Enhanced tomato resistance to gray mold by fungus Beauveria bassiana colonization and its mechanism of action
In order to clarify the effect of fungus Beauveria bassiana colonization on tomato plant dis-ease resistance and its mechanism of action,conidial blastospores suspension of B.bassiana were inocu-lated into tomato plants with root irrigation,and the resistance of tomato against gray mold caused by Botrytis cinerea after colonization by B.bassiana was evaluated with artificial inoculation;the relative content of B.bassiana at different positions of tomato leaves under the stress of B.cinerea was detect-ed.The expression levels of three disease resistance genes,including oxalate oxidase(OXO),chitinase(CHI)and ATP synthase(atpA)in tomato leaves were determined.The results showed that B.bassiana colonization could improve resistance of tomato plants to gray mold,on the 5th day after B.cinerea in-oculation,the incidence rate,lesion diameter and disease index in tomato decreased by 61.6%,41.4%and 26.4%,respectively.It is noteworthy that B.bassiana was more likely to accumulate in the infected leaves and especially areas close to the infection sites,and up-regulated the expression levels of OXO,CHI and atpA genes.The results indicated that B.bassiana could improve plant disease resistance through endophytic colonization and interaction with host plants,and have great application potential in the field for the biological control of plant diseases.