The Molecular Mechanism Of OsACX1 Regulating Rice Resistance To Rice Blast

Rice blast,caused by Magnaporthe oryzae,threats the production of rice(Oryza sativa L.).The most economical and effective method to control rice blast is using the resistant varieties.Acyl-Co A oxidase(ACX)participates in various physiological activities,especially in the hormones synthesis pathway.However,there are few reports about ACX involves in plant disease resistance.In this study,we analyzed the expression and function of OsACX1 in rice and M.oryzae interaction.The research results are as follows:1.There was a highly conserved ACOX domain in OsACX1.Multiple sequences alignment showed that OsACX1 amino acid sequence has high similarity with ACX1 in maize,wheat,sorghum,and Brachypodium distachyon.Subcellular localization analysis showed that OsACX1 was expressed in the nucleus,cytoplasm,and cell membrane.2.The expression of OsACX1 in rice stems and leaves was relatively high,and the expression level in rice roots was relatively low by q PCR.It was found that the expression of OsACX1 increased significantly after jasmonic acid(JA)treatment for 0.5 h,and reached the peak at 2 h.3.After infected with M.oryzae,the expression level of OsACX1 was significantly increased at 24 hour post inoculation.Moreover,OsACX1 was up-regulated after treatment with flg22 and chitin,respectively.Therefore,we inferred that OsACX1 positively regulates the immune response of plants.4.OsACX1-OX and osacx1 transgenic plants were obtained.After inoculation with M.oryzae results showed that the relative lesion number of OsACX1-OX plants was less than Nipponbare(NPB),and the relative lesion number of osacx1 plants was larger than NPB.The expression levels of pathogenesis-related genes Os PR1 a,Os PAL,Os NAC4,and Os MAPK6 in OsACX1-OX plants were significantly increased compared with NPB.These results suggested that OsACX1 positively regulates pathogenesis-related gene expression and enhances the resistance to rice blast.5.Through the statistics of agronomic traits of OsACX1 transgenic rice,it was found that the panicle length and the number of grains per panicle of OsACX1-OX plants were significantly higher than NPB plants.We inferred that OsACX1 may promote the growth and development of rice.6.Four OsACX1 candidate interacting proteins(Os SCP、Os JAZ、Os GCS、Os FBN)were screened by yeast two-hybrid system.Most of these genes were clustered in the phytohormone regulatory pathway and might play an important role in plant defense response.