Physiology and Molecular Biology of Stress ... - KHAM PHA MOI

178 A.R. Reddy and A.S. Raghavendra
9. CONCLUDING REMARKS
Light is critical for growth and development of plants. It is apparent from the foregone
account that plants have evolved multiple strategies of photoprotective and
photoadaptive mechanisms that are critical for survival under conditions of excess
photon absorption. Some of these mechanisms involve changes in pigment-protein
complexes, synthesis and recruitment of enzymes with antioxidant function and abundant
soluble antioxidants in the chloroplasts. Furthermore, the redox conditions in
plant cells may modulate the photosystem components for acclimation to photooxidative
stress. The induction of genes under photooxidative stress for optimized absorption
of light by specific photoreceptors is poorly understood. Analysing the expression
of these genes under different light quality/quantity conditions will enable us to
make specific inferences about the nature and sensitivity of such photoreceptors in
plants. Genetic regulation of antioxidant biosynthesis and overexpression several
antioxidative enzymes should reveal plant acclamatory responses in response to photooxidative
stress. There is a need to understand how the photooxidative stress provoke
several changes in cellular metabolism, reflecting the changed expression of a
common or overlapping set of genes. Detailed information is also required on how the
signaling molecules are integrated with ROS into the general signaling network of a cell
and/or the intracellular production sites affect the signaling pathway. Metabolite, protein
and transcript profiling technology could provide us a holistic understanding of
how plants thrive in highly variable and adverse environments.
10. ACKNOWLEDGEMENTS
Work in our laboratory on photosynthesis and preparation of this article are supported
by grants (to ASR) from Department of Science and Technology (No. SP/SO/A12/98)
and ARR from Council of Scientific and Industrial Research (No. 38 (1063)/03/EMR-II),
both from New Delhi, India.
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