Fusarium andiyazi, a Pathogenic Species Associated with Rice Bakanae Disease in Malaysia

Rice is the main staple food crops for the Malaysian population. Rice is also susceptible to bakanae diseases caused by some Fusarium species and reducing yield, and quality of rice also profit. In this study, several rice fields were surveyed to collect Fusarium isolates associated with bakanae disease. The morphological features of Fusarium andiyazi isolates found on infected rice plants were identified in this investigation. For biological species identification, MAT-1 (Mating type idiomorphs) bearing isolates were crossed with MAT-2 isolates. Crossing was succeeded between cross of two different mating type bearing field isolates. Consequently, there is a possibility of exchange of genetic material within the F. andiyazi population in Malaysia. The identity of the isolates was further determined up to the species level by comparing DNA sequences and phylogenetic analysis of two genes. The phylogenetic analyses of the joined dataset of translation elongation factor 1-alpha (TEF1-α) and RNA polymerase subunit II (RPB2) revealed that all the isolates were F. andiyazi. In pathogenicity tests, F. andiyazi were found to be pathogenic on the susceptible rice cultivars MR211 and MR220. Inoculated rice seedling produced typical bakanae symptom like elongation, thin and yellow leaves. F. andiyazi was further confirmed as pathogenic species by Ultra High-Performance Liquid Chromatography (UPLC) detection of Gibberellic acid (GA3) and Fusaric acid. In this study, F. andiyazi strains have been identified as the responsible pathogen for causing rice bakanae disease in Malaysia and it is the first report of F. andiyazi, as a pathogenic species on rice in Malaysia.