Modulation of defense genes and phenolic compounds in wild blueberry in response to Botrytis cinerea under field conditions

Abstract

Botrytis blight is an important disease of wild blueberry [(Vaccinium angustifolium (Va) and V. myrtilloides (Vm))] with variable symptoms in the field due to differences in susceptibility among blueberry phenotypes. Representative blueberry plants of varying phenotypes were inoculated with spores of B. cinerea. The relative expression of pathogenesis-related genes (PR3, PR4), flavonoid biosynthesis genes, and estimation of the concentration of ten phenolic compounds between uninoculated and inoculated samples at different time points were analyzed. Representative plants of six phenotypes (brown stem Va, green stem Va, Va f. nigrum, tall, medium, and short stems of Vm) were collected and studied using qRT-PCR. The expression of targeted genes indicated a response of inoculated plants to B. cinerea at either 12, 24, 48 or 96 h post inoculation (hpi). The maximum expression of PR3 occurred at 24 hpi in all the phenotypes except Va f. nigrum and tall stem Vm. Maximum expression of both PR genes occurred at 12 hpi in Va f. nigrum. Chalcone synthase, flavonol synthase and anthocyanin synthase were suppressed at 12 hpi followed by an upregulation at 24 hpi. The expression of flavonoid pathway genes was phenotype-specific with their regulation patterns showing temporal differences among the phenotypes. Phenolic compound accumulation was temporally regulated at different post-inoculation time points. M-coumaric acid and kaempferol-3-glucoside are the compounds that were increased with B. cinerea inoculation. Results from this study suggest that the expression of PR and flavonoid genes, and the accumulation of phenolic compounds associated with B. cinerea infection could be phenotype specific. This study may provide a starting point for understanding and determining the mechanisms governing the wild blueberry-B. cinerea pathosystem.

Isolation and functional characterization of a pathogenesis-related protein 4 gene from Panax notoginseng

“…The Panax ginseng PR4 expression level increases in response to phytopathogenic fungi, including Rhizoctonia solani and Colletotrichum gloeosporioides, for up to 72 h post-inoculation (Kim et al, 2014). When Vaccinium myrtillus is infected by Botrytis cinerea, PR4 expression peaks at 12 h (Abbey et al, 2023).…”

Response of Biofortified Green Bean Plants to Colletotrichum lindemuthianum

“…These compounds are bioactive, which means they have a biological impact on the plant and its surroundings; additionally, the plant actively accumulates phenolic compounds during interactions with pathogens [13]. Furthermore, the concentration of specific phenolic compounds has been utilized to discern healthy tissue from diseased tissue in response to pathogen attack [14]. In addition, phenolic compounds serve the dual role of inhibiting the germination of fungal spores and inactivating particular enzymes produced by phytopathogens as part of the plant's defense mechanisms.…”