Prediction Of Candidate Effectors And Cloning And Analysis Of The MATing-type Gene Locus In Setosphaeria Turcica

Nothem leaf blight of corn caused by t Setosphaeria turcica,is one of the most important leaf diseases in maize production areas of China.Its pathogenicity differentiation is a key factor affecting the disease epidemics.At present,the study on the factors relating to pathogenicity mainly focused on cell wall degrading enzymes,melanin,nutrient elements,toxins,and pathogenicity differentiation,and there is no further study on effectors and Mating-type gene locus of S.turcica.Candidate effectors of S.turcica is predicted by bioinformatics methods in this paper and to lay a foundation for further study on the role of effectors in interaction of pathogen and plant;The mating-type gene locus of S.turcica is cloned and analyzed by bioinformatics methods,and to clarify the distribution in the main maize producing areas,to abundant the pathogenesis mechanism and provide a theoretical basis for disease prevention and control.1.Effectors prediction and analysis of Setosphaeria turcica.Based on the information of the existing genome of Setosphaeria turcica 28A,the candidate effectors are predicted by bioinformatics prediction program to acquire 11698 protein sequences,and then the protein cysteine content.peptide length and redundancy are analyzed,and finally obtain 60 eligible candidate effectos,of which 24 protein sequences without any homologous sequence.The results of 60 predictive functional analysis showed that the three effectors had predictive function,and the remaining 57 effectors were hypothetical proteins with unknown function.2.Isolation and identification of Setosphaeria turcica.A total of 99 strains are collected and isolated from Heilongjiang,Jilin,Liaoning,Sichuan and Yunnan provinces in China,and 73 strains of Setosphaeria turcica are identified,8 Cladosporium tenuissimum strains,6 Bipolaris zeicola strains,6 Alternaria alternata strains,5 Alternaria tenuissima strains and 1 Alternaria brassicae strain are identified.The phylogenetic analysis of isolates shows that the strain of S.turcica,A.alternata and B.zeicola are close to each other and form a branch.The A.alternata strain,A.brassicae strain and A.tenuissima strain are relatively close to each other,forming a branch.The C tenuissimum strain forms a small branch,which is relatively distant from other fungi.3.Cloning and bioinformatics analysis of Mating-type gene locus of Setosphaeria turcica.In this paper,the StMAT1-1/StMAT1-2 gene locus are clonedits total length are 12382bp and 12284bp,which contains one MAT gene respectively.The flanking sequences of the two gene locus contain three encoded proteins and three helix structures,and the similarity of the same genein different mating-type gene locus is more than 98%.The StMAT 1-1-1 protein encodes a conserved alpha domain,the StMAT 1-2-1 protein encodes a conserved HMG-BOX domain,and themating type gene is conserved by itself,and the conserved domains encode 379 and 344 amino acids,respectively.The domain plays a role in fungal sexual reproduction.The flanking sequences contain GAP,ORF1,Bgl-1 proteins that functionally synergistically with the sexual reproduction ofmaize.4.Identification of Mating-type of Setosphaeria turcica.The sexual style of S.turcica is heterothallism,and there are Mating-type 1-1(MAT1-1)and Mating-type 1-2(MAT1-2).Of the selected 73 S.turcica strains,MAT1-1 strain accounted for 49.3%,MAT1-2 strain is 43.8%,the ratio ofthese two kinds is close to 1:1,and they are both detected in same strain.