Molecular Biology of Development

Plant development is regulated in very different ways to animals. This is because plants have a relatively simple body plan; they are sessile and must withstand (rather than avoid or escape from) environmental stress; and their growth pattern is indeterminate with the final body shape much more influenced by the external environment than is the case for animals. The fundamental processes governing plant development are regulated by the interaction of internal and environmental signals as mediated by hormones. The genetic basis of many of these processes is now becoming clear and many of the relevant genes have been identified. For applied plant science, the next step is to find ways of exploiting these genes to modify and improve plants. For example, genes controlling stem or root growth could be used to alter plant architecture; those controlling leaf development could be used to modify leaf number, shape, or distribution; those controlling trichome development could be used to increase the number of root hairs and facilitate nutrient uptake; and those controlling flower development could be used to regulate flowering time externally and perhaps even increase the number of flowering cycles (and therefore harvests) per year. Relationships among the many plant genes controlling development are likely to become clearer as functional genomics is used to elucidate functional pathways, hierarchies, and networks.