Regulation of in vitro embryogenesis

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Understanding how cells behave and adopt specific developmental fates under changing environmental conditions is a fundamental question in animal and plant biology. The concept is best exemplified in plants where fully mature (differentiated) cells have the ability to lose their developmental program (de-differentiate) and embark into new pathways through the acquisition of novel fates. This capacity, which increases possibilities of survival during stress conditions and is vital for regenerating damaged tissues or organs, will be studied using in vitro embryogenesis as a model system. During in vitro embryogenesis, cells with a vegetative developmental fate can be reprogrammed to form embryogenic cells and embryos (and eventually plants) by simple chemical manipulations. This vegetative-embryogenic transition can be perturbed (encouraged or repressed) and exploited to identify and analyze the genetic elements underpinning changes in cell development. In this proposal, the in vitro embryogenesis system will be perturbed by altering the levels of SHOOTMERISTEMLESS and plant HEMOGLOBINS. SHOOTMERISTEMLESS is a known regulator of cell fate decision while HEMOGLOBINS regulate the levels of nitric oxide, a ubiquitous signal molecule in animals and plants able to reprogram cell behavior. Cutting edge techniques will define structural, physiological, and molecular changes accompanying these perturbations and will propose genetic models delineating the vegetative-embryogenic transition. The utilization of several plant species including Arabidopsis, Brassica napus (canola) and maize (corn) will make the results relevant for economically important agricultural crops in North America. Collectively these results will provide innovative breakthrough knowledge on cell fate acquisition applicable not only to embryogenesis (and the improvement of propagation systems), but to processes requiring a redirection of cell behavior which are crucial for plant productivity, adaptation to stress conditions, prevention of diseases and ultimately survival.