Function of small GTPase Rab7 in Colletotrichum fructicola

Abstract:

[Objective] Anthracnose, a major disease of tea-oil tree (Camellia oleifera), is mainly caused by Colletotrichum fructicola. In this study, we investigated the biological function of the small-molecule GTPase Rab7 of C. fructicola, aiming to provide a theoretical basis for the prevention and control of anthracnose. [Methods] The CfRAB7 gene knockout vector was constructed based on the principle of homologous recombination. After PEG-mediated protoplast transformation, resistance screening, and verification by PCR and electrophoresis, the mutant strain ∆Cfrab7 and the complementary strain ∆Cfrab7/CfRAB7 were obtained. The growth, sporulation, appressorium formation, stress response, and other biological characteristics of ∆Cfrab7 were explored. [Results] On the PDA and MM plates, ∆Cfrab7 showcased significantly decreased colony diameter, spore production, and appressorium formation. ∆Cfrab7 failed to penetrate cellophane. The oxidative stress (H₂O₂) had higher inhibition rate on the growth of ∆Cfrab7 than on that of WT and ∆Cfrab7/CfRAB7. ∆Cfrab7 did not cause disease spot on the leaves of Ca.oleifera. Furthermore, CfRab7 was required for homotypic vacuole fusion, which was essential for pathogen invasion. [Conclusion] Our findings reveal that CfRAB7 gene plays a vital role in the growth, sporulation, appressorium formation, oxidative stress response, homotypic vacuole fusion, and pathogenicity of C. fructicola.