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Fusarium head blight (FHB), incited by Fusarium graminearum Schwabe is one of the most devastating diseases of wheat. Primary inoculum generated on crop residue is the driving force
of FHB epidemics. Fusarium survival on crop residues is affected by soil microbial antagonists. The incorporation of green manures has been shown to
increase the density and diversity of microbes in soils, particularly the density and the pathogen-inhibitory activity of
specific bacteria and fungi. Evidence of increased streptomycete populations in soil as a response to green manure incorporation,
and their negative effect on the survival of Fusarium oxysporum Schlechtendahl in soil, suggests their potential use to reduce the survival of related pathogens. There is, however, no precedent
for the use of green manures to promote indigenous streptomycete populations to control FHB. This study investigated the use
of green manures (sorghum–sudangrass hybrid [Sorghum bicolor (L.) Moench–S. bicolor (L.) Moench var. sudanense (Piper)] and common buckwheat [Fagopyrum esculentum (Moench)]) for reducing F. graminearum survival in association with wheat residues. Soil bacterial density, streptomycete density and the density and inhibitory
activity of F. graminearum-antagonists were monitored from planting until 3 and 6 months following the incorporation of green manures in greenhouse
and field experiments, respectively. The decomposition of wheat residues and survival of Fusarium in residues was also assessed. The use of green manures did not statistically impact the survival of F. graminearum in wheat residue. However, green manures promoted the development of higher densities and antagonistic abilities of F. graminearum-antagonists in soils. Additionally, streptomycete densities and F. graminearum-antagonist densities were significantly and positively correlated with reduced survival of Fusarium. The results of our study suggest that the use of green manures can enhance populations of indigenous soil microorganisms
antagonistic to the survival of F. graminearum in wheat residue. 相似文献
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Genome-wide association mapping of Fusarium head blight resistance in contemporary barley breeding germplasm 总被引:1,自引:0,他引:1
J. Massman B. Cooper R. Horsley S. Neate R. Dill-Macky S. Chao Y. Dong P. Schwarz G. J. Muehlbauer K. P. Smith 《Molecular breeding : new strategies in plant improvement》2011,27(4):439-454
Utilization of quantitative trait loci (QTL) identified in bi-parental mapping populations has had limited success for improving
complex quantitative traits with low to moderate heritability. Association mapping in contemporary breeding germplasm may
lead to more effective marker strategies for crop improvement. To test this approach, we conducted association mapping of
two complex traits with moderate heritability; Fusarium head blight (FHB) severity and the grain concentration of mycotoxin
associated with disease, deoxynivalenol (DON). To map FHB resistance in barley, 768 breeding lines were evaluated in 2006
and 2007 in four locations. All lines were genotyped with 1,536 SNP markers and QTL were mapped using a mixed model that accounts
for relatedness among lines. Average linkage disequilibrium within the breeding germplasm extended beyond 4 cM. Four QTL were
identified for FHB severity and eight QTL were identified for the DON concentration in two independent sets of breeding lines.
The QTL effects were small, explaining 1–3% of the phenotypic variation, as might be expected for complex polygenic traits.
We show that using breeding germplasm to map QTL can complement bi-parental mapping studies by providing independent validation,
mapping QTL with more precision, resolving questions of linkage and pleiotropy, and identifying genetic markers that can be
applied immediately in crop improvement. 相似文献
4.
Transgenic wheat expressing a barley class II chitinase gene has enhanced resistance against Fusarium graminearum 总被引:1,自引:0,他引:1
Shin S Mackintosh CA Lewis J Heinen SJ Radmer L Dill-Macky R Baldridge GD Zeyen RJ Muehlbauer GJ 《Journal of experimental botany》2008,59(9):2371-2378
Fusarium head blight (FHB; scab), primarily caused by Fusarium graminearum, is a devastating disease of wheat worldwide. FHB causes yield reductions and contamination of grains with trichothecene mycotoxins such as deoxynivalenol (DON). The genetic variation in existing wheat germplasm pools for FHB resistance is low and may not provide sufficient resistance to develop cultivars through traditional breeding approaches. Thus, genetic engineering provides an additional approach to enhance FHB resistance. The objectives of this study were to develop transgenic wheat expressing a barley class II chitinase and to test the transgenic lines against F. graminearum infection under greenhouse and field conditions. A barley class II chitinase gene was introduced into the spring wheat cultivar, Bobwhite, by biolistic bombardment. Seven transgenic lines were identified that expressed the chitinase transgene and exhibited enhanced Type II resistance in the greenhouse evaluations. These seven transgenic lines were tested under field conditions for percentage FHB severity, percentage visually scabby kernels (VSK), and DON accumulation. Two lines (C8 and C17) that exhibited high chitinase protein levels also showed reduced FHB severity and VSK compared to Bobwhite. One of the lines (C8) also exhibited reduced DON concentration compared with Bobwhite. These results showed that transgenic wheat expressing a barley class II chitinase exhibited enhanced resistance against F. graminearum in greenhouse and field conditions. 相似文献
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Overexpression of defense response genes in transgenic wheat enhances resistance to Fusarium head blight 总被引:2,自引:0,他引:2
Mackintosh CA Lewis J Radmer LE Shin S Heinen SJ Smith LA Wyckoff MN Dill-Macky R Evans CK Kravchenko S Baldridge GD Zeyen RJ Muehlbauer GJ 《Plant cell reports》2007,26(4):479-488
Fusarium head blight (FHB) of wheat, caused by Fusarium graminearum and other Fusarium species, is a major disease problem for wheat production worldwide. To combat this problem, large-scale
breeding efforts have been established. Although progress has been made through standard breeding approaches, the level of
resistance attained is insufficient to withstand epidemic conditions. Genetic engineering provides an alternative approach
to enhance the level of resistance. Many defense response genes are induced in wheat during F. graminearum infection and may play a role in reducing FHB. The objectives of this study were (1) to develop transgenic wheat overexpressing
the defense response genes α-1-purothionin, thaumatin-like protein 1 (tlp-1), and β-1,3-glucanase; and (2) to test the resultant
transgenic wheat lines against F. graminearum infection under greenhouse and field conditions. Using the wheat cultivar Bobwhite, we developed one, two, and four lines
carrying the α-1-purothionin, tlp-1, and β-1,3-glucanase transgenes, respectively, that had statistically significant reductions
in FHB severity in greenhouse evaluations. We tested these seven transgenic lines under field conditions for percent FHB disease
severity, deoxynivalenol (DON) mycotoxin accumulation, and percent visually scabby kernels (VSK). Six of the seven lines differed
from the nontransgenic parental Bobwhite line for at least one of the disease traits. A β-1,3-glucanase transgenic line had
enhanced resistance, showing lower FHB severity, DON concentration, and percent VSK compared to Bobwhite. Taken together,
the results showed that overexpression of defense response genes in wheat could enhance the FHB resistance in both greenhouse
and field conditions. 相似文献
7.
H. Ma R. H. Busch O. Riera-Lizarazu H. W. Rines R. Dill-Macky 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》1999,99(3-4):432-436
Anther culture and maize hybridization are two frequently used techniques for doubled haploid production in wheat (Triticum aestivum L.). Information on the field performance of lines derived from these techniques is limited. This study was conducted to
compare the performance of F4:6 lines obtained by single-seed descent with lines obtained by anther culture and maize (Zea mays L.) pollination from the same cross of spring wheat, ’Chris’/MN 7529. Thirty-three lines derived from each of those techniques
were evaluated in six environments for grain yield, protein content, test weight, heading date, kernel weight and plant height.
Mean performance of the single-seed descent lines exceeded performance of the anther culture lines for grain yield, kernel
weight and plant height with no apparent differences for grain protein content, test weight and heading date. No differences
between trait means for the single-seed descent and maize pollination lines were found except for plant height. The best 5
lines from each method for grain yield, protein content and test weight were similar in performance except that the protein
content was higher for the maize pollination lines than for the single-seed descent lines. Acceptable levels of agronomic
performance could be found among lines from each method. Wide acceptance of the doubled haploid technique for pure line production
in breeding programs may, however, be limited by the often poor efficiency of doubled haploid line production, resulting in
smaller population sizes for selection of desirable traits in comparison to the single-seed descent method.
Received: 31 July 1998 / Accepted: 28 November 1998 相似文献
8.
The impact of moisture on the development of Fusarium head blight (FHB) and accumulation of deoxynivalenol (DON) in Fusarium-infected wheat was examined. The field experiments were designed as split-split-plot with five replicates. Main plots were
durations of mist-irrigation [14, 21, 28 and 35 days after inoculation (DAI)]; sub-plots were wheat cultivar; and sub-sub-plots
were F. graminearum isolates differing in aggressiveness and DON production capacity. The wheat cultivars ‘Alsen’ (moderately resistant), ‘2375’
(moderately susceptible) and ‘Wheaton’ (susceptible) were inoculated at anthesis. Severity of FHB was assessed 21 days after
inoculation. Visually scabby kernels (VSK) and mycotxin content (DON, 15-AcDON, 3-AcDON and nivalenol) were determined on
harvested grain. The damage to grain, as measured by VSK, was significantly lower in the treatments receiving the least amount
of mist-irrigation (14 DAI) suggesting that extended moisture promotes disease development. DON was, however, significantly
lower in the 35-DAI misting treatment than in treatments receiving less post-inoculation moisture. The reduction of DON observed
in treatments receiving extended mist-irrigation was greatest in ‘Wheaton’ which recorded the highest FHB severity, VSK and
DON of the cultivars examined. Our results suggest that DON and other trichothecenes may be reduced by late-season moisture
despite increased grain colonization. We suggest that leaching may explain much of the reduction of mycotoxins, and that differences
in tissue morphology and metabolism may determine the rate of leaching from specific tissues. 相似文献
9.
Canci Paulo C. Nduulu Lexingtons M. Muehlbauer Gary J. Dill-Macky Ruth Rasmusson Donald C. Smith Kevin P. 《Molecular breeding : new strategies in plant improvement》2004,14(2):91-104
Validation of quantitative trait loci (QTLs) is a prerequisite to marker assisted selection (MAS), however, only a fraction of QTLs identified for important plant traits have been independently tested for validation. Resistance to the diseases kernel discoloration (KD) and Fusarium head blight (FHB) in barley is complex and technically difficult to assess, and therefore QTLs for these traits are suitable targets for MAS. We selected two lines, from a QTL mapping population created using the resistant variety Chevron, and crossed them to susceptible parents to generate two validation populations. Genetic maps of both populations were developed for five chromosomes covering 15 selected regions containing QTLs for FHB severity, KD score and concentration of deoxynivalenol (DON), a mycotoxin produced by the FHB pathogen. QTL analyses using these validation populations confirmed that five of the possible 15 QTL regions were associated with at least one of the three traits. While some QTL were detected inconsistently across environments, QTL that could be subjected to validation in both populations were confirmed in both populations in seven out of eight instances. A QTL for KD score on chromosome 6(6H) was confirmed in both validation populations in eight of nine environments and was also associated with FHB in three of six environments. A QTL for FHB on chromosome 2(2H) was confirmed and was also associated with KD and heading date. Marker assisted selection at these two QTLs should enhance disease resistance, however, the QTL on chromosome 2(2H) will also delay heading date. 相似文献
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Quantitative trait loci associated with resistance to Fusarium head blight and kernel discoloration in barley 总被引:13,自引:5,他引:8
R. C. de la Pena K. P. Smith F. Capettini G. J. Muehlbauer M. Gallo-Meagher R. Dill-Macky D. A. Somers D. C. Rasmusson 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》1999,99(3-4):561-569
Resistance to Fusarium head blight (FHB), deoxynivalenol (DON) accumulation, and kernel discoloration (KD) in barley are difficult
traits to introgress into elite varieties because current screening methods are laborious and disease levels are strongly
influenced by environment. To improve breeding strategies directed toward enhancing these traits, we identified genomic regions
containing quantitative trait loci (QTLs) associated with resistance to FHB, DON accumulation, and KD in a breeding population
of F4:7 lines using restriction fragment length polymorphic (RFLP) markers. We evaluated 101 F4:7 lines, derived from a cross between the cultivar Chevron and an elite breeding line, M69, for each of the traits in three
or four environments. We used 94 previously mapped RFLP markers to create a linkage map. Using composite interval mapping,
we identified 10, 11, and 4 QTLs associated with resistance to FHB, DON accumulation, and KD, respectively. Markers flanking
these QTLs should be useful for introgressing resistance to FHB, DON accumulation, and KD into elite barley cultivars.
Received: 8 November 1998 / Accepted: 8 January 1999 相似文献
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