ORIGINAL ARTICLE

Structural and Functional Characterisation of the Chitinase Gene in Chickpea under Aluminum Stress

Aluminum (Al³⁺) toxicity in acidic soils severely limits chickpea (Cicer arietinum L.) productivity by impairing root growth and suppressing defence responses. Chitinases are well studied for antifungal activity, but their role under aluminum stress is largely unknown. We present the first structural and functional characterization of chickpea Chitinase 10 (XP_004494478.1) under Al³⁺ stress using in silico approaches. Multiple sequence alignment and phylogenetic analysis revealed strong conservation and close relatedness to legumes such as Medicago truncatula and Cajanus cajan. Conserved domain mapping and 3D modeling confirmed a stable GH19 catalytic fold. The protein–protein interaction analysis demonstrated that Chitinase 10 is acting as a central hub in the stress responses, while the molecular docking analysis demonstrated that Fe³⁺ attaches strongly to a distant site, while Al³⁺ attached comparatively weakly but destructively to the catalytic site near Lys46, Glu228 and Asp231, inhibiting the activity of the enzyme. Our findings reveal that aluminum disrupts the function of Chitinase 10 by disrupting the catalytic site, disrupting its antifungal mode of action. This mechanistic connection indicates that aluminum toxicity disrupts plant defence and provides structural basis to inform breeding or biotechnological applications to improve aluminum tolerance in chickpea.