Endophytic Beauveria spp. Enhance Tomato Growth and Resistance to Botrytis cinerea via Transcriptomic Regulation

Entomopathogenic fungi of the genus <i>Beauveria</i> are recognized for their dual role as insect pathogens and plant endophytes, however the majority of research efforts to date have centered on <i>B. bassiana</i>. To address this bias, we evaluated the endophytic traits of five <i>Beauveria</i> species (<i>B. bassiana</i>, <i>B. brongniartii</i>, <i>B. aranearum</i>, <i>B. amorpha</i>, and <i>B. velata</i>) in tomato (<i>Solanum lycopersicum</i>). Tomato seedlings were inoculated by root drenching with 1 × 10⁸ conidia/mL suspensions, and colonization, plant growth, and resistance to <i>Botrytis cinerea</i> were assessed. All five species colonized tomato tissues, with colonization rates from 33.3% (<i>B. velata</i>) to 56.7% (<i>B. brongniartii</i>). Growth promotion was species dependent: <i>B. bassiana</i>, <i>B. brongniartii</i>, and <i>B. aranearum</i> significantly increased plant height, while <i>B. brongniartii</i> enhanced aboveground biomass. In pathogen assays, all <i>Beauveria</i>-treated plants showed reduced gray mold incidence and severity, with <i>B. brongniartii</i> conferring complete protection. Transcriptome analysis identified 160 differentially expressed genes commonly regulated, including 17 upregulated genes enriched in defense responses, hormone signaling, and photosynthesis. These findings demonstrate that non-<i>B. bassiana</i> species can establish endophytic associations, promote growth, and induce resistance in tomato, expanding the potential of <i>Beauveria</i> spp. as biocontrol agents in sustainable agriculture.