Chickpea Defensin Gene Family: Promising Candidates for Resistance Against Soil-Borne Chickpea Fungal Pathogens

Defensins are broad-spectrum antimicrobial peptides that play an important role in providing innate immunity to various biotic stresses in plants. We identified and characterized 22 defensin (DEF) and defensin-like (DEFL) genes in chickpea (Cicer arientinum) based on their structures, expression, chromosomal localization, conserved motifs, and cis-regulatory elements. The localization of DEF and DEFL genes in chickpea genome revealed the presence of at least two clusters that are likely evolved through local gene duplications. Genotype-specific responses of several CaDEF and CaDEFL genes in fungal bioassays suggested their involvement in defense against fungal pathogens such as hemi-biotrophic F. oxysporum f. sp. ciceris and dry root rot causing necrotrophic R. bataticola. Molecular docking studies revealed interactions of CaDEFs with fungal plasma membrane components such as phosphatidylserine (PS) and glucosylceramide (GluCer) and their binding sites were identified. Our data will be useful to identify potential candidate genes and their role in host-plant resistance in chickpea, besides presenting opportunities for their potential for possible deployment in other crops.