for more than a century (Hagen 1852, translated in [1] - Beverloo et al. [2]), recent advances have be made on the understanding of the control parameters of the flow. In particular, using continuous modeling together with a mu(I) granular rheology seem to be successful in predicting the flow rate for large numbers of beads at the aperture (Staron et al.[3], [4]). Moreover Janda et al.[5] have shown that the packing fraction at the outlet plays an important role when the number of beads at the apeture decreases. Based on these considerations, we have studied experimentally the discharge flow of a granular media from a rectangular silo. We have varied two main parameters: the angle of the hopper, and the bulk packing fraction of the granular material by using bidisperse mixtures. We propose a simple physical model to describe the effect of these parameters, considering a continuous granular media with a dilatancy law at the outlet. This model predicts well the dependance of the flow rate on the hopper angle as well as the dependance of the flow rate on the fine mass fraction of a bidisperse mixture.

Screening for anthracnose disease resistance in strawberry using a detached leaf assay

USDA-ARS?s Scientific Manuscript database

Inoculation of detached strawberry leaves with Colletotrichum species may provide a rapid, non-destructive method of identifying anthracnose resistant germplasm. The reliability and validity of assessing disease severity is critical to disease management decisions. We inoculated detached strawberr...

Xanthium strumarium: a weed host of components of begomovirus-betasatellite complexes affecting crops.

PubMed

Mubin, M; Akhtar, S; Amin, I; Briddon, R W; Mansoor, S

2012-02-01

Xanthium strumarium is a common weed that often shows symptoms typical of begomovirus infection, such as leaf curling and vein thickening. The virus complex isolated from the weed consisted of two begomoviruses along with a betasatellite and an alphasatellite. The first begomovirus was shown to be an isolate of Cotton leaf curl Burewala virus, a new recombinant begomovirus species that is associated with resistance breaking in previously resistant cotton varieties in Pakistan, whereas the second was shown to be an isolate of Tomato leaf curl Gujarat virus (ToLCGV), a begomovirus previously reported to be bipartite. However, there was no evidence for the presence of the second genomic component, DNA B, of ToLCGV in X. strumarium. The betasatellite was shown to be an isolate of Tomato yellow leaf curl Thailand betasatellite, the first time this satellite has been identified in Pakistan. The alphasatellite associated with infection of X. strumarium was shown to be a species recently identified in potato and various weeds; Potato leaf curl alphasatellite. Although each component has been identified previously, this is the first time they have been identified in a single host. These findings reinforce the hypothesis that weeds are reservoirs of crop-infecting begomoviruses that may contribute to virus diversity by virtue of harboring multiple viruses and virus associated components, which may lead to interspecific recombination and component exchange.

Genetic dissection of novel QTLs for resistance to leaf spots and Tomato spotted wilt virus in peanut (Arachis hypogaea L.)

USDA-ARS?s Scientific Manuscript database

Peanut is an import crop, economically and nutritiously, but high production cost is a serious challenge to peanut farmers as exemplified by chemical spray to control foliar diseases such as leaf spots and thrips, the vectors of tomato spotted wilt virus (TSWV). The objective of this research was to...

Modifications in Ginkgo biloba L. in response to environmental pollution

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sharma, G.K.

1989-01-01

Ginkgo biloba L. (maidenhair tree) was studied in polluted and relatively clean habitats of West Tennessee. In spite of its known resistance to smog and automobile exhaust fumes, it exhibited a decrease in leaf length, leaf width, and petiole length in polluted habitats. Furthermore, there was a definite trend towards lower stomatal density along the pollution gradient in selected habitats.

Leaf Pressure Volume Data in Caxiuana and Tapajos National Forest, Para, Brazil (2011)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Powell, Thomas; Moorcroft, Paul

Pressure volume curve measurements on leaves of canopy trees from the from the Caxiuana and Tapajos National Forests, Para, Brazil. Tapajos samples were harvested from the km 67 forested area, which is adjacent to the decommissioned throughfall exclusion drought experimental plot. Caxiuana samples were harvested from trees growing in the throughfall exclusion plots. Data were collected in 2011. Dataset includes: date of measurement, site ID, plot ID, tree ID (species, tree tag #), leaf area, fresh weight, relative weight, leaf water potential, and leaf water loss. P-V curve parameters (turgor loss point, osmotic potential, and bulk modulus of elasticity) canmore » be found in Powell et al. (2017) Differences in xylem cavitation resistance and leaf hydraulic traits explain differences in drought tolerance among mature Amazon rainforest trees. Global Change Biology.« less

Wolbachia infection complexity among insects in the tropical rice-field community.

PubMed

Kittayapong, P; Jamnongluk, W; Thipaksorn, A; Milne, J R; Sindhusake, C

2003-04-01

Wolbachia are a group of intracellular bacteria that cause reproductive alterations in their arthropod hosts. Widely discordant host and Wolbachia phylogenies indicate that horizontal transmission of these bacteria among species sometimes occurs. A likely means of horizontal transfer is through the feeding relations of organisms within communities. Feeding interactions among insects within the rice-field insect community have been well documented in the past. Here, we present the results of a polymerase chain reaction-based survey and phylogenetic analysis of Wolbachia strains in the rice-field insect community of Thailand. Our field survey indicated that 49 of 209 (23.4%) rice-field insect species were infected with Wolbachia. Of the 49 infected species, 27 were members of two feeding complexes: (i) a group of 13 hoppers preyed on by 2 mirid species and parasitized by a fly species, and (ii) 2 lepidopteran pests parasitized by 9 wasp species. Wolbachia strains found in three hoppers, Recilia dorsalis, Nephotettix malayanus and Nisia nervosa, the two mirid predators, Cyrtorhinus lividipennis and Tytthus chinensis, and the fly parasitoid, Tomosvaryella subvirescens, were all in the same Wolbachia clade. In the second complex, the two lepidopteran pests, Cnaphalocrocis medinalis and Scirpophaga incertulas, were both infected with Wolbachia from the same clade, as was the parasitoid Tropobracon schoenobii. However, none of the other infected parasitoid species in this feeding complex was infected by Wolbachia from this clade. Mean (+/- SD) genetic distance of Wolbachia wsp sequences among interacting species pairs of the hopper feeding complex (0.118 +/- 0.091 nucleotide sequence differences), but not for the other two complexes, was significantly smaller than that between noninteracting species pairs (0.162 +/- 0.079 nucleotide sequence differences). Our results suggest that some feeding complexes, such as the hopper complex described here, could be an important means by which Wolbachia spreads among species within arthropod communities.

Suppression of the rice fatty-acid desaturase gene OsSSI2 enhances resistance to blast and leaf blight diseases in rice.

PubMed

Jiang, Chang-Jie; Shimono, Masaki; Maeda, Satoru; Inoue, Haruhiko; Mori, Masaki; Hasegawa, Morifumi; Sugano, Shoji; Takatsuji, Hiroshi

2009-07-01

Fatty acids and their derivatives play important signaling roles in plant defense responses. It has been shown that suppressing a gene for stearoyl acyl carrier protein fatty-acid desaturase (SACPD) enhances the resistance of Arabidopsis (SSI2) and soybean to multiple pathogens. In this study, we present functional analyses of a rice homolog of SSI2 (OsSSI2) in disease resistance of rice plants. A transposon insertion mutation (Osssi2-Tos17) and RNAi-mediated knockdown of OsSSI2 (OsSSI2-kd) reduced the oleic acid (18:1) level and increased that of stearic acid (18:0), indicating that OsSSI2 is responsible for fatty-acid desaturase activity. These plants displayed spontaneous lesion formation in leaf blades, retarded growth, slight increase in endogenous free salicylic acid (SA) levels, and SA/benzothiadiazole (BTH)-specific inducible genes, including WRKY45, a key regulator of SA/BTH-induced resistance, in rice. Moreover, the OsSSI2-kd plants showed markedly enhanced resistance to the blast fungus Magnaporthe grisea and leaf-blight bacteria Xanthomonas oryzae pv. oryzae. These results suggest that OsSSI2 is involved in the negative regulation of defense responses in rice, as are its Arabidopsis and soybean counterparts. Microarray analyses identified 406 genes that were differentially expressed (>or=2-fold) in OsSSI2-kd rice plants compared with wild-type rice and, of these, approximately 39% were BTH responsive. Taken together, our results suggest that induction of SA-responsive genes, including WRKY45, is likely responsible for enhanced disease resistance in OsSSI2-kd rice plants.

Canopy reflectance, photosynthesis, and transpiration. II - The role of biophysics in the linearity of their interdependence

NASA Technical Reports Server (NTRS)

Sellers, P. J.

1987-01-01

The ability of satellite sensor systems to estimate area-averaged canopy photosynthetic and transpirative properties is evaluated. The near linear relationship between the simple ratio (SR) and normalized difference (ND) and the surface biophysical properties of canopy photosynthetically active radiation (PAR) absorption, photosynthesis, and bulk stomatal resistance is studied. The models utilized to illustrate the processes of canopy reflectance, photosynthesis, and resistance are described. The dependence of SR, the absorbed fraction of PAR, and canopy photosynthesis and resistance on total leaf area index is analyzed. It is noted that the SR and ND vegetation indices and vegetation-dependent qualities are near-linearly related due to the proportion of leaf scattering coefficient in visible and near IR wavelength regions. The data reveal that satellite sensor systems are useful for the estimation of photosynthesis and transpirative properties.

Drought resistance in early and late secondary successional species from a tropical dry forest: the interplay between xylem resistance to embolism, sapwood water storage and leaf shedding.

PubMed

Pineda-García, Fernando; Paz, Horacio; Meinzer, Frederick C

2013-02-01

The mechanisms of drought resistance that allow plants to successfully establish at different stages of secondary succession in tropical dry forests are not well understood. We characterized mechanisms of drought resistance in early and late-successional species and tested whether risk of drought differs across sites at different successional stages, and whether early and late-successional species differ in resistance to experimentally imposed soil drought. The microenvironment in early successional sites was warmer and drier than in mature forest. Nevertheless, successional groups did not differ in resistance to soil drought. Late-successional species resisted drought through two independent mechanisms: high resistance of xylem to embolism, or reliance on high stem water storage capacity. High sapwood water reserves delayed the effects of soil drying by transiently decoupling plant and soil water status. Resistance to soil drought resulted from the interplay between variations in xylem vulnerability to embolism, reliance on sapwood water reserves and leaf area reduction, leading to a tradeoff of avoidance against tolerance of soil drought, along which successional groups were not differentiated. Overall, our data suggest that ranking species' performance under soil drought based solely on xylem resistance to embolism may be misleading, especially for species with high sapwood water storage capacity. © 2012 Blackwell Publishing Ltd.

Triton Hopper: Exploring Neptune's Captured Kuiper Belt Object

NASA Technical Reports Server (NTRS)

Oleson, Steve; Landis, Geoffrey

2018-01-01

Neptune's moon Triton is a fascinating object, a dynamic moon with an atmosphere, and geysers. Triton is unique in the outer solar system in that it is most likely a captured Kuiper belt object (KBO), a leftover building block of the solar system. When Voyager flew by it was the coldest body yet found in our solar system (33 degrees Kelvin) and had volcanic activity, geysers, and a thin atmosphere. It is covered in ices made from nitrogen, water, and carbon-dioxide, and shows surface deposits of tholins, organic compounds that may be precursor chemicals to the origin of life. Exploring Triton will be a challenge well beyond anything done in previous missions; but the unique environment of Triton also allows some new possibilities for mobility. We developed a conceptual design of a Triton Hopping probe that both analyzes the surface and collects it for use to propel its hops. The Hopper would land near the South Pole in 2040 where geysers have been detected. Depending the details of propulsion chosen the Hopper should be able to jump over 300 kilometers in 60 hops or less, exploring the surface and thin atmosphere on its way. This craft will autonomously carry out detailed scientific investigations on the surface, below the surface (drilling) and in the upper atmosphere to provide unprecedented knowledge of a KBO-turned moon and expanding NASA's existing capabilities in deep space planetary exploration to include Hoppers using different ices for propellant. Triton is roughly 2700 kilometers in diameter with a surface of mostly frozen nitrogen, mostly water ice crust and core of metal and rock. Its gravity is half that of Earth's Moon and its atmosphere is 170,000th of Earth's or 0.3 of Mars.The mission concept studied investigated the full surface and atmospheric phenomenon: chemical composition of surface and near subsurface materials, the thin atmosphere, volcanic and geyser activity. Measurements of all these aspects of Triton's unique environment can only be made through focused in-situ exploration with a well-instrumented craft. And this craft will be provided revolutionary mobility, nearly global, using in-situ ices as propellants. While other concepts have looked at gathering gases at Mars to propel a hopper, long periods of time are needed to gather the thin CO2 atmosphere. Several gases, mainly nitrogen are on the surface in a readily dense ice form and just need to be picked up, vaporized and used for propellant.

A novel botanical formula prevents diabetes by improving insulin resistance.

PubMed

Kan, Juntao; Velliquette, Rodney A; Grann, Kerry; Burns, Charlie R; Scholten, Jeff; Tian, Feng; Zhang, Qi; Gui, Min

2017-07-05

Type 2 diabetes mellitus (T2DM) is a major risk factor for cardiovascular disease, and the prevalence has increased significantly in recent decades to epidemic proportions in China. Individually, fenugreek (Trigonella foenum graecum) seed, mulberry (Morus alba L.) leaf and American ginseng (Panax quinquefolius) root can improve glycemia in various animal models and humans with impaired glucose metabolism and T2DM. The aim of this study was to design an optimized botanical formula containing these herbal extracts as a nutritional strategy for the prevention of insulin resistance and T2DM. Cell-free α-amylase and α-glucosidase enzyme assays were used to determine inhibitory potential of extracts. Glucose uptake was examined in differentiated human adipocytes using radiolabeled 2-deoxyglucose. Male Sprague Dawley rats were divided and glycemia balanced into 5 groups: two controls (naïve and model) and three doses of the botanical test formula containing standardized fenugreek seed, mulberry leaf and American ginseng extracts (42.33, 84.66 and 169.33 mg/kg BW). Insulin resistance and T2DM was induced by feeding animals a high fat diet and with an alloxan injection. Glucose tolerance was examined by measuring serum glucose levels following an oral glucose load. Fenugreek seed and mulberry leaf dose dependently inhibited α-amylase (IC50 = 73.2 μg/mL) and α-glucosidase (IC50 = 111.8 ng/mL), respectively. All three botanical extracts improved insulin sensitivity and glucose uptake in human adipocytes, which lead to the design of an optimized botanical test formula. In a rat model of insulin resistance and T2DM, the optimized botanical test formula improved fasting serum glucose levels, fasting insulin resistance and the development of impaired glucose tolerance. The reduction in epididymal adipose tissue GLUT4 and PDK1 expression induced by high fat diet and alloxan was blunted by the botanical test formula. A novel botanical formula containing standardized extracts of mulberry leaf, fenugreek seed and American ginseng at a ratio of 1:1.3:3.4 prevented the development of insulin resistance, impaired glucose tolerance and T2DM. Given the rising need for effective non-drug targeting of insulin resistance and progression to T2DM, complementary and alternative nutritional strategies without intolerable side effects could have meaningful impact on metabolic health and diabetes risks.

GROUT HOPPER MODELING STUDY

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lee, S.

2011-08-30

The Saltstone facility has a grout hopper tank to provide agitator stirring of the Saltstone feed materials. The tank has about 300 gallon capacity to provide a larger working volume for the grout slurry to be held in case of a process upset, and it is equipped with a mechanical agitator, which is intended to keep the grout in motion and agitated so that it won't start to set up. The dry feeds and the salt solution are already mixed in the mixer prior to being transferred to the hopper tank. The hopper modeling study through this work will focusmore » on fluid stirring and agitation, instead of traditional mixing in the literature, in order to keep the tank contents in motion during their residence time so that they will not be upset or solidified prior to transferring the grout to the Saltstone disposal facility. The primary objective of the work is to evaluate the flow performance for mechanical agitators to prevent vortex pull-through for an adequate stirring of the feed materials and to estimate an agitator speed which provides acceptable flow performance with a 45{sup o} pitched four-blade agitator. In addition, the power consumption required for the agitator operation was estimated. The modeling calculations were performed by taking two steps of the Computational Fluid Dynamics (CFD) modeling approach. As a first step, a simple single-stage agitator model with 45{sup o} pitched propeller blades was developed for the initial scoping analysis of the flow pattern behaviors for a range of different operating conditions. Based on the initial phase-1 results, the phase-2 model with a two-stage agitator was developed for the final performance evaluations. A series of sensitivity calculations for different designs of agitators and operating conditions have been performed to investigate the impact of key parameters on the grout hydraulic performance in a 300-gallon hopper tank. For the analysis, viscous shear was modeled by using the Bingham plastic approximation. Steady state analyses with a two-equation turbulence model were performed with the FLUENT{trademark} codes. All analyses were based on three-dimensional results. Recommended operational guidance was developed by using the basic concept that local shear rate profiles and flow patterns can be used as a measure of hydraulic performance and spatial stirring. Flow patterns were estimated by a Lagrangian integration technique along the flow paths from the material feed inlet. The modeling results show that when the two-stage agitator consisting of a 45{sup o} pitched propeller and radial flat-plate blades is run at 140 rpm speed with 28 in diameter, the agitator provides an adequate stirring of the feed materials for a wide range of yield stresses (1 to 21 Pa) and the vortex system is shed into the remote region of the tank boundary by the blade passage in an efficient way. The results of this modeling study were used to develop the design guidelines for the agitator stirring and dispersion of the Saltstone feed materials in a hopper tank.« less

Species and population variation to salinity stress in Panicum hemitomon, Spartina patens, and Spartina alterniflora: Morphological and physiological constraints

USGS Publications Warehouse

Hester, M.W.; Mendelssohn, I.A.; McKee, K.L.

2001-01-01

Panicum hemitomon, Spartina patens, and Spartina alterniflora are wide-spread dominant grasses of fresh, brackish, and salt marsh plant communities, respectively. Our previous research identified significant intraspecific variation in salt tolerance and morphology among populations within each species. In this study our objectives were to determine shorter-term physiological/biochemical responses to salinity stress and identify potential indicators of salt tolerance, with the ultimate goal of discerning similarities and differences in the mechanisms of salinity stress resistance. We subjected a subset of six populations within each species, ranging from high to low salt tolerance, to sublethal salinity levels (4, 20, and 30 ppt, respectively, for species) and monitored physiological and growth responses after 1 week (early harvest) and 5 weeks (late harvest). In all three species sublethal salinity levels generally resulted in significantly reduced net CO2 assimilation, leaf expansion, midday leaf xylem pressure, water use efficiency, and live and total biomass; and significantly increased leaf Na+/K+ ratio, leaf proline, leaf glycine betaine, leaf sucrose, root-to-shoot ratio, and dead:total aboveground biomass ratio. All three species displayed significant population (intraspecific) variation in net CO2 assimilation, leaf expansion, water use efficiency, midday leaf xylem pressure, leaf proline, leaf glycine betaine (except Panicum, where it could not be accurately determined), leaf Na+/K+ ratio, leaf sucrose, total plant biomass, dead:total aboveground biomass ratio, and root-to-shoot ratio. General indicators of salt tolerance (regardless of species) included high net CO2 assimilation rates and water use efficiencies, and low ratios of root-to-shoot and dead:total aboveground biomass. Factor analysis and a-priori linear contrasts revealed some unique differences between species in terms of the relative importance of morphology and physiology in explaining intraspecific variation in salt tolerance. Plant morphology (size attributes) were strongly associated with salt tolerance in P. hemitomon, weakly associated with salt tolerance in S. patens, and not associated with salt tolerance in S. alterniflora. Highly salt-tolerant populations of Spartina alterniflora displayed the greatest ion selectivity (lower leaf Na+/K+ ratios), which was not displayed by the other two species. These results suggest that plant size attributes can be very important in explaining population differences in salt tolerance in glycophytes, but may be independent of salt tolerance in halophytes, which have specialized physiological (and/or anatomical) adaptations that can confer salinity stress resistance through mechanisms such as selective ion exclusion and secretion. ?? 2001 Elsevier Science B.V. All rights reserved.

Development of plants resistant to Papaya leaf distortion mosaic virus by intergeneric hybridization between Carica papaya and Vasconcellea cundinamarcensis.

PubMed

Tarora, Kazuhiko; Shudo, Ayano; Kawano, Shinji; Yasuda, Keiji; Ueno, Hiroki; Matsumura, Hideo; Urasaki, Naoya

2016-12-01

In this study, we confirmed that Vasconcellea cundinamarcensis resists Papaya leaf distortion mosaic virus (PLDMV), and used it to produce intergeneric hybrids with Carica papaya . From the cross between C. papaya and V. cundinamarcensis , we obtained 147 seeds with embryos. Though C. papaya is a monoembryonic plant, multiple embryos were observed in all 147 seeds. We produced 218 plants from 28 seeds by means of embryo-rescue culture. All plants had pubescence on their petioles and stems characteristic of V. cundinamarcensis . Flow cytometry and PCR of 28 plants confirmed they were intergeneric hybrids. To evaluate virus resistance, mechanical inoculation of PLDMV was carried out. The test showed that 41 of 134 intergeneric hybrid plants showed no symptoms and were resistant. The remaining 93 hybrids showed necrotic lesions on the younger leaves than the inoculated leaves. In most of the 93 hybrids, the necrotic lesions enclosed the virus and prevented further spread. These results suggest that the intergeneric hybrids will be valuable material for PLDMV-resistant papaya breeding.

Development of plants resistant to Papaya leaf distortion mosaic virus by intergeneric hybridization between Carica papaya and Vasconcellea cundinamarcensis

PubMed Central

Tarora, Kazuhiko; Shudo, Ayano; Kawano, Shinji; Yasuda, Keiji; Ueno, Hiroki; Matsumura, Hideo; Urasaki, Naoya

2016-01-01

In this study, we confirmed that Vasconcellea cundinamarcensis resists Papaya leaf distortion mosaic virus (PLDMV), and used it to produce intergeneric hybrids with Carica papaya. From the cross between C. papaya and V. cundinamarcensis, we obtained 147 seeds with embryos. Though C. papaya is a monoembryonic plant, multiple embryos were observed in all 147 seeds. We produced 218 plants from 28 seeds by means of embryo-rescue culture. All plants had pubescence on their petioles and stems characteristic of V. cundinamarcensis. Flow cytometry and PCR of 28 plants confirmed they were intergeneric hybrids. To evaluate virus resistance, mechanical inoculation of PLDMV was carried out. The test showed that 41 of 134 intergeneric hybrid plants showed no symptoms and were resistant. The remaining 93 hybrids showed necrotic lesions on the younger leaves than the inoculated leaves. In most of the 93 hybrids, the necrotic lesions enclosed the virus and prevented further spread. These results suggest that the intergeneric hybrids will be valuable material for PLDMV-resistant papaya breeding. PMID:28163589

29 CFR 1926.750 - Scope.

Code of Federal Regulations, 2013 CFR

2013-07-01

... engaged in steel erection unless otherwise specified. This subpart does not cover electrical transmission...; car dumpers; stackers/reclaimers; cranes and craneways; bins; hoppers; ovens; furnaces; stacks...

29 CFR 1926.750 - Scope.

Code of Federal Regulations, 2012 CFR

2012-07-01

... engaged in steel erection unless otherwise specified. This subpart does not cover electrical transmission...; car dumpers; stackers/reclaimers; cranes and craneways; bins; hoppers; ovens; furnaces; stacks...

29 CFR 1926.750 - Scope.

Code of Federal Regulations, 2014 CFR

2014-07-01

... engaged in steel erection unless otherwise specified. This subpart does not cover electrical transmission...; car dumpers; stackers/reclaimers; cranes and craneways; bins; hoppers; ovens; furnaces; stacks...

29 CFR 1926.750 - Scope.

Code of Federal Regulations, 2011 CFR

2011-07-01

... engaged in steel erection unless otherwise specified. This subpart does not cover electrical transmission...; car dumpers; stackers/reclaimers; cranes and craneways; bins; hoppers; ovens; furnaces; stacks...

29 CFR 1926.750 - Scope.

Code of Federal Regulations, 2010 CFR

2010-07-01

... engaged in steel erection unless otherwise specified. This subpart does not cover electrical transmission...; car dumpers; stackers/reclaimers; cranes and craneways; bins; hoppers; ovens; furnaces; stacks...

Leaf traits and herbivory levels in a tropical gymnosperm, Zamia stevensonii (Zamiaceae).

PubMed

Prado, Alberto; Sierra, Adriel; Windsor, Donald; Bede, Jacqueline C

2014-03-01

Slow-growing understory cycads invest heavily in defenses to protect the few leaves they produce annually. The Neotropical cycad Zamia stevensonii has chemical and mechanical barriers against insect herbivores. Mechanical barriers, such as leaf toughness, can be established only after the leaf has expanded. Therefore, chemical defenses may be important during leaf expansion. How changes in leaf traits affect the feeding activity of cycad specialist insects is unknown. We investigated leaf defenses and incidence of specialist herbivores on Z. stevensonii during the first year after leaf flush. Herbivore incidence, leaf production, and leaf traits that might affect herbivory-including leaf age, lamina thickness, resistance-to-fracture, work-to-fracture, trichome density, and chlorophyll, water, and toxic azoxyglycoside (AZG) content-were measured throughout leaf development. Principal component analysis and generalized linear models identified characteristics that may explain herbivore incidence. Synchronized leaf development in Z. stevensonii is characterized by quick leaf expansion and delayed greening. Specialist herbivores feed on leaves between 10 and 100 d after flush and damage ∼37% of all leaflets produced. Young leaves are protected by AZGs, but these defenses rapidly decrease as leaves expand. Leaves older than 100 d are protected by toughness. Because AZG concentrations drop before leaves become sufficiently tough, there is a vulnerable period during which leaves are susceptible to herbivory by specialist insects. This slow-growing gymnosperm invests heavily in constitutive defenses against highly specialized herbivores, underlining the convergence in defensive syndromes by major plant lineages.

LEAF WHORL INOCULATION METHOD FOR SCREENING SUGARCANE RUST RESISTANCE

USDA-ARS?s Scientific Manuscript database

Technical Abstract: Sugarcane rust diseases, brown rust caused by Puccinia melanocephala, and orange rust caused by P. kuehnii, are agronomically important diseases in Florida. Cultivar resistance is the best means of controlling these diseases. Natural infection has been the primary means of asses...

Precision phenotyping of epicuticular waxes associated with insect resistance

USDA-ARS?s Scientific Manuscript database

Accurate phenotyping is imperative for linkage mapping and association genetics. Amounts and types of epicuticular waxes on the leaf surface are important for plant-insect interactions. In onion, specific wax profiles are associated with resistance to the insect pest Thrips tabaci. Epicuticular wax ...

Genetic control and combining ability of agronomic attributes and northern leaf blight-related attributes in popcorn.

PubMed

Santos, J S; Amaral Júnior, A T; Vivas, M; Mafra, G S; Pena, G F; Silva, F H L; Guimarães, A G

2017-09-27

The present study was conducted to investigate the genetic control and to estimate the general and specific combining abilities of popcorn for agronomic attributes and attributes related to resistance to northern leaf blight (NLB). The 56 hybrids (F 1 and reciprocals), together with the eight parent lines and six controls, were evaluated in two harvests, in a randomized-block design with four replications. Dominance components were more expressive than the additive components for grain yield and expression of resistance, and hybridization was the most suitable option for obtaining resistant and productive genotypes. For grain yield, popping expansion, and resistance to NLB, there was no significance for reciprocal effects, which indicates that the direction in which the cross is performed does not interfere with the hybrid's performance. Then, the superior hybrids recommended for more profitable growth were P8 x L61, L61 x L76, and L61 x L77.

Application of plant impedance for diagnosing plant disease

NASA Astrophysics Data System (ADS)

Xu, Huirong; Jiang, Xuesong; Zhu, Shengpan; Ying, Yibin

2006-10-01

Biological cells have components acting as electrical elements that maintain the health of the cell by regulation of the electrical charge content. Plant impedance is decided by the state of plant physiology and pathology. Plant physiology and pathology can be studies by measuring plant impedance. The effect of Cucumber Mosaic Virus red bean isolate (CMV-RB) on electrical resistance of tomato leaves was studied by the method of impedance measurement. It was found that the value of resistance of tomato leaves infected with CMV-RB was smaller than that in sound plant leaves. This decrease of impedances in leaf tissue was occurred with increased severity of disease. The decrease of resistance of tomato leaves infected with CMV-RB could be detected by electrical resistance detecting within 4 days after inoculation even though significant visible differences between the control and the infected plants were not noted, so that the technique for measurement of tomato leaf tissue impedance is a rapid, clever, simple method on diagnosis of plant disease.

Synergy between Ursolic and Oleanolic Acids from Vitellaria paradoxa Leaf Extract and β-Lactams against Methicillin-Resistant Staphylococcus aureus: In Vitro and In Vivo Activity and Underlying Mechanisms.

PubMed

Catteau, Lucy; Reichmann, Nathalie T; Olson, Joshua; Pinho, Mariana G; Nizet, Victor; Van Bambeke, Françoise; Quetin-Leclercq, Joëlle

2017-12-16

Combining antibiotics with resistance reversing agents is a key strategy to overcome bacterial resistance. Upon screening antimicrobial activities of plants used in traditional medicine, we found that a leaf dichloromethane extract from the shea butter tree ( Vitellaria paradoxa ) had antimicrobial activity against methicillin-resistant Staphylococcus aureus (MRSA) with further evidence of synergy when combined with β-lactams. Using HPLC-MS, we identified ursolic (UA) and oleanolic acids (OA) in leaves and twigs of this species, and quantified them by HPLC-UV as the major constituents in leaf extracts (21% and 6% respectively). Both pure triterpenic acids showed antimicrobial activity against reference and clinical strains of MRSA, with MICs ranging from 8-16 mg/L for UA to 32-128 mg/L for OA. They were highly synergistic with β-lactams (ampicillin and oxacillin) at subMIC concentrations. Reversion of MRSA phenotype was attributed to their capacity to delocalize PBP2 from the septal division site, as observed by fluorescence microscopy, and to disturb thereby peptidoglycan synthesis. Moreover, both compounds also inhibited β-lactamases activity of living bacteria (as assessed by inhibition of nitrocefin hydrolysis), but not in bacterial lysates, suggesting an indirect mechanism for this inhibition. In a murine model of subcutaneous MRSA infection, local administration of UA was synergistic with nafcillin to reduce lesion size and inflammatory cytokine (IL-1β) production. Thus, these data highlight the potential interest of triterpenic acids as resistance reversing agents in combination with β-lactams against MRSA.

Characterization and genome-wide association mapping of resistance to leaf rust, stem rust and stripe rust in a geographically diverse collection of spring wheat landraces

USDA-ARS?s Scientific Manuscript database

The challenge posed by rapidly changing wheat rust pathogens, both in virulence and in environmental adaptation, calls for the development and application of new techniques to accelerate the process of breeding for durable resistance. To expand the wheat resistance gene pool available for germplasm ...

Verification of STS markers for leaf rust resistance genes of wheat by seven European laboratories.

PubMed

Błaszczyk, Lidia; Chełkowski, Jerzy; Korzun, Victor; Kraic, Jan; Ordon, Frank; Ovesná, Jaroslava; Purnhauser, Laszlo; Tar, Melinda; Vida, Gyula

2004-01-01

A set of Thatcher near-isogenic lines and two breeding lines were used to examine sequence tagged site (STS) markers linked to leaf rust resistance genes Lr9, Lr10, Lr19, Lr24, Lr28, Lr29, Lr35, and a simple sequenced repeat (SSR) marker for Lr39. The selected STS markers for resistance genes Lr9, Lr10, Lr19, Lr24 and Lr28 were identified in seven accessions by seven European laboratories. Near-isogenic lines of the spring wheat Thatcher were used as positive controls. Markers for resistance genes Lr9, Lr10, Lr19, Lr24 were identified in all seven laboratories as amplification products of 1100 bp, 310 bp, 130 bp and 310 bp, respectively. The STS markers linked to resistance genes Lr9, Lr10, Lr19, Lr24, Lr29, Lr35 and the SSR marker for Lr39 were robust and highly specific for these genes and will be useful in marker-assisted selection in wheat. However, the amplification product of 378 bp that corresponded with resistance gene Lr28 was detected in all accessions including genotypes lacking this gene in all seven laboratories. This marker needs to be improved.

Isolate Specificity and Polygenic Inheritance of Resistance in Barley to Diverse Heterologous Puccinia striiformis Isolates.

PubMed

Haghdoust, R; Singh, D; Garnica, D P; Park, R F; Dracatos, P M

2018-05-01

Barley is a host to Puccinia striiformis f. sp. hordei, and is an intermediate or near nonhost to the formae speciales adapted to wheat (P. striiformis f. sp. tritici) and to barley grass (P. striiformis f. sp. pseudo-hordei). The genetic basis of resistance to these forms of P. striiformis is not well understood. Accordingly, a recombinant inbred line (RIL) population was developed using a P. striiformis-susceptible accession (Biosaline-19) and the immune cultivar Pompadour. We investigated the genetic basis of resistance to four diverse P. striiformis isolates (P. striiformis f. sp. pseudo-hordei, and P. striiformis f. sp. tritici pathotypes 104 E137 A-, 134 E16 A+, and 64 E0 A-). and determined that the immunity in Pompadour at the seedling stage to the different P. striiformis isolates was due to quantitative trait loci (QTL) on chromosomes 1H, 3H, 5H, and 7H with both overlapping and distinct specificities. Further histological analysis confirmed the presence of isolate specificity. The RILs were also assessed in the field for resistance to P. striiformis f. sp. pseudo-hordei, P. striiformis f. sp. hordei, and the leaf rust pathogen (P. hordei) to identify pleiotropic QTL loci effective at the adult plant stage and determine whether the leaf rust resistance in Pompadour (Rph20) was also effective to P. striiformis. RILs that were seedling susceptible to P. striiformis f. sp. pseudo-hordei were resistant in the field, implicating the involvement of adult plant resistance (APR). Additional QTLs were identified on chromosome 7H at the same genetic position as Rph23 (APR to leaf rust), suggesting either pleiotropic resistance or the presence of a stripe rust resistance gene closely linked to or allelic with Rph23. Unlike many pleiotropic APR genes identified and isolated in wheat, our data suggest that the Rph20 locus does not confer resistance to the P. striiformis isolates used in this study (P. striiformis f. sp. hordei [χ 2 (independence) = 2.47 P > 0.12] and P. striiformis f. sp. pseudo-hordei [χ 2 (independence) = 0.42 P > 0.60]).

In Situ Field Measurement of Leaf Water Potential Using Thermocouple Psychrometers 1

PubMed Central

Savage, Michael J.; Wiebe, Herman H.; Cass, Alfred

1983-01-01

Thermocouple psychrometers are the only instruments which can measure the in situ water potential of intact leaves, and which can possibly be used to monitor leaf water potential. Unfortunately, their usefulness is limited by a number of difficulties, among them fluctuating temperatures and temperature gradients within the psychrometer, sealing of the psychrometer chamber to the leaf, shading of the leaf by the psychrometer, and resistance to water vapor diffusion by the cuticle when the stomates are closed. Using Citrus jambhiri, we have tested several psychrometer design and operational modifications and showed that in situ psychrometric measurements compared favorably with simultaneous Scholander pressure chamber measurements on neighboring leaves when the latter were corrected for the osmotic potential. PMID:16663267

Screw-fed pump system

DOEpatents

Sprouse, Kenneth M

2014-11-25

A pump system includes a pump that includes a first belt and a second belt that are spaced apart from each other to provide generally straight sides of a passage there between. There is an inlet at one end of the passage and an outlet at an opposite end of the passage, with a passage length that extends between the inlet and the outlet. The passage defines a gap distance in a width direction between the straight sides at the passage inlet. A hopper includes an interior space that terminates at a mouth at the passage inlet. At least one screw is located within the interior space of the hopper and includes a screw diameter in the width direction that is less than or equal to the gap distance.

Fly ash system technology improves opacity

DOE Office of Scientific and Technical Information (OSTI.GOV)

NONE

2007-06-15

Unit 3 of the Dave Johnston Power Plant east of Glenrock, WY, USA had problems staying at or below the opacity limits set by the state. The unit makes use of a Lodge Cottrell precipitator. When the plant changed to burning Power River Basin coal, ash buildup became a significant issue as the fly ash control system was unable to properly evacuate hoppers on the unit. To overcome the problem, the PLC on the unit was replaced with a software optimization package called SmartAsh for the precipitator fly ash control system, at a cost of $500,000. After the upgrade, theremore » have been no plugged hoppers and the opacity has been reduced from around 20% to 3-5%. 2 figs.« less

The plant hopper Issus coleoptratus can detoxify phloem sap saponins including the degradation of the terpene core

PubMed Central

Himmelsbach, Markus; Weth, Agnes; Böhme, Christine; Schwarz, Martin; Bräunig, Peter; Baumgartner, Werner

2016-01-01

ABSTRACT Issus coleoptratus is a small plant hopper which mainly feeds on the phloem sap from ivy. Although all parts of ivy are poisonous as the plant contains saponins, especially hederasaponins, I. coleoptratus can cope with the poison. In contrast to other animals like the stick insect Carausius morosus which accumulates saponins in its body, I. coleoptratus can degrade and disintegrate not only the saponins but even the genines, i.e. the triterpene core of the substances. This is perhaps made possible by a specialised midgut and/or the salivary glands. When the glands and the gut are dissected and added to saponins in solution, the saponins, including the genines, are degraded ex vivo. PMID:26863940

Volumetric dispenser for small particles from plural sources

DOEpatents

Bradley, R.A.; Miller, W.H.; Sease, J.D.

1975-12-16

Apparatus is described for rapidly and accurately dispensing measured volumes of small particles from a supply hopper. The apparatus includes an adjustable, vertically oriented measuring tube and orifice member defining the volume to be dispensed, a ball plug valve for selectively closing the bottom end of the orifice member, and a compression valve for selectively closing the top end of the measuring tube. A supply hopper is disposed above and in gravity flow communication with the measuring tube. Properly sequenced opening and closing of the two valves provides accurate volumetric discharge through the ball plug valve. A dispensing system is described wherein several appropriately sized measuring tubes, orifice members, and associated valves are arranged to operate contemporaneously to facilitate blending of different particles.

Drought resistance in early and late secondary successional species from a tropical dry forest: the interplay between xylem resistance to embolism, sapwood water storage and leaf shedding

Treesearch

Fernando Pineda-Garcia; Horacio Paz; Frederick C. Meinzer

2013-01-01

The mechanisms of drought resistance that allow plants to successfully establish at different stages of secondary succession in tropical dry forests are not well understood. We characterized mechanisms of drought resistance in early and late-successional species and tested whether risk of drought differs across sites at different successional stages, and whether early...

Low light and low ammonium are key factors for guayule leaf tissue shoot organogenesis and transformation.

PubMed

Dong, Niu; Montanez, Belen; Creelman, Robert A; Cornish, Katrina

2006-02-01

A new method has been developed for guayule tissue culture and transformation. Guayule leaf explants have a poor survival rate when placed on normal MS medium and under normal culture room light conditions. Low light and low ammonium treatment greatly improved shoot organogenesis and transformation from leaf tissues. Using this method, a 35S promoter driven BAR gene and an ubiquitin-3 promoter driven GUS gene (with intron) have been successfully introduced into guayule. These transgenic guayule plants were resistant to the herbicide ammonium-glufosinate and were positive to GUS staining. Molecular analysis showed the expected band and signal in all GUS positive transformants. The transformation efficiency with glufosinate selection ranged from 3 to 6%. Transformation with a pBIN19-based plasmid containing a NPTII gene and then selection with kanamycin also works well using this method. The ratio of kanamycin-resistant calli to total starting explants reached 50% in some experiments.

An Evaluation of Frankliniella occidentalis (Thysanoptera: Thripidae) and Frankliniella intonsa (Thysanoptera: Thripidae) Performance on Different Plant Leaves Based on Life History Characteristics

PubMed Central

Li, Wei-Di; Zhang, Peng-Jun; Zhang, Jing-Ming; Zhang, Zhi-Jun; Huang, Fang; Bei, Ya-Wei; Lin, Wen-Cai; Lu, Yao-Bin

2015-01-01

To compare the performance of Frankliniella occidentalis (Pergande) and native Frankliniella intonsa (Trybom) on cucumber and tomato leaves in laboratory, life history characters were investigated, and life tables were constructed using the method of age-stage, two-sex table life. Compared with tomato leaf, there were shorter total preoviposition period (TPOP), higher fecundity, longer female longevity, and higher intrinsic rate of increase (r) of both F. occidentalis and F. intonsa on cucumber leaf. Meanwhile, on cucumber leaf, the shorter TPOP, higher fecundity, longer female longevity, and higher value of r were found on population of F. intonsa but on tomato leaf which were found on population of F. occidentalis. From above, cucumber leaf was the preference to population development of both F. occidentalis and F. intonsa compared with tomato leaf. Nevertheless, on cucumber leaf, population of F. intonsa would grow faster than that of F. occidentalis, which was the opposite on tomato leaf. As to the population development in fields, much more factors would be taken into account, such as pollen, insecticide resistance, and effects of natural enemies etc. PMID:25673049

Leaf waxes and thrips resistance in onion

USDA-ARS?s Scientific Manuscript database

Onion thrips is an important insect pest of onion that damages leaves and bulbs, reduces yields, and transmits important diseases such as iris yellow spot virus and bacterial rots. Growers would benefit from onions resistant to thrips in order to reduce insecticide applications and provide more sust...

The inheritance of resistance to bacterial leaf spot of lettuce caused by Xanthomonas campestris pv. vitians in three lettuce cultivars

PubMed Central

Hayes, Ryan J; Trent, Mark A; Truco, Maria Jose; Antonise, Rudie; Michelmore, Richard W; Bull, Carolee T

2014-01-01

Lettuce yields can be reduced by the disease bacterial leaf spot (BLS) caused by the pathogen Xanthomonas campestris pv. vitians (Xcv) and host resistance is the most feasible method to reduce disease losses. The cultivars La Brillante, Pavane and Little Gem express an incompatible host–pathogen interaction as a hypersensitive response (HR) to California strains of Xcv resulting in resistance. Little was known about the inheritance of resistance; however, resistance to other lettuce pathogens is often determined by resistance gene candidates (RGCs) encoding nucleotide-binding leucine-rich repeat (NB-LRR) proteins. Therefore, we determined the inheritance of BLS resistance in the cultivars La Brillante, Little Gem and Pavane and mapped it relative to RGCs. The reaction to Xcv was analyzed in nine F1, F2 and recombinant inbred line populations of lettuce from HR×compatible or HR×HR crosses. The HR in La Brillante, Pavane and Little Gem is conditioned by single dominant genes, which are either allelic or closely linked genes. The resistance gene in La Brillante was designated Xanthomonas resistance 1 (Xar1) and mapped to lettuce linkage group 2. Xar1 is present in a genomic region that contains numerous NB-LRR encoding RGCs and functional pathogen resistance loci in the RGC2 family. The Xar1 gene confers a high level of BLS resistance in the greenhouse and field that can be introgressed into commercial lettuce cultivars to reduce BLS losses using molecular markers. PMID:26504558

RFLP-facilitated investigation of the quantitative resistance of rice to brown planthopper ( Nilaparvata lugens).

PubMed

Xu, X. F.; Mei, H. W.; Luo, L. J.; Cheng, X. N.; Li, Z. K.

2002-02-01

Quantitative trait loci (QTLs), conferring quantitative resistance to rice brown planthopper (BPH), were investigated using 160 F(11) recombinant inbred lines (RILs) from the Lemont/Teqing cross, a complete RFLP map, and replicated phenotyping of seedbox inoculation. The paternal indica parent, Teqing, was more-resistant to BPH than the maternal japonica parent, Lemont. The RILs showed transgressive segregation for resistance to BPH. Seven main-effect QTLs and many epistatic QTL pairs were identified and mapped on the 12 rice chromosomes. Collectively, the main-effect and epistatic QTLs accounted for over 70% of the total variation in damage scores. Teqing has the resistance allele at four main-effect QTLs, and the Lemont allele resulted in resistance at the other three. Of the main-effect QTLs identified, QBphr5b was mapped to the vicinity of gl1, a major gene controlling leaf and stem pubescence. The Teqing allele controlling leaf and stem pubescence was associated with resistance, while the Lemont allele for glabrous stem and leaves was associated with susceptibility, indicating that this gene may have contributed to resistance through antixenosis. Similar to the reported BPH resistance genes, the other six detected main-effect QTLs were all mapped to regions where major disease resistance genes locate, suggesting they might have contributed either to antibiosis or tolerance. Our results indicated that marker-aided pyramiding of major resistance genes and QTLs should provide effective and stable control over this devastating pest.

Constraints on the evolution of tolerance to herbicide in the common morning glory: resistance and tolerance are mutually exclusive.

PubMed

Baucom, Regina S; Mauricio, Rodney

2008-11-01

Evolutionary biologists explain the maintenance of intermediate levels of defense in plant populations as being due to trade-offs, or negative genetic covariances among ecologically important traits. Attempts at detecting trade-offs as constraints on the evolution of defense have not always been successful, leading some to conclude that such trade-offs rarely explain current levels of defense in the population. Using the agricultural pest Ipomoea purpurea, we measured correlations between traits involved in defense to glyphosate, the active ingredient in Roundup, a widely used herbicide. We found significant allocation costs of tolerance, as well as trade-offs between resistance and two measures of tolerance to glyphosate. Selection on resistance and tolerance exhibited differing patterns: tolerance to leaf damage was under negative directional selection, whereas resistance was under positive directional selection. The joint pattern of selection on resistance and tolerance to leaf damage indicated the presence of alternate peaks in the fitness landscape such that a combination of either high tolerance and low resistance, or high resistance and low tolerance was favored. The widespread use of this herbicide suggests that it is likely an important selective agent on weed populations. Understanding the evolutionary dynamics of herbicide defense traits is thus of increasing importance in the context of human-mediated evolution.

Early diagenesis of mangrove leaves in a tropical estuary: Bulk chemical characterization using solid-state 13C NMR and elemental analyses

NASA Astrophysics Data System (ADS)

Benner, Ronald; Hatcher, Patrick G.; Hedges, John I.

1990-07-01

Changes in the chemical composition of mangrove ( Rhizophora mangle) leaves during decomposition in tropical estuarine waters were characterized using solid-state 13C nuclear magnetic resonance (NMR) and elemental (CHNO) analysis. Carbohydrates were the most abundant components of the leaves accounting for about 50 wt% of senescent tissues. Tannins were estimated to account for about 20 wt% of leaf tissues, and lipid components, cutin, and possibly other aliphatic biopolymers in leaf cuticles accounted for about 15 wt%. Carbohydrates were generally less resistant to decomposition than the other constituents and decreased in relative concentration during decomposition. Tannins were of intermediate resistance to decomposition and remained in fairly constant proportion during decomposition. Paraffinic components were very resistant to decomposition and increased in relative concentration as decomposition progressed. Lignin was a minor component of all leaf tissues. Standard methods for the colorimetric determination of tannins (Folin-Dennis reagent) and the gravimetric determination of lignin (Klason lignin) were highly inaccurate when applied to mangrove leaves. The N content of the leaves was particularly dynamic with values ranging from 1.27 wt% in green leaves to 0.65 wt% in senescent yellow leaves attached to trees. During decomposition in the water the N content initially decreased to 0.51 wt% due to leaching, but values steadily increased thereafter to 1.07 wt% in the most degraded leaf samples. The absolute mass of N in the leaves increased during decomposition indicating that N immobilization was occurring as decomposition progressed.

Early diagenesis of mangrove leaves in a tropical estuary: Bulk chemical characterization using solid-state 13C NMR and elemental analyses

USGS Publications Warehouse

Benner, R.; Hatcher, P.G.; Hedges, J.I.

1990-01-01

Changes in the chemical composition of mangrove (Rhizophora mangle) leaves during decomposition in tropical estuarine waters were characterized using solid-state 13C nuclear magnetic resonance (NMR) and elemental (CHNO) analysis. Carbohydrates were the most abundant components of the leaves accounting for about 50 wt% of senescent tissues. Tannins were estimated to account for about 20 wt% of leaf tissues, and lipid components, cutin, and possibly other aliphatic biopolymers in leaf cuticles accounted for about 15 wt%. Carbohydrates were generally less resistant to decomposition than the other constituents and decreased in relative concentration during decomposition. Tannins were of intermediate resistance to decomposition and remained in fairly constant proportion during decomposition. Paraffinic components were very resistant to decomposition and increased in relative concentration as decomposition progressed. Lignin was a minor component of all leaf tissues. Standard methods for the colorimetric determination of tannins (Folin-Dennis reagent) and the gravimetric determination of lignin (Klason lignin) were highly inaccurate when applied to mangrove leaves. The N content of the leaves was particularly dynamic with values ranging from 1.27 wt% in green leaves to 0.65 wt% in senescent yellow leaves attached to trees. During decomposition in the water the N content initially decreased to 0.51 wt% due to leaching, but values steadily increased thereafter to 1.07 wt% in the most degraded leaf samples. The absolute mass of N in the leaves increased during decomposition indicating that N immobilization was occurring as decomposition progressed. ?? 1990.

Modeling development and quantitative trait mapping reveal independent genetic modules for leaf size and shape.

PubMed

Baker, Robert L; Leong, Wen Fung; Brock, Marcus T; Markelz, R J Cody; Covington, Michael F; Devisetty, Upendra K; Edwards, Christine E; Maloof, Julin; Welch, Stephen; Weinig, Cynthia

2015-10-01

Improved predictions of fitness and yield may be obtained by characterizing the genetic controls and environmental dependencies of organismal ontogeny. Elucidating the shape of growth curves may reveal novel genetic controls that single-time-point (STP) analyses do not because, in theory, infinite numbers of growth curves can result in the same final measurement. We measured leaf lengths and widths in Brassica rapa recombinant inbred lines (RILs) throughout ontogeny. We modeled leaf growth and allometry as function valued traits (FVT), and examined genetic correlations between these traits and aspects of phenology, physiology, circadian rhythms and fitness. We used RNA-seq to construct a SNP linkage map and mapped trait quantitative trait loci (QTL). We found genetic trade-offs between leaf size and growth rate FVT and uncovered differences in genotypic and QTL correlations involving FVT vs STPs. We identified leaf shape (allometry) as a genetic module independent of length and width and identified selection on FVT parameters of development. Leaf shape is associated with venation features that affect desiccation resistance. The genetic independence of leaf shape from other leaf traits may therefore enable crop optimization in leaf shape without negative effects on traits such as size, growth rate, duration or gas exchange. © 2015 The Authors. New Phytologist © 2015 New Phytologist Trust.

Genome-Wide Association Studies of Anthracnose and Angular Leaf Spot Resistance in Common Bean (Phaseolus vulgaris L.)

PubMed Central

Perseguini, Juliana Morini Küpper Cardoso; Oblessuc, Paula Rodrigues; Rosa, João Ricardo Bachega Feijó; Gomes, Kleber Alves; Chiorato, Alisson Fernando; Carbonell, Sérgio Augusto Morais; Garcia, Antonio Augusto Franco; Vianello, Rosana Pereira; Benchimol-Reis, Luciana Lasry

2016-01-01

The common bean (Phaseolus vulgaris L.) is the world’s most important legume for human consumption. Anthracnose (ANT; Colletotrichum lindemuthianum) and angular leaf spot (ALS; Pseudocercospora griseola) are complex diseases that cause major yield losses in common bean. Depending on the cultivar and environmental conditions, anthracnose and angular leaf spot infections can reduce crop yield drastically. This study aimed to estimate linkage disequilibrium levels and identify quantitative resistance loci (QRL) controlling resistance to both ANT and ALS diseases of 180 accessions of common bean using genome-wide association analysis. A randomized complete block design with four replicates was performed for the ANT and ALS experiments, with four plants per genotype in each replicate. Association mapping analyses were performed for ANT and ALS using a mixed linear model approach implemented in TASSEL. A total of 17 and 11 significant statistically associations involving SSRs were detected for ANT and ALS resistance loci, respectively. Using SNPs, 21 and 17 significant statistically associations were obtained for ANT and angular ALS, respectively, providing more associations with this marker. The SSR-IAC167 and PvM95 markers, both located on chromosome Pv03, and the SNP scaffold00021_89379, were associated with both diseases. The other markers were distributed across the entire common bean genome, with chromosomes Pv03 and Pv08 showing the greatest number of loci associated with ANT resistance. The chromosome Pv04 was the most saturated one, with six markers associated with ALS resistance. The telomeric region of this chromosome showed four markers located between approximately 2.5 Mb and 4.4 Mb. Our results demonstrate the great potential of genome-wide association studies to identify QRLs related to ANT and ALS in common bean. The results indicate a quantitative and complex inheritance pattern for both diseases in common bean. Our findings will contribute to more effective screening of elite germplasm to find resistance alleles for marker-assisted selection in breeding programs. PMID:26930078

Genome-Wide Association Studies of Anthracnose and Angular Leaf Spot Resistance in Common Bean (Phaseolus vulgaris L.).

PubMed

Perseguini, Juliana Morini Küpper Cardoso; Oblessuc, Paula Rodrigues; Rosa, João Ricardo Bachega Feijó; Gomes, Kleber Alves; Chiorato, Alisson Fernando; Carbonell, Sérgio Augusto Morais; Garcia, Antonio Augusto Franco; Vianello, Rosana Pereira; Benchimol-Reis, Luciana Lasry

2016-01-01

The common bean (Phaseolus vulgaris L.) is the world's most important legume for human consumption. Anthracnose (ANT; Colletotrichum lindemuthianum) and angular leaf spot (ALS; Pseudocercospora griseola) are complex diseases that cause major yield losses in common bean. Depending on the cultivar and environmental conditions, anthracnose and angular leaf spot infections can reduce crop yield drastically. This study aimed to estimate linkage disequilibrium levels and identify quantitative resistance loci (QRL) controlling resistance to both ANT and ALS diseases of 180 accessions of common bean using genome-wide association analysis. A randomized complete block design with four replicates was performed for the ANT and ALS experiments, with four plants per genotype in each replicate. Association mapping analyses were performed for ANT and ALS using a mixed linear model approach implemented in TASSEL. A total of 17 and 11 significant statistically associations involving SSRs were detected for ANT and ALS resistance loci, respectively. Using SNPs, 21 and 17 significant statistically associations were obtained for ANT and angular ALS, respectively, providing more associations with this marker. The SSR-IAC167 and PvM95 markers, both located on chromosome Pv03, and the SNP scaffold00021_89379, were associated with both diseases. The other markers were distributed across the entire common bean genome, with chromosomes Pv03 and Pv08 showing the greatest number of loci associated with ANT resistance. The chromosome Pv04 was the most saturated one, with six markers associated with ALS resistance. The telomeric region of this chromosome showed four markers located between approximately 2.5 Mb and 4.4 Mb. Our results demonstrate the great potential of genome-wide association studies to identify QRLs related to ANT and ALS in common bean. The results indicate a quantitative and complex inheritance pattern for both diseases in common bean. Our findings will contribute to more effective screening of elite germplasm to find resistance alleles for marker-assisted selection in breeding programs.

Changes of oxidase and hydrolase activities in pecan leaves elicited by black pecan aphid (Hemiptera: Aphididae) feeding.

PubMed

Chen, Yigen; Ni, Xinzhi; Cottrell, Ted E; Wood, Bruce W; Buntin, G David

2009-06-01

The black pecan aphid, Melanocallis caryaefoliae (Davis) (Hemiptera: Aphididae), is a foliar feeder of pecan, Carya illinoinensis (Wangenh.) K. Koch (Juglandaceae). The pest causes chlorosis of leaflet lamina, physiological damage to foliage and trees, and commonly limits the profitability of commercial pecan orchard enterprises. However, key aspects of this host-pest interaction are poorly understood. We report here the effects of M. caryaefoliae feeding on the foliar activity of oxidative (i.e., catalase, lipoxygenase [LOX]-1 and 3, and peroxidase) and hydrolytic (i.e., esterase) enzymes in relation to the degree of aphid resistance among pecan varieties. The 2-yr study showed that M. caryaefoliae-infested foliage exhibited elevated peroxidase activity only in susceptible ('Desirable', 'Sumner', and 'Schley'), but not in resistant ('Cape Fear', 'Gloria Grande', and 'Money Maker') genotypes. Susceptible genotypes also exhibited more severe leaf chlorosis in response to M. caryaefoliae feeding than the resistant genotypes; however, the aphid feeding did not influence catalase or esterase activity in all varieties, except the increase of esterase activity in Desirable and Gloria Grande. Melanocallis caryaefoliae feeding also influences activity of two lipoxygenase isozymes, with LOX3 being more frequently induced than LOX1. Foliar LOX3 activity was more frequently induced by M. caryaefoliae feeding in the moderately resistant 'Oconee' and highly resistant Money Maker and Cape Fear than in the susceptible genotypes. Therefore, the elevation of peroxidase is likely to be associated with aphid susceptibility and contributed to the severe leaf chlorosis, whereas the increase of LOX3 activity might be associated with aphid resistance in pecan. These findings contribute to our understanding of the etiology of M. caryaefoliae-elicited leaf chlorosis on pecan foliage. Such information may also be used to develop enzyme markers for identifying black pecan aphid resistance and/or susceptibility in pecan germplasm.

The typical RB76 recombination breakpoint of the invasive recombinant tomato yellow leaf curl virus of Morocco can be generated experimentally but is not positively selected in tomato.

PubMed

Belabess, Z; Urbino, C; Granier, M; Tahiri, A; Blenzar, A; Peterschmitt, M

2018-01-02

TYLCV-IS76 is an unusual recombinant between the highly recombinogenic tomato yellow leaf curl virus (TYLCV) and tomato yellow leaf curl Sardinia virus (TYLCSV), two Mediterranean begomoviruses (Geminiviridae). In contrast with the previously reported TYLCV/TYLCSV recombinants, it has a TYLCSV derived fragment of only 76 nucleotides, and has replaced its parental viruses in natural conditions (Morocco, Souss region). The viral population shift coincided with the deployment of the popular Ty-1 resistant tomato cultivars, and according to experimental studies, has been driven by a strong positive selection in such resistant plants. However, although Ty-1 cultivars were extensively used in Mediterranean countries, TYLCV-IS76 was not reported outside Morocco. This, in combination with its unusual recombination pattern suggests that it was generated through a rare and possibly multistep process. The potential generation of a recombination breakpoint (RB) at locus 76 (RB76) was investigated over time in 10 Ty-1 resistant and 10 nearly isogenic susceptible tomato plants co-inoculated with TYLCV and TYLCSV clones. RB76 could not be detected in the recombinant progeny using the standard PCR/sequencing approach that was previously designed to monitor the emergence of TYLCV-IS76 in Morocco. Using a more sensitive PCR test, RB76 was detected in one resistant and five susceptible plants. The results are consistent with a very low intra-plant frequency of RB76 bearing recombinants throughout the test and support the hypothesis of a rare emergence of TYLCV-IS76. More generally, RBs were more scattered in resistant than in susceptible plants and an unusual RB at position 141 (RB141) was positively selected in the resistant cultivar; interestingly, RB141 bearing recombinants were detected in resistant tomato plants from the field. Scenarios of TYLCV-IS76 pre-emergence are proposed. Copyright © 2017 Elsevier B.V. All rights reserved.

Measuring Rates of Herbicide Metabolism in Dicot Weeds with an Excised Leaf Assay.

PubMed

Ma, Rong; Skelton, Joshua J; Riechers, Dean E

2015-09-07

In order to isolate and accurately determine rates of herbicide metabolism in an obligate-outcrossing dicot weed, waterhemp (Amaranthus tuberculatus), we developed an excised leaf assay combined with a vegetative cloning strategy to normalize herbicide uptake and remove translocation as contributing factors in herbicide-resistant (R) and -sensitive (S) waterhemp populations. Biokinetic analyses of organic pesticides in plants typically include the determination of uptake, translocation (delivery to the target site), metabolic fate, and interactions with the target site. Herbicide metabolism is an important parameter to measure in herbicide-resistant weeds and herbicide-tolerant crops, and is typically accomplished with whole-plant tests using radiolabeled herbicides. However, one difficulty with interpreting biokinetic parameters derived from whole-plant methods is that translocation is often affected by rates of herbicide metabolism, since polar metabolites are usually not mobile within the plant following herbicide detoxification reactions. Advantages of the protocol described in this manuscript include reproducible, accurate, and rapid determination of herbicide degradation rates in R and S populations, a substantial decrease in the amount of radiolabeled herbicide consumed, a large reduction in radiolabeled plant materials requiring further handling and disposal, and the ability to perform radiolabeled herbicide experiments in the lab or growth chamber instead of a greenhouse. As herbicide resistance continues to develop and spread in dicot weed populations worldwide, the excised leaf assay method developed and described herein will provide an invaluable technique for investigating non-target site-based resistance due to enhanced rates of herbicide metabolism and detoxification.

Screening for Host Plant Resistance to Azalea Lace Bug

USDA-ARS?s Scientific Manuscript database

Azalea Lace bug (ALB) are a major pest of azaleas in the southeast. Adults and nymphs cause visible damage on the upper leaf surface. Host plant resistance to ALB provides “built-in” plant protection and allows for reduced dependency on pesticide applications for both growers and consumers. We have...

Resistance of common bean breeding lines to Phaeoisariopsis griseola isolates from Honduras

USDA-ARS?s Scientific Manuscript database

Angular leaf spot (ALS) disease caused by Phaeoisariopsis griseola Sacc. Ferraris, is currently one of the most important factors limiting bean productivity in Central America. The development of breeding lines which combine resistance to ALS and Bean Golden Yellow Mosaic Virus (BGYMV) and tolerance...

Fruit growing in areas of air pollution by sulfur dioxide (in German)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Guderian, R.

1969-01-01

A review is presented dealing with leaf injuries and reductions in growth, yield, and fruit quality in pome fruits, stone fruits, bush fruits, vines, strawberries, and walnuts caused by sulfur dioxide. References to varietal resistance and the effects of manuring on resistance are provided. 11 references.

Importance of Rootstock and Scion Tomato Mosaic Virus Resistance for Grafting Heirloom Tomatoes

USDA-ARS?s Scientific Manuscript database

During the 2011-2012 tomato production season at a Florida organic farm, heirloom tomato scions grafted onto Tomato yellow leaf curl virus (TYLCV)-resistant tomato rootstocks were observed to undergo a rapid and severe wilt, and ultimately die. The soilborne fungus, Sclerotium rolfsii, was isolated...

Assessment of sweet cherry (Prunus avium L.) genotypes for response to bacterial canker disease

USDA-ARS?s Scientific Manuscript database

Integration of alleles for resistance into new cultivars requires information on the sources of resistance in the germplasm. This study was designed to compare: the efficacy of three inoculation methods (carborundum, mid-rib and shoot), the correlation between the susceptibility of fruit versus leaf...

Influence of leaf water potential on diurnal changes in CO2 and water vapour fluxes

NASA Astrophysics Data System (ADS)

Yu, Qiang; Xu, Shouhua; Wang, Jing; Lee, Xuhui

2007-08-01

Mass and energy fluxes between the atmosphere and vegetation are driven by meteorological variables, and controlled by plant water status, which may change more markedly diurnally than soil water. We tested the hypothesis that integration of dynamic changes in leaf water potential may improve the simulation of CO2 and water fluxes over a wheat canopy. Simulation of leaf water potential was integrated into a comprehensive model (the ChinaAgrosys) of heat, water and CO2 fluxes and crop growth. Photosynthesis from individual leaves was integrated to the canopy by taking into consideration the attenuation of radiation when penetrating the canopy. Transpiration was calculated with the Shuttleworth-Wallace model in which canopy resistance was taken as a link between energy balance and physiological regulation. A revised version of the Ball-Woodrow-Berry stomatal model was applied to produce a new canopy resistance model, which was validated against measured CO2 and water vapour fluxes over winter wheat fields in Yucheng (36°57' N, 116°36' E, 28 m above sea level) in the North China Plain during 1997, 2001 and 2004. Leaf water potential played an important role in causing stomatal conductance to fall at midday, which caused diurnal changes in photosynthesis and transpiration. Changes in soil water potential were less important. Inclusion of the dynamics of leaf water potential can improve the precision of the simulation of CO2 and water vapour fluxes, especially in the afternoon under water stress conditions.

New Generation of Resistant Sugar Beet Varieties for Advanced Integrated Management of Cercospora Leaf Spot in Central Europe

PubMed Central

Vogel, Johannes; Kenter, Christine; Holst, Carsten; Märländer, Bernward

2018-01-01

Cercospora leaf spot (CLS) epidemics in sugar beet have been increasing in recent years causing higher use of fungicides. Concomitantly, the availability of effective fungicides is at risk because of resistance development in the fungus, the lack of new active ingredients as well as restrictive approval practices. A key option for an integrated management of CLS is cultivation of resistant varieties. Because of the yield penalty in resistant varieties, acceptance in commercial practice so far has been low. The aim of our study was to characterize recent sugar beet varieties registered in Germany in terms of resistance and tolerance to CLS and their value for integrated pest management. The genetic basis of CLS resistance in varieties is protected by intellectual property rights even after variety registration and not open to the public due to economic competition. To gain reliable data for cultivation, varieties have to be tested for their resistance traits under field conditions at varying levels of infection with Cercospora beticola. In collaboration with variety related stakeholders, 15 sugar beet varieties were tested in 49 field trials in Germany from 2014 to 2016 for their yield response to CLS. The trials were set up in a split-plot design with and without infection (i.e., with and without fungicide). The classification of varietal reaction to CLS is based on symptomatic leaf area (susceptibility) and the resulting relative yield loss (tolerance). Since the relation between both parameters varied among varieties, it was used as an additional parameter to describe tolerance. On this basis, three groups of varieties were identified. They can be characterized as a susceptible, a resistant and a presumably tolerant cluster. A comparison of the data with an older dataset originating from 2009 to 2011 revealed that yield performance of recent varieties with resistance to C. beticola caught up with susceptible varieties due to breeding progress. They showed no yield penalty in the absence of the disease and better economic performance than susceptible varieties. It is assumed that these varieties will allow a substantial reduction of fungicide use for an advanced integrated pest management under central European conditions. PMID:29535743

New Generation of Resistant Sugar Beet Varieties for Advanced Integrated Management of Cercospora Leaf Spot in Central Europe.

PubMed

Vogel, Johannes; Kenter, Christine; Holst, Carsten; Märländer, Bernward

2018-01-01

Cercospora leaf spot (CLS) epidemics in sugar beet have been increasing in recent years causing higher use of fungicides. Concomitantly, the availability of effective fungicides is at risk because of resistance development in the fungus, the lack of new active ingredients as well as restrictive approval practices. A key option for an integrated management of CLS is cultivation of resistant varieties. Because of the yield penalty in resistant varieties, acceptance in commercial practice so far has been low. The aim of our study was to characterize recent sugar beet varieties registered in Germany in terms of resistance and tolerance to CLS and their value for integrated pest management. The genetic basis of CLS resistance in varieties is protected by intellectual property rights even after variety registration and not open to the public due to economic competition. To gain reliable data for cultivation, varieties have to be tested for their resistance traits under field conditions at varying levels of infection with Cercospora beticola . In collaboration with variety related stakeholders, 15 sugar beet varieties were tested in 49 field trials in Germany from 2014 to 2016 for their yield response to CLS. The trials were set up in a split-plot design with and without infection (i.e., with and without fungicide). The classification of varietal reaction to CLS is based on symptomatic leaf area (susceptibility) and the resulting relative yield loss (tolerance). Since the relation between both parameters varied among varieties, it was used as an additional parameter to describe tolerance. On this basis, three groups of varieties were identified. They can be characterized as a susceptible, a resistant and a presumably tolerant cluster. A comparison of the data with an older dataset originating from 2009 to 2011 revealed that yield performance of recent varieties with resistance to C. beticola caught up with susceptible varieties due to breeding progress. They showed no yield penalty in the absence of the disease and better economic performance than susceptible varieties. It is assumed that these varieties will allow a substantial reduction of fungicide use for an advanced integrated pest management under central European conditions.

The effects of physical and chemical preprocessing on the flowability of corn stover

DOE PAGES

Crawford, Nathan C.; Nagle, Nick; Sievers, David A.; ...

2015-12-20

Continuous and reliable feeding of biomass is essential for successful biofuel production. However, the challenges associated with biomass solids handling are commonly overlooked. In this study, we examine the effects of preprocessing (particle size reduction, moisture content, chemical additives, etc.) on the flow properties of corn stover. Compressibility, flow properties (interparticle friction, cohesion, unconfined yield stress, etc.), and wall friction were examined for five corn stover samples: ground, milled (dry and wet), acid impregnated, and deacetylated. The ground corn stover was found to be the least compressible and most flowable material. The water and acid impregnated stovers had similar compressibilities.more » Yet, the wet corn stover was less flowable than the acid impregnated sample, which displayed a flow index equivalent to the dry, milled corn stover. The deacetylated stover, on the other hand, was the most compressible and least flowable examined material. However, all of the tested stover samples had internal friction angles >30°, which could present additional feeding and handling challenges. All of the ''wetted'' materials (water, acid, and deacetylated) displayed reduced flowabilities (excluding the acid impregnated sample), and enhanced compressibilities and wall friction angles, indicating the potential for added handling issues; which was corroborated via theoretical hopper design calculations. All of the ''wetted'' corn stovers require larger theoretical hopper outlet diameters and steeper hopper walls than the examined ''dry'' stovers.« less

The effects of physical and chemical preprocessing on the flowability of corn stover

DOE Office of Scientific and Technical Information (OSTI.GOV)

Crawford, Nathan C.; Nagle, Nick; Sievers, David A.

Continuous and reliable feeding of biomass is essential for successful biofuel production. However, the challenges associated with biomass solids handling are commonly overlooked. In this study, we examine the effects of preprocessing (particle size reduction, moisture content, chemical additives, etc.) on the flow properties of corn stover. Compressibility, flow properties (interparticle friction, cohesion, unconfined yield stress, etc.), and wall friction were examined for five corn stover samples: ground, milled (dry and wet), acid impregnated, and deacetylated. The ground corn stover was found to be the least compressible and most flowable material. The water and acid impregnated stovers had similar compressibilities.more » Yet, the wet corn stover was less flowable than the acid impregnated sample, which displayed a flow index equivalent to the dry, milled corn stover. The deacetylated stover, on the other hand, was the most compressible and least flowable examined material. However, all of the tested stover samples had internal friction angles >30°, which could present additional feeding and handling challenges. All of the ''wetted'' materials (water, acid, and deacetylated) displayed reduced flowabilities (excluding the acid impregnated sample), and enhanced compressibilities and wall friction angles, indicating the potential for added handling issues; which was corroborated via theoretical hopper design calculations. All of the ''wetted'' corn stovers require larger theoretical hopper outlet diameters and steeper hopper walls than the examined ''dry'' stovers.« less

An NB-LRR gene, TYNBS1, is responsible for resistance mediated by the Ty-2 Begomovirus resistance locus of tomato.

PubMed

Yamaguchi, Hirotaka; Ohnishi, Jun; Saito, Atsushi; Ohyama, Akio; Nunome, Tsukasa; Miyatake, Koji; Fukuoka, Hiroyuki

2018-06-01

An NB-LRR gene, TYNBS1, was isolated from Begomovirus-resistance locus Ty-2. Transgenic plant analysis revealed that TYNBS1 is a functional resistance gene. TYNBS1 is considered to be synonymous with Ty-2. Tomato yellow leaf curl disease caused by Tomato yellow leaf curl virus (TYLCV) is a serious threat to tomato (Solanum lycopersicum L.) production worldwide. A Begomovirus resistance gene, Ty-2, was introduced into cultivated tomato from Solanum habrochaites by interspecific crossing. To identify the Ty-2 gene, we performed genetic analysis. Identification of recombinant line 3701 confirmed the occurrence of a chromosome inversion in the Ty-2 region of the resistant haplotype. Genetic analysis revealed that the Ty-2 gene is linked to an introgression encompassing two markers, SL11_25_54277 and repeat A (approximately 200 kb). Genomic sequences of the upper and lower border of the inversion section of susceptible and resistant haplotypes were determined. Two nucleotide-binding domain and leucine-rich repeat-containing (NB-LRR) genes, TYNBS1 and TYNBS2, were identified around the upper and lower ends of the inversion section, respectively. TYNBS1 strictly co-segregated with TYLCV resistance, whereas TYNBS2 did not. Genetic introduction of genomic fragments containing the TYNBS1 gene into susceptible tomato plants conferred TYLCV resistance. These results demonstrate that TYNBS1 is a functional resistance gene for TYLCV, and is synonymous with the Ty-2 gene.

An introgression on wheat chromosome 4DL in RL6077 (Thatcher*6/PI 250413) confers adult plant resistance to stripe rust and leaf rust (Lr67).

PubMed

Hiebert, Colin W; Thomas, Julian B; McCallum, Brent D; Humphreys, D Gavin; DePauw, Ronald M; Hayden, Matthew J; Mago, Rohit; Schnippenkoetter, Wendelin; Spielmeyer, Wolfgang

2010-10-01

Adult plant resistance (APR) to leaf rust and stripe rust derived from the wheat (Triticum aestivum L.) line PI250413 was previously identified in RL6077 (=Thatcher*6/PI250413). The leaf rust resistance gene in RL6077 is phenotypically similar to Lr34 which is located on chromosome 7D. It was previously hypothesized that the gene in RL6077 could be Lr34 translocated to another chromosome. Hybrids between RL6077 and Thatcher and between RL6077 and 7DS and 7DL ditelocentric stocks were examined for first meiotic metaphase pairing. RL6077 formed chain quadrivalents and trivalents relative to Thatcher and Chinese Spring; however both 7D telocentrics paired only as heteromorphic bivalents and never with the multivalents. Thus, chromosome 7D is not involved in any translocation carried by RL6077. A genome-wide scan of SSR markers detected an introgression from chromosome 4D of PI250413 transferred to RL6077 through five cycles of backcrossing to Thatcher. Haplotype analysis of lines from crosses of Thatcher × RL6077 and RL6058 (Thatcher*6/PI58548) × RL6077 showed highly significant associations between introgressed markers (including SSR marker cfd71) and leaf rust resistance. In a separate RL6077-derived population, APR to stripe rust was also tightly linked with cfd71 on chromosome 4DL. An allele survey of linked SSR markers cfd71 and cfd23 on a set of 247 wheat lines from diverse origins indicated that these markers can be used to select for the donor segment in most wheat backgrounds. Comparison of RL6077 with Thatcher in field trials showed no effect of the APR gene on important agronomic or quality traits. Since no other known Lr genes exist on chromosome 4DL, the APR gene in RL6077 has been assigned the name Lr67.

The 50-kDa protein of Apple chlorotic leaf spot virus interferes with intracellular and intercellular targeting and tubule-inducing activity of the 39-kDa protein of Grapevine berry inner necrosis virus.

PubMed

Isogai, M; Saitou, Y; Takahashi, N; Itabashi, T; Terada, M; Satoh, H; Yoshikawa, N

2003-03-01

To understand why transgenic Nicotiana occidentalis plants expressing a functional movement protein (MP) of Apple chlorotic leaf spot virus (ACLSV) show specific resistance to Grapevine berry inner necrosis virus (GINV), the MPs of ACLSV (50KP) and GINV (39KP) were fused to green, yellow, or cyan fluorescent proteins (GFP, YFP, or CFP). These fusion proteins were transiently expressed in leaf cells of both transgenic (50KP) and nontransgenic (NT) plants, and the intracellular and intercellular trafficking and tubule-inducing activity of these proteins were compared. The results indicate that in epidermal cells and protoplasts from 50KP plant leaves, the trafficking and tubule-inducing activities of GINV-39KP were specifically blocked while those of ACLSV-50KP and Apple stem grooving virus MP (36KP) were not affected. Additionally, when 39KP-YFP and 50KP-CFP were coexpressed in the leaf epidermis of NT plants, the fluorescence of both proteins was confined to single cells, indicating that 50KP-CFP interferes with the cell-to-cell trafficking of 39KP-YFP and vice versa. Mutational analyses of 50KP showed that the deletion mutants that retained the activities described above still blocked cell-to-cell trafficking of 39KP, but the dysfunctional 50KP mutants could no longer impede cell-to-cell movement of 39KP. Transgenic plants expressing the functional 50KP deletion mutants showed specific resistance against GINV. In contrast, transgenic plants expressing the dysfunctional 50KP mutants did not show any resistance to the virus. From these results, we conclude that the specific resistance of 50KP plants to GINV is due to the ability of the 50KP to block intracellular and intercellular trafficking of GINV 39KP.

In Vitro antibacterial efficacy of 21 Indian timber-yielding plants against multidrug-resistant bacteria causing urinary tract infection.

PubMed

Mishra, Monali P; Padhy, Rabindra N

2013-12-01

To screen methanolic leaf extracts of 21 timber-yielding plants for antibacterial activity against nine species of uropathogenic bacteria isolated from clinical samples of a hospital (Enterococcus faecalis, Staphylococcus aureus, Acinetobacter baumannii, Citrobacter freundii, Enterobacter aerogenes, Escherichia coli, Klebsiella pneumoniae, Proteus mirabilis, and Pseudomonas aeruginosa). Bacterial strains were subjected to antibiotic sensitivity tests by the Kirby-Bauer's disc diffusion method. The antibacterial potentiality of leaf extracts was monitored by the agar-well diffusion method with multidrug-resistant (MDR) strains of nine uropathogens. Two Gram-positive isolates, E. faecalis and S. aureus, were resistant to 14 of the 18 antibiotics used. Gram-negative isolates A. baumannii, C. freundii, E. aerogenes, E. coli, K. pneumoniae, P. mirabilis, and P. aeruginosa were resistant to 10, 12, 9, 11, 11, 10, and 11 antibiotics, respectively, of the 14 antibiotics used. Methanolic leaf extracts of Anogeissus acuminata had the maximum zone of inhibition size-29 mm against S. aureus and 28 mm against E. faecalis and P. aeruginosa. Cassia tora had 29 mm as the zone of inhibition size for E. faecalis, E. aerogenes, and P. aeruginosa. Based on the minimum inhibitory concentration and minimum bactericidal concentration values, the most effective 10 plants against uropathogens could be arranged in decreasing order as follows: C. tora > A. acuminata > Schleichera oleosa > Pterocarpus santalinus > Eugenia jambolana > Bridelia retusa > Mimusops elengi > Stereospermum kunthianum > Tectona grandis > Anthocephalus cadamba. The following eight plants had moderate control capacity: Artocarpus heterophyllus, Azadirachta indica, Dalbergia latifolia, Eucalyptus citriodora, Gmelina arborea, Pongamia pinnata, Pterocarpus marsupium, and Shorea robusta. E. coli, followed by A. baumannii, C. freundii, E. aerogenes, P. mirabilis, and P. aeruginosa were controlled by higher amounts/levels of leaf extracts. Phytochemicals of all plants were qualitatively estimated. A majority of timber-yielding plants studied had in vitro control capacity against MDR uropathogenic bacteria.

Amplicon based RNA interference targeting V2 gene of cotton leaf curl Kokhran virus-Burewala strain can provide resistance in transgenic cotton plants

USDA-ARS?s Scientific Manuscript database

An RNAi based gene construct designated “C2” was used to target the V2 region of the cotton leaf curl virus (CLCuV) genome which is responsible for virus movement. The construct was transformed into two elite cotton varieties MNH-786 and VH-289. A shoot apex method of plant transformation using Agr...

Cellulase from Trichoderma harzianum interacts with roots and triggers induced systemic resistance to foliar disease in maize

PubMed Central

Saravanakumar, Kandasamy; Fan, Lili; Fu, Kehe; Yu, Chuanjin; Wang, Meng; Xia, Hai; Sun, Jianan; Li, Yaqian; Chen, Jie

2016-01-01

Trichoderma harzianum is well known to exhibit induced systemic resistance (ISR) to Curvularia leaf spot. We previously reported that a C6 zinc finger protein (Thc6) is responsible for a major contribution to the ISR to the leaf disease, but the types of effectors and the signals mediated by Thc6 from Trichoderma are unclear. In this work, we demonstrated that two hydrolases, Thph1 and Thph2, from T. harzianum were regulated by Thc6. Furthermore, an electrophoretic mobility shift assay (EMSA) study revealed that Thc6 regulated mRNA expression by binding to GGCTAA and GGCTAAA in the promoters of the Thph1 and Thph2 genes, respectively. Moreover, the Thph1 and Thph2 proteins triggered the transient production of reactive oxygen species (ROS) and elevated the free cytosolic calcium levels in maize leaf. Furthermore, the genes related to the jasmonate/ethylene signaling pathway were up-regulated in the wild-type maize strain. However, the ΔThph1- or ΔThph2-deletion mutants could not activate the immune defense-related genes in maize to protect against leaf disease. Therefore, we conclude that functional Thph1 and Thph2 may be required in T. harzianum to activate ISR in maize. PMID:27830829

Cellulase from Trichoderma harzianum interacts with roots and triggers induced systemic resistance to foliar disease in maize.

PubMed

Saravanakumar, Kandasamy; Fan, Lili; Fu, Kehe; Yu, Chuanjin; Wang, Meng; Xia, Hai; Sun, Jianan; Li, Yaqian; Chen, Jie

2016-11-10

Trichoderma harzianum is well known to exhibit induced systemic resistance (ISR) to Curvularia leaf spot. We previously reported that a C6 zinc finger protein (Thc6) is responsible for a major contribution to the ISR to the leaf disease, but the types of effectors and the signals mediated by Thc6 from Trichoderma are unclear. In this work, we demonstrated that two hydrolases, Thph1 and Thph2, from T. harzianum were regulated by Thc6. Furthermore, an electrophoretic mobility shift assay (EMSA) study revealed that Thc6 regulated mRNA expression by binding to GGCTAA and GGCTAAA in the promoters of the Thph1 and Thph2 genes, respectively. Moreover, the Thph1 and Thph2 proteins triggered the transient production of reactive oxygen species (ROS) and elevated the free cytosolic calcium levels in maize leaf. Furthermore, the genes related to the jasmonate/ethylene signaling pathway were up-regulated in the wild-type maize strain. However, the ΔThph1- or ΔThph2-deletion mutants could not activate the immune defense-related genes in maize to protect against leaf disease. Therefore, we conclude that functional Thph1 and Thph2 may be required in T. harzianum to activate ISR in maize.

The grapevine root-specific aquaporin VvPIP2;4N controls root hydraulic conductance and leaf gas exchange under well-watered conditions but not under water stress.

PubMed

Perrone, Irene; Gambino, Giorgio; Chitarra, Walter; Vitali, Marco; Pagliarani, Chiara; Riccomagno, Nadia; Balestrini, Raffaella; Kaldenhoff, Ralf; Uehlein, Norbert; Gribaudo, Ivana; Schubert, Andrea; Lovisolo, Claudio

2012-10-01

We functionally characterized the grape (Vitis vinifera) VvPIP2;4N (for Plasma membrane Intrinsic Protein) aquaporin gene. Expression of VvPIP2;4N in Xenopus laevis oocytes increased their swelling rate 54-fold. Northern blot and quantitative reverse transcription-polymerase chain reaction analyses showed that VvPIP2;4N is the most expressed PIP2 gene in root. In situ hybridization confirmed root localization in the cortical parenchyma and close to the endodermis. We then constitutively overexpressed VvPIP2;4N in grape 'Brachetto', and in the resulting transgenic plants we analyzed (1) the expression of endogenous and transgenic VvPIP2;4N and of four other aquaporins, (2) whole-plant, root, and leaf ecophysiological parameters, and (3) leaf abscisic acid content. Expression of transgenic VvPIP2;4N inhibited neither the expression of the endogenous gene nor that of other PIP aquaporins in both root and leaf. Under well-watered conditions, transgenic plants showed higher stomatal conductance, gas exchange, and shoot growth. The expression level of VvPIP2;4N (endogenous + transgene) was inversely correlated to root hydraulic resistance. The leaf component of total plant hydraulic resistance was low and unaffected by overexpression of VvPIP2;4N. Upon water stress, the overexpression of VvPIP2;4N induced a surge in leaf abscisic acid content and a decrease in stomatal conductance and leaf gas exchange. Our results show that aquaporin-mediated modifications of root hydraulics play a substantial role in the regulation of water flow in well-watered grapevine plants, while they have a minor role upon drought, probably because other signals, such as abscisic acid, take over the control of water flow.

Resistance of Collard Green Genotypes to Bemisia tabaci Biotype B: Characterization of Antixenosis.

PubMed

Domingos, G M; Baldin, E L L; Canassa, V F; Silva, I F; Lourenção, A L

2018-08-01

Bemisia tabaci (Genn.) biotype B (Hemiptera: Aleyrodidae) is an important pest of vegetable crops, including collard greens Brassica oleracea var. acephala (Brassicaceae). The use of resistant genotypes is an interesting option to reduce insect populations and can be used as an important tool for integrated pest management (IPM). This study evaluated 32 genotypes of collard greens against the attack of silver leaf whitefly, with the aim to characterize antixenosis. Initially, a multiple-choice trial was conducted using all genotypes, in which the adult attractiveness was assessed on two leaves per genotype at 24 and 48 h after infestation. After 48 h, one leaf of each genotype was randomly selected for the determination of the number of eggs per square centimeter. From the results of the multiple-choice trial, 13 genotypes were selected for a no-choice oviposition test, following the same method of the previous test. Colorimetric analyses were also performed to establish possible correlations between leaf color and insect colonization. Genotypes HS-20, OE, and VA were less attractive, demonstrating antixenosis. Genotypes LG, VE, J, MG, MOP, HS-20, VA, and MT had less oviposition in the multiple-choice test, which indicated expression of antixenosis. In the no-choice test, genotypes VE, P1C, CCB, RI-919, H, and J had less oviposition, which also characterized antixenosis. Therefore, genotypes VE and J showed the highest resistance stability because both had less oviposition in both test modalities. Thus, the resistance to B. tabaci biotype B indicates the genotypes HS-20, OE, VA, VE, and J are promising for use in breeding programs to develop resistance to whitefly.

A possible link between life and death of a xeric tree in desert.

PubMed

Xu, Gui-Qing; McDowell, Nate G; Li, Yan

2016-05-01

Understanding the interactions between drought and tree ontogeny or size remains an essential research priority because size-specific mortality patterns have large impacts on ecosystem structure and function, determine forest carbon storage capacity, and are sensitive to climatic change. Here we investigate a xerophytic tree species (Haloxylon ammodendron (C.A. Mey.)) with which the changes in biomass allocation with tree size may play an important role in size-specific mortality patterns. Size-related changes in biomass allocation, root distribution, plant water status, gas exchange, hydraulic architecture and non-structural carbohydrate reserves of this xerophytic tree species were investigated to assess their potential role in the observed U-shaped mortality pattern. We found that excessively negative water potentials (<-4.7MPa, beyond the P50leaf of -4.1MPa) during prolonged drought in young trees lead to hydraulic failure; while the imbalance of photoassimilate allocation between leaf and root system in larger trees, accompanied with declining C reserves (<2% dry matter across four tissues), might have led to carbon starvation. The drought-resistance strategy of this species is preferential biomass allocation to the roots to improve water capture. In young trees, the drought-resistance strategy is not well developed, and hydraulic failure appears to be the dominant driver of mortality during drought. With old trees, excess root growth at the expense of leaf area may lead to carbon starvation during prolonged drought. Our results suggest that the drought-resistance strategy of this xeric tree is closely linked to its life and death: well-developed drought-resistance strategy means life, while underdeveloped or overdeveloped drought-resistance strategy means death. Copyright © 2016 Elsevier GmbH. All rights reserved.

Host-induced silencing of essential genes in Puccinia triticina through transgenic expression of RNAi sequences reduces severity of leaf rust infection in wheat.

PubMed

Panwar, Vinay; Jordan, Mark; McCallum, Brent; Bakkeren, Guus

2018-05-01

Leaf rust, caused by the pathogenic fungus Puccinia triticina (Pt), is one of the most serious biotic threats to sustainable wheat production worldwide. This obligate biotrophic pathogen is prevalent worldwide and is known for rapid adaptive evolution to overcome resistant wheat varieties. Novel disease control approaches are therefore required to minimize the yield losses caused by Pt. Having shown previously the potential of host-delivered RNA interference (HD-RNAi) in functional screening of Pt genes involved in pathogenesis, we here evaluated the use of this technology in transgenic wheat plants as a method to achieve protection against wheat leaf rust (WLR) infection. Stable expression of hairpin RNAi constructs with sequence homology to Pt MAP-kinase (PtMAPK1) or a cyclophilin (PtCYC1) encoding gene in susceptible wheat plants showed efficient silencing of the corresponding genes in the interacting fungus resulting in disease resistance throughout the T 2 generation. Inhibition of Pt proliferation in transgenic lines by in planta-induced RNAi was associated with significant reduction in target fungal transcript abundance and reduced fungal biomass accumulation in highly resistant plants. Disease protection was correlated with the presence of siRNA molecules specific to targeted fungal genes in the transgenic lines harbouring the complementary HD-RNAi construct. This work demonstrates that generating transgenic wheat plants expressing RNAi-inducing transgenes to silence essential genes in rust fungi can provide effective disease resistance, thus opening an alternative way for developing rust-resistant crops. © 2017 Her Majesty the Queen in Right of Canada. Plant Biotechnology Journal published by Society for Experimental Biology and The Association of Applied Biologists and John Wiley & Sons Ltd.

Credit WCT. Original 2¾" x 2Y4" color negative is housed ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

Credit WCT. Original 2-¾" x 2-Y4" color negative is housed in the JPL Photography Laboratory, Pasadena, California. View shows JPL staff member John Morrow loading the grinder hopper. The hopper has a 10 mesh screen to filter out particles too large for the mill. Oxidizer is passed steadily to the hammers by a stainless steel feed screw. Oxidizer may be passed through the mill several times depending on the fineness required by a given propellant formula; the maximum charge is 130 pounds (59.0 Kg). The drum below the mill has an electrically conductive plastic liner which receives the ground oxidizer (JPL negative no. JPL10279AC, 27 January 1989) - Jet Propulsion Laboratory Edwards Facility, Oxidizer Grinder Building, Edwards Air Force Base, Boron, Kern County, CA

Overexpression of a thaumatin-like protein gene from Vitis amurensis improves downy mildew resistance in Vitis vinifera grapevine.

PubMed

He, Rongrong; Wu, Jiao; Zhang, Yali; Agüero, Cecilia B; Li, Xinlong; Liu, Shaoli; Wang, Chaoxia; Walker, M Andrew; Lu, Jiang

2017-07-01

Downy mildew is a highly destructive disease in grapevine production. A gene encoding pathogenesis-related (PR) thaumatin-like protein was isolated from the downy mildew-resistant grapevine "Zuoshan-1," a clonal selection from wild Vitis amurensis Rupr. The predicted thaumatin-like protein (VaTLP) has 225 amino acids and it is acidic, with a calculated isoelectric point of 4.8. The full length of the VaTLP gene was transformed into somatic embryogenic calli of V. vinifera 'Thompson Seedless' via Agrobacterium tumefaciens. Real-time RT-PCR confirmed that the VaTLP gene was expressed at a high level in the transgenic grapevines. Improved resistance of the transgenic lines against downy mildew was evaluated using leaf disks and whole plants inoculated with Plasmopara viticola, the pathogen causing grapevine downy mildew disease. Bioassay of the pathogen showed that both hyphae growth and asexual reproduction were inhibited significantly among the transgenic plants. Histological analysis also confirmed this disease resistance by demonstrating the inhibition and malformation of hyphae development in leaf tissue of the transgenic plants. These results indicated that the accumulation of VaTLP could enhance resistance to P. viticola in transgenic 'Thompson Seedless' grapevines.

Potential of tissue culture for breeding root-knot nematode resistance into vegetables.

PubMed

Fassuliotis, G; Bhatt, D P

1982-01-01

Plant protoplast technology is being investigated as a means of transferring root-knot nematode resistance factors from Solanum sisymbriifolium into the susceptible S. melongena. Solanum sisymbriifolium plants regenerated from callus lost resistance to Meloidogyne javanica but retained resistance to M. incognita. Tomato plants cloned from leaf discs of the root-knot nematode resistant 'Patriot' were completely susceptible to M. incognita, while sections of stems and leaves rooted in sand in the absence of growth hormones retained resistance. Changes in resistance persisted for three generations. It is postulated that the exogenous hormonal constituents of the culture medium are modifying the expression of genetic resistance.