An A20/AN1-type zinc finger protein modulates gibberellins and abscisic acid contents and increases sensitivity to abiotic stress in rice (Oryza sativa)

Abstract

The plant hormones gibberellins (GA) and abscisic acid (ABA) play important roles in plant development and stress responses. Here we report a novel A20/AN1-type zinc finger protein ZFP185 involved in GA and ABA signaling in the regulation of growth and stress response. ZFP185 was constitutively expressed in various rice tissues. Overexpression of ZFP185 in rice results in a semi-dwarfism phenotype, reduced cell size, and the decrease of endogenous GA3 content. By contrast, higher GA3 content was observed in RNAi plants. The application of exogenous GA3 can fully rescue the semi-dwarfism phenotype of ZFP185 overexpressing plants, suggesting the negative role of ZFP185 in GA biosynthesis. Besides GA, overexpression of ZFP185 decreased ABA content and expression of several ABA biosynthesis-related genes. Moreover, it was found that ZFP185, unlike previously known A20/AN1-type zinc finger genes, increases sensitivity to drought, cold, and salt stresses, implying the negative role of ZFP185 in stress tolerance. ZFP185 was localized in the cytoplasm and lacked transcriptional activation potential. Our study suggests that ZFP185 regulates plant growth and stress responses by affecting GA and ABA biosynthesis in rice.

Keywords: A20/AN1; abiotic stress; abscisic acid; gibberellins; semi-dwarfism..