Data Sheet 1_Beauvericin production by endophytic and epiphytic Beauveria bassiana in peach (Prunus persica) and implications for insect biocontrol.pdf

Beauveria bassiana (Balsamo) Vuillemin is a well-known entomopathogenic fungus that occupies diverse ecological niches, including soilborne, epiphytic, and endophytic habitats. Its capacity to function as an endophyte has received growing interest in potential applications for sustainable pest management, particularly in woody perennial systems where delivery and persistence of biological control agents are challenging. This study investigated endophytic colonization of peach (Prunus persica Batsch) seedlings by B. bassiana and quantified production of the insecticidal secondary metabolite beauvericin (BEA) in and on plant tissues. Seedlings were inoculated via foliar spray or soil drench. Fungal recovery was assessed from leaf, stem, and root tissues. Colonization patterns indicated systemic movement, however foliar spray increased recovery from leaf tissues and soil drench increased recovery from roots over time. BEA concentrations varied significantly by tissue type, inoculation method, and surface sterilization status. The highest levels were detected in non-surface-sterilized leaves of foliar-sprayed plants, measured two weeks post-inoculation. Surface sterilization prior to extraction significantly reduced detected concentrations, suggesting that BEA is primarily produced by epiphytic fungal growth. Larval bioassays with Tenebrio molitor L. revealed increased mortality associated with foliar-sprayed tissues, aligning with observed BEA levels and suggesting localized insecticidal activity. These findings demonstrate that the spatial dynamics of fungal colonization and metabolite localization are critical considerations for the effective deployment of B. bassiana in biocontrol strategies. Further research is needed to determine how environmental factors, host physiology, fungal strain, and time influence secondary metabolite production in and on plants treated with B. bassiana.

球孢白僵菌（Beauveria bassiana (Balsamo) Vuillemin）是一类广为人知的昆虫病原真菌，其栖息于多样的生态位，涵盖土栖、附生及内生等生境。其作为内生真菌的功能特性在可持续害虫治理的潜在应用中日益受到关注，尤其是在木本多年生栽培系统中，这类系统的生物防治制剂递送与持效性均颇具挑战。本研究针对球孢白僵菌对桃树（Prunus persica Batsch）幼苗的内生定殖情况展开探究，并定量检测了植物组织内外的杀虫次生代谢产物球孢菌素（beauvericin, BEA）的生成量。试验采用叶面喷雾或土壤浇灌的方式对幼苗进行接种。研究人员从叶片、茎秆及根系组织中开展真菌回收检测，以评估定殖效果。定殖模式结果显示真菌具备系统性移动能力，但随培养时间延长，叶面喷雾处理可提升叶片组织中的真菌回收率，而土壤浇灌处理则可提升根系的真菌回收率。BEA的浓度因组织类型、接种方式及表面灭菌处理状态的不同而存在显著差异。在接种两周后，叶面喷雾处理植株的非表面灭菌叶片中检测到了最高的BEA水平。提取前对组织进行表面灭菌处理会显著降低检测到的BEA浓度，这表明BEA主要由附生状态的真菌生长所产生。以黄粉虫（Tenebrio molitor L.）为试虫开展的幼虫生物测定结果显示，经叶面喷雾处理的植物组织可导致试虫死亡率升高，这与观测到的BEA水平相契合，提示该代谢产物具备局部杀虫活性。本研究结果表明，真菌定殖的空间动态特征与代谢产物的定位情况，是球孢白僵菌应用于生物防治策略时需重点考量的关键因素。未来仍需开展进一步研究，以明确环境因子、宿主生理状态、真菌菌株及培养时间如何影响经球孢白僵菌处理的植物组织内外的次生代谢产物合成。