Capsidiol-related genes are highly expressed in response to Colletotrichum scovillei during Capsicum annuum fruit development stages

Abstract

Capsicum annuum is one of the most important horticultural crops worldwide. Anthracnose disease (Colletotrichum spp.) is a major constraint for chili production, causing substantial losses. Capsidiol is a sesquiterpene phytoalexin present in pepper fruits that can enhance plant resistance. The genetic mechanisms involved in capisidiol biosynthesis are still poorly understood. In this study, a 3′ RNA sequencing approach was used to develop the transcriptional profile dataset of C. annuum genes in unripe (Uf) and ripe fruits (Rf) in response to C. scovillei infection. Results showed 4,845 upregulated and 4,720 downregulated genes in UF, and 2,560 upregulated and 1,762 downregulated genes in RF under fungus inoculation. Four capsidiol-related genes were selected for RT-qPCR analysis, two 5-epiaristolochene synthase (CA12g05030, CA02g09520) and two 5-epi-aristolochene-1,3-dihydroxylase genes (CA12g05070, CA01g05990). CA12g05030 and CA01g05990 genes showed an early response to fungus infection in RF (24 h post-inoculation-HPI), being 68-fold and 53-fold more expressed at 96 HPI, respectively. In UF, all genes showed a late response, especially CA12g05030, which was 700-fold more expressed at 96 HPI compared to control plants. We are proving here the first high-throughput expression dataset of pepper fruits in response to anthracnose disease in order to contribute for future pepper breeding programs. Chili peppers originate from the Americas and they are among the oldest cultivated plants, dating from before 3400 BC. Capsicum annuum L. is the most commercially important species, due to its usefulness in the human diet, medicines, beverages, and as ornamentals. Pepper fruits have several nutraceutical benefits for human health, due to a variety of antioxidant, anti-inflammatory, antimicrobial, anti-carcinogenic, and cardio-protective properties 1. Anthracnose is caused by Colletotrichum spp., and represents the major disease of chili fruit worldwide, leading to significant postharvest yield loss and reducing marketability 2. Twenty-four Colletotrichum species have been identified as pathogens of chili anthracnose, with the three main pathogenic species being C. scovillei (previously identified as C. acutatum), C. truncatum (syn. C. capsici), and C. siamense (previously identified as C. gloeosporioides) 3 .

Solanaceous plants switch to cytokinin‐mediated immunity against Ralstonia solanacearum under high temperature and high humidity

“…We thus focused our analysis on functionally conserved and well‐characterized immunity‐related genes, such as these encoding endochitinases (Kuc, 1990), chitinase (B. Guan et al, 2008; B. Lee et al, 2012), SA‐dependent PR protein1 ( PR1 ), PR2 and PR5 (B.P. Thomma et al, 1998), JA‐dependent defensin‐like protein1 ( DEF1 ) (O'Donnell et al, 2003) and phytoalexin biosynthesis‐related 5‐epi‐aristolochene synthase ( 5‐EAS ) (Baba et al, 2020; Lin et al, 2014; Park et al, 2014). These genes were all modulated differentially at the transcriptional level by RSRT or RSHT in the two tested pepper lines and were enriched in processes, including stress response (GO:0080134) and defence response (GO:0006952).…”

Elucidation of the biochemical and molecular basis of the differential disease expression in two cultivars of chili (Capsicum annuum) in response to Colletotrichum capsici infection

“…Enhanced levels of the defense molecules have been positively correlated to an enhanced degree of tolerance toward successful disease establishment (Ramamoorthy and Vellaiswamy, 2001 ; Banu et al, 2019 ). Previous reports have also suggested the role of sesquiterpenoids such as capsidiol and related genes active in pepper fruit in defense against Colletotrichum scovillei ; however, their mechanism of biosynthesis remain to be understood (Baba et al, 2020 ). In our study, the elevated response of the defense molecules was maintained in Beldanga cultivar, but not in the Bullet cultivar which explains the susceptibility of the latter.…”