Yeast Associated with Rice Phylloplane and Their Contribution to Control of Rice Sheath Blight Disease

• Main Authors: Parichat Into, Pannida Khunnamwong, Sasitorn Jindamoragot, Somjit Am-in, Wanwilai Intanoo, Savitree Limtong
• Format: Article
• Language: English
• Published: MDPI AG 2020-03-01
• Series: Microorganisms
• Subjects: phylloplane yeast; antagonistic yeast; rice pathogenic fungi; rice sheath blight; biological control
• Online Access: https://www.mdpi.com/2076-2607/8/3/362

The phylloplane is an important habitat for yeasts and these yeasts may have antagonistic activities against pathogens and could be used as biocontrol agents. To investigate rice phylloplane yeasts, 282 strains were isolated from 89 rice leaf samples and identified as 15 known yeast species in the phylum Ascomycota and 35 known and two potential new species in the phylum Basidiomycota. The majority of rice phylloplane yeasts belonged to the phylum Basidiomycota. The evaluation of antagonistic activities of 83 yeast strains against rice pathogenic fungi <i>Pyricularia</i> <i>oryzae</i>, <i>Rhizoctonia solani</i>, <i>Fusarium moniliforme</i>, <i>Helminthosporium oryzae</i> and <i>Curvularia lunata</i> revealed that 14 strains inhibited these pathogens. Among the antagonistic strains, <i>Torulaspora indica </i>DMKU-RP31, <i>T. indica </i>DMKU-RP35 and <i>Wickerhamomyces anomalus </i>DMKU-RP25 inhibited all rice pathogens tested, and the production of volatile organic compounds, fungal cell wall degrading enzymes and biofilm were the possible antagonistic mechanisms against all rice pathogens tested in vitro. These yeast strains were evaluated for controlling rice sheath blight caused by <i>R. solani</i> in rice plants in the greenhouse and were found to suppress the disease by 60.0&#8722;70.3%, whereas 3% validamycin suppressed by 83.8%. Therefore, they have potential for being developed to be used as biocontrol agents for rice sheath blight.