Browsing by Author "Batra, Jyoti"

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    Expression of terpenoid indole alkaloid biosynthetic pathway genes corresponds to accumulation of related alkaloids in Catharanthus roseus (L.) G. Don
    (Springer, 2005) Dutta, Ajaswrata; Batra, Jyoti; Pandey-Rai, Sashi; Singh, Digvijay; Kumar, Sushil; Sen, Jayanti
    Madagascar periwinkle, Catharanthus roseus (L.) G. Don, a medicinally important plant, produces anticancer dimeric alkaloids, vinblastine and vincristine, in the leaves and accumulates antihypertensive alkaloids, ajmalicine and serpentine, in the roots. This plant grows wild in distant tropical and sub-tropical geographical locations with different agro-climates and shows wide variations in morphological and alkaloid yield-related traits. In order to understand the correlation between the expression of terpenoid indole alkaloid (TIA) pathway genes and accumulation of related alkaloids, six different genetic resources of C. roseus, including the medicinal cultivars Nirmal, Prabal, Dhawal, the mutants gsr-3 and gsr-6, and one horticultural variety, Pacifica blush, were studied. The expression profiles of one early and two late TIA biosynthetic pathway genes, namely, strictosidine synthase, desacetoxyvindoline 4-hydroxylase and deacetyl vindoline 4-O-acetyl transferase were analyzed in these plants. A positive correlation between transcript abundance and accumulation of related alkaloids was observed in the different genetic resources. The potential of these TIA biosynthetic pathway genes for use in screening of high-yielding C. roseus germplasm has been discussed.
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    Growth and terpenoid indole alkaloid production in Catharanthus roseus hairy root clones in relation to left- and right-termini-linked Ri T-DNA gene integration
    (Springer, 2004) Batra, Jyoti; Dutta, Ajaswrata; Singh, Digvijay; Kumar, Sushil; Sen, Jayanti
    Hairy root cultures of Catharanthus roseus var. Prabal were established by infecting the leaves with Agrobacterium rhizogenes agropine-type A4 strain. Two hundred and fifty independent root clones were evaluated for growth, morphology, number of integration of Ri T-DNA genes and alkaloid contents. On the basis of growth pat- tern, type of branching and number of lateral roots we were able to separate the hairy root clones into four categories. However based on the integration of the Ri TL-DNA and TR-DNA genes, there were only three different categories of independent hairy root clones–C1 (rolA&B+/ags+), C2 (rolA&B-/ags+) and C3 (rolA&B+/ags ). Southern hybridization analysis revealed both single and multiple copies of T-DNA integration in the root clones. The accumulation of considerable amounts of the root-specific alkaloids ajmalicine and serpentine was observed in the presence of both the TL-DNA and TR-DNA genes (C1) and the TL-DNA gene (C3) alone. Two rolA&B but ags+ clones (C2) accumulated much less or only very negligible amounts of ajmalicine. The possible role of the TL-DNA and TR-DNA genes on growth and alkaloid accumulation in these root clones is discussed