Katsuhara Maki, Koshio Kazuki, Shibasaka Mineo, Hayashi Yasuyuki, Hayakawa Takahiko, Kasamo Kunihiro
Research Institute for Bioresources, Okayama University, Kurashiki, 710-0046 Japan.
Plant Cell Physiol. 2003 Dec;44(12):1378-83. doi: 10.1093/pcp/pcg167.
Barley HvPIP2;1 is a plasma membrane aquaporin and its expression was down-regulated after salt stress in barley [Katsuhara et al. (2002) Plant Cell Physiol. 43: 885]. We produced and analyzed transgenic rice plants over-expressing barley HvPIP2;1 in the present study. Over-expression of HvPIP2;1 increased (1) radial hydraulic conductivity of roots (Lp(r)) to 140%, and (2) the mass ratio of shoot to root up to 150%. In these transgenic rice plants under salt stress of 100 mM NaCl, growth reduction was greater than in non-transgenic plants. A decrease in shoot water content (from 79% to 61%) and reduction of root mass or shoot mass (both less than 40% of non-stressed plants) were observed in transgenic plants under salt stress for 2 weeks. These results indicated that over-expression of HvPIP2;1 makes rice plants sensitive to 100 mM NaCl. The possible involvement of aquaporins in salt tolerance is discussed.
大麦HvPIP2;1是一种质膜水通道蛋白，在盐胁迫后其表达在大麦中被下调[Katsuhara等人（2002年）《植物细胞生理学》43:885]。在本研究中，我们培育并分析了过量表达大麦HvPIP2;1的转基因水稻植株。HvPIP2;1的过量表达使（1）根的径向水力传导率（Lp(r)）提高到140%，以及（2）地上部与根的质量比提高到150%。在100 mM NaCl盐胁迫下，这些转基因水稻植株的生长受抑制程度大于非转基因植株。在盐胁迫2周的转基因植株中，观察到地上部含水量下降（从79%降至61%）以及根质量或地上部质量减少（均不到非胁迫植株的40%）。这些结果表明，HvPIP2;1的过量表达使水稻植株对100 mM NaCl敏感。本文讨论了水通道蛋白在耐盐性中的可能作用。
