52.ポプラにおける導管液物質と根における遺伝子発現の季節変動とアブシジン酸の関与(口頭発表)

概要

論文の詳細を見る
Deciduous trees show annual periodicity in shoot growth and development. However such periodicity of growth and function of root is not well known. To clarify the seasonal fluctuation of root function, xylem sap was collected from poplar cut branches and the content of sap and the gene expression in root were analyzed. Various xylem sap components showed seasonal fluctuation with peaks from winter to spring. PIP encoding plasma membrane aquaporin and CYCB encoding cyclin B were strongly expressed in root around April when xylem sap quantity increases and around June when growth of root becomes active, respectively. In addition, the gene for 25kDa protein (XSP25) which is highly hydrophilic with abundance of charged amino acids and most abundantly exists in xylem sap was identified by MS analysis, and XSP25 was found to be expressed in root in winter and highly up-regulated by ABA application to autumn root. On the other hand, NCED encoding the enzyme for ABA biosynthesis was up-regulated in shoot, but not in root of cold-treated plants. In the hydroponic culture, the expressions of genes for Ca2+ transporter, XSP25, XSP24 and cell wall invertase in root were up-regulated by short day followed by low temperature. We hypothesize that ABA synthesized in shoot in response to short day and low temperature from autumn to early winter promotes the synthesis of XSP25 in root to protect shoot tissues against cold and/or dry in winter.
2010-10-01