Seto Yoshiya, Hamada Shigeki, Matsuura Hideyuki, Matsushige Mana, Satou Chizuru, Takahashi Kosaku, Masuta Chikara, Ito Hiroyuki, Matsui Hirokazu, Nabeta Kensuke
Laboratory of Bioorganic Chemistry, Division of Applied Bioscience, Research Faculty of Agriculture, Hokkaido University, Kita-9, Nishi-9, Kitaku Sapporo 060-8589, Japan.
Phytochemistry. 2009 Feb;70(3):370-9. doi: 10.1016/j.phytochem.2009.01.004. Epub 2009 Feb 21.
Tuberonic acid (12-hydroxy epi-jasmonic acid, TA) and its glucoside (TAG) were isolated from potato leaflets (Solanumtuberosum L.) and shown to have tuber-inducing properties. The metabolism of jasmonic acid (JA) to TAG in plant leaflets, and translocation of the resulting TAG to the distal parts, was demonstrated in a previous study. It is thought that TAG generated from JA transmits a signal from the damaged parts to the undamaged parts by this mechanism. In this report, the metabolism of TA in higher plants was demonstrated using [12-(3)H]TA, and a glucosyltransferase active toward TA was purified from the rice cell cultures. The purified protein was shown to be a putative salicylic acid (SA) glucosyltransferase (OsSGT) by MALDI-TOF-MS analysis. Recombinant OsSGT obtained by overexpression in Escherichia coli was active not only toward TA but also toward SA. The OsSGT characterized in this research was not specific, but this is the first report of a glucosyltransferase active toward TA. mRNA expressional analysis of OsSGT and quantification of TA, TAG, SA and SAG after mechanical wounding indicated that OsSGT is involved in the wounding response. These results demonstrated a crucial role for TAG not only in potato tuber formation, but also in the stress response in plants and that the SA glucosyltransferase can work for TA glucosylation.
块茎酸（12-羟基表茉莉酸，TA）及其糖苷（TAG）从马铃薯小叶（Solanumtuberosum L.）中分离得到，并被证明具有诱导块茎形成的特性。在之前的一项研究中，已证实植物小叶中茉莉酸（JA）向TAG的代谢，以及生成的TAG向远端部分的转运。据认为，由JA产生的TAG通过这种机制将信号从受损部分传递到未受损部分。在本报告中，使用[12-(3)H]TA证明了高等植物中TA的代谢，并从水稻细胞培养物中纯化了一种对TA具有活性的葡糖基转移酶。通过基质辅助激光解吸电离飞行时间质谱（MALDI-TOF-MS）分析表明，纯化的蛋白质是一种假定的水杨酸（SA）葡糖基转移酶（OsSGT）。通过在大肠杆菌中过表达获得的重组OsSGT不仅对TA有活性，而且对SA也有活性。本研究中鉴定的OsSGT不具有特异性，但这是关于对TA具有活性的葡糖基转移酶的首次报道。对OsSGT的mRNA表达分析以及机械损伤后TA、TAG、SA和SAG的定量分析表明，OsSGT参与了损伤反应。这些结果表明，TAG不仅在马铃薯块茎形成中起关键作用，而且在植物的应激反应中也起关键作用，并且SA葡糖基转移酶可作用于TA的糖基化。
