Anthracnose Resistance Mechanisms in Pepper Species

Anthracnose, caused by Colletotrichum species, poses a major threat to pepper cultivation worldwide, affecting both field production and post-harvest storage. Pepper species deploy a multilayered defence encompassing physical barriers such as cuticle fortification and cell wall thickening, alongside inducible immune responses. Pathogen recognition is mediated by receptor-like kinases at the cell surface and intracellular nucleotide-binding leucine-rich repeat proteins that detect specific fungal effectors. Activation of these receptors triggers signalling cascades involving salicylic acid, jasmonic acid and reactive oxygen species, leading to the synthesis of phytoalexins—most notably the sesquiterpene capsidiol—and pathogenesis-related proteins. Advances in quantitative trait locus mapping and genome-wide association studies have identified key resistance loci and molecular markers. Concurrently, transcriptomic analyses have revealed developmentally regulated gene networks that distinguish unripe from ripe fruit responses, guiding targeted breeding strategies for durable resistance.

Research from Nature Portfolio

High-throughput transcriptome profiling of unripe and ripe Capsicum annuum fruits challenged with Colletotrichum scovillei has illuminated the genetic control of phytoalexin biosynthesis. Researchers identified over 4,000 genes upregulated in unripe fruits and more than 2,500 in ripe fruits upon infection, with pronounced induction of 5-epi-aristolochene synthase and 5-epi-aristolochene-1,3-dihydroxylase genes essential for capsidiol production. Quantitative RT-PCR validation confirmed a rapid and sustained transcript increase in ripe fruits, correlating with enhanced antifungal activity. This seminal dataset offers a foundation for dissecting defence pathways and for integrating capsidiol biosynthesis genes into pepper breeding programmes.

Anthracnose Resistance Mechanisms in Pepper Species publication trend

The graph below shows the total number of articles in anthracnose resistance mechanisms in pepper species across all publications each year (not limited to Nature Index journals).

Technical terms

Anthracnose: A fungal disease of plants, notably pepper, caused by Colletotrichum species, leading to fruit rot and yield loss.

Phytoalexin: A low-molecular-weight antimicrobial compound synthesised de novo by plants in response to pathogen invasion.

Genome-wide association study (GWAS): A method that scans genetic variants across the genome in a population to identify loci associated with a particular trait.

Quantitative trait locus (QTL): A chromosomal region containing genes that contribute to the variation of a complex, quantitative trait such as disease resistance.

Nucleotide-binding leucine-rich repeat (NLR): A family of intracellular immune receptors in plants that recognise specific pathogen effectors and activate defence responses.

References

1. Genome-wide association study of resistance to anthracnose in pepper (Capsicum chinense) germplasm. BMC Plant Biology (2023).
2. Breeding for Anthracnose Disease Resistance in Chili: Progress and Prospects. International Journal of Molecular Sciences (2018).
3. Fine mapping of the major anthracnose resistance QTL AnRGO5 in Capsicum chinense ‘PBC932’. BMC Plant Biology (2020).
4. Evaluation of Anthracnose Resistance in Pepper (Capsicum spp.) Genetic Resources. Horticulturae (2021).
5. Capsidiol-related genes are highly expressed in response to Colletotrichum scovillei during Capsicum annuum fruit development stages. Scientific Reports (2020).
6. The Capsicum baccatum-Specific Truncated NLR Protein CbCN Enhances the Innate Immunity against Colletotrichum acutatum. International Journal of Molecular Sciences (2021).