Exploration Of Bacillus Resources In Extreme Environment Of Qinghai Plateau And Their Signal Pathways Related To Plant Response Induction

The unique climate of Qinghai-Tibet plateau provides a platform for the development of extreme habitat microbial resources.Qinghai province is the largest livestock production base in China,and the sustainable development of grass industry is very important.In this study,we took Bacillus spp.and Kengyilia thoroldiana as research objects.We isolated the strains from extreme areas in Qing-Tibet Plateau,established a resource library of Bacillus spp.We identified and studied their growth-promoting activity toward K.thoroldiana,used the RNA-Seq to investigate the response of K.thoroldiana to Bacillus,revealed the mechanism of Bacillus to promote plant growth and improve plant disease resistance.We used morphological analysis,16 S rDNA and gyrB partial sequence analyses identified them as B.atrophaeus etc.Some of them had a strong ability to resist adverse growth conditions,including high salt content(11%),alkaline environment(pH = 11).They also showed stable nitrogen fixation activity,IAA production capacity and antifungal activity against fungal pathogens of K.thoroldiana.Furthermore,obvious germination and growth-promoting activity were observed in K.thoroldiana treated with Bacillus suspension by soaking the seeds and by root irrigation.We used RNA-Seq to investigate and analyze the differentially expressed genes of K.thoroldiana at different periods(0 h,2 h,4 h,8 h,12 h)after interaction with B.amyloliquefaciens KKLW1.Through the analysis of GO functional annotation and KEGG pathway,Bacillus affects the regulation and expression of genes in multiple signal transduction pathways and metabolic pathways in plants,so as to promote the growth and development of plants and induce plant disease resistance.