The Effect Of Endophytic Actinomycetes OsiSh-10 On Its Host Plant Growth And Preliminary Study On The Mechanism

Endophytes are microorganisms that co-exist within plants without causing diseases or adversely affecting plant development.These endophytes can regulate plant development and stress responses,including promoting plant growth,nitrogen fixation and pathogen resistance.Currently endophytes research mainly focused on the research of endophytic fungi and endophytic bacteria,due to the growth of endogenous actinomyces cycle is long,the reason such as the separation is difficult.For endogenous actinomyces research is relatively small,also focused on the host disease resistance and so on influence on the shape,to promote the growth of small shape,less attention.From previous studies,OsiSh-10 may produce a certain substance against pathogenic bacteria produce certain fungal diseases and resist to indirectly promote the growth of plant.According to many research showed that endogenous bacteria can produce phytohormone,cytokinins,ethylene and other substances to participate in plant physiological and biochemical activities.However,until recently,little comprehensive research on the interaction between endophytes and their hosts has been conducted.Thus,more research is necessary to reveal the mechanisms of phenotype alterations by bacterial endophytes.Due to the artificial inoculation of endophytes,may influence the host plant physiological and biochemical situation,affect the actual use of the endophytic bacteria.So it is very meaningful to research the promotion of endophytes.The main contents and results are as follows:1.To facilitate the use of the research foundation of arabidopsis thaliana thick and simplify the research process,we found that OsiSh-10 directly colonized the root epidermal cells and formed intracellular and extracellular hyphae.This endophyte can inhibit primary root growth while enhancing lateral root and root hair growth.To directly visualize OsiSh-10 colonization inside of plants,we used Streptomyces expressing the EGFP gene(OshiSh-10-EGFP)to infect A.thaliana and found that OsiSh-10-EGFP directly colonized the root epidermal cells and formed intracellular and extracellular hyphae.2.Kinetin,a rarely reported secretion in endophytes,was identified from PDA agar culture of OsiSh-10 using liquid chromatography-mass spectrometry.In order to further explore Osish-10 influence mechanism of arabidopsis root growth.We use GUS staining method and the PCR method to reserch the expression of related genes in arabidopsis.We found that OsiSh-10 can affect auxin polar transport aspects of gene in Arabidopsis.3.To further study the influence of the rice endophytic fungi on plant growth,we co-culture endophytes OsiSh-10 with rice and then found OsiSh-10 can promote the growth of rice.In salt stress experiment,endophytes OsiSh-10 with rice cultivation can alleviate the negative effect brought by the salt stress and improve in rice leaf chlorophyll content and relative water content.In this study,we demonstrate that OsiSh-10,an endophyte Streptomyces albus has impacts on the growth of plant and alleviate the negative effects of salt stress on plant.The research foundation is provided for further implementation of the osiSh-10 practical application.