Biotechnology Division, CSIR-Institute of Himalayan Bioresource Technology, Palampur, Himachal Pradesh 176061, India; Academy of Scientific and Innovative Research (AcSIR), Ghaziabad 201002, India.
Biotechnology Division, CSIR-Institute of Himalayan Bioresource Technology, Palampur, Himachal Pradesh 176061, India.
Microbiol Res. 2024 Sep;286:127818. doi: 10.1016/j.micres.2024.127818. Epub 2024 Jun 26.
The agricultural land in the Indian Himalayan region (IHR) is susceptible to various spells of snowfall, which can cause nutrient leaching, low temperatures, and drought conditions. The current study, therefore, sought an indigenous psychrotrophic plant growth-promoting (PGP) bacterial inoculant with the potential to alleviate crop productivity under cold and drought stress. Psychrotrophic bacteria preisolated from the night-soil compost of the Lahaul Valley of northwestern Himalaya were screened for phosphate (P) and potash (K) solubilization, nitrogen fixation, indole acetic acid (IAA) production, siderophore and HCN production) in addition to their tolerance to drought conditions for consortia development. Furthermore, the effects of the selected consortium on the growth and development of wheat (Triticum aestivum L.) and maize (Zea mays L.) were assessed in pot experiments under cold semiarid conditions (50 % field capacity). Among 57 bacteria with P and K solubilization, nitrogen fixation, IAA production, siderophore and HCN production, Pseudomonas protegens LPH60, Pseudomonas atacamensis LSH24, Psychrobacter faecalis LUR13, Serratia proteamaculans LUR44, Pseudomonas mucidolens LUR70, and Glutamicibacter bergerei LUR77 exhibited tolerance to drought stress (-0.73 MPa). The colonization of wheat and maize seeds with these drought-tolerant PGP strains resulted in a germination index >150, indicating no phytotoxicity under drought stress. Remarkably, a particular strain, Pseudomonas sp. LPH60 demonstrated antagonistic activity against three phytopathogens Ustilago maydis, Fusarium oxysporum, and Fusarium graminearum. Treatment with the consortium significantly increased the foliage (100 % and 160 %) and root (200 % and 133 %) biomasses of the wheat and maize plants, respectively. Furthermore, whole-genome sequence comparisons of LPH60 and LUR13 with closely related strains revealed genes associated with plant nutrient uptake, phytohormone synthesis, siderophore production, hydrogen cyanide (HCN) synthesis, volatile organic compound production, trehalose and glycine betaine transport, cold shock response, superoxide dismutase activity, and gene clusters for nonribosomal peptide synthases and polyketide synthetases. With their PGP qualities, biocontrol activity, and ability to withstand environmental challenges, the developed consortium represents a promising cold- and drought-active PGP bioinoculant for cereal crops grown in cold semiarid regions.
印度喜马拉雅地区（IHR）的农田容易受到各种降雪的影响，这些降雪会导致养分淋失、低温和干旱条件。因此，本研究寻求一种具有土著性的、能在寒冷和干旱胁迫下促进植物生长的（PGP）细菌接种剂。从印度西北部拉胡尔山谷的粪肥中预先分离出的嗜冷细菌，通过对磷酸盐（P）和钾肥（K）的溶解、固氮、吲哚乙酸（IAA）的产生、铁载体和 HCN 的产生进行筛选，以及对干旱条件的耐受性进行筛选，以开发共生体。此外，在寒冷半干旱条件下（田间持水量的 50%），通过盆栽实验评估了所选共生体对小麦（Triticum aestivum L.）和玉米（Zea mays L.）生长发育的影响。在具有 P 和 K 溶解、固氮、IAA 产生、铁载体和 HCN 产生功能的 57 株细菌中，Pseudomonas protegens LPH60、Pseudomonas atacamensis LSH24、Psychrobacter faecalis LUR13、Serratia proteamaculans LUR44、Pseudomonas mucidolens LUR70 和 Glutamicibacter bergerei LUR77 对干旱胁迫具有耐受性（-0.73 MPa）。这些耐旱 PGP 菌株对小麦和玉米种子的定殖导致发芽指数>150，表明在干旱胁迫下没有植物毒性。值得注意的是，一种特殊的菌株 Pseudomonas sp. LPH60 对三种植物病原菌玉米黑粉菌、尖孢镰刀菌和禾谷镰刀菌具有拮抗活性。用共生体处理显著增加了小麦和玉米植株的叶（100%和 160%）和根（200%和 133%）生物量。此外，与密切相关的菌株相比，LPH60 和 LUR13 的全基因组序列比较揭示了与植物养分吸收、植物激素合成、铁载体生产、氢氰酸（HCN）合成、挥发性有机化合物生产、海藻糖和甘氨酸甜菜碱运输、冷激反应、超氧化物歧化酶活性以及非核糖体肽合成酶和聚酮合酶基因簇相关的基因。由于其具有 PGP 特性、生物防治活性和耐受环境挑战的能力，因此开发的共生体代表了一种有前途的冷旱活性 PGP 生物接种剂，可用于寒冷半干旱地区的谷类作物。
