Beauveria bassiana Colonizes the Chiltepin Pepper (Capsicum annuum var. glabriusculum) Using Different Inoculation Techniques under Varying Shading Levels

Abstract

Abstract Chiltepin (Capsicum annuum var. glabriusculum), a wild chili pepper valued for its pungency, may benefit from colonization by endophytic fungi to enhance plant growth; however, such interactions have not yet been studied in this species. This study compared two sodium hypochlorite concentrations (3% and 5%) for surface disinfection during endophyte isolation from Beauveria bassiana-inoculated seedlings (leaf, stem, and root tissues evaluated at 7 days post-inoculation, dpi). Additionally, two inoculation methods (foliar spray and soil drench) were assessed for colonization efficiency under four shading levels (0%, 20%, 55%, and 70%), monitored at 14 and 30 dpi. Fungal isolates exhibiting morphological characteristics consistent with Beauveria were recovered from colonized tissues and confirmed by molecular identification. Plant height and stem diameter were measured at 14 and 28 dpi to evaluate growth promotion. Results demonstrated equivalent surface disinfection efficacy between NaOCl concentrations for endophyte studies. Foliar application achieved greater B. bassiana colonization in stems (14-35%) and leaves (up to 73%) compared with soil drench, while shading had no significant effect. Molecular analyses confirmed the identity of B. bassiana isolated from plant tissues. In terms of growth promotion, control plants exhibited greater height and stem diameter than inoculated plants. These findings demonstrate that a NaOCl concentration of 3-5% is effective for chiltepin tissue disinfection and provide the first report of B. bassiana colonization in this species, identifying foliar application as the most effective method for endophytic establishment.