Beauveria bassiana (Bals.) Vuillemin (B. bassiana) is an entomopathogenic fungus that establishes endophytic symbiosis with plants. In the present study, the effects of B. bassiana strains colonization in growing Zea mays L. (Z. mays), crop production, and drought tolerance were evaluated. Z. mays seeds were inoculated with B. bassiana strains (GHA, PTG4, and PTG6), using 1 × 106 blastospores/mL and methyl cellulose (MC) or cornstarch (CS) as adherents. Colonization was determined by B. bassiana recovery from plant tissues plated on PDA medium. Plant height, fresh and dry weight, and flowering time were analyzed to assess plant performance. Drought tolerance was evaluated by stopping watering for 10 days, watering again, and determining vigor recovery after 24 h. Results showed 100% endophytic roots colonization, regardless of adherent type or strain tested. Colonization was variable in shoots and leaves, but GHA strain achieved the highest inoculation rates, including 88% in stems and 50% in leaves, which did not depend on adherent type used; for PTG4 strain, adherent type had an important effect (MC = 100% stems and leaves; CS = 63% stems and 25% leaves). For PTG6 strain, the best adherent type was CS (71% stems and 75% leaves), whereas MC showed variable inoculation percentage (25% stems and 75% leaves). Interestingly, only MCPTG4 treatment showed consistent positive effects on germination percentage (day 5 = 46 ± 2%; day 14 = 87 ± 7%) compared with controls (CC = 63 ± 4%, CMC = 50 ± 3%, CCS = 47 ± 0%). In addition, the other treatments showed low germination percentages at day 5 (7 ± 7% to 46 ± 2%), which recovered at day 14 (53 ± 0% to 73 ± 8%), except for MCPTG6 treatment with 23 ± 10% germination. About plant performance, not significant effects on plant height and fresh/dry weight in all the treatments were observed. However, B. bassiana-treated plants, using either GHA, PTG4 or PTG6 strains, and MC as adherent, showed tolerance to drought and flowered one to two weeks earlier, providing evidence supporting further applications of these seed treatments in agricultural systems, for abiotic stress sustainable management practices.

中文翻译：

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内生白僵菌促进玉米耐旱和早花

球孢白僵菌 (Bals.) Vuillemin (B. bassiana) 是一种昆虫病原真菌，可与植物建立内生共生关系。在本研究中，对 B. bassiana 菌株定植对玉米生长、作物生产和耐旱性的影响进行了评估。使用 1 × 106 芽生孢子/mL 和甲基纤维素 (MC) 或玉米淀粉 (CS) 作为粘附体，用 B. bassiana 菌株（GHA、PTG4 和 PTG6）接种 Z. mays 种子。通过从接种在 PDA 培养基上的植物组织中的球孢杆菌恢复来确定定植。分析植物高度、鲜重和干重以及开花时间以评估植物性能。通过停止浇水 10 天，再次浇水，并在 24 小时后确定活力恢复来评估耐旱性。结果显示 100% 内生根定植，无论粘附类型或应变测试如何。在芽和叶中的定植是可变的，但 GHA 菌株获得了最高的接种率，包括茎中的 88% 和叶中的 50%，这与所使用的贴壁类型无关；对于 PTG4 菌株，贴壁类型具有重要影响（MC = 100% 茎和叶；CS = 63% 茎和 25% 叶）。对于 PTG6 菌株，最佳贴壁类型是 CS（71% 茎和 75% 叶），而 MC 显示可变的接种百分比（25% 茎和 75% 叶）。有趣的是，与对照（CC = 63 ± 4%，CMC = 50 ± 3%，CCS = 47）相比，只有 MCPTG4 处理对发芽百分比（第 5 天 = 46 ± 2%；第 14 天 = 87 ± 7%）显示出一致的积极影响± 0%)。此外，其他处理在第 5 天显示低发芽率（7 ± 7% 至 46 ± 2%），在第 14 天恢复（53 ± 0% 至 73 ± 8%），除了 MCPTG6 处理 23 ± 10% 发芽。关于植物性能，在所有处理中均未观察到对株高和鲜/干重的显着影响。然而，使用 GHA、PTG4 或 PTG6 菌株和 MC 作为附着体，用球孢酵母处理的植物表现出对干旱的耐受性并提前一到两周开花，这为支持这些种子处理在农业系统中的进一步应用提供了证据，用于非生物强调可持续管理实践。