The Functional Analysis Of Hexose Transporter Gene MoRco3 And MoSnf3 In Magnaporthe Oryzae

Hexose transporter is an important sugar transporter which applied to uptake and transporter hexose.Trough bioinformatic analysis,we identified 67 hypothetical hexose transporters in Magnaporthe oryzae.Among them,the amino acid residues of MGG₀3620,MGG₁5700,MGG₀6203,MGG₀0040,MGG₁3651,MGG₀5946 are highly homologous to the hexose transporters that had been identified in Neurospora crassa?Aspergillus nidulans?Saccharomyces cerevisiae and Colletrotrichum graminicola.What is more,the gene expressions of the hexose transporters are quite different from each other during the stage of appresorium development.Moreover,the expression of 25 genes were enhanced after infection of rice for 48h,which means these genes may involve in the pathogenetic process of the fungus.In the research,we choosed two genes MGG 03620 and MGG₁5700,which are highly homologous to Snf3 in yeast.In Magnaporther comparative database,MGG₀3620 is noted as glucose transporter MoRco3,while MGG₁5700 is a hypothetical protein,we named it MoSnf3.Through the method of SOE-PCR,we got the knockout mutants of both gene MoRco3 and MoSnf3.MoRco3 knockout mutant grew slower and with less melanin than the wild type.What is more,both the conidiation and pathogenicity reduced.On the contrary,the overexpression transformant of MoRco3 produced more melanin while the amount of conidiation did not change.Compared with widetype Guy11,MoSnf3 knockout mutant produced more abnormal conidia with less septum.Occording to the carbon related experiment,we found that MoRco3 knockout mutants were sensitive to glucose,mannose,fructose and galactose.What is more,both of two genes have high expression in low concentration of glucose condition.So we consider them as high affinity hexose transporters.Through qRT-PCR,we found that both of gene MoRco3 and MoSnf3 down regulated in the mutant ?CreA,therefore,gene MoRco3 and MoSnf3 may also involve in carbon catabolite repression pathway.