Effect of elevated atmospheric CO2 level on the abiotic and biotic stress tolerance of cereals

Abstract Effect of elevated CO2 level (EC) was studied on the tolerance of cereals to elevated temperature and drought and on the resistance of wheat to fungal diseases. In general, elevated growth temperature did not affect final grain size, thus having less harmful effects than heat stress or drought during grain-filling. The plants subjected to low water supply levels or elevated temperature had higher biomass and grain yield at EC than at the ambient level. Susceptible wheat varieties were, however, usually more prone to diseases when grown at EC, while resistant varieties remained resistant even at EC

A sárga pigment tartalommal összefüggő molekuláris markerek azonosítása őszi durum búzában (Triticum durum Desf.) = Identification of molecular markers linked to yellow pigment content in winter durum wheat (Triticum durum Desf.)

A nagy sárgapigment-tartalom a durum búza egyik legértékesebb beltartalmi tulajdonsága. A pályázat időtartama alatt célunk az őszi durum búza sárga pigment tartalmával összefüggő molekuláris markerek azonosítása volt. A sárgapigment-tartalommal szorosan korreláló sárgaindex alapján eltérő szülőkkel utódpopulációt hoztunk létre, melyből a pályázat időtartama alatt 98 kiegyenlített törzset alakítottunk ki. Ezek, valamint a szülők DNS-ét felhasználva, "bulk" szegregáns analízissel a sárgaindex tartalommal összefüggő molekuláris markereket azonosítottunk, melyhez 520 RAPD primert használtunk. Munkánk során 5 primerrel 9 polimorf markert azonosítottunk. Korrelációanalízissel megállapítottuk a markerek és a két évben mért sárgaindex átlagok kapcsoltságát. A determinációs koefficiens értéke 0 és 13% között volt, legszorosabb kapcsoltságot az OPA16-800 markerrel számítottuk. Többszörös regresszióval mind a 9 markert figyelembe véve R2=0,4205, a 4 szignifikáns markerrel R2=0,3773 volt a többszörös determinációs koefficiens értéke. Diszkriminancia analízissel ellenőriztük, hogy a sárgaindex alapján elvégzett csoportosítást mennyire támasztják alá a marker adatok. Mind a 9 markert használva a törzsek 80%-ának csoportba sorolása helyesnek bizonyult. Négy markerrel ugyanez az érték 77% volt, azonban az elemzés a kis sárgaindexű törzsek 93,47%-ának besorolását alátámasztotta, így e 4 markerrel a rossz technológiai minőségű törzsek nagy valószínűséggel azonosíthatók. | High yellow pigment content is one of the most valuable chemical traits of durum wheat. The aim of the project was to identify molecular markers linked to the yellow pigment content of winter durum wheat. A progeny population was created from parents differing for the yellow index and 98 advanced lines were developed during the course of the project. Bulk segregant analysis was carried out on the DNA of these lines and on the parental partners using 520 RAPD primers in order to identify molecular markers linked to the yellow index. Nine polymorphic markers were detected using five primers. Correlation analysis was used to determine linkage between the markers and the yellow index (mean of two years). The value of the coefficient of determination ranged from 0 to 13%, the closest linkage being calculated for marker OPA16-800. When multiple regression involved all nine markers the coefficient of multiple determination had a value of R2 = 0.4205, while this value was R2 = 0.3773 for the four significant markers. Discriminant analysis was used to check whether the marker data confirmed the groupings based on yellow index. When all nine markers were used the grouping of 80 % of the lines proved to be correct, while this figure was 77 % for the four markers. However, this latter analysis confirmed the grouping of 93.47 % of lines with low yellow index, suggesting that these four markers could be used with high accuracy to identify lines with poor technological quality

1H, 15N backbone assignment and comparative analysis of the wild type and G12C, G12D, G12V mutants of K-Ras bound to GDP at physiological pH

K-Ras protein is a membrane-bound small GTPase acting as a molecular switch. It plays a key role in many signal transduction pathways regulating cell proliferation, differentiation, survival, etc. It alternates between its GTP-bound active and the GDP-bound inactive conformers regulated by guanine nucleotide exchange factors and GTPase activating proteins. Its most frequent oncogenic mutants are G12C, G12D, and G12V that have impaired GTPase activity, thus induce malignant tumors. Here we report the resonance assignment of the backbone 1H and 15N nuclei of K-Ras wildtype, G12C, G12D and G12V proteins’ catalytic G domain (1–169 residues) in GDP-bound state, and 13C of backbone and side chains of G12C mutant at physiological pH 7.4. Triple resonance data were used to get secondary structure information and backbone dynamics of G12C, the best-known drug target among K-Ras mutants. Simultaneous investigation of G12C, G12D and G12V mutants, along with the wild type form at the very same conditions allowed us to perform a comprehensive analysis based on the combined chemical shifts to reveal the effect of mutation at G12 position on structure. Intriguingly, the G12C and G12V mutants found to be structurally very similar at the three most important regions of K-Ras (P-loop, Switch-I, Switch-II), while the G12D mutant significantly differs at P-loop and Switch-II from the wildtype as well as G12C and G12V mutants. However, in Switch-I it hardly deviates from the wildtype protein

Seedling Resistance to Stagonospora nodorum Blotch in Wheat Genotypes

In two independent experiments set up in the greenhouse the seedling resistance to Stagonospora nodorum blotch was investigated in 92 varieties, breeding lines and genotypes with a known genetic background. The greatest area under the disease progress curve calculated from lesion type was 37.06, while in the case of the most resistant genotype this value was 0.38. Many of the lines and varieties bred in Martonvásár proved to have excellent resistance in terms of both percentage of infected leaf area and lesion type. Observations indicate that, depending on the aim of the experiment, the efficient selection of breeding lines is possible in the seedling stage either on the basis of the area under the disease progress curve calculated for lesion types, or on the basis of lesion types scored 7, 11 or 14 days after inoculation

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

Key message 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. Abstract 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. © 2014 The Author(s)

Régi magyar búzafajták kalászfuzárium ellenállóságának és minőségének vizsgálata = Studying of Fusarium blight resistance and quality of the old Hungarian wheat varieties

Magyarországon a kalászfuzárium (KF) egészen az 1970-es évek elejéig mindössze sporadikusan fordult elő. Észszerűnek tűnt megvizsgálni, hogy az 1920-1950 között nemesített búzafajták genetikailag determinált FHB rezisztenciája hozzájárult-e a gazdasági károk elkerüléséhez. Korábbi megfigyeléseink szerint a Bánkúti 1201 fajta kimagaslóan ellenállónak bizonyult a fuzáriummal mesterségesen fertőzött kísérletekben. Kísérleteinkben 1960 előtt nemesített magyar fajták KF rezisztenciáját teszteltük mesterségesen fertőzve. Ötéves adataink alapján a fajták és az e fajtákból származó törzsek átlagos KF fertőzöttsége 9,2-51,0% között alakult, 30 törzs kalászfertőzöttsége 20% alatt volt. A BKT9086-95/Mv Magvas keresztezésből származó 250 egymag-utód (SSD) módszerrel létrehozott törzs KF rezisztenciáját teszteltük kalászka fertőzéssel, üvegházban és szántóföldön. Az eredmények alapján 15 rezisztens és 15 fogékony genotípust választottunk ki bulk szegregáns analízishez. Az egyesített és a szülőkből származó DNS mintákat 81 primer kombinációval teszteltük (AFLP) és reakciónként átlagosan 5,02 polimorfizmust figyeltünk meg a szülők között. A rezisztens szülőéhez hasonló mintázat 16 törzsben volt jelen. A technológia minőség és a KF rezisztencia között laza volt, vagy hiányzott az összefüggés. A régi magyar búzafajták értékes források lehetnek a KF rezisztencianemesítésben. | In Hungary Fusarium head blight (FHB) occurred only sporadically until the early 1970s. It thus seemed worthwhile investigating whether the wheat varieties bred from the 1920s to the 50s carried genetically determined FHB resistance that contributed to the lack of economic loss. Earlier observations indicated that the variety Bánkúti 1201 had outstanding resistance to FHB in experiments artificially inoculated with Fusarium species. In our experiments inoculation tests were made on the FHB resistance of Hungarian wheat varieties bred prior to 1960. Averaged over five years, the field scab infection of these wheat varieties and of lines derived from them ranged from 9.2 to 51.0%, with infection rates below 20% for 30 lines. A total of 250 lines of single seed descent (SSD) from the cross BKT9086-95/Mv Magvas were tested for FHB resistance by means of single floret inoculation in greenhouse and field experiments. Based on the results, 15 resistant and 15 susceptible genotypes were selected for the purpose of bulk segregation analysis. DNA of the two bulk samples and the parents were tested with a total of 81 primer combinations (AFLP), and an average of 5.02 polymorphisms per reaction was found between the parents. Patterns similar to that of the resistant parent were found in 16 cases. The correlation between the technological quality data and the FHB resistance was very weak or absent. The old Hungarian wheat varieties might be valuable sources in FHB resistance breeding

Impact of Elevated Atmospheric CO2 Level on Powdery Mildew (Blumeria graminis f.sp. tritici) Severity in Wheat Depends on the Pathotype × Genotype Interaction

AbstractDisease resistance is influenced by a variety of environmental factors. The rise in the atmospheric CO2 level affects plant metabolism, physiology and development; which has an impact on pathogen invasion and the disease progress. The aim of the present work was to investigate the effect of CO2 enrichment on powdery mildew (PM) infection in winter wheat. Disease severity caused by two PM pathotypes was studied in Conviron PGV-36 growth chambers at ambient (390ppm) and elevated (750 pm) CO2 levels on seven varieties with different levels of resistance.Elevated CO2 (EC) resulted in more severe PM infection by pathotype R51 in most genotypes (Bezosztaja 1, Ukrainka, Libellula, Mv Mambo, Mv Emma), compared to ambient CO2, while pathotype R76 caused similar or lower infection level depending on the genotype. The two pathotypes, however, affected Ukrainka in a different way, as R51 resulted in higher while R76 in less severe infection due to elevated CO2. In the case of Apache, neither pathotype caused any change in PM severity in response to EC. The resistant variety, Mv Regiment, remained resistant to either R51 or R76 even at EC.During the progress of PM infection, the stomatal conductance of infected wheat leaves increased in general, at both CO2 levels. Despite the fact that R51 has the most virulence factors (infecting all of the 8 wheat genotypes used in the Nover differential set for identification of PM pathotypes while R76 infects 7; Frauenstein et al. 1979), R76 usually caused more severe initial disease symptoms than R51 at ambient CO2 level. In three varieties (Bezosztaja 1, Ukrainka, Libellula), however, R51 lead to the most severe final infection level.These findings underline the importance of resistance traits against diseases in a future environment with elevated atmospheric CO2 levels.This research was supported by the National Scientific Research Fund OTKA K-105949