ABSTRACT
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.
ABSTRACT
Phytohormones play critical roles in plant growth and development. Brassinosteroids (BRs) are essential group of phytohormones required for optimum growth of plants and their deficiency causes distinctive dwarf phenotypes in plants. Homeostasis of BRs in plants is maintained by DWARF4 enzyme that mediates multiple 22?-hydroxylation steps in brassinosteroid biosynthesis. Arabidopsis plants over-expressing DWARF4 show increase in inflorescence, number of branches and siliques; thereby increased number of seeds/plant. This suggests that engineering DWARF4 biosynthesis in Brassica plant can be strategized to enhance yield in mustard. In the present study (i) we cloned dwarf4 gene from Arabidopsis using gene specific PCR strategy, (ii) elucidated the three-dimensional structure of DWARF4 protein at molecular level where it revealed presence of four beta sheets and 20 alpha-helices, and (iii) transformed mustard cultivar Pusa Jaikisan with an objective to develop transgenic mustard with enhanced number of siliques. We obtained several putative transgenics with an average transformation efficiency of 3.3%. Molecular characterization with nptII specific primers confirmed presence of transgene in six putative transgenic plants.
ABSTRACT
Rice is a staple food for humans and its demand in 2035 has been put at 852 million tons. Knowledge on genes and genome architecture helps in better understanding of growth and development mechanisms for crop improvement. Transgenic crops may offer a solution by means of higher yield and resistance to biotic and abiotic stresses. In this context, modification of Agrobacterium mediated transformation protocol for indica rice cultivar is imperative to increase transformation efficiency and reduce duration of transgenic development. Here, we developed an efficient Agrobacterium mediated transformation protocol using early scutellum derived calli of the indica rice cultivar Pusa Sugandh 2. Competency of 3, 4, 5 and 6 day old primary calli was compared with 21- day old secondary calli for Agrobacterium mediated transformation using a modified pCAMBIA 1304 harbouring GFP-GUS fusion gene driven by maize ubiquitin 1 promoter. The highest competency with stable transformation efficiency of 51% was observed for 5-6 day old primary calli. Molecular analysis confirmed stable integration of the transgene. Transgenic lines of Pusa Sugandh 2 were developed within a short period of two months using 5-6 day old primary calli.
ABSTRACT
Plants have developed several adaptive strategies to enhance the availability and uptake of phosphorus (P) from the soil under conditions of P deficiency. Exudation of organic acids like citrate is one of the important strategies. In this study, we developed transgenic pigeonpea (Cajanus cajan) over-expressing Dacus carota citrate synthase (DcCs) gene to increase the synthesis and exudation of citrate. Transgenic plants were generated through agro bacterium mediated in-planta transformation technique. Integration and expression of the transgene was confirmed by genomic Southern and RT-PCR analysis. We observed that the transgenic lines had more tissue P and chlorophyll content, and also citrate synthase content higher in the roots. Further, transgenic lines had more vigorous root system both under P sufficient and deficient conditions with more lateral roots and root hairs under P deficient conditions. We conclude that the transgenic pigeonpea plants have the capacity to acquire more P under P deficient conditions.