Antagonistic microbes isolated from fermentation broth of plant wastes against anthracnose of Camellia oleifera caused by Colletotrichum siamense

Abstract

Abstract Camellia oleifera is an important edible oil woody plant in China. Anthracnose is a serious disease of C. oleifera, causing severe economic losses and posing a huge threat to the C. oleifera industry. The fungi Colletotrichum siamense is one of the main pathogens causing anthracnose of Camellia oleifera. In this study, antifungal activity of microorganisms isolated from fermentation broth against C. siamense were investigated for the first time. 8 strains were isolated and purified from fermentation broth. By morphological observation, gene sequence analysis, among the strains, 4 isolates were identified as Trichoderma harzianum and 4 isolates were identified as Bacillus subtilis. The result showed that 8 isolates displayed a relatively good potential on inhibiting the mycelial growth in C. siamense, but T. harzianum was more effective than B. subtilis as a biocontrol agent, with the best efficiency of 73.56%. In the vitro treatments, the combination of T. harzianum and B. subtilis were the most effective treatments in reducing the incidence and severity of anthracnose in C.oleifera, with the highest efficiency of 77.56%. It can be concluded that T. harzianum and B. subtilis are promising biocontrol agents to manage anthracnose in C.oleifera. These promising results provided valuable information on using fermentation broth of plant wastes as a new source of antagonists to control fungi disease.