Insights into VdCmr1-mediated protection against high temperature stress and UV irradiation in Verticillium dahliae

Authors: FANG, YULIN - Beijing Forestry University; Klosterman, Steven; TIAN, CHENGMING - Beijing Forestry University; WANG, YONGLIN - Beijing Forestry University

Submitted to: Environmental Microbiology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 5/24/2019
Publication Date: 6/1/2019
Citation: Fang, Y., Klosterman, S.J., Tian, C., Wang, Y. 2019. Insights into VdCmr1-mediated protection against high temperature stress and UV irradiation in Verticillium dahliae. Environmental Microbiology. 21(8):2977-2996. https://doi.org/10.1111/1462-2920.14695.
DOI: https://doi.org/10.1111/1462-2920.14695

Interpretive Summary: The fungus Verticillium dahliae V. dahliae is a broad host range plant pathogen that affects numerous important crops and its survival in the soil for long periods essentially means that crop rotation is ineffective for control. The discovery and understanding of which molecules that the pathogen uses to survive long periods in the soil is critical to develop new means to control this pathogen. Once plants are infected with V. dahliae there are no successful control measures. In this research, we analyzed the full complement of expressed genes and proteins in Verticillium dahliae under conditions of ultraviolet light (UV) stress, and high temperature stress in both a mutant strain of V. dahliae defective in its response to these stresses, and in a normal strain. The results reveal insights into the biochemical and molecular mechanisms used by the fungus to cope with high temperature and UV stress. If these coping strategies can be inhibited, these findings from this study may be exploited to reduce the survival of the fungus in the field.

Technical Abstract: The fungus Verticillium dahliae causes vascular wilt disease on more than 200 plant species, including economically important crop and ornamental plants worldwide. Because this fungus can survive for years in soil, control measures that target V. dahliae in the environment outside of the plant host may be effective for disease control. Yet little attention has been focused on abiotic stresses in this fungus. We previously demonstrated that the transcription factor-encoding gene VdCmr1 is required for melanin production and increased survival following U.V. irradiation, but not for microsclerotia production or virulence, in V. dahliae. In the current study, we applied transcriptomic and proteomic analyses of the response of VdCmr1 genetic mutant and wild type of V. dahliae to high temperature (HT) and U.V. irradiation. The results indicate that VdCmr1 contributes to the entry to the diapause period in V. dahliae in response to HT, to minimize protein misfolding and denaturation. The VdCmr1 deletion also results in the misregulation of DNA repair machinery, suggestive of reduced DNA repair capacity under U.V. stress and in correlation with the low survival rate of UV-treated VdCmr1 mutants. Furthermore, we discovered a putative VdCmr1-dependent gene cluster, associated with secondary metabolism and stress responses. These results further support the roles of VdCmr1 in protection of fungi from HT or U.V. irradiation, and the additional insights into the mechanism of this protection may eventually be useful to exploit vulnerabilities in the fungus for more effective disease control.