TaNF-YA7-5B, a gene encoding nuclear factor Y (NF–Y) subunit A in Triticum aestivum, confers plant tolerance to PEG-inducing dehydration simulating drought through modulating osmotic stress-associated physiological processes

Abstract

Members of nuclear factor-Y (NF–Y) transcription factors play important roles in regulating physiological processes associated with abiotic stress responses. In this study, we characterized TaNF-YA7-5B, a gene encoding wheat NY-YA subunit, in mediating plant adaptation to PEG-inducing dehydration stress. TaNF-YA7-5B shares high similarities to its homologs across various plant species. The TaNF-YA7-5B protein is specified by its conserved domains as plant NF-YA members and targets onto nucleus after endoplasmic reticulum assortment. Yeast two-hybrid assays indicated that TaNF-YA7-5B interacts with TaNF-YB2 and TaNF-YC7, two members of NF-YB and NF-YC subfamilies, suggesting a heterotrimer constituted by TaNF-YA7-5B and above NF-YB and -YC partners. TaNF-YA7-5B displayed induced expression upon drought and whose PEG-inducing dehydration-elevated transcripts were restored under normal recovery condition, suggesting its involvement in plant PEG-inducing dehydration response through modifying transcription efficiency. Overexpressing TaNF-YA7-5B conferred plant improved growth under PEG-inducing dehydration, which was ascribed largely to the gene function in regulating stomata closing and leaf water retention, osmolyte biosynthesis, and cellular ROS homeostasis. The expression of P5CS gene TaP5CS2 and antioxidant enzyme (AE) genes, namely, TaSOD3, TaCAT1, and TaPOD4, was upregulated and downregulated in lines with overexpression and knockdown of TaNF-YA7-5B, respectively; transgene analysis on them validated their functions in positively regulating proline accumulation and ROS scavenging under PEG-inducing dehydration. RNA-seq analysis revealed modified transcription of numerous genes underlying TaNF-YA7-5B enriched by GO terms ‘biological process’, ‘cellular components’, and ‘molecular function’. Therefore, TaNF-YA7-5B is a crucial regulator for plant drought adaptation through comprehensively integrating diverse physiological processes associated with drought acclimation.