Study On StSERKs (Solanum Tuberosum) In Mediating Brassinolide Signaling Pathway And Plant Immunity

In the model plant Arabidopsis thaliana,BRI1 is involved in the transduction of BR signals.As the main receptor for BR(Brassinosteroids,BRs),the mutant bri1-5 exhibits a BR-deficient phenotype.Somatic Embryogenesis Receptor Kinases(SERKs),as co-receptors,are involved in the transduction of BR signals.At the same time,BAK1 and BKK1 are involved in the immune response of plants.The double mutant of bak1-4 bkk1-1 is normally cultured under sterile conditions to produce lethality of seedlings.The weak double mutant of bak1-3 bkk1-1 can complete the life history under normal culture conditions,but its seedling cotyledons will have a etiolated phenotype,and the marker gene PR1 associated with plant defense response will be significantly up-regulated,reactive oxygen species and salicylic acid will accumulate in vivo.In this study,Arabidopsis mutants bri1-5 and bak1-3 bkk1-1 were used as experimental background genetic material to study the function of potato SERKs in BR signal transduction and immune response.The sequences of SERKs in Arabidopsis were compared with the sequences in patato datebase,three StSERKs genes were identified.Therefore,the expression pattern of StSERKs was analyzed firstly,and three StSERKs genes were overexpressed in bri1-5 to study the function in BR signaling pathway.The results showed that StSERK1 and StSERK3 B could significantly suppress the BR-deficient phenotype of bri1-5,while StSERK3 A had no significant inhibition;Through physiological experiments and molecular level tests,StSERKs could be involved in the regulation of BRI1-mediated BR signaling pathway.Three StSERKs genes were overexpressed in bak1-3 bkk1-1 to study the function of StSERKs in immune resistance signaling pathway.The results showed that overexpression of StSERKs significantly suppressed the immune system activation phenotype of bak1-3 bkk1-1.The real-time fluorescent qRT-PCR technique was emploied to test the expression of cell death marker gene FMO1 and the defense response marker gene PR1.The results should that FMO1 and PR1 were significantly down-regulated in StSERKs overexpressed transgenic material.The tests of marker gene SID2 for salicylic acid synthesis and the marker gene EDS1 in the plant immune pathway ETI were also showed significantly down-regulated.This study demonstrat that StSERKs play an important roles in brassinosteroid transduction and immune resistance systems of plants.