RESUMEN
Phloroglucinol or 2,4-diacetyl phloroglucinol (DAPG) is a polyketide compound produced by gram negative soil bacteria Pseudomonas. It shows broad spectrum antibacterial and antifungal properties against soil-borne plant pathogens. In Pseudomonas spp., genes for biosynthesis of 2,4-DAPG are localized in phlABCD operon. All the four genes in phlABCD operon are indispensable and DAPG synthesis is attenuated even in the absence of one of the genes. In the present study, we identified and cloned phlC gene from an Indian strain of Pseudomonas and analyzed its sequence. The structural details ofthe PHLC protein was generated by three-dimensional homology modelling. Additionally, stereo-chemical properties of PHLC were analyzed by Ramachandran plot analysis and the generated model was validated by PDBsum. Our results demonstrate that the cloned PHLC protein contains structural features typical of a condensing enzyme involved inpolyketide synthesis.
RESUMEN
Globally, abiotic stresses affect growth and yield of an economically and industrially important field crop flax, Linum usitatissimum. Being genomically unmapped, the molecular details of abiotic stress signaling in flax has not been elucidated. One such important and most damaging abiotic stress in flax is hydropenia or drought that inhibits growth and development of the plant. With the release of its genome sequence, there is a renewed interest in functional genomics study in flax. In an endeavour to get insights into the molecular events of hydropenia i.e., drought stress, an in-depth study of four marker genes induced by drought stress was carried out in flax. Expression profiling of these four drought responsive genes viz. erd1, hat, plD δ and zfa in flax were correlated to the expression profile in model crops such as Arabidopsis and rice. Based on phenotypic expression, relative water content and semi-quantitative PCR expression data, we confirmed the applicability of these four genes in screening drought tolerant varieties of an industrially important crop like flax.
RESUMEN
In a combined approach of phenotypic and genotypic characterization, 28 indigenous rhizobial isolates obtained from different chickpea growing regions in peninsular and northern India were analyzed for diversity. The field isolates were compared to two reference strains TAL620 and UPM-Ca142 representing M. ciceri and M. mediterraneum respectively. Phenotypic markers such as resistance to antibiotics, tolerance to salinity, temperature, pH, phosphate solubilization ability, growth rate and also symbiotic efficiency showed considerable diversity among rhizobial isolates. Their phenotypic patterns showed adaptations of rhizobial isolates to abiotic stresses such as heat and salinity. Two salt tolerant strains (1.5% NaCl by T1 and T4) with relatively high symbiotic efficiency and two P-solubilising strains (66.7 and 71 mg/ml by T2 and T5) were identified as potential bioinoculants. Molecular profiling by 16S ribosomal DNA Restriction Fragment Length Polymorphism (RFLP) revealed three clusters at 67% similarity level. Further, the isolates were differentiated at intraspecific level by 16S rRNA gene phylogeny. Results assigned all the chickpea rhizobial field isolates to belong to three different species of Mesorhizobium genus. 46% of the isolates grouped with Mesorhizobium loti and the rest were identified as M. ciceri and M. mediterraneum, the two species which have been formerly described as specific chickpea symbionts. This is the first report on characterization of chickpea nodulating rhizobia covering soils of both northern and peninsular India. The collection of isolates, diverse in terms of species and symbiotic effectiveness holds a vast pool of genetic material which can be effectively used to yield superior inoculant strains.