Plant, Animal & Microbe Genomes X Conference Plant, Animal & Microbe Genomes X ConferenceJanuary 12-16, 2002
Town & Country Convention Center
San Diego, CA
Session: Plant Session Lecture
Plants spend their life in one position, and thrive in locations where they are exposed to a wide variety of environmental conditions. This versatility is possible because they continuously monitor and respond to environmental stimuli such as light, temperature and the availability of nutrients. Such responses alter the growth habit and form of the plant adapting it to its particular environment. A major developmental transition in the life cycle of plants is from vegetative growth to flowering. This transition is usually controlled by environmental signals such as daylength and temperature. These responses are important in the adaptation of plants to growth in particular locations and produce characteristic seasonal patterns in flowering. We have studied the control of flowering in the model species Arabidopsis thaliana and are elucidating the molecular mechanisms that regulate flowering in response to environmental conditions. Flowering of Arabidopsis is triggered by long daylengths (or photoperiods) and by extended exposure to low temperatures (or vernalization). Both responses ensure that plants flower during spring or early summer, and are controlled by independent genetic pathways. We have identified and studied a class of mutants that disrupt the control of flowering by daylength, and have cloned the genes affected by these mutations. This has allowed us to propose how the functions of these genes are related, and suggest a mechanism by which the pathway may be activated by changes in daylength (Suarez-Lopez et al (2001) Nature 410, 1116 - 1120; Samach et al (2000) Science 288, 1613-1616.). Furthermore, the photoperiod pathway and the vernalization pathways converge to regulate the expression of the same set of genes involved in the early stages of flower development, and we have begun to study how these pathways interact at the molecular level to produce a coherent flowering response to these distinct environmental stimuli. Also plants show a wide variety of responses to daylength, and we are interested in how the activity of the pathway is modified to generate different photoperiodic response types and other flowering behaviours. I'll compare the control of flowering in Arabidopsis with what is known in other species that show different flowering responses.