Research:
Abiotic stress tolerance in crop plants
Difference in seed size of drought stressed and well-watered plants. Transgenic plants show little difference in seed size, regardless of conditions, while non-transgenic plants vary greatly in seed size. (Shou et al, 2004b)
A late-spring cold snap or early fall frost can severely reduce crop yield. Cold acclimation, the exposure of plants to mild cold stress, induces mild oxidative stress which can improve tolerance to later, more severe chilling stress. Among the molecular changes induced by cold acclimation is the induction of Mitogen-activated protein kinase (MAPK) cascades. The molecular signaling carried through MAPK pathways lead to induction of stress responsive proteins. Our hypothesis is that a plant could be acclimated genetically; if its stress-induced pathways or proteins were turned on in the absence of stress, would it be better able to withstand sudden severe stress such as subfreezing temperatures? The figures below and at right show improvement of chilling and drought tolerance in corn achieved through introducing a gene encoding the MAP kinase kinase kinase, NPK1. A similar strategy is underway to improve salt, drought and cold tolerance in rice.
Cold tolerant transgenic plant and non-cold tolerant control plant after exposed to freezing temperatures (Shou et al, 2004a).
