No abstract

Summary The role of abscisic acid (ABA) receptors, PYR1/PYL/RCAR (PYLs), is well established in ABA signalling and plant drought response, but limited research has explored the regulation of wheat PYLs in this process, especially the effects of their allelic variations on drought tolerance or grain yield. Here, we found that the overexpression of a TaABFs‐regulated PYL gene, TaPYL1‐1B , exhibited higher ABA sensitivity, photosynthetic capacity and water‐use efficiency (WUE), all contributed to higher drought tolerance than that of wild‐type plants. This heightened water‐saving mechanism further increased grain yield and protected productivity during water deficit. Candidate gene association analysis revealed that a favourable allele TaPYL1‐1B In‐442 , carrying an MYB recognition site insertion in the promoter, is targeted by TaMYB70 and confers enhanced expression of TaPYL1‐1B in drought‐tolerant genotypes. More importantly, an increase in frequency of the TaPYL1‐1B In‐442 allele over decades among modern Chinese cultivars and its association with high thousand‐kernel weight together demonstrated that it was artificially selected during wheat improvement efforts. Taken together, our findings illuminate the role of TaPYL1‐1B plays in coordinating drought tolerance and grain yield. In particular, the allelic variant TaPYL1‐1B In‐442 substantially contributes to enhanced drought tolerance while maintaining high yield, and thus represents a valuable genetic target for engineering drought‐tolerant wheat germplasm.

Background Trehalose-6-phosphate phosphatases genes (TPPs) are involved in the development and stress response of plants by regulating the biosynthesis of trehalose, though little is currently known about TPPs in common wheat (Triticum aestivum L.). Results In this study, we performed a genome-wide identification of the TPP gene family in common wheat, and identified a total of 31 TaTPP genes. These were subdivided into six subfamilies based on the phylogenetic relationships and the conservation of protein in six monocot and eudicot plants. The majority of TPP genes were represented by 2–3 wheat homoalleles (named TaTPPX_ZA, TaTPPX_ZB, or TaTPPX_ZD), where Z is the location on the wheat chromosome of the gene number (X). We also analyzed the chromosomal location, exon-intron structure, orthologous genes, and protein motifs of the TaTPPs. The RNA-seq data was used to perform an expression analysis, which found 26 TaTPP genes to be differentially expressed based on spatial and temporal characteristics, indicating they have varied functions in the growth and development of wheat. Additionally, we assessed how the promoter regulatory elements were organized and used qRT-PCR in the leaves to observe how they were expressed following ABA, salt, low tempreture, and drought stress treatments. All of these genes exhibited differential expression against one or more stress treatments. Furthermore, ectopic expression of TaTPP11 in Arabidopsis exhibited a phenotype that delayed plant development but did not affect seed morphology. Conclusions TaTPPs could serve important roles in the development and stress response in wheat. These results provide a basis for subsequent research into the function of TaTPPs.

No abstract

Drought stress limits wheat production and threatens food security world-wide. While ethylene-responsive factors (ERFs) are known to regulate plant response to drought stress, the regulatory mechanisms responsible for a tolerant phenotype remain unclear.Here, we describe the positive regulatory role of TaERF87 in mediating wheat tolerance to drought stress. TaERF87 overexpression (OE) enhances drought tolerance, while silencing leads to drought sensitivity in wheat. RNA sequencing with biochemical assays revealed that TaERF87 activates the expression of the proline biosynthesis genes TaP5CS1 and TaP5CR1 via direct binding to GCC-box elements. Furthermore, proline accumulates to higher levels in TaERF87-and TaP5CS1-OE lines than that in wild-type plants under well-watered and drought stress conditions concomitantly with enhanced drought tolerance in these transgenic lines.Moreover, the interaction between TaERF87 and the bHLH transcription factor TaAKS1 synergistically enhances TaP5CS1 and TaP5CR1 transcriptional activation. TaAKS1 OE also increases wheat drought tolerance by promoting proline accumulation. Additionally, our findings verified that TaERF87 and TaAKS1 are targets of abscisic acid-responsive element binding factor 2 (TaABF2).Together, our study elucidates the mechanisms underlying a positive response to drought stress mediated by the TaABF2-TaERF87/TaAKS1-TaP5CS1/TaP5CR1 module, and identifies candidate genes for the development of elite drought-tolerant wheat varieties.