Comparative characterization of GmSPX members reveals that GmSPX3 is involved in phosphate homeostasis in soybean
Comparative characterization of GmSPX members reveals that GmSPX3 is involved in phosphate homeostasis in soybean
复制标题
GmSPX 成员的比较表征揭示 GmSPX3 参与大豆磷酸盐稳态
DOI：
10.1093/aob/mcu147
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发表时间：
2014
期刊：
影响因子：
4.2
通讯作者：
Liao Hong
中科院分区：
文献类型：
--
作者：
Yao Zhufang;Tian Jiang;Liao Hong
背景与目的SPX（SYG 1/Pho 81/XPR 1）结构域蛋白是植物磷信号转导途径中的重要组成部分，调节植物体内磷平衡。然而，大豆（Glycine max）中GmSPX成员的特性和功能在很大程度上仍然未知。随后，通过实时定量PCR（qPCR）分析，研究了GmSPX成员在营养液或砂培中生长的大豆的各种组织中的表达模式。通过35 S：GmSPX-GFP在洋葱表皮细胞中的瞬时表达研究了GmSPX的亚细胞定位。结果共鉴定出9个GmSPX基因成员，通过系统发育分析将其分为3个类群。在大豆中观察到GmSPX成员对营养（氮、磷、钾和铁）缺乏或接种丛枝菌根真菌和根瘤菌的不同反应。此外，GmSPX各成员的亚细胞定位也存在差异，其中GmSPX 3、GmSPX 7和GmSPX 8定位于细胞核，其余GmSPX成员则定位于细胞核和细胞质。对核定位和磷饥饿反应基因GmSPX 3在大豆转基因复合植株中的功能进行了分析。过量表达GmSPX 3导致高磷处理下地上部和根中磷浓度的增加，并增加了大豆毛状根中7个磷饥饿响应基因的转录。
Background and AimsProteins containing the SPX (SYG1/Pho81/XPR1) domain are vital components in the phosphorus (P) signalling pathway, and regulate phosphate (Pi) homeostasis in plants. However, the characteristics and functions of GmSPX members in soybean (Glycine max) remain largely unknown.MethodsBLAST searching revealed nineGmSPXmembers in the soybean genome. Subsequently, expression patterns ofGmSPXmembers were investigated in various tissues of soybean grown in nutrient solution or sand culture through quantitative real-time PCR (qPCR) analysis. Sub-cellular localization of GmSPX was examined via transient expression of35S:GmSPX-GFPin epidermal cells of onion (Allium cepa). Finally, soybean transgenic composite plants were generated to studyGmSPX3functions.Key ResultsNine GmSPX members were identified, which were classified into three groups based on phylogenetic analysis. Diverse responses ofGmSPXmembers to deficiencies of nutrients (nitrogen, phosphorus, potassium and iron) or inoculation of arbuscular mycorrhizal fungi and rhizobia were observed in soybean. In addition, variations of sub-cellular localization of GmSPX members were found. Among them, GmSPX3, GmSPX7 and GmSPX8 were localized in the nuclei, and the other GmSPX members were confined to the nuclei and cytoplasm. The nuclear-localized and Pi starvation responsive-gene,GmSPX3, was functionally analysed in soybean transgenic composite plants. Overexpression ofGmSPX3led to increased P concentrations in both shoots and roots in the high-P treatment, and increased transcription of seven Pi starvation-responsive genes in soybean hairy roots.ConclusionsTaken together, the results suggest thatGmSPX3is a positive regulator in the P signalling network, and controls Pi homeostasis in soybean.