Insights Into Responses Of VdCmr1 To High Temperature Stress And UV Irradiation In Verticillium Dahliae

The fungus Verticillium dahliae,an important soil-borne pathogenic fungus,is widely distributed in the world and causes vascular wilt disease on more than 200 plant species,causing great economic losses.However,there are still no effective control methods for management.The melanized microsclerotia play an important role in the life cycle and disease transmission of V.dahliae,and they are the key to reveal the mechanism of this disease and to control it.Melanin accumulation during microsclerotia formation provides protection against some stresses such as UV irradiation and extreme temperatures,enzymatic hydrolysis,osmotic pressure,oxidation,and nutrient deficiency,leading to better survival of the fungi.At present,the regulation mechanism of melanin is still unclear.In order to clarify the protective mechanism of melanin to V.dahliae,we conducted a functional study on the important transcription factor VdCmr1,and explored the response mechanism of Cmrl in response to high-temperature(HT)and UV irradiation stresses from the transcriptome and proteomics level.The main findings are as follows:(1)VdCmrl is a key regulator of melanin biosynthesis and regulates melanin biosynthesis,but it is not involved in the regulation of microsclerotia formation;(2)VdCmrl regulates pyruvate metabolism processes and a gene cluster to cope with stresses;(3)VdCmrl may inhibit fatty acid metabolism and secondary metabolism related processes,contributing to the entry to the diapause period in V.dahliae,and regulate the genes related to protein misfolding and denaturation in response to HT;(4)VdCmrl may respond to ultraviolet radiation by regulating DNA repair mechanisms and ubiquitination-related processes to repair damaged DNA and degrade damaged DNA;(5)The C2H2 domain,Zn(?)2-Cys6 domain and MHR domain of VdCmrl are all involved in the stress response.This results clarify the regulation mechanism of VdCmr1,a key regulator of melanin synthesis,in response to high temperature stress and ultraviolet radiation,and the results extend the understanding of the regulation mechanism of Cmr1-type transcription factor orthologues in filamentous fungi.The regulation of melanin synthesis and its protective mechanism may eventually be useful to screen effective fungal target sites for more effective disease control.