Download Biologically active oligosaccharides (oligosaccharins

臨時生物科学セミナー（第１６４回）
日
時：平成２０年１１月２５日（火）１６：３０～１８：００
場
所：理学部２号館 第二講義室（２２３号室）
講演題目：Patterning Genes in Land Plants
講演者名：John L. Bowman (School of Biological Sciences, Monash
University, Australia; Department of Plant Biology, University of California
Davis, USA)
John L. Bowman 1,2, Sandra K. Floyd 1, Keiko Sakakibara 1, Chris Zalewski
2
, Karen Yip 2, Pia Sappl 1, Dyani Lewis 1, Lukas Brand 1, Eduardo FloresSandoval 1
As more plant genome sequences become available, researchers are increasingly using
comparative genomics to address some of the major questions in plant biology. Such
questions include the evolution of photosynthesis and multicellularity, and the
developmental genetic changes responsible for changes in body plan and the origin of
important plant innovations such as roots, leaves, and vascular tissue. We have focused
on tracing the evolutionary history of genes involved in pattern formation. In
particular, we have investigated the history of genes involved in establishing leaf
polarity in Arabidopsis. We find that some genes are evolutionarily recent, evolving
coincident with the evolution of leaves in seed plants. However, other genes predate
the evolution of leaves, implying a co-option from a more ancestral role.
Expression and functional studies in early diverging lineages of land plants
provide clues as to ancestral functions, and thus to the evolution of land plant
morphology. For example, Class III HD-Zip genes act to promote meristem
development, adaxial leaf development and vascular development in
Arabidopsis. Since the latter two tissues do not exist in early diverging land plant
lineages, apical growth and meristem development may represent an ancestral
function. Expression analyses in moss and liverworts support this hypothesis, but also
suggest a more direct role in response to light, an environmental parameter that is key
in molding the plastic development of plants, and establishing polarity in liverworts in
particular. Thus, ancestral roles of patterning genes may lie in interactions with
environmental parameters critical in the transition from an aquatic algal ancestor to a
land plant.
東京大学理学部生物学科植物学コース