Screening of endophytic fungi from rice (Oryza sativa L.) against rice pathogenic fungi

Abstract

This study aimed to isolate endophytic fungi from rice plants in northeastern Thailand. A total of 230 isolates from 130 rice plants were obtained and grouped into 57 morphotypes based on morphological features. The antagonistic activities were investigated in the dual culture assay against 6 rice pathogenic fungi, namely Magnaporthegrisea, Fusarium sp. FSK1, Fusarium sp. FSK2, Bipolarisoryzae, Curvularialunata and Rhizoctoniasolani. The result showed that twelve endophytic fungi were able to inhibit the growth of at least one tested pathogen. This study found that endophytic fungi isolate GR03, which the sequence analysis of ITS1-ITS2 region of rDNA was similarity to Trichodermaharzianum, was effective to inhibit the growth of all the tested pathogens, by more than 75%. Furthermore, the isolate GR03 was able to produce degrading enzymes (chitinase, protease and cellulase) and plant growth promoters (IAA and phosphate solubilization). The efficacy of controlling seedling rot of rice was evaluated using blotter test. The result indicated that seed treatment with a spore suspension of GR03 reduce the incidence of seedling rot caused by B. oryzae, C. lunata and Fusarium sp. FSK2 with 87%, 93.3% and 47.5%, respectively. The effectiveness of endophytic fungi to enhance rice seedlings (Khao Dowk Mali 105 variety) growth under greenhouse condition were assessed. The result showed that seed treatment with GR03 increased root length, shoot height, fresh weight and dry weight of shoot, when compared with control. This study suggested that the isolate GR03 has the potential to be used as biological control agent for rice diseases.