Transgenic Analysis Reveals 5' Abbreviated OsRGLP2 Promoter(s) as Responsive to Abiotic Stresses.

Germins and germin-like proteins are ubiquitous, expressed at various developmental stages and in response to various abiotic and biotic stresses. In this study, to functionally validate the OsRGLP2 promoter, 5' deletion analysis of the promoter sequences was performed and the deletion fragments fused with the ß-glucuronidase (GUS) and green fluorescent protein reporter genes were used for transient expression in tobacco as well as for generating stable transgenic Arabidopsis plants. Very high level of GUS activity was observed in agroinfiltrated tobacco leaves by the construct carrying the P-1063 and P-565 when subjected to abiotic stresses. Histochemical analysis of transgenic Arabidopsis plants revealed expression of reporter gene in root, leaf and stem sections of plants harboring P-1063 and P-565. Real-time qPCR analysis of transiently expressed tobacco leaves and transgenic Arabidopsis plants subjected to several abiotic stresses supported histochemical data and showed that P-565 responded to all the stresses to which the full-length promoter was responsive. The data suggest that P-565 may be a good alternative to full-length promoter region that harbors the necessary cis-elements in providing stable and high level of expression in response to wound, salt and temperature stresses.

Sperm sexing in Nili-Ravi buffalo through modified swim up: Validation using SYBR® green real-time PCR.

Sperm sexing through flow-sorting technology is relatively expensive, requires considerable technical support and is actually not practicable in many developing countries. The aim of this study was to investigate the feasibility of producing enriched pools of X or Y chromosome-bearing sperm by a modified swim-up method. For this purpose semen was collected from five mature Nili-Ravi buffalo bulls for a period of six weeks. The qualifying ejaculates were divided into two aliquots for further processing through modified swim-up or control (untreated). After processing, semen was cryopreserved in tris citric acid extender using standard techniques. Semen quality was assessed at pre dilution, post dilution and post thawing. Validation of technique was done by using SYBR® green real time PCR using two sets of primers, PLP and SRY for X and Y chromosome of buffalo genes, respectively. Sperm recovery rates, pre freeze and post thaw sperm quality were found significantly higher in X chromosome bearing sperm fraction than Y chromosome bearing fraction and control. Mean fold relative expression of X bearing sperm was significantly higher (4-5 fold) in X chromosome bearing fraction of supernatant than Y chromosome bearing fraction (0.06 fold), similarly mean fold relative expression of Y chromosome bearing sperm was significantly higher in Y chromosome bearing fraction (4 fold) of supernatant than X chromosome bearing fraction (0.15 fold) compared to control (1.00). In conclusion, a modified swim up method proved to be an effective method for Nili-Ravi buffalo sperm sexing as validated by real time PCR.

Ectopic Expression of Plant RNA Chaperone Offering Multiple Stress Tolerance in E. coli.

Members of the plant glycine-rich RNA-binding proteins (GR-RBPs) family have been reported in flowering, development, circadian rhythms, biotic and abiotic stresses. Particularly, GR-RBPs are reported to function as RNA chaperones, promoting growth and acclimation during cold shock. It is indispensable to further question the efficacy and mechanism of GR-RBPs under various environmental strains. Monitoring the expression of stress-regulated proteins under stress conditions has been a beneficial strategy to study their functional roles. In an effort to elucidate the NtGR-RBP1 function, stress markers such as salinity, drought, low temperature and heat stresses were studied. The NtGR-RBP1 gene was expressed in E. coli followed by the exposure to stress conditions. Recombinant E. coli expressing NtGR-RBP1 were more tolerant to stresses, e.g., salinity, drought, cold and heat shock. Recombinants exhibited higher growth rates compared to control in spot assays. The tolerance was further confirmed by monitoring the growth in liquid culture assays. Cells expressing NtGR-RBP1 under salt (500 mM NaCl), drought (20% PEG), cold (4 and 20 °C) and heat stresses (50 °C) had enhanced growing ability and better endurance. Our study supports the notion that the protective role of NtGR-RBP1 may contribute to growth and survival during diverse environmental stresses.

Molecular Characterization of a MYB Protein from Oryza sativa for its Role in Abiotic Stress Tolerance

ABSTRACT The MYB family represents one of the most abundant classes of transcriptional regulators that perform pivotal role under different developmental processes and abiotic stresses. In present study, a MYB gene from Oryza sativa was selected for functional characterization. Bioinformatics analysis revealed that OsMYB1 cDNA encodes R2-R3 type DNA binding domain consisting of 413 amino acids having size of 44 kDa and pI of 6.24. DNA binding domain containing region was cloned and over-expressed in E. coli. Then, the survival of pGEX-OsMYB1 transformed E. coli cells was compared with control plasmid under different concentrations of NaCl, mannitol, high and low temperature. pGEX-OsMYB1 enhanced the survival of cells at high temperature and salinity. Electrophoretic mobility shift assays (EMSAs) have shown that recombinant OsMYB1 protein was able to bind with DIG labeled probe containing MYB binding site. RT-qPCR analysis revealed high MYB1 expression under wounding, salt, drought and heat stresses in rice. Expression was 23 fold higher in response to wounding demonstrating the worth of OsMYB1 up-regulation in wounding. Intrinsic disorder profile predicted that OsMYB1 exhibits 60% degree of intrinsic disorder proposing that these regions might be involved in DNA binding specificity and protein-protein interaction. The positive response of OsMYB1 suggests that its over-expression in crop plants may help in providing protection to plants to grow under abiotic stresses.