Luo Jin-Song, Huang Jing, Zeng Da-Li, Peng Jia-Shi, Zhang Guo-Bin, Ma Hai-Ling, Guan Yuan, Yi Hong-Ying, Fu Yan-Lei, Han Bin, Lin Hong-Xuan, Qian Qian, Gong Ji-Ming
National Key Laboratory of Plant Molecular Genetics and CAS center for excellence in Molecular Plant Sciences, Shanghai Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, Shanghai, 200032, China.
University of Chinese Academy of Sciences, Beijing, 100049, China.
Nat Commun. 2018 Feb 13;9(1):645. doi: 10.1038/s41467-018-03088-0.
Pollution by heavy metals limits the area of land available for cultivation of food crops. A potential solution to this problem might lie in the molecular breeding of food crops for phytoremediation that accumulate toxic metals in straw while producing safe and nutritious grains. Here, we identify a rice quantitative trait locus we name cadmium (Cd) accumulation in leaf 1 (CAL1), which encodes a defensin-like protein. CAL1 is expressed preferentially in root exodermis and xylem parenchyma cells. We provide evidence that CAL1 acts by chelating Cd in the cytosol and facilitating Cd secretion to extracellular spaces, hence lowering cytosolic Cd concentration while driving long-distance Cd transport via xylem vessels. CAL1 does not appear to affect Cd accumulation in rice grains or the accumulation of other essential metals, thus providing an efficient molecular tool to breed dual-function rice varieties that produce safe grains while remediating paddy soils.
重金属污染限制了可用于种植粮食作物的土地面积。解决这一问题的一个潜在办法可能在于对粮食作物进行分子育种，以实现植物修复，即在秸秆中积累有毒金属的同时生产出安全且营养丰富的谷物。在此，我们鉴定出一个水稻数量性状基因座，我们将其命名为叶片1镉（Cd）积累基因座（CAL1），它编码一种防御素样蛋白。CAL1优先在根外皮层和木质部薄壁细胞中表达。我们提供的证据表明，CAL1通过在细胞质中螯合镉并促进镉分泌到细胞外空间来发挥作用，从而降低细胞质镉浓度，同时驱动镉通过木质部导管进行长距离运输。CAL1似乎不影响水稻籽粒中镉的积累或其他必需金属的积累，因此为培育既能生产安全谷物又能修复稻田土壤的双功能水稻品种提供了一种有效的分子工具。
