Cloning and expression analysis of the SAURX gene in Gossypium hirsutum

Abstract

[ Objective ] Small auxin up RNAs ( SAURs ), which belong to a kind of auxin early response gene , play an key role in plant cell elongation. This study aims to clone fiber development-related SAUR genes , study their expression pattern and biological function. There is of great significance for exploring the mechanism of fiber development. [ Methods ] A gene encoding SAUR protein was cloned from Gossypi- um hirsutum , and was named GhSAURX . Expression pattern , subcellular localization , phenotypic identi- fication of the transgenic Arabidopsis , and expression of auxin-related genes were performed. [ Results ] Phylogenetic analysis revealed that GhSAURX had close relationship with SAUR76 , SAUR77 , and SAUR78 in Arabidopsis , and was belonged to the SAUR76 subfamily. qRT-PCR showed that the highest expression level of GhSAURX was observed in fiber of 15 , 18 and 21 DPA , when fiber was elongating fast. Meanwhile , GhSAURX showed much higher expression level in varieties with long fiber than that in varieties with short fiber. Analysis of subcellular localization indicated that GhSAURX was distributed in cytoplasm and nucleus. Overexpression of GhSAURX promoted the elongation of the primary roots and hypocotyls under dark condition in Arabidopsis , and enhanced the expression of auxin-related genes , such as YUCCA6 , ARF7 , and PIN4 . [ Conclusion ] Our results indicated that GhSAURX functions in the cell elongation mediated by auxin.

Keywords

• gossypium hirsutum
• auxin
• saur
• cell elongation
• expression analysis