一个 bZIP 转录因子，CaLMF，介导了喜树中喜树碱的光调控生物合成。

A bZIP transcription factor, CaLMF, mediated light-regulated camptothecin biosynthesis in Camptotheca acuminata.

机构信息

School of Biological Engineering, Dalian Polytechnic University, Dalian, China.

Key Laboratory of Plant Ecology, Northeast Forestry University, Harbin, China.

出版信息

Tree Physiol. 2019 Mar 1;39(3):372-380. doi: 10.1093/treephys/tpy106.

DOI:10.1093/treephys/tpy106

PMID:30289548

Abstract

Camptothecin (CPT) has powerful biological activities and its analogs, irinothecan and topothecan, are effective anti-cancer drugs for clinical therapy. Camptothecin was first isolated from Camptotheca acuminata and its low accumulation in planta limits drug supply in the market. Previous works have confirmed that many environmental factors and plant hormones/elicitors could regulate CPT biosynthesis, but only light irradiance has a negative effect on CPT production in C. acuminata. Although light irradiance has been identified as a negative CPT biosynthesis regulator in C. acuminata for many years, the mechanisms of this regulation are still unknown. In order to search possible signal components involved in the process of light-regulated CPT biosynthesis, coexpression analysis was carried out according to the transcriptome database of Camptotheca above-ground green tissues. From coexpression analysis, a light-responsive bZIP transcription factor, CaLMF (Light-Mediated CPT biosynthesis Factor), was identified and further investigations showed that overexpression of CaLMF down-regulated the expression of CPT biosynthesis genes and decreased the accumulation of CPT in leaves, while light-regulated expression of CPT biosynthesis genes and CPT production were abolished in CaLMF silencing leaves under shading treatment. Our results show that CaLMF is a significant light signaling component, which mediates light-regulated CPT biosynthesis in C. acuminata.

摘要

喜树碱（CPT）具有强大的生物学活性，其类似物伊立替康和拓扑替康是临床治疗有效的抗癌药物。喜树碱最初从喜树中分离得到，其在植物中的低积累限制了市场上药物的供应。以前的工作已经证实，许多环境因素和植物激素/诱导剂可以调节 CPT 生物合成，但只有光照对喜树中 CPT 的产生有负面影响。尽管光照已被确定为喜树中 CPT 生物合成的负调节剂多年，但这种调节的机制仍不清楚。为了寻找可能参与光调控 CPT 生物合成过程的信号成分，根据喜树地上绿色组织的转录组数据库进行了共表达分析。从共表达分析中，鉴定到一个光响应 bZIP 转录因子 CaLMF（光介导的 CPT 生物合成因子），进一步的研究表明，CaLMF 的过表达下调了 CPT 生物合成基因的表达并降低了叶片中 CPT 的积累，而在遮荫处理下 CaLMF 沉默叶片中 CPT 生物合成基因的光调控表达和 CPT 的产生被废除。我们的结果表明，CaLMF 是一个重要的光信号成分，它介导了喜树中光调控的 CPT 生物合成。