Genetic differences in nitrate uptake in two clones of the common reed, Phragmites australis
Genetic differences in nitrate uptake in two clones of the common reed, Phragmites australis
复制标题
DOI：
10.1270/jsbbs.55.297
复制
发表时间：
2005-09-01
期刊：
影响因子：
2.4
通讯作者：
Hasegawa, H
中科院分区：
文献类型：
--
作者：
Araki, R;Mori, M;Hasegawa, H
芦苇（Phragmites australis）是一种常见的芦苇，可用于去除河湖水体中的富营养物质。本研究旨在探讨芦苇硝酸盐吸收能力的遗传差异，以期培育出可用于植物修复的芦苇。从日本琵琶湖沿着的湖滨湿地芦苇群落中分离出两个芦苇无性系（W-6和W-8），用于研究其吸收硝酸盐的生理和分子基础。硝态氮吸收的K（m）s分别为80.8和45.2 μ M，V（max）s分别为10.62和2.37 μ mol g（-1）根f.w. h（-1），表明W-6和W-8的硝酸盐吸收动力学参数存在显著差异。为了在分子水平上研究这些差异，我们从两个芦苇无性系中分离了一个高亲和力的硝酸盐转运蛋白基因（NRT 2），并分析了芦苇NRT 2的结构和表达。芦苇NRT 2的氨基酸序列由523个残基组成，与其它单子叶植物NRT 2的氨基酸序列相似性较高。芦苇NRT 2在用200 μ M硝酸盐处理的根中强烈表达。芦苇NRT 2在W-6和W-8之间有3个氨基酸替换。在两个克隆之间也观察到NRT 2转录的差异。目前尚不清楚硝酸盐动力学参数的差异是否是由于芦苇NRT 2的结构或表达。这些结果表明，选择基因型更有用的硝酸盐的去除的可能性。
Phragmites australis, common reed, could be useful in removing eutrophic substances from river and lake water. In this study, the genetic differences in nitrate uptake ability of the reed were investigated with a view to breeding a reed plant useful for phytoremediation. Two reed clones (W-6 and W-8) isolated from a reed community in the lakeside wetland along Lake Biwa, Japan, were used for a study on the physiological and molecular basis of nitrate uptake. K(m)s for nitrate uptake were 80.8 and 45.2 mu M and V(max)s for nitrate uptake were 10.62 and 2.37 mu mol g(-1) root f.w. h(-1) in W-6 and W-8, respectively, suggesting that there were critical differences in kinetic parameters for nitrate uptake. To investigate these differences at the molecular level, we isolated a high-affinity nitrate transporter gene (NRT2) from the two reed clones and analyzed the reed NRT2 structure and expression. The deduced amino acid sequence of the reed NRT2 consisted of 523 residues and had a high similarity to NRT2 from other monocots. Reed NRT2 was strongly expressed in roots treated with 200 mu M nitrate. There were three amino acid substitutions of the reed NRT2 between W-6 and W-8. Differences in NRT2 transcription were also observed between the two clones. It was not clear whether the difference in kinetic parameters for nitrate was due to the reed NRT2 structure or expression. These results indicate the possibility of selecting genotypes more useful for the removal of nitrate.