Characteristics And Functional Analysis Of C6 Transcription Factor MaRcp In Metarhizium Acridum

Metarhizium acridum,as a special entomopathogenic fungus of Locusta migratoria manilensis,which is now widely used to control locust disasters.The spores are the main infestation unit of entomopathogenic fungi,and they are also the initiation and completion of cell differentiation processes.They play a key role in the growth and reproduction of fungi.Sporulation is a reproduction process of filamentous fungi.Most filamentous fungi have two conidiation patterns:the normal conidiation pattern that conidia differentiation form the hyphae at the top or lateral,and the microcycle conidiation pattern that the conidia directly form the conidia which not through the mycelial stage.At present,many studies with regard to the normal conidiation pattern of entomopathogenic fungi,and there are few studies on the microcycle conidiation pattern.Compared with the normal conidiation process,the microcycle conidiation has many advantages because it lacks or greatly limits the growth of mycelium.For example,increase conidial yield,shorten conidial time,enhance the resistance of spores and so on.Therefore,studying the mechanism of regulating microcycle conidiation can provide theoretical basis and new technical guidance for the improvement of biocontrol fungus.This study screened the gene C6 transcription factor MaRcp,which was differentially expressed during the normal conidiation and microcycle conidiation of M.acridum for functional research.In this study,the bioinformatics analysis found that the cDNA length of MaRcp from M.acridum is 954 bp,it encodes a 34.9 kDa protein with an isoelectric point of 8.2.In addition,it has also been found that MaRcp protein contains a Zn?II?2Cys6 binuclear cluster domain similar to GAL4.The function of MaRcp in M.acridum was studied by constructing deletion and complementation strains of the C6 transcription factor.The results showed that the conidiation patterns of the MaRcp deletion strain in under normal culture conditions?on 1/4 SDAY medium?was shifted from normal conidiation to microcycle conidiation.Through the analysis of expression patterns at the conidiation stage,it was found that MaRcp was consistently highly expressed during sporulation.The study also found that the conidia morphology of the MaRcp deletion strain was changed and cell compartment length was shortened compared to the wild type and complementation strains.After deletion of MaRcp,the germination was advanced and the time for 50%conidial germination(GT₅₀)was advanced by two hours.In addition,the sporulation was advanced and the conidial yield was increased.The resistance to heat shock and UV irradiationand was increased,and the half-inhibition time was significantly prolonged 4 h and 1 h,respectively.However,it had no effect on pathogenicity.So far,this gene has been studied more in plant pathogenic fungi,but little research has been done in entomopathogenic fungi,and the mechanism of regulating microcycle conidiation is not yet clear.Therefore,an in-depth study of the mechanism of C6transcription factor regulation the conidiation in M.acridum,it has a very important and practical application significance in excavating its potential as a biocontrol fungus.