A total of 246 fungal isolates representing 36 genera and 72 species were isolated from the soil samples collected from Indian Himalayan region. Twenty-one species belonged to the genus Penicillium alone. All the Penicillium species were screened for phosphate solubilizing activity on Pikovskaya agar at 21°C. Eight species of Penicillium, exhibiting formation of halos (zone of solubilization) around the fungal colonies in qualitative plate assays, were selected for quantitative estimations. In quantitative estimations that were conducted upto day 30 (at 3 days interval), seven species of Penicillium brought maximum solubilization after day 15, while P. oxalicum showed maximum solubilization after day 21 of incubation. The increase in solubilization coincided with decrease in pH of the broth. Acid phosphatase activity was 1.5-2.0 times higher in comparison to alkaline phosphatase. Many of these species showed wide range of tolerance for temperature, pH and salt concentration.

An endophytic fungus has been isolated from the lateral roots of lentil (Lens esculenta Moench), growing under mountain ecosystem of Indian Himalayan Region (IHR). While the fungus was observed as fast growing with white scanty mycelium turning to turmeric brown in 5 days of incubation at 25 °C, it also produced a unique odor. The fungus exhibited growth between 4 and 30 °C (optimum 25 °C) and tolerated pH between 2.0 and 13.5 (optimum 4-6). Based on phenotypic (colony morphology and microscopy) and genotypic (18S rRNA analysis) characters, the fungus was identified as Trichoderma gamsii (99% similarity). The fungus was evaluated for its plant growth promotion and biocontrol properties. The fungus was found to be positive for phosphate solubilization, chitinase activity, and production of ammonia and salicylic acid, while the results for production of IAA, HCN, and siderophores were negative. Out of the seven phytopathogenic fungi tested, it showed antagonism against six. Bioassays conducted under green house using four test crops (two cereals and two legumes) showed its potential in plant growth promotion. The fungus has potential to be developed as a bioformulation for application under mountain ecosystem.

Ten species of Aspergillus isolated from soil samples collected from different locations in the Indian Himalayan region have been studied for their growth requirements and tricalcium phosphate solubilization at different temperatures. The Aspergillus species could grow at low temperature and tolerated a wide range of pH. Phosphate solubilization by various Aspergillus species ranged between 374 lg/ml (A. candidus) to 1394 lg/ml (A. niger) at 28°C, 33 lg/ml (A. fumigatus) to 2354 lg/ml (A. niger) at 21°C, 93 lg/ml (A. fumigatus) to 1452 lg/ml (A. niger) at 14°C, and 21 lg/ml (A. wentii) to 83 lg/ml (A. niger) at 9°C. At 21 and 28°C, phosphate solubilization showed a decrease within 4 weeks of incubation, whereas at 9°C and 14°C, it continued further up to 6 weeks of incubation. In general, phosphate solubilization by different Aspergillus species was recorded at a maximum of 28°C or 21°C; biomass production was favored at 21°C or 14°C. Conversely, A. nidulans and A. sydowii exhibited maximum phosphate solubilization at 14°C and produced maximum biomass at 21°C. Data suggest that suboptimal conditions (higher or lower temperature) for fungal growth and biomass production were optimal for the production of metabolites involved in phosphate solubilization. Significant negative correlations were obtained between pH and phosphate solubilization for eight species at 28°C, for seven at 21°C, and for nine at 14°C. Extracellular phosphatase activity was exhibited only in case of A. niger, whreas intracellular phosphatase activity was detected in all species, the maximum being in A. niger. Statistically significant positive or negative correlations were obtained between phosphate solubilization and other parameters in most cases at different temperatures.

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Three species of Aspergillus, namely, A. niger, A. glaucus and A. sydowii, isolated from soil samples collected from the Indian Himalayan Region (IHR), have been investigated for solubilization of aluminium phosphate and iron phosphate in the presence of different carbon and nitrogen sources. Preference of each fungal species varied for nitrogen and carbon sources, in terms of phosphate-solubilization. Among three species, Aspergillus niger gave the best results; it solubilized 32% and 8% of the supplemented aluminium phosphate and iron phosphate, respectively. The results indicated that the effect of carbon and nitrogen sources can influence the phosphate solubilizing efficiency of all the three Aspergillus spp. tested. All the three species were found to be plant-growth promoters in bioassays conducted under greenhouse conditions. The Al and Fe phosphate solubilization efficiency, investigated in the present study, is at the lower end of their previously reported tricalcium phosphate solubilization efficiency. The cultures are likely to have better field applications in agrobiotechnology, due to their potential towards solubilization of Al and Fe phosphates, which are known to have lower solubility through microbial activity.