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[前沿资讯 ] Chasing high and stable wheat grain mineral content: Mining diverse spring genotypes under induced drought stress 进入全文
PubMed Central
Climate change-induced drought has an effect on the nutritional quality of wheat. Here, the impact of drought at different plant stages on mineral content in mature wheat was evaluated in 30 spring-wheat lines of diverse backgrounds (modern, old and wheat-rye-introgressions). Genotypes with rye chromosome 3R introgression showed a high accumulation of several important minerals, including Zn and Fe, and these also showed stability across drought conditions. High Se content was found in genotypes with chromosome 1R. Old cultivars (K, Mg, Na, P and S) and 2R introgression lines (Fe, Ca, Mn, Mg and Na) demonstrated high mineral yield at early and late drought, respectively. Based on the low nutritional value often reported for modern wheat and negative climate effects on the stability of mineral content and yield, genes conferring high Zn/Fe, Se, and stable mineral yield under drought at various plant stages should be explicitly explored among 3R, 1R, old and 2R genotypes, respectively.
[前沿资讯 ] A novel variation of TaGW2-6B increases grain weight without penalty in grain protein content in wheat (Triticum aestivum L.) 进入全文
SpringerLink
Yield and quality are two crucial breeding objects of wheat therein grain weight and grain protein content (GPC) are two key relevant factors correspondingly. Investigations of their genetic mechanisms represent special significance for breeding. In this study, 199 F2 plants and corresponding F2:3 families derived from Nongda3753 (ND3753) and its EMS-generated mutant 564 (M564) were used to investigate the genetic basis of larger grain and higher GPC of M564. QTL analysis identified a total of 33 environmentally stable QTLs related to thousand grain weight (TGW), grain area (GA), grain circle (GC), grain length (GL), grain width (GW), and GPC on chromosomes 1B, 2A, 2B, 4D, 6B, and 7D, respectively, among which QGw.cau-6B.1, QTgw.cau-6B.1, QGa.cau-6B.1, and QGc.cau-6B.1 shared overlap confidence interval on chromosome 6B. This interval contained the TaGW2 gene playing the same role as the QTLs, so TaGW2-6B was cloned and sequenced. Sequence alignment revealed two G/A SNPs between two parents, among which the SNP in the seventh exon led to a premature termination in M564. A KASP marker was developed based on the SNP, and single-marker analysis on biparental populations showed that the mutant allele could significantly increase GW and TGW, but had no effect on GPC. Distribution detection of the mutant allele through KASP marker genotyping and sequence alignment against databases ascertained that no materials harbored this allele within natural populations. This allele was subsequently introduced into three different varieties through molecular marker-assisted backcrossing, and it was revealed that the allele had a significant effect on simultaneously increasing GW, TGW, and even GPC in all of three backgrounds. Summing up the above, it could be concluded that a novel elite allele of TaGW2-6B was artificially created and might play an important role in wheat breeding for high yield and quality.
[前沿资讯 ] Different wheat loci are associated to heritable free asparagine content in grain grown under different water and nitrogen availability 进入全文
SpringerLink
The amount of free asparagine in grain of a wheat genotype determines its potential to form harmful acrylamide in derivative food products. Here, we explored the variation in the free asparagine, aspartate, glutamine and glutamate contents of 485 accessions reflecting wheat worldwide diversity to define the genetic architecture governing the accumulation of these amino acids in grain. Accessions were grown under high and low nitrogen availability and in water-deficient and well-watered conditions, and plant and grain phenotypes were measured. Free amino acid contents of grain varied from 0.01 to 1.02 mg g−1 among genotypes in a highly heritable way that did not correlate strongly with grain yield, protein content, specific weight, thousand-kernel weight or heading date. Mean free asparagine content was 4% higher under high nitrogen and 3% higher in water-deficient conditions. After genotyping the accessions, single-locus and multi-locus genome-wide association study models were used to identify several QTLs for free asparagine content located on nine chromosomes. Each QTL was associated with a single amino acid and growing environment, and none of the QTLs colocalised with genes known to be involved in the corresponding amino acid metabolism. This suggests that free asparagine content is controlled by several loci with minor effects interacting with the environment. We conclude that breeding for reduced asparagine content is feasible, but should be firmly based on multi-environment field trials. Key message: Different wheat QTLs were associated to the free asparagine content of grain grown in four different conditions. Environmental effects are a key factor when selecting for low acrylamide-forming potential.
[前沿资讯 ] Response to heat stress and glutenins allelic variation effects on quality traits in durum wheat 进入全文
Wiley Online Library
In the context of climate change, high temperature is one of the main abiotic stresses hampering durum wheat production. Through the characterization of an international panel of 271 genotypes, this study investigates the effects of heat stress on quality traits and identifies which glutenins (Glu-1, Glu-2 and Glu-3 loci) alleles are the most important to obtain high gluten strength under optimal and high temperature conditions. In parallel with the wide variability observed in the panel, the genotype and environmental effects, including their interaction, showed highly significant effect on test weight, thousand kernel weight, grain protein content (GPC), sodium dodecyl sulphate sedimentation volume (SDSS) and SDSS index. Only one genotype maintained test weight and thousand kernel weight under heat-stress conditions whereas for GPC, SDSS and SDSS index, most genotypes increased values. All Glu loci had significant effects on grain protein content (with the exception of Glu-B2), SDSS and SDSS Index. None of the Glu loci interacted with the environment or years under study. Among the identified alleles, Glu-A1b, Glu-B1an, Glu-B1a, Glu-B2a, Glu-A3a.x, Glu-A3d, Glu-B3a and Glu-B3ax (including the LMW-2 pattern) were associated with high values for SDSS and SDSS Index. Genotypes identified in this study, with good performances under optimal and high temperature growing conditions, could be useful for breeding programs. The non-interaction of the Glu loci with the environment facilitates the introgression of desired alleles regardless of high growing temperatures.
[学术文献 ] Efficiency of indirect selection for fusarium head blight resistance and mycotoxin accumulation in winter wheat (Triticum aestivum L.) 进入全文
WILEY online Library
Fusarium head blight (FHB) is one of the most devastating diseases of wheat and can lead to significant yield losses as well as a contamination of the crop with mycotoxins that are a major concern in cereal-based food and feed products. The aims of this study were thus to investigate the relationship between resistance against multiple Fusarium species and to assess the potential of an indirect phenotypic and genomic selection for the resistance against the accumulation of several mycotoxins in wheat. Strong phenotypic and genetic correlations between the mycotoxin contents, FHB severity and FHB-associated traits were observed, irrespective of if traits were assessed in trials inoculated with a DON or HT-2/T-2 producing Fusarium species. A multi-stage phenotypic or genomic selection with low anther retention being used for an indirect selection among early generation selection candidates, followed by an evaluation of the pre-selected set in disease nurseries, and lastly by assessing the mycotoxin content of the most promising genotypes is suggested as a suitable strategy to breed for wheat cultivars with reduced risk of mycotoxin accumulation.
[前沿资讯 ] Molecular characterization of a novel heat shock transcription factor gene TaHsfA2-11 and its overexpression improves thermotolerance in wheat 进入全文
ScienceDirect
High temperature is a major constrait limiting the yield and quality of wheat. Wheat heat shock transcription factor (Hsf) plays important roles in regulating plant response to heat shock. In previous study, we found there are 82 Hsfs in wheat and TaHsfA2–11 expression was obviously upregulated by heat stress. In this study, we aim to investigate TaHsfA2–11 function and regulating mechanism in response to heat shock through genetic transformation into wheat Fielder. Gene expression analyses results showed that TaHsfA2–11 was expressed in all detected tissues and the most highly expressed level was in wheat mature roots. The expression level of TaHsfA2–11 was strongly upregulated by heat shock in wheat leaves. Subcellular localization results represented that TaHsfA2–11 is located to the nucleus. Transgenic wheat seedlings overexpressing TaHsfA2–11 showed stronger thermotolerance than the control Fielder after treated under 50 °C for 12 h. After heat shock, the TaHsfA2–11 overexpressing lines showed increased survival rate, chlorophyll content, POD (Peroxidase) activity, SOD (Superoxide dismutase) activity and photosynthetic rate, and decreased relative electrolyte leakage and MDA (malondialdehyde) content compared with Fielder. The results of RNA-sequence data demonstrated that TaHsfA2–11 can regulate many heat response genes, such as Hsp genes TaHsp16.6 and TaHsp21, ER (Endoplasmic reticulum) stress genes TaBiP2 and TaERDJ3A, photoprotectant for PSII gene TaELIPHV58, flavone biosynthesis related genes TaUGT-2A and TaPMaT, etc after heat stress. These results showed that TaHsfA2–11 can impove thermotolerance perhaps through effecting signal pathway of heat, ER stress, photosynthesis and ROS (Reactive Oxygen Species). The findings will provide useful gene resource for performing genetic modification of wheat thermotolerance in heat-resistant breeding.
