Research Projects

Plant specific NAC transcription factors (TFs) are the largest group of TFs, involved in diverse biological processes ranging from seed germination to flowering and both biotic and abiotic stress responses. Membrane-bound NAC transcription factors (NACMTFs) are a special group that remains anchored to the internal or cellular membrane in an inactive form and resumes activity upon detachment from the membrane and entering into the nucleus. Since plasma membrane residing proteins act as the sensor for external stimuli such as adverse environments, bound MTFs could potentially act as a sensor for rapid gene regulation. The focus of this project proposal is on tomato newly discovered MTF SlNACMTF3, since it is differentially expressed and activated in multiple tissues and stresses, throughout the life cycle of tomato, and directly involved in the regulation of both biotic and abiotic stress-response related genes. Our continuing research for better understanding the molecular mechanism of activation of SlNACMTF3 and its biological significance revealed the role of membrane-bound rhomboid proteases in releasing the MTF, preferable DNA recognition motif of the MTF, and the genes having the motif in their promoter and likely regulated by SlNACMTF3. A closer inspection of these genes’ functional identity suggests SlNACMTF3 activation will alter ‘cell cycle regulation’ and stress-genes expression. The exact nature of regulations of SlNACMTF3’s expression remains elusive. Moreover, the biological significance of this type of alternate mode of its regulation is yet to be explored. Likewise, the question arises why the biological process, such as cell cycle regulation, has to be regulated by a MTF during stress? We are also questioning how the rhomboid-SlNACMTF3-stress/cell-cycle genes axis is controlled during stress and soon after withdrawal of stress. Most of the experiments will be conducted after application of thermal stress; however, biotic stresses also will be tested wherever feasible. Utilizing plant molecular biology, biotechnology, cell biology, omics and bioinformatics tools, we intend to analyze the major mode of regulation of expression of SlNACMTF3, molecular mechanisms, and the physiological processes controlled by the MTF. Observations will help understand the signalling processes that are to be rapidly regulated when the plant perceives stress. This study will also generate the scope and resources for research to investigate why certain biological signaling events are to be controlled by a transcription factor present in the system in an inactive form; however, a pool of the factor becomes instantly available upon the perception of stress. A broader understanding of the role of MTFs will facilitate devising strategies to impart stress resilience in tomato plants via biotechnological or fast forward breeding approaches.