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Ranjita Sinha and Manchikatla V Rajam
Homeostasis of cellular Polyamines (PAs) is very important for proper growth and development of living organisms. Development of male sex organ and gametophyte in plants is a complex process involving many known and unknown pathways. PAs are actively involved in the development of anther and pollen. In the present study, oat arginine decarboxylase (ADC) gene has been over-expressed in tapetum of tomato using tapetum-specific TA29 promoter to perturb the PA homeostasis in order to see its implication on male fertility. Tapetum-specific ADC overexpression resulted in PA accumulation, mainly in free and bound fractions in the anther of transgenics. Transgenic lines displayed abnormal pollen and tapetum development. Pollen grains were aborted and distorted in morphology and tapetum showed premature degeneration in ADC transgenics. These transgenics failed to set seeds, but cross pollination with normal pollen from wild type plants restored the seed setting indicating that s ADC over-expression did not affect female fertility. ADC over-expression also did not affect the growth and morphology of transgenics. The present study suggests that the excess of PAs in anther is lethal for pollen and tapetum development and overexpression of ADC gene can be an effective approach for the engineering of male sterility in plants.