RNAi-mediated silencing of spermidine synthase gene results in reduced reproductive potential in tobacco
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Spermidine belongs to a class of polycationic compounds known as polyamines. Polyamines are known to be involved in a wide range of biological processes but the exact role and contribution of different polyamines to these processes are still not clear. In the present study, we have tried to understand the contribution of triamine spermidine to the growth and development of tobacco by downregulating spermidine synthase gene (SPDS) using RNA interference. Down-regulatioin of SPDS gene resulted in decreased spermidine levels and a slight increase in the levels of its precursor, the diamine putrescine and the molecule downstream of Spd, the tetraamine spermine. While the vegetative growth of the transgenics remained largely unaffected, SPDS down-regulation resulted in smaller size of flowers, decreased pollen viability and seed setting, and a reduced and delayed seed germination. When subjected to abiotic stress, the transgenics showed an increased tolerance to salinity and drought conditions owing to a steady intracellular pool of putrescine and spermine. The results not only highlight the importance of spermidine in determining reproductive potential in plants but have also help delineate its function from that of putrescine and spermine.
KeywordsPolyamines Spermidine synthase RNAi Reproductive potential Abiotic stress tolerance Tobacco
Eukaryotic translation initiation factor 5A
We are grateful to the University of Delhi for R & D grant, and Department of Biotechnology, New Delhi and Department of Science and Technology (DST), New Delhi for financial support (to MVR). AC acknowledges the Council of Scientific and Industrial Research, New Delhi for the senior research fellowship. We also thank the University Grants Commission for special assistance programme (DRS-III), DST for FIST (Level 2) programme and DU-DST PURSE (Phase II) grant.
Compliance with ethical standards
Conflict of interest
The authors declare that they do not have conflict of interests.
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