Cen Xinyi, Li Hua, Zhang Yanhua, Huang Lingfeng, Luo Yuanrong
Key Laboratory of the Ministry of Education for Coastal and Wetland Ecosystems, Xiamen University, Xiamen 361102, China.
Xiamen City Key Laboratory of Urban Sea Ecological Conservation and Restoration (USER), Xiamen University, Xiamen 361102, China.
Plants (Basel). 2024 Sep 27;13(19):2703. doi: 10.3390/plants13192703.
The objective of the present study was to isolate endophytes from the roots of the halophyte , which is applied for aquatic phytoremediation. From these endophytes, siderophore-producing bacteria were specifically isolated for their potential capacity to promote plant growth. The siderophore production capacity of the isolated bacteria was quantified, and a high-yield siderophore-producing strain was selected for further investigation. A total of 33 endophytic bacteria were successfully isolated and identified using a culturable approach. Of these, 10 siderophore-producing bacteria were identified using the selective agar assay, displaying siderophore unit (SU) values ranging from 11.90% to 80.39%. It is noteworthy that sp. QZ-E9 exhibited the highest siderophore production capacity, achieving an SU of 80.39%. A microcosm co-cultivation experiment was conducted with the strain QZ-E9 in iron-deficient conditions (2 μmol/L Fe⁺). The results demonstrated that strain QZ-E9 significantly enhanced the growth of , by increases in both fresh weight (1.41 g) and root length (18.7 cm). Furthermore, fluorescence in situ hybridization (FISH) was utilized to ascertain the colonization pattern of strain QZ-E9 within the plant roots. The analysis demonstrated that strain QZ-E9 exhibited extensive colonization of the epidermal and outer cortical cells of roots, as well as the intercellular spaces and vascular tissues. This colonization indicated that sp. QZ-E9 plays a crucial role in promoting the growth of , presumably through its siderophore-mediated iron acquisition mechanism.
本研究的目的是从用于水生植物修复的盐生植物根部分离内生菌。从这些内生菌中，专门分离出具有产铁载体能力的细菌，因其具有促进植物生长的潜在能力。对分离出的细菌的产铁载体能力进行了定量分析，并选择了一株高产铁载体的菌株进行进一步研究。采用可培养方法成功分离并鉴定出33株内生细菌。其中，通过选择性琼脂试验鉴定出10株产铁载体细菌，其铁载体单位（SU）值在11.90%至80.39%之间。值得注意的是，QZ-E9菌株表现出最高的产铁载体能力，SU值达到80.39%。在缺铁条件（2 μmol/L Fe⁺）下，对QZ-E9菌株进行了微观共培养实验。结果表明，QZ-E9菌株显著促进了（植物名称缺失）的生长，鲜重增加了1.41 g，根长增加了18.7 cm。此外，利用荧光原位杂交（FISH）确定了QZ-E9菌株在植物根部的定殖模式。分析表明，QZ-E9菌株在（植物名称缺失）根部的表皮细胞、外皮层细胞、细胞间隙和维管组织中广泛定殖。这种定殖表明，QZ-E9菌株在促进（植物名称缺失）生长方面起着关键作用，可能是通过其铁载体介导的铁获取机制。
