Mineral phosphate solubilization defective mutants of Pseudomonas sp. express pleiotropic phenotypes

Pseudomonas sp,, Psd 201, which showed adequate mineral phosphate solubiliz ation (MPS) activity on TCP and MSM assays was subjected to random mutagene sis through nitrosoguanidine (MNNG) to isolate mutants defective in MPS fun ctioning. Simultaneously random Tn5 insertions into Psd 201 genome were als o caused using Tn5 vector, pGS9, Four MPS and two delayed solubilization (M PSd) mutants were selected from MNNG-treated cultures. Tn5 insertions yield ed four Psd 201::Tn5 derivatives with MPS-phenotypes, These mutants showed different phenotypic classes with respect to metabolic and cell surface pro perties. The nature of pleiotropies shown by these mutants indicated that t hese mutational lesions might have occurred in some of the regulatory mps l oci as well, since the level of expression of zone and time of solubilizati on got affected in some mutants.