骆驼刺可培养内生细菌的分离及功能特性

Isolation and functional characterization of culturable endophytic bacteria from Alhagi sparsifolia Shap.

摘要:

【背景】植物内生菌与宿主存在长期协同演化，是研究微生物多样性和适应性进化的宝库。骆驼刺(Alhagi sparsifolia Shap.)具有耐干旱、耐盐碱等极强的抗逆特性，而有关骆驼刺内生菌的研究较少。【目的】解析骆驼刺可培养内生菌多样性，评价菌株抗逆、促生特性。【方法】采用组织匀浆法和梯度稀释法分离纯化骆驼刺内生菌，利用16S rRNA基因序列比对初步明确菌株的分类定位，进一步测定菌株的抗逆、促生及抑菌功能特性。【结果】从骆驼刺中共分离获得了14株可培养内生细菌，分属于芽孢杆菌属(Bacillus)、短状杆菌属(Brachybacterium)、微杆菌属(Microbacterium)、棒杆菌属(Corynebacterium)、土壤芽孢杆菌属(Solibacillus)、谷氨酸杆菌属(Glutamicibacter)、亮杆菌属(Leucobacter)、短杆菌属(Brevibacterium)及不动杆菌属(Acinetobacter)这9个菌属，其中芽孢杆菌属菌株所占比例最高(33.33%)；所获得的菌株表现出不同水平的抗逆、促生及抑菌特性，其中Bacillus subtilis L-1展现出较强的抗逆特性，可耐受20% NaCl及20%的PEG6000胁迫，同时对4种病原细菌及3种病原真菌具有抑菌作用。【结论】骆驼刺内生细菌具有抗逆、促生及抑菌特性，为进一步挖掘和利用相关内生菌资源提供了研究基础和科学依据。

Abstract:

[Background] Endophytes represent valuable resources for investigating microbial diversity and adaptive evolution, owing to their long-term co-evolutionary relationship with their hosts. Alhagi sparsifolia Shap. exhibits robust tolerance to stress conditions including drought and saline-alkali. However, the studies about the endophytes of A.sparsifolia remain limited. [Objective] To analyze the diversity of culturable endophytic bacteria and evaluate the stress tolerance and plant growth-promoting effects of the strains. [Methods] Endophytic bacteria were isolated from A.sparsifolia by the tissue homogenization and gradient dilution methods. The strains were identified by comparison of 16S rRNA gene sequences. Subsequently, we determined the stress tolerance, plant growth-promoting effects, and antimicrobial activities of the strains. [Results] A total of 14 culturable endophytic bacterial strains were isolated from A.sparsifolia, belonging to 9 genera (Bacillus, Brachybacterium, Microbacterium, Corynebacterium, Solibacillus, Glutamicibacter, Leucobacter, Brevibacterium, and Acinetobacter), among which Bacillus was dominant (33.33%). These strains exhibited varying levels of stress tolerance, plant growth-promoting effects, and antimicrobial activities. Notably, Bacillus subtilis L-1 demonstrated strong tolerance to 20% NaCl solution and 20% PEG6000 and inhibitory effects on four pathogenic bacterial species and three pathogenic fungal species. [Conclusion] Our study revealed the stress tolerance, plant growth-promoting effects, and antimicrobial activities of culturable endophytic bacterial resources in A.sparsifolia. The findings provide a scientific basis for further exploration and utilization of these valuable resources.