Gene Expression in Tomato Fruitworm (Helicoverpa zea ) That Fed on Tomato Plants Infected With the Entomopathogenic Fungus (Beauveria bassiana)

摘要

Beauveria bassiana has been identified as an entomopathogenic fungus, which assists and improve different immunity and resistance against herbivorous insects and plant pathogens. However, the study of the induced defense, molecular activities, physiological mechanism of the tomato fruitworm fed with wounded tomato plants that have been colonized with entomopathogenic fungus has not been described. Here, we studied the effect of B. bassiana on the physiology, biochemical process and gene expression of tomato fruitworm that fed on wounded tomato plant in the presence and absence of the endophytic fungi. Tomato plant was grown from seed and inoculated with B. bassiana GHA fungi to the tomato plant roots and leaves or sprayed with water and serving as the control treatment. Third instar tomato fruitworm, (Helicoverpa zea) were fed on either control treatment and test treatment plant leaves giving rise to four treatments of control non-wounded no-fungus (CNW), control wounded no-fungus (CW), fungus non-wounded (F NW) and fungus wounded (FW) tomato plants. The tomato fruitworm were harvested for RNA extraction and then reverse transcribed to cDNA. Real time-quantitative polymerase chain reaction was conducted on the cDNA to determine the gene expression of the fruitworm and its response to endophytic colonization of the tomato plants. The results indicate significant difference in the expression of specific tomato fruitworm genes that are associated with immune-related genes, digestion related genes, detoxification-related genes and molting, growth and development related genes in the caterpillar that fed on fungus wounded tomato plants when compared to the control treatments. The comparative profiling and specific stimulation of these genes shows suppression and a direct counter-attack defenses mechanism to the improved tomato plant defense as a result of B. bassiana colonization. The B. bassiana infection seems to have detrimental effect on the caterpillar overall defense mechanisms and forms a protective structure for the tomato plant.