Nitric Oxide Accelerates Germination in Chickpea
We are living in an era where the enhancement of crop productivity is of key importance to achieve food security in the nation. For long, studies have been done to understand the role of nitric oxide in controlling respiration, stress response, and plant growth. However, no significant study has been done to understand its relevance in the process of germination.
The researchers from National Institute of Plant Genome Research (NIPGR) unveiled the role of nitric oxide in enhancing germination via regulation of respiration in chickpea. The researchers Pandey S, Kumari A, Manu Shree, Kumar V, Singh P, Bharadwaj C, Loake GJ, Parida SK, Masakapalli SK, Gupta KJ invested their efforts over the years to come up with such great research work.
We would like to highlight the contribution of Indian organizations such as NIPGR and DBT in providing necessary funding and other associated support to the scientists.
Dr. Jagadis K. Gupta shared brief insights about the study and other associated details in the interview with ‘The Scientific Reporters’. Here we share an interesting interview with the scientist, which not only helps in understanding the research work but also highlights the importance of scientists to come up and share their work for better science communication.
Please share some brief insight about your recent work on nitric oxide signaling in chickpea germination.
Dr. Jagadis – Nitric oxide (NO) is a free radical signaling molecule that plays a crucial role throughout the plant growth, development and stress response. In this study, we investigated the role of NO in the germination of seeds, which is very crucial in the plant life cycle. For performing various functions, plants need to generate energy in the form of ATP. For generation of energy plant needs oxygen which is important for driving oxidative phosphorylation that yields ATP. In comparison to animal systems plants don’t have an efficient transport system for delivery of oxygen. Due to an inefficient system for delivery of oxygen, some bulky tissues such as seeds, tubers, roots experience hypoxia (low oxygen). Under hypoxia conditions, tissues generate nitric oxide. Hence we checked the role of hypoxia-induced nitric oxide on germination.
We compared the germination of Desi and Kabuli varieties of chickpea. We found that Desi germinates faster than Kabuli. The germination rate of Desi was always higher than the Kabuli. Then we investigated the molecular and biochemical mechanisms behind the delay of germination in Kabuli. After germination, the seeds undergo a series of metabolic, biochemical and molecular changes. During this process, they also generate reactive oxygen species. If they are not detoxified efficiently the produced ROS can damage DNA, RNA, proteins and eventually affects the germination.
We found that Kabuli has reduced internal oxygen than Desi variety. The reduced internal oxygen increased ROS and delayed germination.
Interestingly we found that Kabuli produces less NO hence they showed increased ROS. Hence we provided nitric oxide to Kabuli and we found increased germination and reduced ROS. We found that the application of nitric oxide increased expression of genes involved in cell cycle and increased the metabolic abundance of various amino acids, organic acids and increased flux via oxidative pentose phosphate pathway.
Finally, we understood that nitric oxide is a major requirement for the germination of chickpea. In collaboration with Dr. Swarup Parida we obtained a recombinant inbred line (RIL) which was generated in a cross between Desi and Kabuli. The RIL produced more NO and germinated faster than Kabuli. Taken together we successfully demonstrated that NO is a very vital requirement for seed germination and we found a way to achieve maximum germination in Kabuli.
How present research work is different from earlier similar work?
Dr. Jagadis – Previously, it was demonstrated that nitric oxide inhibits respiration but there was no clue on the relevance of this phenomenon on germination. In this study, we successfully demonstrated that NO inhibits respiration thereby it enhances internal oxygen, reduces ROS and accelerates metabolic pathways and energy production which is required for germination. Hardly any reports are available on use of breeding approaches to enhance NO and promote plant development. I am very happy that we unlocked the mechanism and made significant advancements in the field.
What will be its significance, if made available for real agriculture practices?
Dr. Jagadis – I am very confident that it will have tremendous significance in the field. There are three ways in which our discovery can help in agriculture. The first is in the process is we are generating NO-releasing nanoparticles to use them for agriculture practices. The second way is using genome editing, wherein one can enhance NO production in seeds to augment germination. The third way is using breeding programs that focus on enhancing NO production, which can definitely help in increasing the germination of seeds and ultimately help in increasing food security. Chickpea is the third most-produced important legume. It was estimated that 90 % of chickpea cultivated in Asia including a large portion in India. The identified mechanism certainly helps in enhancing crop productivity.
What was the role of Indian organizations in supporting the research work?
Dr. Jagadis – National Institute of Plant Genome Research is an autonomous Institute of Department of Biotechnology, Govt of India. I must thank the tremendous support of NIPGR and DBT in conducting this study. NIPGR has the best infrastructure for plant science research. Excellent directorship of Dr. Ramesh V. Sonti at NIPGR has provided us great encouragement in conducting both basic and applied studies. We have a field facility in Meerut, which is helping our needs to grow germplasm and conduct field experiments. Ramalingaswami Fellowship from DBT is a flexible grant and a well-designed program that greatly helped us. Indo-Swiss joint research program from the Department of Biotechnology has also provided support to work on chickpea.
What are the challenges faced during the discovery?
Dr. Jagadis – The measurement of internal oxygen is very challenging. The sensor has to reach different depths of tissue to sense oxygen. It took several weeks for us to standardize the method to measure internal oxygen in chickpea seeds. I am very happy that we succeeded finally. Hardworking and motivated students have contributed to the success of this study.
What are the future plans wrt to the discovery and findings?
Dr. Jagadis – Using genome editing technologies we are trying to enhance NO levels in chickpea. If we succeed, we can improve the germination capacity of Kabuli chickpea.
NO is known to induce defense responses. In light of this, we are examining defense response activation in seeds in response to NO. We are in the process of generating nitric oxide-releasing nanoparticles to enhance germination capacity and defense responses in chickpea. We are planning to test this mechanism in other crops to explore our findings further.
Recently, you participated in a press conference at Voronezh Russia to discuss the importance of post-genomic technologies for improving nutrition value of crops and the role in the improvement of human health. Please share your experience?
It was amazing. I recently edited Methods in Molecular Biology on Nitrogen Metabolism where Prof Vasily Popov contributed a methods article. He found my research on mitochondria interesting. He invited me to deliver an inaugural talk on Post Genomic Technologies in Voronezh. On the first day, we had a press conference where all members discussed the importance of post-genomic technologies. I was amazed to see several interesting questions such as importance of bacteria and fungus on increasing plant productivity, growth and nutritional value of crops.
The conference was well organized and got an excellent response from the audience and one of the major questions was whether our Phytoglobin-NO cycle discovery can win the Nobel Prize. My answer was ‘anything can happen’ probably it will win Nobel or any other big prize. I was lucky that my collaborator in Pgb-NO cycle, AbirIgamberdiev was also there with me during my seminar. He translated my answer in Russian. I also visited various departments and we are now looking forward to some Indo-Russian collaboration. On the third day, I delivered another talk to Russian Ph.D. students where I could see their great interest on mitochondrial metabolism.