玉蜀黍黑粉菌（Ustilagomaydis）是一类可侵染玉米的真菌，可导致系统性侵染病害：玉米病果穗短小，不吐花丝，除苞叶外整个果穗都变成一包黑粉，为病菌的冬孢子。

最近，研究人员发现了一个重复效应蛋白Rsp3（repetitivesecretedprotein3），在田间分离的菌株中表现出很强的长度多态性。Rsp3是毒性和花青素积累的主要原因。在活体营养阶段，Rsp3蛋白在菌丝表面与两个玉米DUF26-domain蛋白AFP1和AFP2发生互作。AFP1可以结合到甘露糖上，并在rsp3突变体中表现出抗菌活性。抑制玉米中的AFP1和AFP2蛋白可以部分恢复rsp3突变体的毒性作用。Rsp3效应蛋白通过封闭AFP1和AFP2的抗菌活性来提高黑粉菌的致毒性。Rsp3在所有已知的黑粉菌和丝黑穗菌中都有同源蛋白，这些蛋白都具有相似的功能。

NatureCommunications,27April

TheUstilagomaydisrepetitiveeffectorRsp3blockstheantifungalactivityofmannose-bindingmaizeproteins

Author

Lay-SunMa,LeiWang,ChristineTrippel,BerndZechmann,GertBangeRegineKahmann*

*:DepartmentofOrganismicInteractions,MaxPlanckInstituteforTerrestrialMicrobiology,Germany

Abstract

Tocausediseaseinmaize,thebiotrophicfungusUstilagomaydissecretesalargearsenalofeffectorproteins.Here,wefunctionallycharacterizetherepetitiveeffectorRsp3(repetitivesecretedprotein3),whichshowslengthpolymorphismsinfieldisolatesandishighlyexpressedduringbiotrophicstages.Rsp3isrequiredforvirulenceandanthocyaninaccumulation.Duringbiotrophicgrowth,Rsp3decoratesthehyphalsurfaceandinteractswithatleasttwosecretedmaizeDUF26-domainfamilyproteins(designatedAFP1andAFP2).AFP1bindsmannoseanddisplaysantifungalactivityagainstthersp3mutantbutnotagainstastrainconstitutivelyexpressingrsp3.MaizeplantssilencedforAFP1andAFP2partiallyrescuethevirulencedefectofrsp3mutants,suggestingthatblockingtheantifungalactivityofAFP1andAFP2bytheRsp3effectorisanimportantvirulencefunction.Rsp3orthologsarepresentinallsequencedsmutfungi,andtheorthologfromSporisoriumreilianumcan







































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