Sativene-Related\nSesquiterpenoids with Phytotoxic\nand Plant-Promoting Activities from the Plant Pathogenic Fungus Bipolaris sorokiniana Based on a Molecular Networking\nStrategy

Sativene-related sesquiterpenoids including <i>seco</i>-sativene analogs are a large member of fungal secondary metabolites\nwith phytotoxic and growth-promoting effects on different plants.\nIn this report, a series of sativene-related sesquiterpenoids with\ndiverse carbon skeletons (<b>1</b>–<b>9</b>, sativene/isosativene/<i>seco</i>-sativene/cyclosativene/<i>seco</i>-isosativene\nring systems) were isolated from the plant pathogenic fungus Bipolaris sorokiniana based on a molecular networking\nstrategy. The undescribed structures were elucidated based on NMR\nspectra, X-ray diffraction analysis, chemical derivation, and calculated\nelectronic circular dichroism calculations. Bipolaric acid (<b>1</b>) has a bicyclo[3.2.1] nonane skeleton (<i>seco</i>-sativene), bipolarone (<b>2</b>) is a unique cage-like cyclosativene\nsesquiterpenoid first isolated from fungi, and bipolariols A (<b>3</b>) and B (<b>4</b>) contain a novel octahydro-1,4-ethano\nisobenzofuran ring system (<i>seco</i>-isosativene). The\npossible biosynthetic pathways of these sesquiterpenoids (<b>1</b>–<b>9</b>) were proposed based on their structural features.\nDrechslerine B (<b>8</b>) exhibited phytotoxic activities to\ngreen foxtails, and compounds <b>5</b>–<b>7</b> and <b>9</b> showed growth-promoting effects with varying\ndegrees on seedling growth of Arabidopsis thaliana.