Phytotoxic Hemiketal-Containing Polyketides from the Endophytic Fungus <i>Trichoderma koningiopsis</i> WZ-196 with the OSMAC Strategy and Molecular Network Technology

Thirty highly oxidized hemiketal-containing polyketides, including 10 new ones (<b>1</b>-<b>10</b>) and 20 known analogues (<b>11</b>-<b>30</b>), were obtained from the endophytic fungus <i>Trichoderma koningiopsis</i> WZ-196 with the OSMAC strategy in combination with molecular network analysis. Their structures were elucidated through comprehensive spectroscopic analysis, together with NMR and ECD calculations. The phytotoxic activities of all compounds were evaluated using <i>Arabidopsis thaliana</i> (dicotyledonous) and <i>Oryza sativa</i> (monocotyledonous) as model systems. The results showed that most compounds exhibited significant inhibitory effects on seedling growth. Notably, compound <b>9</b> demonstrated the strongest phytotoxic activity against <i>A. thaliana</i> with an IC₅₀ value of 8.09 μM, while <b>24</b> markedly suppressed the growth of <i>O. sativa</i> with an IC₅₀ value of 9.42 μM, outperforming the commercial herbicide glyphosate under identical experimental conditions. These findings highlight the potential of hemiketal-containing polyketides derived from endophytic fungi as promising candidates for developing novel bioherbicides.