OsABA8ox2, an ABA catabolic gene, suppresses root elongation of rice seedlings and contributes to drought response

Publication date: Available online 10 December 2019Source: The Crop JournalAuthor(s): Yan Zhang, Xiaoping Wang, Yanzhong Luo, Lan Zhang, Yuan Yao, Lu Han, Zhenhua Chen, Lei Wang, Yubin LiAbstractIn rice, OsABA8ox encodes abscisic acid (ABA) 8′-hydroxylase, which catalyzes the committed step of ABA catabolism. The contribution of ABA catabolism in root development remains unclear. We investigated the role of OsABA8ox2 in root growth and development and drought response. GUS staining results showed that OsABA8ox2 was expressed mainly in roots at seedling stage and was strongly expressed in the meristematic zone of the radicle. OsABA8ox2 expression in roots was markedly decreased after 0.5 h polyethylene glycol (PEG) treatment and increased after 0.5 h rehydration, implying that OsABA8ox2 is a drought-responsive gene. OsABA8ox2 knockout mediated by the CRISPR-Cas9 system increased drought-induced ABA and indole-3-acetic acid accumulation in roots, conferred increased ABA sensitivity, and promoted a narrower and more vertically oriented root system architecture (RSA) beneficial to drought tolerance. OsABA8ox2 overexpression suppressed root elongation and increased stomatal conductance and transpiration rate. Consequently, OsABA8ox2 knockout dramatically improved rice drought tolerance, whereas OsABA8ox2 overexpression seedlings were hypersensitive to drought stress, suggesting that OsABA8ox2 contributes to drought response in rice. Compared with wild type, functional leaves...
Source: The Crop Journal - Category: Food Science Source Type: research