This study investigates the biocontrol potential of extracts derived from the liquid co-cultivation of Saccharomyces cerevisiae and Pachysolen tannophilus , as well as from their respective monocultures, using xylose and xylulose as carbon sources, against phytopathogenic fungi affecting rice crops. LC-HRMS analysis, combined with advanced dereplication techniques, led to the annotation of several diketopiperazines, including cyclo(leucylprolyl), cyclo(phenylalanine-4-hydroxyproline), cyclo(prolylvalyl), cyclo(leucylvalyl), cyclo(phenylalanylprolyl), and cyclo(leucyl-4-hydroxyprolyl). The antifungal activity of the extracts was evaluated against Magnaporthe oryzae , Bipolaris oryzae , and Rhizoctonia solani , the causal agents of rice blast, brown spot, and sheath blight, respectively. In vitro assays included dual culture bioassays, assessments of conidial germination, and appressorium formation analysis. The co-culture extract completely inhibited appressorium formation (100%) and reduced conidial germination by 78%, exhibiting a minimum inhibitory concentration (MIC) of 1.25 mg/mL. Additionally, extracts from P. tannophilus at the same concentration showed notable antifungal effects, inhibiting 97.33% of appressorium formation and reducing conidial germination by 83.67% in M. oryzae , underscoring their potential in phytopathogen control. These findings indicate that the bioactive metabolites present in the extracts, particularly the annotated diketopiperazines, offer significant bioactive potential and represent a promising and sustainable alternative to conventional agrochemicals for rice disease management. • Co-culture extract fully inhibited appressorium formation in M. oryzae • P. tannophilus extract reduced conidial germination by 83.67% • LC-HRMS enabled annotation of antifungal diketopiperazines • Biocontrol potential against rice pathogens using xylose/xylulose-based extracts
Silva et al. (Sun,) studied this question.