RT-qPCR based quantitative analysis of gene expression in C. annuum L. in response of P. capsici infection

Abstract

Despite the economic importance of chili pepper (C. annuum), its productivity is considerably affected by oomycete pathogen, Phytophthora capsici. P. capsici is a soil-borne pathogen, has a broad host range in the families of Solanaceae. Previously a progress has been made to detect and analyze the gene expression associated with the pathogen infection in some landraces of C. annuum. However, the understanding of the disease response in different landraces of pepper against P. capsici infection is yet limited. Hence, the aim of the present study was to analyze gene expression associated with P. capsici infection using RT-qPCR from our Illumina sequencing results of previously established resistant (GojamMecha_9086) and susceptible (Dabat_80045) varities. Based on RT-qPCR results, the highest expression level (~ 2.70 fold) was exhibited by glycine-rich cell wall structural protein-like (GRCW) gene followed by non-specific lipid transfer protein GPI-anchored 2-like gene (~1.99 fold) in RI leaves while the expression of glycine-rich cell wall structural protein-like was significantly down regulated in SI landrace leave (with ~ -2.86-fold change), showing their involvement during P. capsici infection. However, the squamosa promoter-binding protein 1(SPBP) gene was down-regulated in both RI (~ -1.64 fold) and SI (~ -1.95) leafs. In conclusion, the level of resistance and susceptibility in the two contrasting landraces is possibly due to the difference in the level of genes expression and molecular variations in the resistance mechanism. The current findings could be used as a basis by molecular breeders for selection of landraces containing defence related genes and help in improving chili pepper. Further functional validation using reverse genetics methods such as VIGS, RNAi and CRISPR/Cas9 system is needed.