Breeding for low cadmium barley by introgression of a Sukkula-like transposable element
Breeding for low cadmium barley by introgression of a Sukkula-like transposable element
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DOI：
10.1038/s43016-020-0130-x
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发表时间：
2020-08-01
期刊：
影响因子：
23.2
通讯作者：
Ma, Jian Feng
中科院分区：
文献类型：
--
作者：
Lei, Gui Jie;Fujii-Kashino, Miho;Ma, Jian Feng
大麦是世界上第四大粮食作物，也是镉的主要来源之一，镉对人类健康构成严重威胁。在这里，我们确定了一个基因编码的P型重金属ATP酶3（HvHMA 3）负责在大麦籽粒镉积累。HvHMA 3来自日本的高镉大麦品种Haruna Nijo和来自阿富汗的低镉大麦品种BCS 318，在氨基酸水平上具有97%的同源性。此外，HvHMA 3从两个品种表现出类似的运输活动，镉和相同的亚细胞定位在液泡膜。然而，HvHMA 3在BCS 318中的表达是在Haruna Nijo中的两倍。一个3.3-脱氢酶Sukkula样转座因子被发现插入在低镉品种的基因上游，作为启动子，增强HvHMA 3的表达。通过回交将这种插入基因渗入到一个优良大麦品种中，导致在Cd污染土壤中生长的籽粒中Cd积累减少，而不产生产量损失。在世界上其他一些大麦地方品种中也发现了插入降低镉积累的现象。我们的研究结果表明，Sukkula样转座因子的插入在上调HvHMA 3的表达中起着重要作用。人类暴露于高毒性重金属镉（Cd）的主要来源是饮食。本研究确定了一个基因编码的P型重金属ATP酶3（HvHMA 3），这是负责镉在大麦籽粒中的积累。一个Sukkula样的转座因子被发现在上调HvHMA 3的表达，从而减少镉在籽粒中的积累发挥了重要作用。
Barley is the fourth most produced cereal crop in the world and one of the major dietary sources of cadmium (Cd), which poses serious threats to human health. Here, we identify a gene that encodes a P-type heavy metal ATPase 3 (HvHMA3) responsible for grain Cd accumulation in barley. HvHMA3 from the high Cd barley variety Haruna Nijo in Japan and the low Cd variety BCS318 in Afghanistan shared 97% identity at the amino acid level. In addition, the HvHMA3 from both varieties showed similar transport activity for Cd and the same subcellular localization at the tonoplast. However, the expression of HvHMA3 was double in BCS318 than in Haruna Nijo. A 3.3-kilobase Sukkula-like transposable element was found to be inserted upstream of the gene in the low Cd variety, which functioned as a promoter and enhanced the expression of HvHMA3. Introgression of this insertion to an elite barley cultivar through backcrossing resulted in decreased Cd accumulation in the grain grown in Cd-contaminated soil without yield penalty. The decreased Cd accumulation resulting from the insertion was also found in some other barley landraces in the world. Our results indicate that insertion of the Sukkula-like transposable element plays an important role in upregulating HvHMA3 expression.The primary source of human exposure to the highly toxic heavy metal cadmium (Cd) is diet. This study identified a gene encoding a P-type heavy metal ATPase 3 (HvHMA3) that is responsible for Cd accumulation in barley grain. A Sukkula-like transposable element was found to play an important role in upregulating the expression of HvHMA3, thereby decreasing Cd accumulation in the grain.