Abstract: Lecanicillium lecanii (JMC-01) can form symbionts after colonizing cabbage plants to defend against Myzus persicae. We tested the toxicity of JMC-01 and JMC-01-cabbage symbionts to Myzus persicae by leaf spraying method and observed the infection of JMC-01 to Myzus persicae. We further analyzed the defense-related pathway changes of cabbage plants after colonization by JMC-01 by transcriptomic sequencing. JMC-01 showed 75% virulence against adult aphids at five days post-infection, while the JMC-01-cabbage symbiont induced 58.67% and 66.67% mortality in adults and 1st-instar nymphs, respectively. Nymphal mortality was significantly higher than that of adult aphids. The infection patterns of mycelial in Myzus persicae depended on the inoculation method, either through direct spraying with JMC-01 spore suspension or via feeding on colonized leaves. Direct application of spore suspension demonstrated superior infection efficacy and mortality rates against Myzus persicae. Furthermore, cabbage plants inoculated with JMC-01 exhibited altered defense-related gene expression, with a total of 989 differentially expressed genes being identified. GO enrichment and KEGG pathway analyses revealed significant alterations in defense-related pathways, including hydrolytic enzyme activity acting on glycosyl bonds, cell wall metabolism, photosynthesis-antenna proteins, glucosinolate biosynthesis, MAPK signaling-plant pathway, and sulfur metabolism. Lecanicillium lecanii (JMC-01) can enhance plant resistance through endophytic colonization, with significant potential for application in biological control systems.

Key words: endogenous fungi, interaction, symbiont