Publications of NIPGR Scientists

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Author: search.filters.author.Deswal, RenuSubject: search.filters.subject.Catharanthus roseus

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    New evidences about strictosidine synthase (Str) regulation by salinity, cold stress and nitric oxide in Catharanthus roseus
    (Springer, 2013) Dutta, Ajaswrata; Sen, Jayanti; Deswal, Renu
    Alkaloid production in plants is altered by abiotic stressors, but the mechanism(s) are poorly understood. Present study provides novel evidences about differential regulation of strictosidine synthase (Str), the key gene of terpenoid indole alkaloid (TIA) biosynthetic pathway in response to salinity and low temperature stress in Catharanthus roseus. HPLC analysis of terpene indole alkaloids correlated with differential regulation of Str by low temperature and salinity stress. Administration of exogenous calcium and calcium channel modulator preferentially regulated Str transcript. In addition, administration of kinase and phosphatase inhibitors modulated Str expression. Involvement of nitric oxide (NO) signaling was ascertained by NO donor and nitric oxide synthase (NOS) scavenger treatments. This finding suggests co-ordinated action of calcium, protein kinases, phosphatases and nitric oxide in abiotic stress signaling for TIA biosynthetic pathway in C. roseus.
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    Downregulation of terpenoid indole alkaloid biosynthetic pathway by low temperature and cloning of a AP2 type C-repeat binding factor (CBF) from Catharanthus roseus (L). G. Don
    (Springer, 2007) Dutta, Ajaswrata; Sen, Jayanti; Deswal, Renu
    Plants produce secondary metabolites in response to various external signals. Coordinated transcriptional control of biosynthetic genes emerges as a major mechanism dictating the accumulation of secondary metabolites in plant cells. However, information about stress regulation of secondary metabolites and the molecular mechanisms regulating these specialized pathways are poorly understood. Here, we show that terpenoid indole alkaloid (TIA) biosynthetic pathway is differentially regulated in response to different abiotic stresses in Catharanthus roseus, a model medicinal plant producing important anticancer and antihypertensive drugs. Semiquantitative RT-PCR analysis of TIA and related primary pathway genes in response to dehydration, low temperature, salinity, UV-light and wounding revealed their negative regulation in response to low temperature. HPLC analysis further supports the notion that TIA biosynthetic pathway is negatively controlled by low temperature stress.