Identification Of Rice Endophyte 2P Strain And Analysis Of Its Biocontrol Effect And Mechanism

Endogenous bacteria with biocontrol effects widely exist in the micro-ecosystems of plants.These endogenous bacteria exert their biocontrol effects through various mechanisms to protect plants from pathogens.These mechanisms include antagonism,competition,parasitism,promotion of plant growth,and induction of local or systemic disease resistance in plants.Compared with other control methods,the use of biocontrol endogenous bacteria to control plant diseases is more environment-friendly and green,which can effectively prevent diseases while reducing damage to the environment and plants themselves.Plant endogenous bacteria can exist in plant tissues and cell spaces,and have strong colonization ability,which is conducive to occupying a favorable niche in the competition with pathogenic bacteria.Our lab isolated an endogenous bacterium from rice bacterial leaf blight samples and named it 2P.In this study,we carried out a series of experiments in order to explore the potential of 2P as biocontrol bacteria.2P was identified as Curtobacterium flaccumfaciens by biological identification,molecular biological identification and Biolog microbial automatic analysis system identification.It is found by measurement that 2P had no obvious pathogenicity to rice,pepper,eggplant,potato,soybean,etc.and had colonization ability in these crops.When 2P was mixed with rice leaf blight pathogen PXO99A and rice bacterial leaf streak pathogen RS105,and inoculated onto the rice leaves,both two disease were suppressed.These results showed that 2P had a good biocontrol effect on these two rice diseases.In order to understand the inhibition mechanism of 2P on rice bacterial blight disease,we measured the effect of 2P on the growth of PXO99A in vitro.The results showed that 2P can inhibit the growth of PXO99A in NB medium,but this interaction was not related to 2P’s sterile supernatant,and may rely on direct contact between the two bacteria.Under static cultivation,the inhibition effect of 2P on PXO99A was more significant,and 2P could produce bacterial membrane substances.In the case of confront culture,2P could grow around PXO99A and affect the growth of PXO99A.The interaction mechanism between 2P and PXO99A after direct contact needs further studyIn summary,rice endogenous bacterium 2P belongs to Curtobacterium flaccumfaciens.2P has no obvious pathogenicity to rice and most other crops,and can effectively control rice bacterial leaf blight and rice bacterial leaf streak.2P can effectively inhibit the growth of PXO99A in NB medium,but this inhibition is not related to the supernatant of 2P,and its in-depth interaction mechanism needs further study.