University of Hyderabad, Hyderabad
Speaker’s Profile: Prof. Agepati S Raghavendra is a Professor at the Dept. of Plant Sciences, University of Hyderabad. He was also a SERB J C Bose Fellow, DFG Mercator Visiting Professor (Germany), AvH JSPS Senior Visiting Scientist (Japan), and a Visiting Professor at several Institutes abroad. He has successfully supervised 11 MPhil and 24 Ph.D. students. Professor Raghavendra published >220 research papers and is one of the highly cited scientists from the School of Life Sciences, University of Hyderabad. He is a fellow of all four science Academies in India (INSA, IASc, NASI & NAAS) as well as the TWAS. He was elected fellow of the Indian Academy of Sciences in 1999.
Swagata Dasgupta, IIT, Kharagpur
The uniqueness of plant mitochondria: Relevance to crop improvement and climate change
The structure and components of plant cells are quite different from animal cells. Further, plant mitochondria have several features that make them quite distinct from animal mitochondria. Some of these are the operation of a cyanide-insensitive alternative pathway, the capacity to use glycine as a substrate for respiratory O2 uptake, the ability to utilize external NAD(P)H by NAD(P)H dehydrogenase and the use of uncoupling proteins (UCP). The combined operation of NAD(P)H dehydrogenase and UCP provides an interesting bypass of oxidative phosphorylation to sustain electron transport and dissipate excess NADH without focusing on ATP production. Otherwise, the excess NADH can lead to the accumulation of excess reactive oxygen species (ROS). The cyanide-insensitive respiration in plant mitochondria, catalyzed by a protein called alternative oxidase (AOX), bestows them the ability to survive under anoxygenic atmospheres, such as submerged conditions. AOX does not yield as much ATP as the cytochrome oxidase but can generate significant amounts of heat. The resulting elevation of temperature helps plants resist cold conditions or release volatiles that attracts pollinating insects. The pungent odor and the warmth are attractive features in specialized flowers like Arum spadix, illustrating an example of an AOX- promoted pollination system. Plant mitochondria are efficient in interacting with other compartments in a plant cell, namely chloroplasts, peroxisomes, and cytosol, to optimize metabolism and sustain growth/yield. While emphasizing the uniqueness of plant mitochondria, I would try to explain how mitochondrial metabolism can help plants adapt to climate changes in terms of flooding, global warming, and elevated CO2.