Microbiology Laboratory, UGC Centre for Advanced Study, Department of Botany, Burdwan University, Burdwan, 713104, WB, India; Department of Botany, Government General Degree College, Singur, Hooghly, 712409, WB, India.
Microbiology Laboratory, UGC Centre for Advanced Study, Department of Botany, Burdwan University, Burdwan, 713104, WB, India.
J Plant Physiol. 2018 Dec;231:434-442. doi: 10.1016/j.jplph.2018.10.010. Epub 2018 Oct 12.
Increasing soil salinity is often associated with accelerated ethylene production in plants, leading to overall growth reduction. The salt-tolerant 1-aminocyclopropane-1-carboxylic acid (ACC) deaminase-producing PGPR may alleviate salt stress by reducing the production of stress ethylene. In this study, a salt-tolerant ACC deaminase-producing strain named P50 was isolated from a coastal rice field in Odisha, India, which enhanced the growth of rice seedlings under salt stress. The P50 strain was identified as Burkholderia sp. based on phenotypic characteristics, MALDI-TOF MS data for ribosomal proteins and 16S rDNA sequence-based homology. Various PGP traits of strain P50 were characterized, among which the ACC deaminase activity was optimized at different physical conditions and confirmed by enzyme assay, as well as FTIR. The IAA, EPS and proline production of this strain were estimated under increasing NaCl concentrations essential for plant growth promotion under salt stress. Finally, the P50 strain was utilized in a gnotobiotic assay using rice seedlings (cv. Swarnamasuri) under saline stress. Seedlings treated with the P50 strain showed improvement in various morphological and biochemical characteristics, ROS scavenging antioxidant enzymatic activities, and reduced amounts of stress ethylene compared to non-inoculated strains under salinity. In addition, isolation of the ACC deaminase mutant of this strain was not found to reduce stress ethylene, confirming that the P50 strain was associated with a reduction in stress ethylene. Strain P50 was also found to colonize the root surfaces of rice seedlings associated with the plant-microbe interaction process. Thus, as an effective salt-tolerant PGPR, strain P50 can be utilized in salt-affected agricultural fields to improve plant growth in a sustainable manner.
土壤盐度升高通常与植物中乙烯产量的加速有关，导致整体生长减少。耐盐 1-氨基环丙烷-1-羧酸 (ACC) 脱氨酶产生的 PGPR 可以通过减少应激乙烯的产生来缓解盐胁迫。在这项研究中，从印度奥里萨邦沿海稻田中分离出一株耐盐 ACC 脱氨酶产生菌 P50，该菌在盐胁迫下增强了水稻幼苗的生长。根据表型特征、核糖体蛋白的 MALDI-TOF MS 数据和 16S rDNA 序列同源性，将 P50 菌株鉴定为伯克霍尔德氏菌属。对菌株 P50 的各种 PGPR 特性进行了表征，其中 ACC 脱氨酶活性在不同物理条件下进行了优化，并通过酶测定和傅里叶变换红外光谱 (FTIR) 进行了确认。在促进盐胁迫下植物生长所必需的 NaCl 浓度增加的情况下，估计了该菌株的 IAA、EPS 和脯氨酸的产生。最后，在盐胁迫下使用水稻幼苗（Swarnamasuri 品系）进行了无菌试验，利用 P50 菌株。与非接种菌株相比，用 P50 菌株处理的幼苗在各种形态和生化特征、ROS 清除抗氧化酶活性以及应激乙烯的减少方面均得到改善。此外，该菌株的 ACC 脱氨酶突变体的分离并未发现降低应激乙烯，这证实了 P50 菌株与应激乙烯的减少有关。还发现 P50 菌株能够定植于水稻幼苗的根表面，与植物-微生物相互作用过程有关。因此，作为一种有效的耐盐 PGPR，P50 菌株可用于受盐影响的农业领域，以可持续的方式促进植物生长。
