TBCC Domain-Containing Protein Regulates Sporulation and Virulence of Phytophthora capsici via Nutrient-Responsive Signaling

Phytopathogenic oomycetes, particularly , the causal agent of Phytophthora blight disease in essential vegetables and fruit crops, remains a persistent challenge in the vegetable production industry. However, the core molecular regulators of the pathophysiology and broad-range host characteristics of remain unknown. Here, we used transcriptomics and CRISPR-Cas9 technology to functionally characterize the contributions of a novel gene ( ) coding for a hypothetical protein with a tubulin-binding cofactor C domain with a putative chloroplast-targeting peptide (cTP) to the pathophysiological development of . We observed significant upregulation in the expression of during pathogen-host interactions. However, the vegetative growth of the ∆ strains was not significantly different from the wild-type strains. gene replacement significantly compromised the sporulation, pathogenic differentiation, and virulence of . At the same time, ∆ strains were sensitive to cell wall stress-inducing osmolytes. These observations, coupled with the close evolutionary ties between and pathogenic oomycetes and algae, partly support the notion that is a conserved determinant of pathogenesis. This study provides insights into the significance of tubulin-binding cofactors in and underscores the potential of PcTbcc1 as a durable target for developing anti-oomycides to control phytopathogenic oomycetes.