title: GASA14 regulates leaf expansion and abiotic stress resistance by modulating reactive oxygen species accumulation.
abstract: Gibberellic acid (GA) can regulate many plant developmental processes. GAST1 has been identified as a GA-stimulated transcript, and Arabidopsis GAST-like genes are known to constitute the GASA family. However, the functions of most GASA genes are not clear at present. In this study, the function of GASA14, a member of the GASA family, was investigated. GASA14 expression was upregulated by GA and downregulated by the transcriptional regulators that repress GA responses, the DELLA proteins GAI and RGA. Phenotypic analysis showed that growth of the GASA14 null mutant (gasa14-1) line was retarded, and the growth of the 35S::GASA14 lines were promoted in young plants. Furthermore, seed germination of the gasa14-1 plants showed more sensitivity to paclobutrazol (an inhibitor of GA biosynthesis) than Columbia (Col) plants, suggesting that GASA14 is required for GA-dependent responses. Analysis of the responses of the gasa14-1 and 35S::GASA14 lines to abscisic acid (ABA) and salt revealed that germination and seedling establishment of gasa14-1 were poorer than those of Col plants and that the 35S::GASA14 lines were more resistant to ABA and salt. Further analysis showed that overexpression of GASA14 could suppress reactive oxygen species (ROS) accumulation. Taken together, these results demonstrated that GASA14 regulates leaf expansion and abiotic stress resistance by modulating ROS accumulation. Because GASA14 contains both GASA (GA-stimulated in Arabidopsis) and PRP (proline-rich protein) domains, the PRP domain coding sequence was overexpressed in Col plants and it was found that the growth of the transgenic plants and the responses to ABA and salt were not altered. These results thus suggest that the GASA domain is necessary for the functions of GASA14.
authors: Guangdong Key Lab of Biotechnology for Plant Development, College of Life Sciences, South China Normal University, Guangzhou 510631, Guangdong, PR China.
authors: Shulan
authors: S
authors: Sun
authors: Haoxiang
authors: H
authors: Wang
authors: Hongmei
authors: H
authors: Yu
authors: Chunmei
authors: C
authors: Zhong
authors: Xiaoxia
authors: X
authors: Zhang
authors: Jianzong
authors: J
authors: Peng
authors: Xiaojing
authors: X
authors: Wang
mesh_terms: D000040:Abscisic Acid / Q000494:pharmacology; D017360:Arabidopsis / Q000187:drug effects / Q000235:genetics / Q000254:growth & development / Q000378:metabolism*; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism*; D002462:Cell Membrane / Q000378:metabolism; D018506:Gene Expression Regulation, Plant; D018525:Germination; D005875:Gibberellins / Q000096:biosynthesis / Q000235:genetics; D006861:Hydrogen Peroxide / Q000378:metabolism; D018515:Plant Leaves / Q000187:drug effects / Q000254:growth & development* / Q000378:metabolism; D017382:Reactive Oxygen Species / Q000378:metabolism*; D055051:Salt-Tolerant Plants / Q000187:drug effects / Q000235:genetics / Q000254:growth & development; D012639:Seeds / Q000254:growth & development / Q000378:metabolism; D015398:Signal Transduction; D012965:Sodium Chloride / Q000494:pharmacology; D013312:Stress, Physiological; D014230:Triazoles / Q000494:pharmacology
chemical_list: D029681:Arabidopsis Proteins; D005875:Gibberellins; D017382:Reactive Oxygen Species; D014230:Triazoles; C093242:GASA protein, Arabidopsis; D012965:Sodium Chloride; C053370:paclobutrazol; D000040:Abscisic Acid; D006861:Hydrogen Peroxide; C007842:gibberellic acid