Department of Botany and Microbiology, College of Sciences, King Saud University, P.O. Box 2455, Riyadh, 11451, Saudi Arabia.
Department of Agricultural Microbiology, Faculty of Agricultural Sciences, Aligarh Muslim University, Aligarh, 202002, Uttar Pradesh, India.
Chemosphere. 2022 May;295:133843. doi: 10.1016/j.chemosphere.2022.133843. Epub 2022 Feb 2.
Environmental challenges like drought, salinity, heavy metals and pesticides directly/indirectly influence the environment and decreased the agricultural output. During its long developmental stages, cereal crops including wheat is exposed to a variety of abiotic/biotic stressors. Certain beneficial soil bacteria that can ameliorate environmental stresses can be exploited as crop growth promoters/enhancers under adverse situations. In this study, Beijerinckia fluminensis BFC-33 (accession no. MT672580) isolated from potato rhizosphere tolerated variousabiotic (drought, salinity, temperature, heavy metals, and fungicides) stresses. Strain BFC-33 demonstrated multifarious plant-growth-promoting (PGP) characteristics, such as the production of indole-3-acetic acid, P-solubilization, ACC deaminase, ammonia, siderophore, HCN, EPS, and extracellular enzymes. The antagonistic potential of BFC-33 against major fungal pathogens was ranked: Alternaria alternata (79.2%)>Rhizoctonia solani (69%)>Fusarium oxysporum (23.5%)>Ustilaginoidea virens (17%). Furthermore, bacterization of wheat seeds witha multi-stress-tolerant strain revealed B. fluminensis as a plant growth enhancer and biocontrol agent. For instance, increase in root length (cm) in BFC-33 inoculated wheat exposed to abiotic and biotic stresses at the seedling stage was ranked: B. fluminensis (24.2)>B. fluminensis + 100μgTBZLmL (21.3) = B. fluminensis + 2%PEG (21.3)>B. fluminensis + 100 mM NaCl (19.7)>B. fluminensis + 100μgPbmL (19) = B. fluminensis 100μgMNZBmL (19)>B. fluminensis + A. alternata (17.4)>B. fluminensis + 100μgCdmL (17)>B. fluminensis + F. oxysporum (13.4). In addition, increase in carotenoid accumulation (mg gFW) in the foliage of BFC-33 inoculated wheat exposed to fungal infection was ranked: BFC-33 (3.88)>BFC-33+ A. alternata (3.0)>BFC-33+ R. solani (2.78)>BFC-33+ F. oxysporum (2.44). Moreover, BFC-33 inoculation significantly (p ≤ 0.05) reduced stress-induced stressor molecules (proline and TBARS) and electrolyte leakage. Furthermore, B. fluminensis BFC-33 potentially enhanced the defense responses in wheat seedlings by increasing phenylalanine ammonia lyase (PAL), β-1,3 glucanase, and polyphenol oxidase (PPO), which play a significant role in protecting plants from phytopathogens. Even so, by successfully establishing a product with the requisite effects under field settings, selecting multi-stress-tolerant and antagonistic plant growth promoting rhizobacteria (PGPRs) would be helpful to end-users. Future use of native multi-stress-tolerant bacteria as biocontrol agents in conjunction with existing drought, salinity, heavy metal, and pesticide tolerance might contribute to global food security.
环境挑战，如干旱、盐度、重金属和农药，直接/间接影响环境并降低农业产量。在其漫长的发育阶段，包括小麦在内的谷类作物会暴露在各种非生物/生物胁迫下。某些有益的土壤细菌可以在不利条件下被利用为作物生长促进剂/增强剂，以缓解环境压力。在这项研究中，从马铃薯根际中分离出的贝日阿托氏菌 BFC-33（登录号 MT672580）耐受各种非生物（干旱、盐度、温度、重金属和杀菌剂）胁迫。菌株 BFC-33表现出多种植物生长促进（PGP）特性，如吲哚-3-乙酸的产生、磷的溶解、ACC 脱氨酶、氨、铁载体、HCN、EPS 和细胞外酶。BFC-33 对主要真菌病原体的拮抗潜力排名为：链格孢菌（79.2%）>立枯丝核菌（69%）>尖孢镰刀菌（23.5%）>玉米赤霉（17%）。此外，用多抗压力菌株对小麦种子进行细菌接种，发现贝日阿托氏菌是一种植物生长增强剂和生物防治剂。例如，在幼苗期暴露于生物和非生物胁迫下，接种 BFC-33 的小麦根长（cm）增加的排名为：贝日阿托氏菌（24.2）>贝日阿托氏菌+100μgTBZLmL（21.3）=贝日阿托氏菌+2%PEG（21.3）>贝日阿托氏菌+100mMNaCl（19.7）>贝日阿托氏菌+100μgPbmL（19）=贝日阿托氏菌 100μgMNZBmL（19）>贝日阿托氏菌+链格孢菌（17.4）>贝日阿托氏菌+100μgCdmL（17）>贝日阿托氏菌+尖孢镰刀菌（13.4）。此外，在接种 BFC-33 的小麦叶片中类胡萝卜素积累（mg gFW）增加的排名为：BFC-33（3.88）>BFC-33+链格孢菌（3.0）>BFC-33+立枯丝核菌（2.78）>BFC-33+尖孢镰刀菌（2.44）。此外，BFC-33 接种显著（p≤0.05）降低了胁迫诱导的胁迫分子（脯氨酸和 TBARS）和电解质渗漏。此外，贝日阿托氏菌 BFC-33 通过增加苯丙氨酸解氨酶（PAL）、β-1,3 葡聚糖酶和多酚氧化酶（PPO），增强了小麦幼苗的防御反应，这些酶在保护植物免受植物病原体侵害方面发挥着重要作用。即便如此，通过在田间环境中成功建立具有所需效果的产品，选择多抗压力和拮抗的植物生长促进根际细菌（PGPR）将有助于最终用户。未来将本土多抗压力细菌用作生物防治剂与现有的干旱、盐度、重金属和农药耐受性结合使用，可能有助于全球粮食安全。
