2018年第三周小麦文献推荐（1.21）——2017年中国小麦领域高被引学者都有谁？

最近有老师私下问我有没有认识优秀一点的学生，推荐读他的博士。我想了一圈没有，在我们公众号里比较活跃的人多数都是博士。后面我脑洞大开，如果有机会后面我们会针对我们公众号推送的一些内容出一些测试题，成绩优秀的奖励红包，择优向老师们推荐。也欢迎热爱小麦的小伙伴给我们投稿，分享实验和学习心得等。

还要说说今天看到的高被引学者榜单，我看了下我们小麦领域应该是4人，分别是：康振生院士、何中虎研究员、贾继增研究员、刘宝教授。这4位学者做小麦的应该都认识，我们前面也推送过很多他们研究组的文章，在公众号内搜索即可。如果名单有遗漏，欢迎留言补充。虽然我头发不是特别长，但是我见识特别短。

好了，继续我们今天的文献推荐。

1 Natural variation and genetic make‑up of leaf blade area in spring barley

Despite long-standing studies in the morpho-physiological characters of leaf blade area (LA) in cereal crops, advanced genetic studies to explore its natural variation are lacking. The importance of modifying LA in improving cereal grain yield and the genes controlling leaf traits have been well studied in rice but not in temperate cereals. To better understand the natural genetic variation of LA at four developmental stages, main culm LA was measured from 215 worldwide spring barleys including 92 photoperiod-sensitive accessions [PHOTOPERIOD RESPONSE LOCUS 1 (Ppd-H1)] and 123 accessions with reduced photoperiod sensitivity (ppd-H1) locus under controlled greenhouse conditions (long-day; 16/8 h; ~ 20/~ 16 °C day/night). The LA of Ppd-H1-carrying accessions was always smaller than in ppd-H1-carrying accessions. We found that nine SNPs from the Ppd-H1 gene were present in the collection of which marker 9 (M9; G/T in the CCT-domain) showed the most significant and consistent effect on LA at all studied developmental stages. Genome-wide association scans (GWAS) showed that the accessions carrying the ppd-H1 allele T/M9 (late heading) possessed more genetic variation in LA than the Ppd-H1 group carrying G/M9 (early heading). Several QTL with major effects on LA variation were found close to plant stature-related heading time, phytohormone- and sugar-related genes. The results provide evidence that natural variation of LA is an important source for improving grain yield, adaptation and canopy architecture of temperate cereals.

2 A major QTL controlling the tolerance to manganese toxicity in barley (Hordeum vulgare L.)

Waterlogging stress disturbs plant metabolism through increased ion (manganese and iron) toxicity resulting from the changes in the soil redox potential under hypoxic conditions. Our previous study found a significant correlation between the tolerance to Mn2+ toxicity and waterlogging stress tolerance in barley, suggesting that waterlogging tolerance could be increased by improving the tolerance to Mn2+ toxicity. In this study, a doubled-haploid (DH) population from the cross between barley varieties Yerong and Franklin (waterlogging-tolerant and -sensitive, respectively) was used to identify QTL controlling tolerance to Mn2+ toxicity based on chlorophyll content and plant survival as selection criteria. Four significant QTL for plant survival under Mn2+ stress (QSur.yf.1H, QSur.yf.3H, QSur.yf.4H, and QSur.yf.6H) were identified in this population at the seedling stage. Two significant QTL (QLC.yf.3H and QLC.yf.6H) controlling leaf chlorosis under Mn2+ stress were identified on chromosomes 3H and 6H close to QSur.yf.3H and QSur.yf.6H. The major QTL QSur.yf.3H, located near the marker Bmag0013, explained 21% of the phenotypic variation. The major QTL for plant survival on 3H was validated in a different DH population (TX9425/Naso Nijo). This major QTL could potentially be used in breeding programmes to enhance tolerance to both manganese toxicity and waterlogging.

3 Genome wide identification of wheat and Brachypodium type one protein phosphatases and functional characterization of durum wheat TdPP1a

Reversible phosphorylation is an essential mechanism regulating signal transduction during development and environmental stress responses. An important number of dephosphorylation events in the cell are catalyzed by type one protein phosphatases (PP1), which catalytic activity is driven by the binding of regulatory proteins that control their substrate specificity or subcellular localization. Plants harbor several PP1 isoforms accounting for large functional redundancies. While animal PP1s were reported to play relevant roles in controlling multiple cellular processes, plant orthologs remain poorly studied. To decipher the role of plant PP1s, we compared PP1 genes from three monocot species, Brachypodium, common wheat and rice at the genomic and transcriptomic levels. To gain more insight into the wheat PP1 proteins, we identified and characterized TdPP1a, the first wheat type one protein phosphatase from a Tunisian durum wheat variety Oum Rabiaa3. TdPP1a is highly conserved in sequence and structure when compared to mammalian, yeast and other plant PP1s. We demonstrate that TdPP1a is an active, metallo-dependent phosphatase in vitro and is able to interact with AtI2, a typical regulator of PP1 functions. Also, TdPP1a is capable to complement the heat stress sensitivity of the yeast mutant indicating that TdPP1a is functional also in vivo. Moreover, transient expression of TdPP1a::GFP in tobacco leaves revealed that it is ubiquitously distributed within the cell, with a strong accumulation in the nucleus. Finally, transcriptional analyses showed similar expression levels in roots and leaves of durum wheat seedlings. Interestingly, the expression in leaves is significantly induced following salinity stress, suggesting a potential role of TdPP1a in wheat salt stress response.

4 Estimating the responses of winter wheat yields to moisture variations in the past 35 years in Jiangsu Province of China

Jiangsu is an important agricultural province in China. Winter wheat, as the second major grain crop in the province, is greatly affected by moisture variations. The objective of this study was to investigate whether there were significant trends in changes in the moisture conditions during wheat growing seasons over the past decades and how the wheat yields responded to different moisture levels by means of a popular drought index, the Standardized Precipitation Evapotranspiration Index (SPEI). The study started with a trend analysis and quantification of the moisture conditions with the Mann-Kendall test and Sen’s Slope method, respectively. Then, correlation analysis was carried out to determine the relationship between de-trended wheat yields and multi-scalar SPEI. Finally, a multivariate panel regression model was established to reveal the quantitative yield responses to moisture variations. The results showed that the moisture conditions in Jiangsu were generally at a normal level, but this century appeared slightly drier in because of the relatively high temperatures. There was a significant correlation between short time scale SPEI values and wheat yields. Among the three critical stages of wheat development, the SPEI values in the late growth stage (April-June) had a closer linkage to the yields than in the seedling stage (October-November) and the over-wintering stage (December-February). Moreover, the yield responses displayed an asymmetric characteristic, namely, moisture excess led to higher yield losses compared to moisture deficit in this region. The maximum yield increment could be obtained under the moisture level of slight drought according to the 3-month SPEI at the late growth stage, while extreme wetting resulted in the most severe yield losses. The moisture conditions in the first 15 years of the 21stcentury were more favorable than in the last 20 years of the 20th century for wheat production in Jiangsu.

5 Effect of Fusarium head blight management practices on mycotoxin contamination of wheat straw

Management of Fusarium graminearum-associated mycotoxins in wheat grain has been extensively evaluated, but little is known about management of mycotoxins in straw. Two research trials were conducted at four locations from 2011 to 2014. The objective of the first trial was to determine the efficacy of fungicides, and the objective of the second trial was to evaluate the use of integrated disease management strategies, for the control of Fusarium head blight (FHB) and reducing the concentration of the Fusarium mycotoxins deoxynivalenol, 3-acetyl-deoxynivalenol, and 15-acetyl-deoxynivalenol in straw. In the first trial, it was determined that demethylation inhibitor (DMI) fungicides did not offer significant (P ≤ 0.05) reductions of mycotoxin concentrations in the straw compared to a no-fungicide control treatment, but significant (P ≤ 0.05) reductions in mycotoxin concentration were observed in the control when compared to treatments with the application of quinone outside inhibitor (QoI)-containing fungicides. In the second trial, mycotoxin concentrations in the straw were significantly (P ≤ 0.05) reduced in the moderately resistant cultivar compared to the susceptible cultivar, but were not effected by the use of a fungicide. The practices typically used to manage Fusarium mycotoxins in wheat grain, especially the selection of resistant cultivars and not using a QoI fungicide, may be an effective means to reduce mycotoxin concentrations in the straw.

6 Adult Plant Leaf Rust Resistance Derived from the Soft Red Winter Wheat Cultivar ‘Caldwell’ Maps to Chromosome 3BS

‘Caldwell’ is a US soft red winter wheat (Triticum aestivum L.) that has partial, adult plant resistance to the leaf rust pathogen Puccinia triticinaEriks. A line of ‘Thatcher2/Caldwell’ with adult plant resistance derived from Caldwell was crossed with ‘Thatcher’ to develop a population of recombinant inbred lines (RILs). The parents and RIL population were evaluated for segregation of leaf rust resistance in four field tests. A genetic map of the RIL population was constructed using 90K single-nucleotide polymorphism (SNP) markers with the Illumina Infinium iSelect 90K wheat bead array. Significant effects for reduction of leaf rust severity in all four tests were found for a quantitative trait locus on chromosome 3BS. Simple sequence repeat (SSR) markers linked to the adult plant resistance gene *Lr74 and kompetitive allele specific polymerase chain reaction (KASP) assay markers were added to the map on chromosome 3BS. Thatcher and the resistant Thatcher2/Caldwell parent were negative for the presence of *Sr2 on chromosome 3BS based on the tightly linked marker csSr2. The SSR marker cfb5006 linked closely to Lr74 mapped the closest to the logarithm of odds peak for leaf rust resistance on chromosome 3BS. The SNP and SSR markers on chromosome 3BS can be used to add Caldwell leaf rust resistance to wheat breeding germplasm.

7 Can spelt wheat be used as heterotic group for hybrid wheat breeding?

The feasibility to switch from line to hybrid breeding is currently a hot topic in the wheat community. One limitation seems to be the lack of divergent heterotic groups within wheat adapted to a certain region. Spelt wheat is a hexaploid wheat that can easily be crossed with bread wheat and that forms a divergent genetic group when compared to elite bread wheat. The aim of this study was to investigate the potential of Central European spelt as a heterotic group for Central European bread wheat. We performed two large experimental field studies comprising in total 43 spelt lines, 14 wheat lines, and 273 wheat–spelt hybrids, and determined yield, heading time, plant height, resistance against yellow rust, leaf rust, and powdery mildew, as well as protein content and sedimentation volume. Heterosis of yield was found to be lower than that of hybrids made between elite wheat lines. Moreover, heterosis of the quality trait sedimentation volume was negative. Consequently, spelt wheat does not appear suited to be used as heterotic group in hybrid wheat breeding. Nevertheless, high combining abilities of a few spelt lines with elite bread wheat lines make them interesting resources for pre-breeding in bread wheat. Thereby, the low correlation between line per se performance and combining ability of these spelt lines shows the potential to unravel the breeding value of genetic resources by crossing them to an elite tester.

8 Genomic, Biochemical, and Modeling Analyses of Asparagine Synthetases from Wheat

9 Overexpression of a wheat (Triticum aestivum L.) bZIP transcription factor gene, TabZIP6, decreased the freezing tolerance of transgenic Arabidopsis seedlings by down-regulating the expression of CBFs

The basic leucine zipper (bZIP) proteins play important roles against abiotic stress in plants, including cold stress. However, most bZIPs involved in plant freezing tolerance are positive regulators. Only a few bZIPs function negatively in cold stress response. In this study, TabZIP6, a Group C bZIP transcription factor gene from common wheat (Triticum aestivum L.), was cloned and characterized. The transcript of TabZIP6 *was strongly induced by cold treatment (4°C). TabZIP6 is a nuclear-localized protein with transcriptional activation activity. Arabidopsis plants overexpressing *TabZIP6 *showed decreased tolerance to freezing stress. Microarray as well as quantitative real-time PCR (qRT-PCR) analysis showed that CBFs and some key COR genes, including COR47 and COR15B, were down-regulated by cold treatment in *TabZIP6-overexpressing Arabidopsis lines. TabZIP6 was capable of binding to the G-box motif and the CBF1 and CBF3 *promoters in yeast cells. A yeast two-hybrid assay revealed that TabZIP6, as well as the other two Group S bZIP proteins involved in cold stress tolerance in wheat, Wlip19 and TaOBF1, can form homodimers by themselves and heterodimers with each other. These results suggest that TabZIP6 may function negatively in the cold stress response by binding to the promoters of CBFs, and thereby decreasing the expression of downstream COR genes in TabZIP6-overexpressing Arabidopsis seedlings.

10 Pangenome analyses of the wheat pathogen Zymoseptoria tritici reveal the structural basis of a highly plastic eukaryotic genome

We constructed and analyzed the pangenome of Zymoseptoria tritici, a major pathogen of wheat that evolved host specialization by chromosomal rearrangements and gene deletions. We used single-molecule real-time sequencing and high-density genetic maps to assemble multiple genomes. We annotated the gene space based on transcriptomics data that covered the infection life cycle of each strain. Based on a total of five telomere-to-telomere genomes, we constructed a pangenome for the species and identified a core set of 9149 genes. However, an additional 6600 genes were exclusive to a subset of the isolates. The substantial accessory genome encoded on average fewer expressed genes but a larger fraction of the candidate effector genes that may interact with the host during infection. We expanded our analyses of the pangenome to a worldwide collection of 123 isolates of the same species. We confirmed that accessory genes were indeed more likely to show deletion polymorphisms and loss-of-function mutations compared to core genes.

11 2017年小麦基因编号

https://shigen.nig.ac.jp/wheat/komugi/genes/macgene/supplement2017.pdf

12 Genetic dissection of the relationships between grain yield components by genome-wide association mapping in a collection of tetraploid wheats

Increasing grain yield potential in wheat has been a major target of most breeding programs. Genetic advance has been frequently hindered by negative correlations among yield components that have been often observed in segregant populations and germplasm collections. A tetraploid wheat collection was evaluated in seven environments and genotyped with a 90K SNP assay to identify major and stable quantitative trait loci (QTL) for grain yield per spike (GYS), kernel number per spike (KNS) and thousand-kernel weight (TKW), and to analyse the genetic relationships between the yield components at QTL level. The genome-wide association analysis detected eight, eleven and ten QTL for KNS, TKW and GYS, respectively, significant in at least three environments or two environments and the mean across environments. Most of the QTL for TKW and KNS were found located in different marker intervals, indicating that they are genetically controlled independently by each other. Out of eight KNS QTL, three were associated to significant increases of GYS, while the increased grain number of five additional QTL was completely or partially compensated by decreases in grain weight, thus producing no or reduced effects on GYS. Similarly, four consistent and five suggestive TKW QTL resulted in visible increase of GYS, while seven additional QTL were associated to reduced effects in grain number and no effects on GYS. Our results showed that QTL analysis for detecting TKW or KNS alleles useful for improving grain yield potential should consider the pleiotropic effects of the QTL or the association to other QTLs.

13 Molecular marker assisted breeding and genome composition analysis of Zhengmai 7698, an elite winter wheat cultivar

Zhengmai 7698 is an elite winter wheat variety widely cultivated in the Southern regions of the Yellow-Huai River Valley of China. Here, we report the molecular markers used for breeding Zhengmai 7698 and the genome composition of this cultivar revealed using genome-wide SNPs. A total of 26 DNA markers derived from the genes controlling gluten protein quality, grain hardness, flour color, disease resistance, or pre-harvesting sprouting resistance were used during breeding. Consequently, Zhengmai 7698 had strong gluten, high grain hardness index, white flour color, and high levels of resistance to powdery mildew, stripe rust infections, and pre-harvesting sprouting. Using genome complexity reduction, 28,996 high-quality SNPs distributed on 21 wheat chromosomes were identified among Zhengmai 7698 and its three parental lines (4B269, Zhengmai 9405 and Zhoumai 16). Zhengmai 7698 shared 12,776, 14,411 and 16,085 SNPs with 4B269, Zhengmai 9405 and Zhoumai 16, respectively. Thus, the contributions of 4B269, Zhengmai 9405 and Zhoumai 16 to the genome of Zhengmai 7698 were comparable. Interestingly, Zhengmai 7698 had 307 unique SNPs that are absent in all three parents. We suggest that molecular markers facilitate selection of a wheat cultivar with multiple elite traits. Analysis of genome composition with SNPs may provide useful clues for further dissecting the genetic basis of improved wheat performance.

14 Characterization of a new Pm2 allele associated with broad-spectrum powdery mildew resistance in wheat line Subtil

Wheat powdery mildew is a severe disease affecting yield and quality. Host resistance was proved to be effective and environment-friendly. Wheat line Subtil is an elite germplasm resource resistant to 28 of 30 tested Bgt isolates. Genetic analysis showed that the powdery mildew resistance in Subtil was conferred by a single dominant gene, temporarily designated PmSub. Using bulked segregant analysis, PmSub was mapped to chromosome arm 5DS, and flanked by the markers Bwm16 and Cfd81/Bwm21 at 5.0 and 0.9 cM, respectively. Allelism tests further confirmed PmSub was allelic with documented Pm2 alleles. Then, homologous sequences of Pm2a related sequence was cloned from Subtil and Chinese Spring. It was completely identical to the reported Pm2a sequence, but significantly different from that of Chinese Spring. A marker SWGI067 was developed based on the sequence divergence of homologous sequence in Subtil and Chinese Spring. SWGI067 was closely linked to PmSub, indicating that the gene PmSub itself was different from the cloned Pm2a related sequence. Meanwhile, Subtil produced significantly different reaction pattern compared with other genotypes with Pm genes at or near Pm2 locus. Therefore, PmSub was most likely a new allele of Pm2. PmSub has opportunities for marker-assisted selecting for high-efficiency wheat improvement.

15 Discovery of Consistent QTLs of Wheat Spike-Related Traits under Nitrogen Treatment at Different Development Stages

Spike-related traits such as spike length (Sl), fertile spikelet number (Fsn), sterile spikelet number (Ssn), grain number per spike (Gns), and thousand-kernel weight (Tkw) are important factors influencing wheat yield. However, reliably stable markers that can be used for molecular breeding in different environments have not yet been identified. In this study, a double haploid (DH) population was used for quantitative trait locus (QTL) mapping of five spike-related traits under four different nitrogen (N) supply dates in two locations and years. Seventy additive QTLs with phenotypic variation ranging from 4.12 to 34.74% and 10 major epistatic QTLs were identified. Eight important chromosomal regions on five chromosomes (1B, 2B, 2D, 5D, and 6A) were found. Sixteen stable QTLs were detected for which N application had little effect. Among those stable QTLs, QSl.sdau-2D-1, and QSl.sdau-2D-2, with phenotypic variation explained (PVE) of 10.4 and 24.2%, respectively, were flanked by markers Xwmc112 and Xcfd53 in the same order. The QTLs QSsn.sdau-2B-1, QFsn.sdau-2B-1, and QGns.sdau-2B, with PVE ranging from 4.37 to 28.43%, collocated in the Xwmc179-Xbarc373 marker interval. The consistent kernel wheat QTL (QTkw.sdau-6A) on the long arm of chromosome 6A, flanked by SSR markers Xbarc1055 and Xwmc553, showed PVE of 5.87–15.18%. Among these stable QTLs, the two flanking markers Xwmc112 and Xcfd53 have been validated using different varieties and populations for selecting Sl. Therefore, these results will be of great value for marker-assisted selection (MAS) in breeding programs and will accelerate the understanding of the genetic relationships among spike-related traits at the molecular level.

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