Advanced Statistical Methods in Biometric Research.

https://digital.csic.es/bitstream/10261/248575/1/emergiplant.pdf

Emerging roles for conjugated sterols in plants.

A comprehensive review on chlorpyrifos toxicity with special reference to endocrine disruption: Evidence of mechanisms, exposures and mitigation strategies.

Brassinosteroids (BRs) are an important group of plant steroidal hormones that are actively involved in a myriad of key growth and developmental processes from germination to senescence. Moreover, BRs are known for their effective role in alleviation of stress-induced changes in normal metabolism via the activation of different tolerance mechanisms. Efforts to improve plant growth through exogenous application of BRs (through different modes such as foliar spray, presowing seed treatment, or through root growing medium) have gained considerable ground world over. It has been widely demonstrated that the exogenous application of BRs to stressed plants imparts the stress tolerance mechanisms. In BR-induced regulation of physio-biochemical processes in plants, interaction (crosstalk) of BRs with other phytohormones has been reported. This crosstalk may fine-tune the effective roles of other hormones in regulating stress tolerance. The multifaceted role of BRs consolidated so far has reflected their immense potential to help plants in counteracting the stress-induced changes. The effects of introgression and up- and down-regulation of BR-related genes reported so far to improve crop productivity have been presented here. Strong evidence exists that BRs are involved in signal transduction particularly in the regulation of the mitogen-activated protein kinase (MAPK) cascade, which in turn is involved in controlled development, cell death, and the perception of pathogen-associated molecular pattern (PAMP) signaling. How far BRs are involved in signal transduction pathways operative under stressful environments has also been comprehensively discussed in this review.

Brassinosteroids regulate growth in plants under stressful environments and crosstalk with other potential phytohormones.

Oryza sativa class III peroxidase (OsPRX38) overexpression in Arabidopsis thaliana reduces arsenic accumulation due to apoplastic lignification.

Background 
Sterol glycosyltrnasferases (SGT) are enzymes that glycosylate sterols which play important role in plant adaptation to stress and are medicinally important in plants like Withania somnifera. The present study aims to find the role of WsSGTL1 which is a sterol glycosyltransferase from W. somnifera, in plant’s adaptation to abiotic stress.


Methodology 
The WsSGTL1 gene was transformed in Arabidopsis thaliana through Agrobacterium mediated transformation, using the binary vector pBI121, by floral dip method. The phenotypic and physiological parameters like germination, root length, shoot weight, relative electrolyte conductivity, MDA content, SOD levels, relative electrolyte leakage and chlorophyll measurements were compared between transgenic and wild type Arabidopsis plants under different abiotic stresses - salt, heat and cold. Biochemical analysis was done by HPLC-TLC and radiolabelled enzyme assay. The promoter of the WsSGTL1 gene was cloned by using Genome Walker kit (Clontech, USA) and the 3D structures were predicted by using Discovery Studio Ver. 2.5.


Results 
The WsSGTL1 transgenic plants were confirmed to be single copy by Southern and homozygous by segregation analysis. As compared to WT, the transgenic plants showed better germination, salt tolerance, heat and cold tolerance. The level of the transgene WsSGTL1 was elevated in heat, cold and salt stress along with other marker genes such as HSP70, HSP90, RD29, SOS3 and LEA4-5. Biochemical analysis showed the formation of sterol glycosides and increase in enzyme activity. When the promoter of WsSGTL1 gene was cloned from W. somnifera and sequenced, it contained stress responsive elements. Bioinformatics analysis of the 3D structure of the WsSGTL1 protein showed functional similarity with sterol glycosyltransferase AtSGT of A. thaliana.


Conclusions 
Transformation of WsSGTL1 gene in A. thaliana conferred abiotic stress tolerance. The promoter of the gene in W.somnifera was found to have stress responsive elements. The 3D structure showed functional similarity with sterol glycosyltransferases.

/pdf/overexpression-of-wssgtl1-gene-of-withania-somnifera-5an54tbgtw.pdf

Overexpression of WsSGTL1 Gene of Withania somnifera Enhances Salt Tolerance, Heat Tolerance and Cold Acclimation Ability in Transgenic Arabidopsis Plants

This report describes Agrobacterium tumefaciens-mediated transformation of Withania somnifera—an important Indian medicinal plant. A. tumefaciens strain LBA4404, containing the binary vector pIG121Hm was used for transformation, along with the gusA reporter gene with intron under the transcriptional control of the Cauliflower Mosaic Virus (CaMV) 35S promoter. The leaf segments from two-and-a-half-month-old green house-grown seedlings were more efficient in transformation, as compared to those from the in vitro-grown shoots. Second expanded leaf from the shoot tip gave the highest transient transformation efficiency. Selection of transgenic shoots was done in the presence of 50 mg l−1 kanamycin. Polymerase chain reaction analysis of T0 transgenic plants showed the presence of gusA and nptII genes. The expression of these transgenes in T1 progeny was confirmed by RT-PCR. The integration of gusA gene was confirmed by Southern blot analysis. The transformation efficiency was found to be 1.67%.

Agrobacterium tumefaciens-mediated transformation of Withania somnifera (L.) Dunal: an important medicinal plant

Leaf explants of the second or third node were collected from field-grown elite Jatropha curcas trees and incubated in Murashige and Skoog’s (Physiol Plant 15:473–497, 1962) medium supplemented with growth regulators. Direct shoot organogenesis was induced when explants were incubated in a medium containing 0.5 mg l−1 benzyladenine (BA) and 0.1 mg l−1 indolebutyric acid (IBA). A maximum of seven shoot buds differentiated within 6 weeks of culture incubation. Indirect shoot organogenesis was obtained when explants were incubated in the medium supplemented with 0.5 mg l−1 BA along with 1.0 mg l−1 each of 2,4-dichlorophenoxyacetic acid (2,4-D) and indoleacetic acid (IAA). A pulse treatment of 0.5 mg l−1 thidiazurone (TDZ) and 0.1 mg l−1 IBA for 5 days was necessary for shoot organogenesis in green compact callus before subculture into 0.5 mg l−1 BA and 0.1 mg l−1 IBA containing medium. Leaf explants of J. curcas, collected from the field, contained endophytic bacterial contamination, which expressed itself after 2–3 subcultures. These bacteria were cultured and identified as Enterobacter ludwigii. After staining, these were found as gram-negative bacteria. Their sensitivity against different antibiotics has been tested by culturing them with different antibiotic stabs for 72 h. Finally, Augmentin® was found as the most effective and suitable antibiotic which not only controlled the bacteria within 2–3 subcultures but also supported the regeneration system and growth of the regenerated shoots and such cultures have been grown for a long-term of over 2 years without any contamination.

Establishment of long-term proliferating shoot cultures of elite Jatropha curcas L. by controlling endophytic bacterial contamination

Swiss albino mice were exposed to formulated cypermethrin (CMR) and/or or chlorpyrifos (CPF) through oral gavages for 60 days. Test doses of CMR (0.69, 1.38 or 2.76mg/kg/day) or CPF (0.5, 1.0 or 2.0mg/kg/day) or CMR + CPF (0.69 + 0.5, 1.38 + 1.0 or 2.76 + 2.0mg/kg/day) were based on the acute oral median lethal doses of CMR or CPF. Chromosome aberrations (CA), micronucleus (MN) induction, cell cycle perturbations, apoptosis and reactive oxygen species (ROS) generation were analysed in bone marrow cells. To explore the involvement of ROS induction, HaCat cells were exposed in vitro to arbitrary concentrations of CMR and/or CPF. Exposure of CMR (2.76mg/kg/day) induced significant inhibition of mitotic index. Significant (P < 0.01) frequencies of CA and MN were observed with the CMR at 1.38mg/kg/day, whereas CPF or its mixture CMR + CPF showed at highest doses. Chromosome/chromatid breaks and fragments were found to be major aberrations in all the treatment groups. Highest doses of CMR or CMR + CPF revealed significant (P < 0.01 or 0.001) elevation of G0/G1 peak, while CPF-exposed cells revealed significant (P < 0.01) declined in G1 phase. Decline in S phase was observed with highest dose of CMR only. Apoptosis induction measured by gating cell population beside G1 peak showed 3- to 4-fold increase in apoptotic cells in CPF-exposed mice as compared to control or CMR or CMR + CPF-treated mice. Further, all the treatment groups in vivo as well as in vitro revealed significant generation of ROS in comparison with the control group. Present results, together with the earlier reports, which substantiate ROS generation may be major cause of genotoxicity, cell cycle perturbations and apoptosis, nonetheless co-exposure of low doses of CMR and CPF mixture does not potentiate genotoxicity.

/pdf/ros-dependent-genotoxicity-cell-cycle-perturbations-and-5anhekbnss.pdf

ROS-dependent genotoxicity, cell cycle perturbations and apoptosis in mouse bone marrow cells exposed to formulated mixture of cypermethrin and chlorpyrifos.

/pdf/genetic-divergence-studies-in-ajwain-trachyspermum-ammi-l-4rvxw20ikv.pdf

Vibha Pandey

Papers

Overexpression of WsSGTL1 Gene of Withania somnifera Enhances Salt Tolerance, Heat Tolerance and Cold Acclimation Ability in Transgenic Arabidopsis Plants

Agrobacterium tumefaciens-mediated transformation of Withania somnifera (L.) Dunal: an important medicinal plant

Establishment of long-term proliferating shoot cultures of elite Jatropha curcas L. by controlling endophytic bacterial contamination

ROS-dependent genotoxicity, cell cycle perturbations and apoptosis in mouse bone marrow cells exposed to formulated mixture of cypermethrin and chlorpyrifos.

Genetic Divergence Studies in Ajwain (Trachyspermum ammi L.) Genotypes