BioProject

Rice blast is a major disease of rice, caused by the fungus Magnaporthe oryzae. More...

Rice blast is a major disease of rice, caused by the fungus Magnaporthe oryzae. Different host environments can lead to differences in the genome of M. oryzae, which may affect its ability to infect rice. Additionally, other non-rice blast fungi can also cause similar rice diseases, which can exacerbate the complexity of the disease and the difficulty of prevention and control. Therefore, a comprehensive understanding of the genomes of fungi causing rice diseases is crucial for developing effective management strategies. In this study, we isolated and identified three different fungal strains from diseased barnyardgrass leaves, which were named SCAU-1, SCAU-2, SCAU-6 and were found belonging to Epicoccum sorghinum, M. oryzae, and Exserohilum rostratum, respectively. The results of pathogenicity test revealed that all the three isolated fungal strains could infect rice and barley leaves, and the results of amplification test using primers targeting a range of avirulence genes indicated that these three isolated fungal strains have eight avirulence genes, i.e., Avr-Pik, Avr-Pizt, Avr-Pia, Avr-Pi9, Avr-Pib, ACE1, PWL2, and PWL3. Additionally, Avr-Pita1 and Avr-Pita2 were only present in SCAU-2. Furthermore, we conducted whole-genome sequencing and analysis to understand the genetic variations and potential virulence factors relating to the host specificity of these three fungal pathogens. The results showed that the assembled genome sizes of SCAU-1,SCAU-2 and SCAU-6 were 31.16 Mb, 41.20 Mb, and 34.86 Mb, encoding 11242, 11594, and 11408 genes respectively. By annotating in the pathogenicity-related databases, we predicted 24, 18, and 30 key genes potentially associated with pathogenicity in SCAU-1, SCAU-2, and SCAU-6, respectively. We clarified the evolutionary relationships among the three pathogenic strains and observed that these isolated strains underwent gene family contractions and expansions to adapt to different hosts and environmental conditions. Moreover, we identified three unique effector proteins in SCAU-2 that were not found in any known databases. In summary, our research results provide clues to the pathogenic mechanisms of the pathogens based on the genomic information, and point out a potential risk for future rice disease management. Less...