Overexpression of the barley aquaporin HvPIP2;1 increases internal CO2 conductance and CO2 assimillation in the leaves of transgenic rice plants
Overexpression of the barley aquaporin HvPIP2;1 increases internal CO2 conductance and CO2 assimillation in the leaves of transgenic rice plants
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DOI：
10.1093/pcp/pch070
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发表时间：
2004-01-01
影响因子：
4.9
通讯作者：
Katsuhara, M
中科院分区：
文献类型：
--
作者：
Hanba, YT;Shibasaka, M;Katsuhara, M
测量了过表达大麦水通道蛋白HvPIP2的转基因水稻叶片的CO2扩散内导(g(i))和CO2同化率并研究了相关的解剖学特征；1．这项研究的目的是检验水通道蛋白促进二氧化碳在叶子内扩散的假设。通过同时测量气体交换和碳同位素比来估计完整叶子的 g(i) 值。表达最高水平 Aq-抗-HvPIP2;1 的转基因水稻植物的叶子显示 g(i) 与野生型水稻植物叶子中的 g(i) 相比增加了 40%。 g(i) 的增加伴随着 CO2 同化率增加 14% 和气孔导度 (g(s)) 增加 27%。具有低水平 Aq-抗-HvPIP2;1 的转基因植物显示 g(i) 和 CO2 同化率降低。在Aq-anti-HvPIP2;1水平较高的植物中，叶肉细胞尺寸减小，表皮和叶肉细胞的细胞壁增厚，表明叶子已变得干燥。尽管这种解剖结构的变化可以部分抵消水通道蛋白导致的 g(i) 的增加，但水通道蛋白含量的增加克服了这种不利影响。
The internal conductance for CO2 diffusion (g(i)) and CO2 assimilation rate were measured and the related anatomical characteristics were investigated in transgenic rice leaves that overexpressed barley aquaporin HvPIP2;1. This study was performed to test the hypothesis that aquaporin facilitates CO2 diffusion within leaves. The g(i) value was estimated for intact leaves by concurrent measurements of gas exchange and carbon isotope ratio. The leaves of the transgenic rice plants that expressed the highest levels of Aq-anti-HvPIP2;1 showed a 40% increase in g(i) as compared to g(i) in the leaves of wild-type rice plants. The increase in g(i) was accompanied by a 14% increase in CO2 assimilation rate and a 27% increase in stomatal conductance (g(s)). The transgenic plants that had low levels of Aq-anti-HvPIP2;1 showed decreases in g(i) and CO2 assimilation rate. In the plants with high levels of Aq-anti-HvPIP2;1, mesophyll cell size decreased and the cell walls of the epidermis and mesophyll cells thickened, indicating that the leaves had become xeromorphic. Although such anatomical changes could partially offset the increase in g(i) by the aquaporin, the increase in aquaporin content overcame such adverse effects.