青葙属植物锰富集性状差异及其与SRAP标记的关联分析

Manganese toxicity is a major constraint for plant growth in acid soil. Phytoremediation is a promising green technique for Mn removal from contaminated soil. Elucidating the genetic and molecular basis of Mn hyperaccumulation is a key node to improve Mn phytoremediation. In this project, a new Mn hyperaccumulator, Celosia argentea Linn., will be used as a model plant. A major advantage of C. argentea is available crosses with its nonaccumulator sister species Celosia cristata L. Based on the specialty, a segregation F2 population will be obtained from the crosses between C. argentea and C. cristata. The differences of Mn accumulation in the different Celosia genus plants and F2 population will be observed. Sequence-related amplified polymorphism (SRAP) system for C. argentea will be established and optimized. The molecular markers tightly linked to genes controlling Mn hyperaccumulation in C. argentea will be screened by association analysis of manganese accumulation with SRAP markers. The accomplishment of this project will give new information for the identification of genes involved in Mn hyperaccumulation, and will lay a foundation for directional breeding of Mn hyperaccumulators. The results from this study will provide theoretical and practical contributions to the understanding molecular genetic basis of Mn hyperaccumulation and the enhancement of Mn phytoremediation efficiency.

锰毒是酸性土壤中突出的危害因素。植物修复技术是清除土壤锰污染的有效手段。而阐明锰超富集植物的分子遗传学基础是提高土壤锰污染植物修复效率的关键所在。本项目在发现锰超富集植物青葙的基础上，巧妙地利用青葙与同属非富集植物鸡冠花的可杂交性，构建锰富集性状分离的资源群体；观测不同青葙属植物及性状分离群体的锰富集性状差异；建立和优化青葙的SRAP-PCR体系；通过锰富集性状多样性与SRAP标记多态性的关联分析，寻找与锰超富集性状紧密连锁的标记位点，为锰超富集基因的精准定位提供线索，为锰超富集植物的定向育种奠定基础。本项目的研究对于揭示锰超富集植物的分子遗传学机制和提高土壤锰污染植物修复效率具有重要的理论和现实意义。

锰毒是酸性土壤中突出的危害因素。植物修复技术是清除土壤锰污染的有效手段。而阐明锰超富集植物的分子遗传学基础是提高土壤锰污染植物修复效率的关键所在。本项目利用青葙属植物锰富集性状的差异，研究了青葙锰超富集机制；在建立青葙的SRAP-PCR体系的基础上，通过锰富集性状多样性与SRAP标记多态性的关联分析，筛选锰超富集性状紧密连锁的标记位点；在镉/锰复合污染的条件下，初步研究了青葙对镉/锰的共富集特征和交互作用。上述研究取得如下重要结果：（1）青葙锰富集和耐受能力显著强于同属近缘种鸡冠花、台湾青葙和凤尾鸡冠花，并且四种植物的锰富集性状差异与亲缘关系一致。（2）筛选出9对青葙属植物SRAP-PCR的扩增引物，共获得312条多态性条带，通过与锰富集性状进行关联分析，发现一个SRAP标记M2E5与锰超富集能力密切相关。（3）青葙叶片中的锰主要以草酸盐形式存在，而液泡是锰的主要贮存场所。这表明螯合解毒和区隔化分布是青葙耐受锰的两种主要机制。（4）锰胁迫下，青葙叶片中的P-ATPase和ATP合酶的表达量增加。这表明青葙可能通过上调P-ATPase增加Mn向液泡的转运，降低锰对细胞的毒害。（5）青葙能够同时超富集Mn和Cd。当土壤中同时存在Mn和Cd时，青葙叶片中的Mn和Cd含量最高可以达到29,000和276 mg/kg。这些研究结果为进一步揭示青葙锰超富集的分子遗传学机理提供了新线索，为利用青葙修复镉/锰复合污染土壤提供了理论依据。