Centro de Investigación en Micorrizas y Sustentabilidad Agroambiental, CIMYSA, Facultad de Ingeniería y Ciencias, Universidad de La Frontera, Avenida Francisco Salazar, 01145, Temuco, Chile.
Rhizosphere Biology Laboratory, Department of Microbiology, Bharathidasan University, Tiruchirappalli, Tamil Nadu, 620 024, India.
Environ Sci Pollut Res Int. 2019 Sep;26(27):27647-27659. doi: 10.1007/s11356-019-05939-9. Epub 2019 Jul 23.
Aluminum (Al) is a major constraint for plant growth by inducing inhibition of root elongation in acid soils around the world. Besides, drought is another major abiotic stress that adversely affects growth and productivity of agricultural crops. The plant growth-promoting (PGP) rhizobacterial strains are useful choice to decrease these stressful effects and is now extensively in practice. However, the use of bacterial inoculation has not been attempted for the mitigation of Al stress in plants growing at high Al levels under drought stress. Therefore, in the present study, Al- and drought-tolerant bacterial strains were isolated from Lactuca sativa and Beta vulgaris rhizospheric soils. Among the bacterial isolates, two strains, CAM12 and CAH6, were selected based on their ability to tolerate high levels of Al (8 mM) and drought (15% PEG-6000, w/v) stresses. The bacterial strains CAM12 and CAH6 were identified as Bacillus megaterium and Pantoea agglomerans, respectively, by 16S rRNA gene sequence homology. Moreover, both strains showed multiple PGP traits even in the presence of abiotic stresses. In the pot experiments, inoculation of the strains CAM12 and CAH6 as individually or as included in a consortium improved the Vigna radiata growth under abiotic stress conditions and reduced Al uptake in plants. However, the most effective treatment was seen with bacterial consortium that allowed the plants to tolerate abiotic stress effectively and achieved better growth. These results indicate that bacterial consortium could be used as a bio-inoculant for enhancing V. radiata growth in soil with high Al levels subjected to drought conditions.
铝（Al）是世界范围内酸性土壤中根系伸长抑制的主要限制因素，从而影响植物生长。此外，干旱是另一种主要的非生物胁迫因素，它会对农业作物的生长和生产力产生不利影响。植物促生（PGP）根际细菌菌株是减少这些胁迫影响的有用选择，现在已广泛应用。然而，在高铝水平下干旱胁迫条件下生长的植物中，尚未尝试使用细菌接种来减轻铝胁迫。因此，在本研究中，从莴苣和糖甜菜根际土壤中分离出耐铝和耐旱的细菌菌株。在细菌分离物中，根据其耐受高浓度铝（8 mM）和干旱（15% PEG-6000，w/v）胁迫的能力，选择了两个菌株 CAM12 和 CAH6。细菌菌株 CAM12 和 CAH6 通过 16S rRNA 基因序列同源性鉴定为巨大芽孢杆菌和成团泛菌，分别。此外，即使在存在非生物胁迫的情况下，这两种菌株均表现出多种 PGP 特性。在盆栽实验中，单独接种或包含在联合体中的菌株 CAM12 和 CAH6 均可改善非生物胁迫条件下豇豆的生长，并减少植物对铝的吸收。然而，最有效的处理方法是使用细菌联合体，它可以使植物有效耐受非生物胁迫并实现更好的生长。这些结果表明，细菌联合体可以用作生物接种剂，用于在高铝水平的土壤中增强豇豆在干旱条件下的生长。
