A bZIP transcription factor, CaLMF, mediated light-regulated camptothecin biosynthesis in Camptotheca acuminata
A bZIP transcription factor, CaLMF, mediated light-regulated camptothecin biosynthesis in Camptotheca acuminata
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bZIP 转录因子 CaLMF 介导喜树光调节喜树碱生物合成
DOI：
10.1093/treephys/tpy106
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发表时间：
2019-03-01
期刊：
影响因子：
4
通讯作者：
Yu, Fang
中科院分区：
文献类型：
--
作者：
Chang, Chunhao;Liu, Zhiwen;Yu, Fang
喜树碱（CPT）具有强大的生物活性，其类似物伊立替坎和拓扑替坎是临床治疗的有效抗癌药物。喜树碱首次从喜树中分离得到，其在植物中的低积累限制了市场上的药物供应。以往的研究已经证实，许多环境因素和植物激素/激发子都可以调节CPT的生物合成，但只有光照对CPT的产生有负面影响。尽管多年来光照已被确定为针叶树CPT生物合成的负调节因子，但这种调节机制仍不清楚。为了寻找光调控CPT生物合成过程中可能参与的信号成分，根据喜树地上绿色组织转录组数据库进行共表达分析。通过共表达分析，确定了光响应性bZIP转录因子CaLMF （Light-Mediated CPT biosynthesis factor，光介导CPT生物合成因子），进一步研究表明，过表达CaLMF可下调CPT生物合成基因的表达，减少CPT在叶片中的积累，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的产生被消除。我们的研究结果表明，CaLMF是一个重要的光信号成分，介导光调控CPT的生物合成。
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.