Plant Stature Related receptor-like Kinanse2 (PSRK2) acts as a factor that determines stem elongation toward gibberellins response in rice

Gibberellins (GAs) are a family of plant hormones that are important to multiple aspects of plant growth and development, especially stem elongation. A <i>PSRK2</i> was obtained through screening and identifying RLK dominant negative mutants. Phenotype of the loss-of-function mutants, <i>psrk2-DN</i> and <i>psrk2-RNAi</i>, showed that <i>PSRK2</i> could influence the length of the uppermost and fourth internodes, indicating that PSRK2 might regulate cell division in the intercalary meristems and/or cell elongation in the internodes. Moreover, the expression pattern showed that <i>PSRK2</i> was strongly expressed in the joined-nodes after the start-up of reproductive growth, but undetectable in leaves. <i>PSRK2</i> expression was also found to be induced by GA₃, and PSRK2 was involved in GA signaling in cereal aleurone cells, and PSRK2 influence the relative length of the second leaf sheaths in seedling stage. These results indicate PSRK2 is a component of GA signaling pathway that controls stem elongation by negatively regulating GA responses. <b>Abbreviations</b>: <i>Os: Oryza sativa; At: Arabidopsis thaliana</i>; RNAi: RNA interfere; DN: Dominate Negative; SMART: Simple Modular Architecture Research Tool; Uni : Uniconazol; PSRK2: Plant Stature Related receptor-like Kinase 2; RLK: Receptor-like Kinase; GA: Gibberellin; IAA: indole-3-acetic acid; BL: Brassinosteroid PSRK2 could influence the length of internodes in rice, indicating that PSRK2 might regulate cell division and/or cell elongation in GA signaling pathway