Function Analysis Of MFS Transporters In Response To Environmental Stresses In Fusarium Graminearum

Fusarium head blight（FHB）is one of the most devastating diseases currently restricting wheat production and food safety.Fusarium gramnearium,as the main pathogen causing wheat scab,can respond to external stress quickly and exhibit strong environmental adaptability.However,the mechanism of F.graminearum responding to multiple stresses is still unclear.The Major Facilitator Superfamily（MFS）is ubiquitous in all kingdoms of life from bacteria to eukaryotes,which is the largest superfamily of secondary active transporters known.The MFS transporters are responsible for transporting various substrates by using electrochemical gradient as the driving force,which plays important roles in stress responding and other biological processes.MFS transporters FLU1 of Candida albicans and FLR1 of Saccharomyces cerevisiae both function in toxic substances transport such as demethylation inhibitors.MFS transporter Bcmfs G is involved in the efflux of glucosinolate-breakdown products in Botrytis cinerea.In this study,the functions of 43 MFS transporters in response to fungicides,antimicrobial substances and ion stresses were studied in F.graminearum employing bioinformatics,genetics and biochemistry approaches.In summary,the results are as follows:1.The 43 MFS mutants were determined the sensitivity to 6 common fungicides.The results showed that DHA transporter FgQdr2 was involved in the transport of prochloraz,tebuconazole,fludioxonil and iprodione in F.graminearum.While DHA transporter FgAfl T transports specifically the azole fungicide prochloraz.It was found that FgQdr2,as an MFS antiporter,transports fungicide reversely in a cation co-transport mode.And the expression of FgQDR2 was be activated by K⁺/H⁺.2.The 43 MFS mutants were detected the sensitivity to antimicrobial substances produced by plants and microorganisms.The results showed that FgQdr2 mediated two-benzoxazolinone transport.And DHA transporters Fg06569,FgFfz1 and FgMfs2 were involved in the transportion of antagonistic compounds produced by Penicillium oxalicum and Tarlaromyces purpureognus.3.The sensitivity determination and transcription analyses showed that Fpn1transporter FgFpn1 and PrsC transporter FgPrsC participate in the transport of Fe²⁺and Mg²⁺,respectively.SIT transporter FgStr3 and FgMir B participates in the balance of iron homeostasis.4.we explored other biological functions for the above MFS transporters involved in stress response,and found that FgQdr2 also regulates mycelial growth,sexual and asexual development,pathogenicity and DON synthesis.In addition,the PrsC transporter Fg05119 modulates sexual reproduction and pathogenicity,and the SIT transporter FgSit1 regulates asexual reproduction in F.graminearum.This study mainly analyzes the function of MFS transporters in response to fungicides,antimicrobial substances and ion stresses in F.graminearum,which provide a theoretical basis for the strong environmental adaptability of F.graminearum,broadens the research on the function of MFS protein in fungi and gives new ideas for the control of wheat head blight.