Recently, the phytoremediation and safe utilization of cadmium (Cd) polluted soil by mulberry planting and sericulture have attracted researchers' attention. However, the understandings of related molecular mechanisms of mulberry response to Cd are still limited. Meanwhile, there are few reports on the diversity of the Cd tolerance and accumulation ability of different mulberry cultivars. Here, we obtained two mulberry cultivars with significant differences in Cd accumulation: high Cd accumulation cultivar FC and low Cd accumulation cultivar G12. Ionomics analysis showed that the distribution pattern of Na is the most similar to that of Cd in both G12 and FC. In transcriptomics analysis, the results of GO and KEGG enrichment analyses showed that cell wall organization-related genes were significantly affected by Cd stress, while cell division-related genes were significantly down-regulated. The expression levels of several Cd-chelation and transporter genes (AGT2, MT2, HIPP26, MTP9 and DTX43/44) were higher in all groups of G12 than those of FC, while the expression level of PCR2 and ABCC2 were higher in all groups of FC than those of G12. In untargeted metabolomics analysis, compared with FC, the metabolites of G12 were less affected by Cd stress in phenylpropanoid, flavonoid and isoflavonoid biosynthesis pathways. Notably, the content of rutin in FC was significantly lower than that of G12. These results provide theoretical support and candidate cultivars for mulberry application in Cd polluted soil, and candidate genes for mulberry genetic modification and molecular breeding in the future.

近年来，植桑养蚕对镉（Cd）污染土壤的植物修复及安全利用引起了研究人员的关注。然而，对桑树响应镉的相关分子机制的认识仍然有限。同时，关于不同桑树品种对镉的耐受性和积累能力的差异性报道较少。在这里，我们获得了两个镉积累差异显着的桑树品种：高镉积累品种FC和低镉积累品种G12。离子组学分析表明，在G12和FC中，Na的分布模式与Cd的分布模式最为相似。在转录组学分析中，GO和KEGG富集分析结果表明细胞壁组织相关基因受镉胁迫显着影响，而细胞分裂相关基因则显着下调。几种镉螯合和转运蛋白基因的表达水平（G12各组AGT2、MT2、HIPP26、MTP9、DTX43/44）均高于FC，而PCR2、ABCC2在各FC组中的表达量均高于G12。在非靶向代谢组学分析中，与FC相比，G12的代谢物在苯丙烷、黄酮和异黄酮生物合成途径中受镉胁迫的影响较小。值得注意的是，FC中芦丁的含量明显低于G12。这些结果为桑树在镉污染土壤中的应用提供了理论支持和候选品种，也为今后桑树基因改造和分子育种提供了候选基因。