Study the Role of Carbamoyl Phosphate Synthase Sub unit CgCPS1 Gene Involved in Virulence and Regulate Stress Tolerance in Colletotrichum Gloeosporioides

Abstract

Glomerella leaf spot (GLS) is a devastating contagious disease of apple which is caused by a fungi Colletotrichum gloeosporioides. Pathogenicity of C. gloeosporioides is hypothesized to be associated with arginine biosynthesis pathway. Carbamoyl phosphate synthase (CAP1) is an enzyme which catalyses the synthesis of carbamoyl phosphate, which is involved in arginine biosynthesis. Arginine is among one of the several types of amino acids, which plays crucial role in biochemical and physiological functions of fungi. Virulence may be contained by disrupting the arginine biosynthesis pathway. In this study, for the first time, cap1 gene ortholog (CgCPS1) has been identified and disrupted experimentally. To assess the effects of CgCPS1, we knocked out CgCPS1 in C. gloeosporioides by Agrobacterium tumefaciens-mediated transformation (ATMT) and evaluated its effects on virulence and stress tolerance through infection assay, growth on selective media, osmotic stress assay and subcellular localization assay. The results showed that successful deletion of CgCPS1 and mutant Δcgcps1-1 and Δcgcps1-2 showed slow growth rate, defects in appressorium formation and failure to develop lesions on apple leaves and fruits leading to loss of virulence while complementation strain (CgCPS1-C) fully restored its pathogenicity. Furthermore, mutant strains showed extreme sensitivity to high osmotic stress displaying that cgcps1 plays a vital role in stress response. These findings suggest that CgCPS1 is major factor that mediates pathogenicity in C. gloeosporioides by encoding carbamoyl phosphate that is involved in arginine biosynthesis and conferring virulence in C. gloeosporioides. These findings help to control the fungal pathogenicity and to reduce the loss in apple yield.