Temasek Life Sciences Laboratory, 1 Research Link, National University of Singapore, Singapore 117604, Singapore.
Department of Biological Sciences, National University of Singapore, Singapore 117543, Singapore.
Int J Mol Sci. 2021 Jan 12;22(2):681. doi: 10.3390/ijms22020681.
Production of a volatile phenylpropene; eugenol in sweet basil is mostly associated with peltate glandular trichomes (PGTs) found aerially. Currently only one eugenol synthase (EGS), ObEGS1 which belongs to PIP family is identified from sweet basil PGTs. Reports of the presence of eugenol in roots led us to analyse other EGSs in roots. We screened for all the PIP family reductase transcripts from the RNA-Seq data. In vivo functional characterization of all the genes in showed their ability to produce eugenol and were termed as . Among all, displayed highest expression in PGTs and in roots. Further, eugenol was produced only in the roots of soil-grown plants, but not in roots of aseptically-grown plants. Interestingly, eugenol production could be induced in roots of aseptically-grown plants under elicitation suggesting that eugenol production might occur as a result of environmental cues in roots. The presence of transcript and protein in aseptically-grown plants indicated towards post-translational modifications (PTMs) of ObEGS4. Bioinformatics analysis showed possibility of phosphorylation in ObEGS4 which was further confirmed by in vitro experiment. Our study reveals the presence of multiple eugenol synthases in sweet basil and provides new insights into their diversity and tissue specific regulation.
甜罗勒叶片中的毛毡状腺毛（peltate glandular trichomes，PGTs）中产生的挥发性苯基丙烯；丁香酚，主要与该结构相关。目前仅从甜罗勒 PGTs 中鉴定到一个属于 PIP 家族的丁香酚合酶（eugenol synthase，EGS），即 ObEGS1。根中存在丁香酚的报道促使我们分析根中的其他 EGS。我们从 RNA-Seq 数据中筛选了所有 PIP 家族还原酶转录本。在体内对所有基因进行功能鉴定，发现它们都有产生丁香酚的能力，因此被命名为 。其中， 在 PGTs 和 中表达最高。此外，只有在土培植物的根中才会产生丁香酚，而在无菌培养植物的根中则不会。有趣的是，在无菌培养植物的根中，通过诱导可以产生丁香酚，这表明丁香酚的产生可能是根中环境信号的结果。无菌培养植物中存在 转录本和蛋白表明 ObEGS4 可能发生了翻译后修饰（PTMs）。生物信息学分析显示 ObEGS4 中可能存在磷酸化，体外实验进一步证实了这一点。本研究揭示了甜罗勒中存在多个丁香酚合酶，并为它们的多样性和组织特异性调控提供了新的见解。
