Biochemical and Molecular Characterization of PvPAP3, a Novel Purple Acid Phosphatase Isolated from Common Bean Enhancing Extracellular ATP Utilization
Biochemical and Molecular Characterization of PvPAP3, a Novel Purple Acid Phosphatase Isolated from Common Bean Enhancing Extracellular ATP Utilization
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DOI：
10.1104/pp.109.147918
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发表时间：
2010-02-01
期刊：
影响因子：
7.4
通讯作者：
Liao, Hong
中科院分区：
文献类型：
--
作者：
Liang, Cuiyue;Tian, Jiang;Liao, Hong
紫色酸性磷酸酶（PAPs）在植物中具有多种生理功能。在这项研究中，我们纯化了一种新的PAP，PvPAP 3，从普通菜豆（菜豆）的根下生长的磷（Pi）饥饿。PvPAP 3被鉴定为作用于特异性底物ATP的34-kD单体，具有宽的pH范围和高热稳定性。PvPAP 3的活性对酒石酸不敏感，表明PvPAP 3是PAP样蛋白。氨基酸序列比对和系统发育分析表明，PvPAP 3属于植物PAP类，具有低分子量。35 S：PvPAP 3绿色荧光蛋白在洋葱表皮细胞中的瞬时表达证实了其可能锚定在质膜上并分泌到质外体中。磷饥饿诱导菜豆叶片和根中PvPAP 3的表达，且PvPAP 3的表达与磷的有效性和磷饥饿的持续时间密切相关。此外，诱导PvPAP 3的表达更快，更高的磷效率的基因型，G19833，比磷低效的基因型，DOR 364，这表明可能的作用PvPAP 3在磷效率在豆类。利用转基因菜豆毛状根系统进行的体内分析表明，当ATP作为唯一的外部磷源时，来自PvPAP 3过表达转基因系的菜豆毛状根的生长和磷吸收显著增强。综上所述，我们的研究结果表明，PvPAP 3是一种新的PAP，可能通过提高细胞外ATP作为磷源的利用率，在菜豆适应缺磷的过程中发挥作用。
Purple acid phosphatases (PAPs) play diverse physiological roles in plants. In this study, we purified a novel PAP, PvPAP3, from the roots of common bean (Phaseolus vulgaris) grown under phosphate (Pi) starvation. PvPAP3 was identified as a 34-kD monomer acting on the specific substrate, ATP, with a broad pH range and a high heat stability. The activity of PvPAP3 was insensitive to tartrate, indicating that PvPAP3 is a PAP-like protein. Amino acid sequence alignment and phylogenetic analysis suggest that PvPAP3 belongs to the group of plant PAPs with low molecular mass. Transient expression of 35S:PvPAP3-green fluorescent protein in onion (Allium cepa) epidermal cells verified that it might anchor on plasma membrane and be secreted into apoplast. Pi starvation led to induction of PvPAP3 expression in both leaves and roots of common bean, and expression of PvPAP3 was strictly dependent on phosphorus (P) availability and duration of Pi starvation. Furthermore, induction of PvPAP3 expression was more rapid and higher in a P-efficient genotype, G19833, than in a P-inefficient genotype, DOR364, suggesting possible roles of PvPAP3 in P efficiency in bean. In vivo analysis using a transgenic hairy root system of common bean showed that both growth and P uptake of bean hairy roots from the PvPAP3 overexpression transgenic lines were significantly enhanced when ATP was supplied as the sole external P source. Taken together, our results suggest that PvPAP3 is a novel PAP that might function in the adaptation of common bean to P deficiency, possibly through enhancing utilization of extracellular ATP as a P source.