Rhizospheric soil samples and roots from 3-month-old Triticum aestivum (wheat var. Lokwan) plants (five plants each from ten fields) grown in the Mehsana region of Gujarat, India (latitude 23° 42′ N and longitude 72° 33′ E), were collected in sterile polyvinyl bags separately by following the composite sampling method and transported under ice-cold conditions. The cultures that inhibited fungal growth were quantified for chitinase production on minimal medium containing (20 g/L) colloidal chitin (Hsu & Lockwood, 1975). The organic acid responsible for the phosphate solubilization of the two most effective solubilizers was determined as follows. The cultures were grown on minimal medium [0.2 g (NH₄)2SO₄ /L, 0.06 g MgSO₄.7H₂O /L, 50 g PEG 6000 /L] supplemented with glucose (20 g/L), 1 ml trace salts solution (1.0 g ZnSO₄.7H20 /L, 1.0 g MnCl₂.4H₂O /L, 1.0 g CaCl₂ /L) for 7 days.

The gene expression of IDH, ICL and MS was monitored using specifically designed primers during the exponential phase (third day) and the malate-producing stationary phase (seventh day). The qRT-PCR analysis showed no significant change in IDH expression during the malate-producing stationary phase (seventh day) in either mhcr0816 or mhce0811, as compared to the growth phase (third day). A several fold increase in expression of ICL and MS in the stationary phase of mhcr0816 correlated with high malate production (50-55 mM, pH 2.9) and phosphate solubilization (1916 mg/L). Expression of ICL and MS in mhce0811 did not alter drastically during the acid-production phase; The enzymes assays correlated with the gene expression studies of IDH, ICL and MS in both the test (mhcr0816) and control (mhce0811) isolates. The IDH activity lacked significant alteration in both the cultures before (third day) and during acid production (seventh day). However, significantly elevated level of ICL (fourfold) and MS (tenfold) explained the malic acid overproduction and high phosphate solubilization in mhcr0816 as compared to mhce0811.

Rhizospheric soil samples and roots from 3-month-old Triticum aestivum (wheat var. Lokwan) plants (five plants each from ten fields) grown in the Mehsana region of Gujarat, India (latitude 23° 42′ N and longitude 72° 33′ E), were collected in sterile polyvinyl bags separately by following the composite sampling method and transported under ice-cold conditions. The cultures that inhibited fungal growth were quantified for chitinase production on minimal medium containing (20 g/L) colloidal chitin (Hsu & Lockwood, 1975). The organic acid responsible for the phosphate solubilization of the two most effective solubilizers was determined as follows. The cultures were grown on minimal medium [0.2 g (NH₄)2SO₄ /L, 0.06 g MgSO₄.7H₂O /L, 50 g PEG 6000 /L] supplemented with glucose (20 g/L), 1 ml trace salts solution (1.0 g ZnSO₄.7H20 /L, 1.0 g MnCl₂.4H₂O /L, 1.0 g CaCl₂ /L) for 7 days.

The gene expression of IDH, ICL and MS was monitored using specifically designed primers during the exponential phase (third day) and the malate-producing stationary phase (seventh day). The qRT-PCR analysis showed no significant change in IDH expression during the malate-producing stationary phase (seventh day) in either mhcr0816 or mhce0811, as compared to the growth phase (third day). A several fold increase in expression of ICL and MS in the stationary phase of mhcr0816 correlated with high malate production (50-55 mM, pH 2.9) and phosphate solubilization (1916 mg/L). Expression of ICL and MS in mhce0811 did not alter drastically during the acid-production phase; The enzymes assays correlated with the gene expression studies of IDH, ICL and MS in both the test (mhcr0816) and control (mhce0811) isolates. The IDH activity lacked significant alteration in both the cultures before (third day) and during acid production (seventh day). However, significantly elevated level of ICL (fourfold) and MS (tenfold) explained the malic acid overproduction and high phosphate solubilization in mhcr0816 as compared to mhce0811.