Fungal disease meets its match: Fusarium head blight (FHB), caused by a fungus, reduces wheat crop yield and introduces toxins into the harvest. From the assembly of the genome of Thinopyrum elongatum , a wild relative of wheat used in breeding programs to improve cultivated wheat, Wang et al. cloned a gene that can address both problems (see the Perspective by Wulff and Jones). The encoded glutathione S -transferase detoxifies the trichothecene toxin and, when expressed in wheat, confers resistance to FHB. Science , this issue p. eaba5435 ; see also p. 822

Background: Salt and drought are the main abiotic stresses that restrict the yield of crops. Peroxidases (PRXs) are involved in various abiotic stress responses. Furthermore, only few wheat PRXs have been characterized in the mechanism of the abiotic stress response. Results: In this study, a novel wheat peroxidase (PRX) gene named TaPRX-2A, a member of wheat class III PRX gene family, was cloned and its response to salt stress was characterized. Based on the identification and evolutionary analysis of class III PRXs in 12 plants, we proposed an evolutionary model for TaPRX-2A, suggesting that occurrence of some exon fusion events during evolution. We also detected the positive selection of PRX domain in 13 PRXs involving our evolutionary model, and found 2 or 6 positively selected sites during TaPRX-2A evolution. Quantitative reverse transcription–polymerase chain reaction (qRT–PCR) results showed that TaPRX-2A exhibited relatively higher expression levels in root tissue than those exhibited in leaf and stem tissues. TaPRX-2A expression was also induced by abiotic stresses and hormone treatments such as polyethylene glycol 6000, NaCl, hydrogen peroxide (H₂O₂), salicylic acid (SA), methyljasmonic acid (MeJA) and abscisic acid (ABA). Transgenic wheat plants with overexpression of TaPRX-2A showed higher tolerance to salt stress than wild-type (WT) plants. Confocal microscopy revealed that TaPRX-2A-eGFP was mainly localized in cell nuclei. Survival rate, relative water content, and shoot length were higher in TaPRX-2A-overexpressing wheat than in the WT wheat, whereas root length was not significantly different. The activities of superoxide dismutase (SOD), peroxidase (POD), and catalase (CAT) were enhanced in TaPRX-2A-overexpressing wheat compared with those in the WT wheat, resulting in the reduction of reactive oxygen species (ROS) accumulation and malondialdehyde (MDA) content. The expression levels of downstream stress-related genes showed that RD22, TLP4, ABAI, GST22, FeSOD, and CAT exhibited higher expressions in TaPRX-2A-overexpressing wheat than in WT under salt stress. Conclusions: The results show that TaPRX-2A plays a positive role in the response to salt stress by scavenging ROS and regulating stress-related genes.

In this study, we carried out an evolutionary, transcriptional, and functional analyses of the trihelix transcription factor family. A total of 319 trihelix members, identified from 11 land plant species, were classified into five clades. The results of phylogeny indicate the binding domains of GT1 and GT2 diverged early in the existence of land plants. Genomic localization revealed that the trihelix family members were highly conserved among cereal species, even though some homeologs generated during the tetraploidy of maize were lost. Three-dimensional structural analyses and an examination of subcellular localization of this family supported the involvement of all five clades in transcriptional regulation. Furthermore, the family members from all clades in sorghum and rice showed a broad and dynamic expression pattern in response to abiotic stresses, indicating regulatory subfunctionalization of their original functions. This finding is further supported by the phenotypes of enhanced tolerance to cold, salt, and drought in transgenic plants overexpressing Sb06g023980 and Sb06g024110. In contrast, few Arobidopsis genes showed inducible expression under abiotic stress conditions, which may indicate a functional shift. Finally, our co-expression analysis points to the involvement of this family in various metabolic processes, implying their further functional divergence.

Key message The quantitative trait loci (QTLs) for grain morphological traits were identified via nested association mapping and validated in a natural wheat population via haplotype analysis. Abstract Grain weight, one of the three most important components of crop yield, is largely determined by grain morphological traits. Dissecting the genetic bases of grain morphology could facilitate the improvement of grain weight and yield production. In this study, four wheat recombinant inbred line populations constructed by crossing the modern variety Yanzhan 1 with three semi-wild wheat varieties (i.e., Chayazheda, Yutiandaomai, and Yunnanxiaomai from Xinjiang, Tibet, and Yunnan, respectively) and one exotic accession Hussar from Great Britain were investigated for grain weight and eight morphological traits in seven environments. Eighty-eight QTLs for all measured traits were totally identified through nested association mapping utilizing 14,643 high-quality polymorphic single nucleotide polymorphism (SNP) markers generated by 90 K SNP array. Among them, 64 (72.7%) QTLs have the most favorable alleles donated by semi-wild wheat varieties. For 14 QTL clusters affecting at least two grain morphological traits, nine QTL clusters were located in similar position with known genes/QTL, and the other five were novel. Three important novel QTLs (i.e., qTGW-1B.1, qTGW-1B.2, and qTGW-1A.1) were further validated in a natural wheat population via haplotype analysis. The favorable haplotypes for these three QTLs might be used in marker-assisted selection for the improvement of wheat yield by modifying morphological traits.