Pathogeniticy And Sequence Difference Of GMK1 Gene In Gaeumannomyces Causing Wheat Take-All Disease

Gaewnannomyces graminis , a filamentous ascomycete, was an important root pathogen of cereal that caused take-all disease and resulted in severe crop losses worldwide. In this research, 35 strains of wheat take-all fungi from different locations were investigated. The results were as followed:1.Measurement of pathogenicity differentiation of Gaeuinannomyces graminis in wheat, barley ,rye, rice ,oat and corn .The results revealed: In all of crops which were inculated with the same strain , take-all disease in wheat was the most severe, then in barley, rye, rice .however, we could hardly observe symptom in oat and com. Of all strains which were inculated in the same host, pathogenicities were very severe in G4,G13,G18,G28and G35, slight in G11,G17,G19,G26 . 2.Nucleotide sequence alignments of 12 strains which had been selected from 35 strains according to their pathogenicities. With degenerated primers F1,R1, We amplified partial sequences of GMK1 gene, spanning partial exon2, exon3 and an intron between them. Further cloning, sequencing, aligning showed: 490bp fragment was gotten from 12 strains, these nucleotide sequences produced from different strains suggested thatthe variations were very limited ,except that there was a base which changed in G26, G25, G4, G8 and G13. The nucleotide sequences of the different strain had 99% identity compared with each other, this showed Gaeumannomyces graminis was highly conserved in coevolution with hosts. At last,We analyzed the relations between different strain pathogenicities and their nucleotide sequences and found they were not directly relative.