Phloem unloading via the apoplastic pathway is essential for shoot distribution of root-synthesized cytokinins

编号 040030902

推送时间 20210920

研究领域 森林培育 

年份 2021 

类型 期刊 

语种 英语

标题 Phloem unloading via the apoplastic pathway is essential for shoot distribution of root-synthesized cytokinins

来源期刊 Plant Physiology

期 第309期

发表时间 20210427

关键词 ABC transporter;  apoplastic pathway;  cytokinin;  long-distance transport;  phloem unloading;  shoot distribution; 

摘要 Root-synthesized cytokinins are transported to the shoot and regulate the growth, development, and stress responses of aerial tissues. Previous studies have demonstrated that Arabidopsis (Arabidopsis thaliana) ATP binding cassette (ABC) transporter G family member 14 (AtABCG14) participates in xylem loading of root-synthesized cytokinins. However, the mechanism by which these root-derived cytokinins are distributed in the shoot remains unclear. Here, we revealed that AtABCG14-mediated phloem unloading through the apoplastic pathway is required for the appropriate shoot distribution of root-synthesized cytokinins in Arabidopsis. Wild-type rootstocks grafted to atabcg14 scions successfully restored trans-zeatin xylem loading. However, only low levels of root-synthesized cytokinins and induced shoot signaling were rescued. Reciprocal grafting and tissue-specific genetic complementation demonstrated that AtABCG14 disruption in the shoot considerably increased the retention of root-synthesized cytokinins in the phloem and substantially impaired their distribution in the leaf apoplast. The translocation of root-synthesized cytokinins from the xylem to the phloem and the subsequent unloading from the phloem is required for the shoot distribution and long-distance shootward transport of root-synthesized cytokinins. This study revealed a mechanism by which the phloem regulates systemic signaling of xylem-mediated transport of root-synthesized cytokinins from the root to the shoot.

服务人员 孙小满

服务院士 尹伟伦

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