4.キュウリ根の水分屈性におけるオーキシン動態制御機構の解析(口頭発表)

概要

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Hydrotropism is a response of root to a moisture gradient. Because of the necessity of water acquisition, root hydrotropism has been considered as an important tropism. Recent analyses using Arabidopsis have emphasized the contribution of polar auxin transport to differential auxin distribution as well as to gravitropism. Our previous results also suggested that differential auxin distribution plays a pivotal role in root hydrotropism. Nonetheless, how auxin distribution is controlled in this phenomenon remains unclear. In search of the molecules that control auxin redistribution in hydrotropic response, we found that inhibitors of auxin efflux significantly reduced hydrotropism in cucumber seedlings. Moreover, our immunohistochemical analyses revealed that the expression of putative auxin efflux facilitator CsPIN5 was diminished at the dry side of the distal elongation zone of hydrotropically responding roots, whereas it was maintained at the corresponding region of the humid side. Considering the previous results that auxin-responsive gene expression is mainly occurred at the humid side of distal elongation zone of cucumber seedlings, our present results suggests that CsPIN5-mediated auxin efflux plays definite role in regulating auxin redistribution during hydrotropic response in cucumber seedlings.
2007-10-05