Polymorphic variant of a candidate effector potentially involved in the specific interaction between Sporisorium scitamineum and sugarcane.

NATÁLIA OLIVEIRA DE ARAÚJO; JULIANA BENEVENUTO; NATALIA MIELNICHUK ; CLAUDIA BARROS MONTEIRO-VITORELLO

Piracicaba

Encuentro; 32º Encontro sobre temas de genética e melhoramento; 2015

Escola Superior de Agricultura Luiz de Queiroz-Universidad de Sao Paulo

.Sporisorium scitamineum is a biotrophic pathogen establishing a specific interaction with sugarcane. Secreted effector proteins play a central role in biotrophic interactions, suppressing the plant immune system and altering the host metabolism to support the fungal growth and development. Effectors are emerging as tools in resistance breeding programs to accelerate the identification of pathogen races and host resistance genes. Through computational predictions and transcriptomic analysis, a S. scitamineum putative secreted effector, unique to this fungus with regard to three close-related species, and exclusively expressed during sugarcane interaction was identified. This gene, automatically named as g1052 in the genome annotation, was used in the present study to perform a screening into 24 haploid strains of S. scitamineum derived from 12 naturally infected plants found in different regions of Brazil and Argentina. After gene amplification and further sequencing, two polymorphisms were found: one at position 25 and another at position 472 from a total of 513 base pairs alignment (comprising from the putative start to the stop codons). Each polymorphism affected the first base of the respective codon, leading to non-synonymous substitutions. It is noteworthy that only two haplotypes were obtained with high haplotype diversity (Hd=0,514). Maximum Likelihood tree based on the protein sequences showed that there is no variation among strains derived from the same infected plant. Moreover the two haplotypes are characteristically/specifically distributed between isolates from Brazil and Argentina, except for isolated 39 (collected in Ribeirão Preto-SP) that shares the same haplotype with Argentine isolates. Additional experiments are needed to characterize the function of this gene and to associate the haplotypes found here with differences in aggressiveness that could indicate the presence of races.