青花椒种质资源重金属镉积累的差异分析

Differential analysis on heavy metal cadmium accumulation of Zanthoxylum armatum germplasm resources

  • 摘要: 【目的】 分析青花椒种质资源镉积累的差异,探讨镉积累特性及富集机制,为青花椒品种选育和镉防控提供理论依据。【方法】 以重庆市江津区花椒国家林木种质资源库中生产性状较好的九叶青花椒、早熟九叶青花椒、关岭藤椒、四川藤椒、云南藤椒和云南大麻椒6个种质为试验材料,测定叶片、枝干、枝皮、果皮、种子和根系6个部位的镉含量,分析镉富集与转运特征;选取镉富集能力差异较大的种质,对其根系代谢物进行非靶向代谢组学分析。【结果】 不同青花椒种质同一部位的镉含量存在差异,其中云南藤椒各部位镉含量均较高于其他种质。同一青花椒种质各部位镉含量也存在差异,除关岭藤椒外,其他种质各部位镉含量均以枝皮为最高,其次是叶片、根系,且均高于种子、枝干、果皮。各青花椒种质根系对土壤镉均有富集能力,富集系数为3.470~12.780,其中云南藤椒的富集能力显著强于其他种质(P<0.05,下同),早熟九叶青花椒显著弱于其他种质。根系到果皮、根系到叶片、根系到枝干、根系到枝皮、根系到种子的转运系数分别为0.264~0.530、1.494~3.294、0.324~0.642、1.408~3.628、0.330~0.943。对镉富集能力差异最大的早熟九叶青花椒与云南藤椒根系代谢物进行非靶向代谢组学分析,共鉴定出520个差异代谢物,其中196个代谢物上调表达,324个代谢物下调表达,2个种质间存在明显差异;与早熟九叶青花椒根系代谢物相比,云南藤椒根系代谢物中有机酸、生物碱呈上调表达趋势;KEGG代谢通路富集分析结果表明,差异代谢物主要富集在异黄酮生物合成、苯丙氨酸代谢、精氨酸生物合成、牛磺酸和亚牛磺酸代谢、亚油酸代谢等通路。【结论】 青花椒种质资源对土壤镉的积累存在差异,早熟九叶青花椒富集能力较弱,云南藤椒富集能力较强,其富集能力差异可能与根系代谢物有关。

     

    Abstract: 【Objective】 To analyze the differences in cadmium( Cd) accumulation among Zanthoxylum armatum germ-plasm resources, explore the characteristics of cadmium accumulation and enrichment mechanisms, which could provide theoretical reference for the breeding of Z. armatum varieties and cadmium control. 【Method】 Six germplasms with good production traits from the National Forest Tree Germplasm Resource Repository of Zanthoxylum armatum in Jiangjin Dis-trict, Chongqing, including Z. armatum ‘ Jiuyeqinghuajiao’, Z. armatum ‘ Zaoshu Jiuyeqinghuajiao’, Guanling Z. armatum, Sichuan Z. armatum, Yunnan Z. armatum, Yunnan Zanthoxylum sp., were used as experimental materials. The Cd content in 6 parts, including leaves, stems, branch bark, pericarp, seeds and roots, was measured to analyze the charac-teristics of Cd enrichment and transport. And germplasms with great differences in Cd enrichment ability were selected for untargeted metabolomics analysis on root metabolites. 【Result】 Differences in Cd content were observed in the same part among different Z. armatum germplasms, with Yunnan Z. armatum showing higher cadmium content in all parts com-pared to other germplasms. Within the same germplasm, variations in Cd content were also found among different parts. Except for Guanling Z. armatum, the branch bark had the highest Cd content in other germplasms, followed by leaves and roots, which were higher than those in seeds, stems and pericarp. All Z. armatum germplasms had soil Cd enrichment ability in their roots, with enrichment coefficients ranging from 3.470 to 12.780. Yunnan Z. armatum showed significantly stronger enrichment ability than other germplasms( P<0.05, the same below), while Z. armatum‘ Zaoshu Jiuyeqinghua-jiao’ was significantly weaker than other germplasms. The transfer coefficients from root to pericarp, root to leaf, root to stem, root to branch bark, and root to seed were 0.264-0.530, 1.494-3.294, 0.324-0.642, 1.408-3.628 and 0.330-0.943 respectively. Untargeted metabolomics analysis was conducted on the root metabolites of Z. armatum‘ Zaoshu Jiuyeqing-huajiao’ and Yunnan Z. armatum, which had the greatest difference in Cd enrichment ability. A total of 520 differential metabolites were identified, including 196 up-regulated and 324 down-regulated metabolites, with significant differences between the 2 germplasms. Compared with the root metabolites of Z. armatum‘ Zaoshu Jiuyeqinghuajiao’, the root me-tabolites of Yunnan Z. armatum showed an up-regulated trend in organic acids and alkaloids. The results of KEGG meta-bolic enrichment analysis indicated that the differential metabolites were mainly enriched in pathways such as isoflavonoid biosynthesis, phenylalanine metabolism, arginine biosynthesis, taurine and hypotaurine metabolism, and linoleic acid metabolism. 【Conclusion】 There are differences in the accumulation of soil Cd by Z. armatum germplasm resources. Specifically, Z. armatum‘ Zaoshu Jiuyeqinghuajiao’ demonstrated relatively low accumulation ability, whereas Yunnan Z. armatum shows high enrichment ability. This variation in Cd enrichment might be associated with root metabolites.

     

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