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  UV-B mediated responses in rice

The life on the earth is sustained by sunlight, which is used by plants to carry out photosynthesis. A fraction of Sunlight is also composed of short- wavelength ultraviolet light (UV-B, 280-320 nm), whose level is increasing due to thinning of the ozone layer in the stratosphere. One of the major effect of increased UV-B radiation would be the loss in the productivity of plant species. It  has  been predicted that every 1% decline in  the  ozone layer would lead to a 1% decrease in crop yield (Coohill,  1991). In a country like India where food supply is already under strain due to an ever increasing population, even small losses of the food supply by UV-B can be disastrous to society.

    The research in this lab is to find mechanisms through which the plants can resist increase in UV-B radiation. We are investigating the following areas:

 1.  One way plants can protect themselves against UV-B  light is by the induction of DNA photolyase which can repair the UV-B  damaged DNA.  Our lab is examining the possible role of DNA photolyase in rice to protect plants against UV-B damage.

 2.  Accumulation  of the  UV-B absorbing pigments is another way by  which  plants alleviate  the  harmful effects of UV-B light. We shown that in rice and  maize seedlings, induction of anthocyanin and phenylalanine ammonia lyase (PAL), a key enzyme in anthocyanin biosynthetic pathway, is triggered by UV-B light.  We are currently examining the role of anthocyanin and other flavonoids as UV-B protecting compounds in rice.

Dark-grown seedlings

Sunlight-exposed seedlings

 

Four day old dark-grown rice seedlings (left) were exposed to a 30 min pulse of sunlight and photographed for anthocyanin accumulation after 24 hour dark incubation (right)

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