Tomato Growth Promotion Induced by Stress Tolerant Phosphate Solubilizing Pseudomonas simiae in Arid trans-Himalaya

Abstract

Pseudomonas simiae isolated from Seabuckthorn rhizosphere solubilised insoluble phosphate at 4-40 ºC, pH 4-12 and in presence of 1-5 per cent salt concentration. The optimum condition was observed at 28 ºC, pH 6 and devoid of any salt stress. Ca 3 (PO 4 ) 2 was solubilised to a great extent than FePO 4 and AlPO 4 . The isolate possess plant growth promoting attributes such as IAA (32 mg l -1 ), siderophore (78 percent) and HCN (0.1 OD at A 625 ) production. Seed bacterisation resulted in 30 per cent and 51 per cent enhanced shoot and root length, respectively in tomato seedling. Pot experiments revealed enhanced plant growth in P. simiae treated plants in both green shade net and open field conditions. Fruit yield was 9.8 per cent and 19.8 per cent higher over control in open and shade net condition, respectively.

Psychrophilic Bacterial Phosphate-Biofertilizers: A Novel Extremophile for Sustainable Crop Production under Cold Environment

“…Among agronomically potential organisms, cold-active phosphate solubilizing bacteria, for example, Pseudomonas, have been recovered from glacial ice habitats [18] and other cold ecosystems worldwide such as Andean mountain glaciers [31,32], polar environments [33,34], cold deserts [35,36], Himalayan soils [27,37], and alpine soils [38,39]. Some notable plant growth-promoting bacteria inhabiting the extreme cold environments are Pseudomonas [40,41], Serratia and Staphylococcus [42], Exiguobacterium [43], Rahnella [44], Stenotrophomonas and Leucobacter [45], and Flavobacterium [46]. Cold active microbes have prompted researchers to discover new coldtolerant bacterial species possessing plant growth-promoting abilities [17,43,47], to produce cold-resistant enzymes [48,49] and mitigation of cold effects in plants in agroecosystem to optimize crop production [45].…”

“…Although reports indicating the functional response of plant growth-promoting rhizobacteria (PGPR) strains at low temperatures are available, studies on the P dissolving activity of soil microbiome at low temperatures (≤10 • C) are scarce. Despite this, Dolkar et al [40] documented the potentiality of cold-tolerant P-solubilizing P. simiae, recovered from the Seabuckthorn rhizosphere, in plant growth promotion at low-temperature conditions. They observed a significant increase of 30% and 51% in shoot and root length in P. simiae inoculated tomato grown in pots maintained in the greenhouse, and 9.8% and 19.8% in open field conditions, respectively.…”