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Sucrose non-fermenting 1-related protein kinase 2 (SnRK2) is a plant-specific serine/threonine kinase involved in response to adverse environmental stimuli. Previous studies showed that TaSnRK2.4 was involved in response to abiotic stresses and conferred enhanced tolerance to multiple stresses in Arabidopsis. Further experiments were performed to decipher the underlying mechanisms and discover new functions. The genomic sequences of TaSnRK2.4s locating on chromosome 3A, 3B and 3D were obtained. Sequencing identified one and 13 variations of TaSnRK2.4–3A and TaSnRK2.4-3B, respectively, but no variation was detected in TaSnRK2.4-3D. The markers 2.4AM1, 2.4BM1 and 2.4BM2 were developed based on three variations. Association analysis showed that both TaSnRK2.4-3A and TaSnRK2.4-3B were significantly associated with thousand-kernel weight (TKW), and that SNP3A-T and SNP3B-C were favorable alleles for higher TKW. Yeast two-hybrid and split luciferase assays showed that TaSnRK2.4 physically interacted with abiotic stress responsive protein TaLTP3, suggesting that TaSnRK2.4 enhanced abiotic stress tolerance by activating TaLTP3. Our studies suggested that TaSnRK2.4 have potential in improving TKW and response to abiotic stress.

Fructans are major nonstructural carbohydrates in wheat (Triticum aestivum L.). Fructan 1-fructosyltransferase (1-FFT) is the key enzyme in fructan biosynthesis. In the present study, 96 sequence variants were detected in the 1-FFT-A1 gene among 26 wheat accessions including UR208, and 15 of them result in amino acid substitutions, forming four haplotypes. Two markers M39 and M2164 were developed based on the InDel21-39 and SNP-2164 polymorphisms to distinguish the three haplotypes in the 1-FFT-A1. 1-FFT-A1 was located on chromosome 4A using marker M2164 and was flanked by markers Xcwm27 and 6-SFT-A1. By association analysis using a natural wheat population consisted of 154 accessions, the results showed that the two markers were significantly associated with water-soluble carbohydrate (WSC) content in the lower internode stem and total stem at the early and middle grain filling stages, 1000-grain weight (TGW) at different grain filling stages and peduncle length (PLE). Comparison of the effects of three haplotypes on agronomic traits indicated that TGW, PLE and total number of spikelets per spike (TNSS) were significantly influenced by haplotypes. HapIII showed a significant positive effect on TGW, PLE and TNSS.

Summary TaTEF-7A is a functional regulatory factor gene for grain number and other traits, and its diagnostic markers could be used in marker-assisted selection to improve yield potential in wheat., In this study, TaTEF-7A, a member of the transcript elongation factor gene family, and its flanking sequences were isolated. TaTEF-7A was located on chromosome 7A and was flanked by markers Xwmc83 and XP3156.3. Subcellular localization revealed that TaTEF-7A protein was localized in the nucleus. This gene was expressed in all organs, but the highest expression occurred in young spikes and developing seeds. Overexpression of TaTEF-7A in Arabidopsis thaliana produced pleiotropic effects on vegetative and reproductive development that enhanced grain length, silique number, and silique length. No diversity was found in the coding region of TaTEF-7A, but 16 single nucleotide polymorphisms and Indels were detected in the promoter regions of different cultivars. Markers based on sequence variations in the promoter regions (InDel-629 and InDel-604) were developed, and three haplotypes were identified based on those markers. Haplotype–trait association analysis of the Chinese wheat mini core collection revealed that TaTEF-7A was significantly associated with grain number per spike. Phenotyping of near-isogenic lines (NILs) confirmed that TaTEF-7A increases potential grain yield and yield-related traits. Frequency changes in favoured haplotypes gradually increased in cultivars released in China from the 1940s. Geographic distributions of favoured haplotypes were characterized in six major wheat production regions worldwide. The presence of Hap-7A-3, the favoured haplotype, showed a positive correlation with yield in a global set of breeding lines. These results suggest that TaTEF-7A is a functional regulatory factor for grain number per spike and provide a basis for marker-assisted selection.