Graduate School of Agricultural and Life Sciences, The University of Tokyo, Japan.
J Exp Bot. 2011 Nov;62(15):5727-34. doi: 10.1093/jxb/err300. Epub 2011 Sep 9.
The contamination of food crops by cadmium (Cd) is a major concern in food production because it can reduce crop yields and threaten human health. In this study, knockout rice plants (Oryza sativa) tagged with the gene trap vector pGA2707 were screened for Cd tolerance, and the tolerant line lcd was obtained. The lcd mutant showed tolerance to Cd on agar plates and in hydroponic culture during early plant development. Metal concentration measurements in hydroponically grown plants revealed significantly less Cd in the shoots of lcd plants compared with wild-type (WT) shoots. When cultured in the field in soil artificially contaminated with low levels of Cd, lcd showed no significant difference in the Cd content of its leaf blades; however, the Cd concentration in the grains was 55% lower in 2009 and 43% lower in 2010. There were no significant differences in plant dry weight or seed yield between lcd and wild-type plants. LCD, a novel gene, is not homologous to any other known gene. LCD localized to the cytoplasm and nucleus, and was expressed mainly in the vascular tissues in the roots and phloem companion cells in the leaves. These data indicate that lcd may be useful for understanding Cd transport mechanisms and is a promising candidate rice line for use in combating the threat of Cd to human health.
镉（Cd）污染农作物是粮食生产中的一个主要问题，因为它会降低作物产量并威胁人类健康。在这项研究中，筛选了带有基因捕获载体 pGA2707 的基因敲除水稻植株以提高其对 Cd 的耐受性，并获得了耐受株系 lcd。lcd 突变体在琼脂平板和水培培养中对早期植物发育阶段的 Cd 具有耐受性。在水培条件下生长的植物中进行的金属浓度测量表明，lcd 植株地上部分的 Cd 含量明显低于野生型（WT）植株。当在人为用低浓度 Cd 污染的土壤中进行田间培养时，lcd 叶片中的 Cd 含量没有显著差异；然而，2009 年和 2010 年，lcd 植株的籽粒中 Cd 浓度分别降低了 55%和 43%。lcd 和野生型植株之间的植物干重或种子产量没有显著差异。lcd 是一个新基因，与任何其他已知基因都没有同源性。lcd 定位于细胞质和细胞核中，主要在根部的维管束组织和叶片中的韧皮伴胞中表达。这些数据表明，lcd 可能有助于理解 Cd 转运机制，是一种有前途的候选水稻株系，可用于应对 Cd 对人类健康的威胁。
