Impact of Helicoverpa armigera Hübner (Lepidoptera: Noctuidae) infestation and wounding on gene expression of defense-related genes and chlorophyll fluorescence in common bean.

Abstract

Plants have evolved complex defense mechanisms against biotic stressors. Many plant defense-related genes that play crucial roles in regulating defense responses have been identified in common bean (Phaseolus vulgaris L.). However, the functional roles of phenylalanine ammonia-lyase (PvPAL ), lipoxygenase (PvLOX ), glutathione S-transferase (PvGST ) and peroxidase (PvPOD ) in response to herbivory and wounding remain unclear in common bean. In this study, we investigated the expression patterns of PvPAL, PvLOX, PvGST and PvPOD genes in common bean under wounding and infestation by a major pest, Helicoverpa armigera , using quantitative real-time PCR (qRT-PCR) for the first time. The expression patterns of these genes in response to insect attack and wounding were compared. Moreover, the effects of wounding and H. armigera on the chlorophyll fluorescence parameters (F v /F m , PI ABS , ABS/RC, TRo/RC, ETo/RC and DIo/RC ) were also determined in common bean. Our results revealed that all genes were significantly upregulated in response to H. armigera , whereas PvPAL and PvPOD were downregulated in wounding. Notably, PvLOX and PvGST genes may play significant roles in the defense system of common bean against both wounding and H. armigera infestation. Furthermore, significant reductions in F v /F m , PI ABS and ETo/RC were determined under both wounding and H. armigera infestation. These findings suggest that H. armigera is more severe than wounding, leading to distinct gene expression profiles and photosynthetic responses in common bean. The study provides valuable insights for both researchers and breeders in future studies associated with insect stress and resilience breeding efforts.