Responses of roots to signals from environmentally perturbed shoots

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My long-term interests are: (i) What are the mechanisms by which plants sense & respond to environmental stress/change. (ii) What is the role of hormones & other signal molecules as messengers & amplifiers of a fluctuating environment? (iii) How do shoots communicate with roots & roots communicate with shoots? Environmental change/stress triggers the production of multiple signals & these acting in concert modify growth & development in ways that increase survival. Roots & shoots are trapped in dissimilar environments, yet both organs must act cooperatively. Above- & below-ground organs need to efficiently exchange information about conditions being experienced by the other distant organ. What processes do these messages trigger when they reach the target organ? What is the identity of messages passing between organs in response to sensing of environmental alteration? How are such messages coordinated? How do the networks of interacting messages function? In this proposal I will focus on the question, what happens in roots when they receive messages/signals from environmentally perturbed shoots? Roots make up approximately 50% of the world's terrestrial plant biomass yet there is surprisingly little research on roots compared to aboveground tissues. Being buried in the soil presents technical challenges. While investigation of roots is fraught with difficulties, we have developed techniques that allow us to effectively probe the physiology & biochemistry of this inadequately understood organ. The hypothesis being tested is: Shoots, subjected to range of environmental perturbations (different red/far red irradiation, UV-B, wind stress, high CO2) will send signals to roots triggering them to quickly modify their metabolism & growth & development. Some of the parameters to be measured are: changes in levels of root hormones (concentrating on ethylene in the first instance), metabolic fingerprinting & footprinting of roots & root exudates, & monitoring of root architecture & morphology with MacRhizo software.