Disruption of the amino acid transporter CsAAP2 inhibits auxin-mediated root development in cucumber
Disruption of the amino acid transporter CsAAP2 inhibits auxin-mediated root development in cucumber
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DOI：
10.1111/nph.18947
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发表时间：
2023-05-02
期刊：
影响因子：
9.4
通讯作者：
Sui，Xiaolei
中科院分区：
文献类型：
--
作者：
Yao，Xuehui;Li，Hujian;Sui，Xiaolei
氨基酸转运蛋白是植物体内有机氮分配的主要介质，对植物的生长发育至关重要。尽管氨基酸转运蛋白基因在黄瓜基因组中具有重要意义，但目前对黄瓜中氨基酸转运蛋白基因的研究还相对较少，共鉴定出86个氨基酸转运蛋白基因。进一步鉴定了氨基酸渗透酶（AAP）亚家族成员在不同组织中的表达模式，发现CsAAP 2基因在黄瓜根维管细胞中高表达，CsAAP 2基因敲除后，根分生组织发育受阻，导致侧根发生延迟，根伸长受到抑制。此外，aap2突变体的根系发育缺陷严重阻碍了黄瓜的生长，且其根系中的氨基酸和木质素含量较高。结果表明，突变体根系具有较强的酸化能力。此外，在theaap2突变体中，生长素的极性运输在根尖被破坏，导致根中生长素水平高。有趣的是，微碱性培养基通过刺激生长素途径挽救了它们严重降低的根生长。
Amino acid transporters are the principal mediators of organic nitrogen distribution within plants and are essential for plant growth and development. Despite this importance, relatively few amino acid transporter genes have been explored and elucidated in cucumber (Cucumis sativus).Here, a total of 86 amino acid transporter genes were identified in the cucumber genome. We further identified Amino Acid Permease (AAP) subfamily members that exhibited distinct expression patterns in different tissues.We found that theCsAAP2as a candidate gene encoding a functional amino acid transporter is highly expressed in cucumber root vascular cells.CsAAP2knockout lines exhibited arrested development of root meristem, which then caused the delayed initiation of lateral root and the inhibition of root elongation. What is more, the shoot growth ofaap2mutants was strongly retarded due to defects in cucumber root development.Moreover,aap2mutants exhibited higher concentrations of amino acids and lignin in roots. We found that the mutant roots had a stronger ability to acidize medium. Furthermore, in theaap2mutants, polar auxin transport was disrupted in the root tip, leading to high auxin levels in roots. Interestingly, slightly alkaline media rescued their severely reduced root growth by stimulating auxin pathway.