Expression And Regulation Of Rice OSMPK14Gene

MAPK (mitogen-activated protein kinase) is a highly conserved serine/threonine protein kinase, widely identified from yeast to plants and animals, act as an important component of MAPK cascade. It has been shown that plant MAPKs are involved in various processes, including cell division, developmental regulation, biotic and abiotic stresses, plant hormone response and so on.Previously, a rice MAPK gene named as OsMPK14was cloned from rice panicle by our lab. The gene ubiquitously express in rice leaves and roots, mainly accumulated in the mesophyll cells. In order to uncover the expression and regulation of OsMPK14in rice growth and development processes, the relationship between MAPK pathway and phytochrome-mediated light signal pathway, and abiotic stresss responses, the expression profiles of the gene in Nipponbare(Wt), phytochrome A and B mutants (phyA,phyB)rice were detected in this study.The contents of soluble sugar, soluble protein and MDA in the heading stage of three rice varieties were analyzed, the results showed that the values in phyB leaves were lower compared with that in Wt, suggesting that the rice phyB mutant might exhibit drought tolerance compared to Wt in the heading stage.By semi-quantitative RT-PCR and real time PCR, expression profile of OsMPK14in tillering (30d)、 heading (60d) and maturity (90d) stages of three rice varieties were detected. The result revealed that OsMPK14was differentially expressed in these varieties. The expression of OsMPK14was fluctuating in Wt and phyA, but the expression of OsMPK14in. phyB mutant was increased continuedly, suggesting that the rice phytochrome B might negatively regulate the expression of OsMPK14.In order to study the effect of abiotic stress (salt and drought treatment) on the expression of OsMPK14, RT-PCR and qRT-PCR were also applied to detect OsMPK14expression profile in the rice seedlings and reproductive period leaves after drought and salt treatment The result revealed that the change of the expression levels was not significant in phyA and phyB mutants seedlings when exposed to salt and drought stresses, which in contrast with that in reproductive period. In addition, the effects of exogenous H2O2on expression of OsMPK14in rice seedlings were detected, the result revealed that exogenous H2O2may inhibit OsMPK14expression in Wt and phyB mutant seedlings. In order to identify the function of OsMPK14in rice growth, development and abiotic stress response by transgenic technology, the plant over-expression vector pCAMBIA1390-UBQ-OsMPK14was constructed using recombinant DNA technology, which will help the further study on OsMPK14function and the relationship between rice light signal pathway.Taken together, the study deepens the understanding of rice OsMPK14, and its function in the salt, drought and exogenous H2O2stress response, and relationship between MAPK pathway and phytochrome-mediated light signal pathway. It is important to uncover rice molecular mechanism under abiotic stress, which will provide some important clues to cultivate new stress-tolerance crop varieties using transgenic strategies.