The CC-NB-LRR protein BSR1 from Brachypodium confers resistance to Barley stripe mosaic virus in gramineous plants by recognising TGB1 movement protein.

Although some nucleotide binding, leucine-rich repeat immune receptor (NLR) proteins conferring resistance to specific viruses have been identified in dicot plants, NLR proteins involved in viral resistance have not been described in monocots. We have used map-based cloning to isolate the CC-NB-LRR (CNL) Barley stripe mosaic virus (BSMV) resistance gene barley stripe resistance 1 (BSR1) from Brachypodium distachyon Bd3-1 inbred line. Stable BSR1 transgenic Brachypodium line Bd21-3, barley (Golden Promise) and wheat (Kenong 199) plants developed resistance against BSMV ND18 strain. Allelic variation analyses indicated that BSR1 is present in several Brachypodium accessions collected from countries in the Middle East. Protein domain swaps revealed that the intact LRR domain and the C-terminus of BSR1 are required for resistance. BSR1 interacts with the BSMV ND18 TGB1 protein in planta and shows temperature-sensitive antiviral resistance. The R390 and T392 residues of TGB1ND (ND18 strain) and the G196 and K197 residues within the BSR1 P-loop motif are key amino acids required for immune activation. BSR1 is the first cloned virus resistance gene encoding a typical CNL protein in monocots, highlighting the utility of the Brachypodium model for isolation and analysis of agronomically important genes for crop improvement.

Sequence-based mapping identifies a candidate transcription repressor underlying awn suppression at the B1 locus in wheat.

Awns are stiff, hair-like structures which grow from the lemmas of wheat (Triticum aestivum) and other grasses that contribute to photosynthesis and play a role in seed dispersal. Variation in awn length in domesticated wheat is controlled primarily by three major genes, most commonly the dominant awn suppressor Tipped1 (B1). This study identifies a transcription repressor responsible for awn inhibition at the B1 locus. Association mapping was combined with analysis in biparental populations to delimit B1 to a distal region of 5AL colocalized with QTL for number of spikelets per spike, kernel weight, kernel length, and test weight. Fine-mapping located B1 to a region containing only two predicted genes, including C2H2 zinc finger transcriptional repressor TraesCS5A02G542800 upregulated in developing spikes of awnless individuals. Deletions encompassing this candidate gene were present in awned mutants of an awnless wheat. Sequence polymorphisms in the B1 coding region were not observed in diverse wheat germplasm whereas a nearby polymorphism was highly predictive of awn suppression. Transcriptional repression by B1 is the major determinant of awn suppression in global wheat germplasm. It is associated with increased number of spikelets per spike and decreased kernel size.

FLOWERING LOCUS T2 regulates spike development and fertility in temperate cereals.

FLOWERING LOCUS T2 (FT2) is the closest paralog of the FT1 flowering gene in the temperate grasses. Here we show that overexpression of FT2 in Brachypodium distachyon and barley results in precocious flowering and reduced spikelet number, while down-regulation by RNA interference results in delayed flowering and a reduced percentage of filled florets. Similarly, truncation mutations of FT2 homeologs in tetraploid wheat delayed flowering (2-4 d) and reduced fertility. The wheat ft2 mutants also showed a significant increase in the number of spikelets per spike, with a longer spike development period potentially contributing to the delayed heading time. In the wheat leaves, FT2 was expressed later than FT1, suggesting a relatively smaller role for FT2 in the initiation of the reproductive phase. FT2 transcripts were detected in the shoot apical meristem and increased during early spike development. Transversal sections of the developing spike showed the highest FT2 transcript levels in the distal part, where new spikelets are formed. Our results suggest that, in wheat, FT2 plays an important role in spike development and fertility and a limited role in the timing of the transition between the vegetative and reproductive shoot apical meristem.

The anther-specific CYP704B is potentially responsible for MSG26 male sterility in barley.

KEY MESSAGE: Plant male sterility is a valuable trait in breeding and hybrid seed production. The barley male-sterility gene msg26 was mapped to a 0.02-cM region that anchors to a 506-kb low-quality assembly between two cleaved amplified polymorphic sequence (CAPS) markers, SP1M14 and SP1M49. The barley gene HORVU4Hr1G074840, which encodes a putative cytochrome P450 CYP704B protein, appears to be a strong candidate for the MSG26 trait. Barley (Hordeum vulgare L.) is an important cereal crop worldwide. Traditional breeding in barley is time-consuming and labor-intensive. The use of male-sterile genotypes may significantly improve the efficacy of hybrid breeding and seed production. The barley accession 'GSHO745' is a spontaneous male-sterile mutant from the barley variety, 'Unitan'. The male sterility in 'GSHO745' is controlled by the recessive gene, msg26 (originally named as ms-u). We revealed that the barley plants homozygous for msg26 proceeded normally through Meiosis II until the tetrad stage, but became fully defective in the late uninucleate microspores and developed pollen-less anthers. Using seven barley F2 populations, we mapped MSG26 to a 0.02-cM region that anchored to a 506-kb low-quality assembly between two cleaved amplified polymorphic sequence markers, SP1M14 and SP1M49. The HORVU4Hr1G074840 gene that encodes a putative cytochrome P450 protein (CYP704B) was identified as the most plausible candidate for MSG26. First, HORVU4Hr1G074840 is located in a collinear region of the rice CYP704B2 and the maize CYP704B1. Both of these genes are essential for male gamete production. Second, the male-sterile allele of HORVU4Hr1G074840 in GSHO745 contained a 4-bp deletion in the last exon. The resulting frame shift causes a Gly436Gln substitution, scrambles the sequence of the remainder of the protein, and forms a new termination site at the 70th triplet of the shifted reading frame. We thus called the variant protein CYP704B:p.G436Qfs*70. Third, the barley HORVU4Hr1G074840 gene was specifically expressed in anthers. Altogether, HORVU4Hr1G074840 represents a strong candidate for MSG26 in barley.

Wheat Stripe Rust Resistance Protein WKS1 Reduces the Ability of the Thylakoid-Associated Ascorbate Peroxidase to Detoxify Reactive Oxygen Species.

Stripe rust is a devastating fungal disease of wheat caused by Puccinia striiformis f. sp tritici (Pst). The WHEAT KINASE START1 (WKS1) resistance gene has an unusual combination of serine/threonine kinase and START lipid binding domains and confers partial resistance to Pst. Here, we show that wheat (Triticum aestivum) plants transformed with the complete WKS1 (variant WKS1.1) are resistant to Pst, whereas those transformed with an alternative splice variant with a truncated START domain (WKS1.2) are susceptible. WKS1.1 and WKS1.2 preferentially bind to the same lipids (phosphatidic acid and phosphatidylinositol phosphates) but differ in their protein-protein interactions. WKS1.1 is targeted to the chloroplast where it phosphorylates the thylakoid-associated ascorbate peroxidase (tAPX) and reduces its ability to detoxify peroxides. Increased expression of WKS1.1 in transgenic wheat accelerates leaf senescence in the absence of Pst. Based on these results, we propose that the phosphorylation of tAPX by WKS1.1 reduces the ability of the cells to detoxify reactive oxygen species and contributes to cell death. This response takes several days longer than typical hypersensitive cell death responses, thus allowing the limited pathogen growth and restricted sporulation that is characteristic of the WKS1 partial resistance response to Pst.

Remapping of the stripe rust resistance gene Yr10 in common wheat.

KEY MESSAGE: Yr10 is an important gene to control wheat stripe rust, and the search for Yr10 needs to be continued. Wheat stripe rust or yellow rust is a devastating fungal disease caused by Puccinia striiformis f. sp. tritici (Pst). Host disease resistance offers a primary source for controlling wheat stripe rust. The stripe rust resistance gene Yr10 confers the race-specific resistance to most tested Pst races in China including CYR29. Early studies proposed that Yr10 was a nucleotide-binding site, leucine-rich repeat gene archived as GenBank accession AF149112 (hereafter designated the Yr10 candidate gene or Yr10 CG ). In this study, we revealed that 15 Chinese wheat cultivars positive for Yr10 CG are susceptible to CYR29. We then expressed the Yr10 CG cDNA in the common wheat 'Bobwhite'. The Yr10 CG -cDNA positive transgenic plants were also susceptible to CYR29. Thus, it is highly unlikely that Yr10 CG corresponds to the Yr10 resistance gene. Using the Yr10 donor 'Moro' and the Pst-susceptible wheat 'Huixianhong', we generated two F3 populations that displayed a single Mendelian segregation on the Yr10 gene, and used them to remap the Yr10 gene. Six markers were placed in the Yr10 region, with the Yr10 CG gene now mapping about 1.2-cM proximal to the Yr10 locus and the Xsdauw79 marker is completely linked to the Yr10 locus. Apparently, the Yr10 gene has not yet been identified. Fine mapping and positional cloning of Yr10 is important for gene pyramiding for stripe rust resistance in wheat.

Regulation of FLOWERING LOCUS T by a microRNA in Brachypodium distachyon.

The highly conserved florigen gene FLOWERING LOCUS T (FT) functions at the core of the flowering pathways. Extensive studies have examined the transcriptional regulation of FT; however, other layers of FT regulation remain unclear. Here, we identified miR5200 a Pooideae-specific microRNA that is expressed in leaves and targets Brachypodium distachyon FT orthologs for mRNA cleavage. miR5200 was abundantly expressed in plants grown under short-day (SD) conditions but was dramatically repressed in plants transferred to long-day (LD) conditions. We also found that the epigenetic chromatin status, specifically the levels of histone methylation marks, at miR5200 precursor loci changed in response to daylength. Moreover, artificial interruption of miR5200 activity by target mimicry in B. distachyon altered flowering time in SD but not in LD conditions, suggesting that miR5200 functions in photoperiod-mediated flowering time regulation. Together, these findings illustrate a posttranscriptional regulation mechanism of FT and provide insights into understanding of the multiple concerted pathways for flowering time control in plants.

Fine mapping of barley locus Rps6 conferring resistance to wheat stripe rust.

KEY MESSAGE: Barley resistance to wheat stripe rust has remained effective for a long time and, therefore, the genes underlying this resistance can be a valuable tool to engineer durable resistance in wheat. Wheat stripe rust, caused by Puccinia striiformis f. sp. tritici (Pst), is a major disease of wheat that is causing large economic losses in many wheat-growing regions of the world. Deployment of Pst resistance genes has been an effective strategy for controlling this pathogen, but many of these genes have been defeated by new Pst races. In contrast, genes providing resistance to this wheat pathogen in other grass species (nonhost resistance) have been more durable. Barley varieties (Hordeum vulgare ssp. vulgare) are predominately immune to wheat Pst, but we identified three accessions of wild barley (Hordeum vulgare ssp. spontaneum) that are susceptible to Pst. Using these accessions, we mapped a barley locus conferring resistance to Pst on the distal region of chromosome arm 7HL and designated it as Rps6. The detection of the same locus in the cultivated barley 'Tamalpais' and in the Chinese barley 'Y12' by an allelism test suggests that Rps6 may be a frequent component of barley intermediate host resistance to Pst. Using a high-density mapping population (>10,000 gametes) we precisely mapped Rps6 within a 0.14 cM region (~500 kb contig) that is colinear to regions in Brachypodium (<94 kb) and rice (<9 kb). Since no strong candidate gene was identified in these colinear regions, a dedicated positional cloning effort in barley will be required to identify Rps6. The identification of this and other barley genes conferring resistance to Pst can contribute to our understanding of the mechanisms for durable resistance against this devastating wheat pathogen.

Comparative analysis of protein-protein interactions in the defense response of rice and wheat.

BACKGROUND: Despite the importance of wheat as a major staple crop and the negative impact of diseases on its production worldwide, the genetic mechanisms and gene interactions involved in the resistance response in wheat are still poorly understood. The complete sequence of the rice genome has provided an extremely useful parallel road map for genetic and genomics studies in wheat. The recent construction of a defense response interactome in rice has the potential to further enhance the translation of advances in rice to wheat and other grasses. The objective of this study was to determine the degree of conservation in the protein-protein interactions in the rice and wheat defense response interactomes. As entry points we selected proteins that serve as key regulators of the rice defense response: the RAR1/SGT1/HSP90 protein complex, NPR1, XA21, and XB12 (XA21 interacting protein 12). RESULTS: Using available wheat sequence databases and phylogenetic analyses we identified and cloned the wheat orthologs of these four rice proteins, including recently duplicated paralogs, and their known direct interactors and tested 86 binary protein interactions using yeast-two-hybrid (Y2H) assays. All interactions between wheat proteins were further tested using in planta bimolecular fluorescence complementation (BiFC). Eighty three percent of the known rice interactions were confirmed when wheat proteins were tested with rice interactors and 76% were confirmed using wheat protein pairs. All interactions in the RAR1/SGT1/ HSP90, NPR1 and XB12 nodes were confirmed for the identified orthologous wheat proteins, whereas only forty four percent of the interactions were confirmed in the interactome node centered on XA21. We hypothesize that this reduction may be associated with a different sub-functionalization history of the multiple duplications that occurred in this gene family after the divergence of the wheat and rice lineages. CONCLUSIONS: The observed high conservation of interactions between proteins that serve as key regulators of the rice defense response suggests that the existing rice interactome can be used to predict interactions in wheat. Such predictions are less reliable for nodes that have undergone a different history of duplications and sub-functionalization in the two lineages.

Sequencing trait-associated mutations to clone wheat rust-resistance gene YrNAM.

Stripe (yellow) rust, caused by Puccinia striiformis f. sp. tritici (Pst), can significantly affect wheat production. Cloning resistance genes is critical for efficient and effective breeding of stripe rust resistant wheat cultivars. One resistance gene (Yr10CG) underlying the Pst resistance locus Yr10 has been cloned. However, following haplotype and linkage analyses indicate the presence of additional Pst resistance gene(s) underlying/near Yr10 locus. Here, we report the cloning of the Pst resistance gene YrNAM in this region using the method of sequencing trait-associated mutations (STAM). YrNAM encodes a non-canonical resistance protein with a NAM domain and a ZnF-BED domain. We show that both domains are required for resistance. Transgenic wheat harboring YrNAM gene driven by its endogenous promoter confers resistance to stripe rust races CYR32 and CYR33. YrNAM is an ancient gene and present in wild wheat species Aegilops longissima and Ae. sharonensis; however, it is absent in most wheat cultivars, which indicates its breeding value.

ZmMS1/ZmLBD30-orchestrated transcriptional regulatory networks precisely control pollen exine development.

Because of its significance for plant male fertility and, hence, direct impact on crop yield, pollen exine development has inspired decades of scientific inquiry. However, the molecular mechanism underlying exine formation and thickness remains elusive. In this study, we identified that a previously unrecognized repressor, ZmMS1/ZmLBD30, controls proper pollen exine development in maize. Using an ms1 mutant with aberrantly thickened exine, we cloned a male-sterility gene, ZmMs1, which encodes a tapetum-specific lateral organ boundary domain transcription factor, ZmLBD30. We showed that ZmMs1/ZmLBD30 is initially turned on by a transcriptional activation cascade of ZmbHLH51-ZmMYB84-ZmMS7, and then it serves as a repressor to shut down this cascade via feedback repression to ensure timely tapetal degeneration and proper level of exine. This activation-feedback repression loop regulating male fertility is conserved in maize and sorghum, and similar regulatory mechanism may also exist in other flowering plants such as rice and Arabidopsis. Collectively, these findings reveal a novel regulatory mechanism of pollen exine development by which a long-sought master repressor of upstream activators prevents excessive exine formation.

Role of reactive oxygen species in lesion mimic formation and conferred basal resistance to Fusarium graminearum in barley lesion mimic mutant 5386.

This study investigated the barley lesion mimic mutant (LMM) 5386, evidenced by a leaf brown spot phenotype localized on the chromosome 3H, and its conferred basal resistance to Fusarium graminearum. RNA-seq analysis identified 1453 genes that were differentially expressed in LMM 5386 compared to those in the wild type. GO and KEGG functional annotations suggested that lesion mimic formation was mediated by pathways involving oxidation reduction and glutathione metabolism. Additionally, reactive oxygen species (ROS) accumulation in brown spots was substantially higher in LMM 5386 than in the wild-type plant; therefore, antioxidant competence, which is indicated by ROS accumulation, was significantly lower in LMM 5386. Furthermore, the reduction of glycine in LMM 5386 inhibited glutathione biosynthesis. These results suggest that the decrease in antioxidant competence and glutathione biosynthesis caused considerable ROS accumulation, leading to programmed cell death, which eventually reduced the yield components in LMM 5386.

Overexpression of isochorismate synthase enhances salt tolerance in barley.

Isochorismate synthase (ICS) is a key enzyme for the synthesis of salicylic acid (SA) in plants. SA plays an important role in the response of plants to abiotic stress. In this study, transgenic barley was constructed to evaluate the function of ICS under salt stress. ICSOE lines showed obvious salt stress tolerance, this results from the increased outward Na+ flux and inward K+ flux in roots, thereby maintaining a lower cytosolic Na+/K+ ratio under salt stress. Overexprssion of ICS also improved Na+ sequestration in shoots under salt stress. In addition, ICSOE lines displayed less accumulation of reactive oxygen species and oxidative damage, accompanied by higher activity of antioxidant enzymes. The improved Na+/K+ ratio, Na+ sequestration, and antioxidative competence play an important role in the enhanced salt tolerance of ICSOE lines. These findings help to elucidate the abiotic stress resistance of the ICS pathway in barley.

Overexpression of isochorismate synthase enhances drought tolerance in barley.

Isochorismate synthase (ICS) is a key enzyme for the synthesis of salicylic acid (SA) in plants. SA mediates plant responses to both biotic and abiotic stresses. In previous studies, we found that overexpression of ICS (ICSOE) or suppression of ICS (ICSRNAi) affected the host response to Fusarium graminearum in barley. However, whether the barley ICS gene plays a role in adapting to abiotic stresses remains to be determined. In the present study, expression of the ICS gene was upregulated when treated with 20 % PEG6000, and ICSOE lines were more drought tolerant than wild type (WT) and ICSRNAi. In addition, the abscisic acid (ABA) levels in the ICSOE lines were higher than those in the WT and ICSRNAi lines under drought stress. High ABA levels significantly reduced Gs and E, which may impact water retention under drought stress. Under drought conditions, the activity of antioxidant enzymes was significantly higher in the ICSOE lines, correlating with a lower levels of reactive oxygen species (ROS) and malondialdehyde (MDA). Enhanced antioxidant competence also contributed to drought tolerance in ICSOE lines. These findings help elucidate the abiotic stress resistance of the ICS pathway in barley.

The CArG-box located upstream from the transcriptional start of wheat vernalization gene VRN1 is not necessary for the vernalization response.

In diploid wheat (Triticum monococcum), and likely in other Triticeae species, the VRN1 gene is essential for the initiation of the reproductive phase, and therefore, a detailed characterization of its regulatory regions is required to understand this process. A CArG-box (MADS-box-binding site) identified in the VRN1 promoter upstream from the transcription initiation site has been proposed as a critical regulatory element for the vernalization response. This hypothesis was supported by the genetic linkage between CArG-box natural deletions and dominant Vrn1 alleles for spring growth habit and by physical interactions with VRT2, a MADS-box protein proposed as a putative flowering repressor regulated by vernalization. Here, we describe a T. monococcum accession with a strong vernalization requirement and a 48-bp deletion encompassing the CArG-box in the VRN1 promoter. Genetic analyses of 2 segregating populations confirmed that this VRN1 allele is completely linked with a strong winter growth habit (vrn-A(m)1b). Transcript levels of the VRN1 allele with the 48-bp deletion were very low in unvernalized plants and increased during vernalization to levels similar to those detected in other wild-type vrn-A(m)1 alleles. Taken together, these results indicate that the CArG-box found upstream of the VRN1 transcription initiation site is not essential for the vernalization response.

The involvement of cytokinin and nitrogen metabolism in delayed flag leaf senescence in a wheat stay-green mutant, tasg1.

In the present study on a wheat stay-green mutant, tasg1, we found that its delayed senescence at the late filling stage was related to the high cytokinin (CK) and N contents. RNA sequencing suggested that several genes may be responsible for the different senescence processes between wild-type (WT) and tasg1 plants. WT and tasg1 seedlings were treated with NH4NO3, lovastatin, and 6-benzylaminopurine (BAP), and the results suggested that the feedback of CK with N content regulated the leaf senescence in the tasg1 plants. Furthermore, a knock-out of the candidate gene cisZOGT1 (catalytic O-glucosylation in cis-zeatin) in the wheat mutant pool 'Kronos' exhibited delayed senescence at the late grain filling stage. Overall, our results suggested the cisZOGT1 gene has an important role in regulating wheat leaf senescence by regulating CK and N metabolism. At the same time, CK and N metabolism involved in delayed flag leaf senescence of tasg1 may be by a feedback pattern.

An ancestral NB-LRR with duplicated 3'UTRs confers stripe rust resistance in wheat and barley.

Wheat stripe rust, caused by Puccinia striiformis f. sp. tritici (Pst), is a global threat to wheat production. Aegilops tauschii, one of the wheat progenitors, carries the YrAS2388 locus for resistance to Pst on chromosome 4DS. We reveal that YrAS2388 encodes a typical nucleotide oligomerization domain-like receptor (NLR). The Pst-resistant allele YrAS2388R has duplicated 3' untranslated regions and is characterized by alternative splicing in the nucleotide-binding domain. Mutation of the YrAS2388R allele disrupts its resistance to Pst in synthetic hexaploid wheat; transgenic plants with YrAS2388R show resistance to eleven Pst races in common wheat and one race of P. striiformis f. sp. hordei in barley. The YrAS2388R allele occurs only in Ae. tauschii and the Ae. tauschii-derived synthetic wheat; it is absent in 100% (n = 461) of common wheat lines tested. The cloning of YrAS2388R will facilitate breeding for stripe rust resistance in wheat and other Triticeae species.

Isochorismate-based salicylic acid biosynthesis confers basal resistance to Fusarium graminearum in barley.

Salicylic acid (SA) plays an important role in signal transduction and disease resistance. In Arabidopsis, SA can be made by either of two biosynthetic branches, one involving isochorismate synthase (ICS) and the other involving phenylalanine ammonia-lyase (PAL). However, the biosynthetic pathway and the importance of SA remain largely unknown in Triticeae. Here, we cloned one ICS and seven PAL genes from barley, and studied their functions by their overexpression and suppression in that plant. Suppression of the ICS gene significantly delayed plant growth, whereas PAL genes, both overexpressed and suppressed, had no significant effect on plant growth. Similarly, suppression of ICS compromised plant resistance to Fusarium graminearum, whereas similar suppression of PAL genes had no significant effect. We then focused on transgenic plants with ICS. In a leaf-based test with F. graminearum, transgenic plants with an up-regulated ICS were comparable with wild-type control plants. By contrast, transgenic plants with a suppressed ICS lost the ability to accumulate SA during pathogen infection and were also more susceptible to Fusarium than the wild-type controls. This suggests that ICS plays a unique role in SA biosynthesis in barley, which, in turn, confers a basal resistance to F. graminearum by modulating the accumulation of H2 O2 , O2- and reactive oxygen-associated enzymatic activities. Although SA mediates systemic acquired resistance (SAR) in dicots, there was no comparable SAR response to F. graminearum in barley. This study expands our knowledge about SA biosynthesis in barley and proves that SA confers basal resistance to fungal pathogens.

Identification and evaluation of resistance to powdery mildew and yellow rust in a wheat mapping population.

Deployment of cultivars with genetic resistance is an effective approach to control the diseases of powdery mildew (PM) and yellow rust (YR). Chinese wheat cultivar XK0106 exhibits high levels of resistance to both diseases, while cultivar E07901 has partial, adult plant resistance (APR). The aim of this study was to map resistance loci derived from the two cultivars and analyze their effects against PM and YR in a range of environments. A doubled haploid population (388 lines) was used to develop a framework map consisting of 117 SSR markers, while a much higher density map using the 90K Illumina iSelect SNP array was produced with a subset of 80 randomly selected lines. Seedling resistance was characterized against a range of PM and YR isolates, while field scores in multiple environments were used to characterize APR. Composite interval mapping (CIM) of seedling PM scores identified two QTLs (QPm.haas-6A and QPm.haas-2A), the former being located at the Pm21 locus. These QTLs were also significant in field scores, as were Qpm.haas-3A and QPm.haas-5A. QYr.haas-1B-1 and QYr.haas-2A were identified in field scores of YR and were located at the Yr24/26 and Yr17 chromosomal regions respectively. A second 1B QTL, QYr.haas-1B-2 was also identified. QPm.haas-2A and QYr.haas-1B-2 are likely to be new QTLs that have not been previously identified. Effects of the QTLs were further investigated in multiple environments through the testing of selected lines predicted to contain various QTL combinations. Significant additive interactions between the PM QTLs highlighted the ability to pyramid these loci to provide higher level of resistance. Interactions between the YR QTLs gave insights into the pathogen populations in the different locations as well as showing genetic interactions between these loci.

Wheat Ms2 encodes for an orphan protein that confers male sterility in grass species.

Male sterility is a valuable trait for plant breeding and hybrid seed production. The dominant male-sterile gene Ms2 in common wheat has facilitated the release of hundreds of breeding lines and cultivars in China. Here, we describe the map-based cloning of the Ms2 gene and show that Ms2 confers male sterility in wheat, barley and Brachypodium. MS2 appears as an orphan gene within the Triticinae and expression of Ms2 in anthers is associated with insertion of a retroelement into the promoter. The cloning of Ms2 has substantial potential to assemble practical pipelines for recurrent selection and hybrid seed production in wheat.