TaFDL2‐1A confers drought stress tolerance by promoting ABA biosynthesis, ABA responses, and ROS scavenging in transgenic wheat

• Published in: The Plant journal : for cell and molecular biology 2022-11, Vol.112 (3), p.722-737
• Main Authors: Wang, Bingxin, Li, Liqun, Liu, Mingliu, Peng, De, Wei, Aosong, Hou, Beiyuan, Lei, Yanhong, Li, Xuejun
• Format: Article
• Language: English
• Subjects: ABA biosynthesis; ABA response; Abscisic acid; Acid resistance; Biosynthesis; Cultivars; Drought; Drought resistance; drought tolerance; Gene regulation; Genetic analysis; Hypersensitivity; Plant breeding; Reactive oxygen species; Resistance factors; ROS scavenging; Scavenging; Stomata; TaFDL2‐1A; Transcription factors; Transgenic plants; transgenic wheat; Triticum aestivum; Wheat
• ISSN: 0960-7412; 1365-313X
• DOI: 10.1111/tpj.15975

SUMMARY Plants have developed various protective mechanisms to survive drought stress. Previously, it was shown that a wheat bZIP transcription factor gene TaFD‐Like2‐1A (TaFDL2‐1A) can confer drought tolerance in Arabidopsis. However, the biological functions related to drought stress tolerance of TaFDL2‐1A in wheat (Triticum aestivum L.) remain unclear. In the present study, overexpression of TaFDL2‐1A in the wheat cultivar Fielder improved drought resistance and conferred abscisic acid (ABA) hypersensitivity. Further analysis showed that overexpression of TaFDL2‐1A increased the hypersensitivity of stomata to drought stress and endogenous ABA content under drought conditions. Genetic analysis and transcriptional regulation analysis indicated that TaFDL2‐1A binds directly to the promoter fragments of TaRAB21s and TaNCED2s via ACGT core cis‐elements, thereby activating their expression, leading to enhanced ABA responses and endogenous ABA accumulation. In addition, our results demonstrate that overexpression of TaFDL2‐1A results in higher SOD and GPX activities in wheat under drought conditions by promoting the expression of TaSOD1 and TaGPx1‐D, indicating enhanced reactive oxygen species (ROS) scavenging. These results imply that TaFDL2‐1A positively regulates ABA biosynthesis, ABA responses, and ROS scavenging to improve drought stress tolerance in transgenic wheat. Our findings improve our understanding of the mechanisms that allow the wheat bZIP transcription factor to improve drought resistance and provide a useful reference gene for breeding programs to enhance drought resistance. Significance Statement TaFDL2‐1A promotes abscisic acid biosynthesis by targeting three TaNCED2 homologs and increases the antioxidant capacity by enhancing TaSOD1 and TaGPx1‐D expression, thereby increasing drought resistance in transgenic wheat (Triticum aestivum L.).