菊花CmMYC2在舌状花绿色性状形成过程中的功能研究

doi:10.16420/j.issn.0513-353x.2021-0524

摘要/Abstract

摘要：

以白色的毛华菊（Chrysanthemum vestitum）和菊花（C. morifolium）浅绿色品种‘春晓’、深绿色品种‘绿安娜’和切花品种‘绿扣’为试验材料，研究叶绿素合成相关的basic helix-loop-helix（bHLH）类转录因子基因CmMYC2的表达规律，进行了基因功能的初探，并验证了CmMYC2对叶绿素合成基因启动子活性的调节。结果表明，在毛华菊、‘春晓’和‘绿安娜’的舌状花和叶片中，CmMYC2的表达量依次升高，且与舌状花和叶片中叶绿素含量呈显著正相关。ABA处理抑制了‘绿扣’舌状花和叶片中叶绿素的积累以及CmMYC2和叶绿素合成相关基因的表达。聚类热图显示ABA处理的‘绿扣’舌状花和叶片及毛华菊、‘春晓’和‘绿安娜’叶片中CmMYC2和叶绿素合成相关基因出现类似的表达模式，它们的表达量呈显著相关。在‘绿扣’叶片中瞬时过表达CmMYC2，显著促进了叶绿素的积累，并且叶绿素合成相关基因HEMA1、CRD1、CHLG1和PORA1均不同程度上调。本氏烟草（Nicotiana benthamiana）瞬时转录激活试验结果显示，CmMYC2显著增强了HEMA1和CHLI1基因的启动子活性。

关键词: 菊花, 花色, 叶绿素, 转录因子, CmMYC2

Abstract:

White Chrysanthemum vestitum and light green C. morifolium‘Chunxiao’，dark green C. morifolium‘Green anna’，as well as cut flower variety C. morifolium‘Lükou’were used to investigate the expression pattern and gene function of chlorophyll synthesis-related bHLH transcription factor gene CmMYC2. In addition，the regulation of chlorophyll synthesis-related genes by CmMYC2 was also studied. The results showed that the expression of CmMYC2 was gradually increased in ray florets and leaves of C. vestitum，C. morifolium‘Chunxiao’and‘Green Anna’，which was highly correlated with chlorophyll accumulation in these materials. Abscisic acid（ABA）treatment inhibited the accumulation of chlorophyll in ray florets and leaves of‘Lükou’and the expression of CmMYC2 and chlorophyll synthesis-related genes. The cluster heat map showed that there was a significant correlation between the expression pattern of CmMYC2 and chlorophyll synthesis-related genes in ray florets and leaves of ‘Lükou’under ABA treatment and in leaves of C. vestitum，C. morifolium‘Chunxiao’and ‘Green Anna’. Transient over-expression of CmMYC2 in leaves of‘Lükou’significantly promoted the accumulation of chlorophyll，and the chlorophyll synthesis-related genes，including HEMA1，CRD1，CHLG1 and PORA1 were notably induced by CmMYC2. The transient trans-activation assay in leaves of tobacco（Nicotiana benthamiana）showed the promoter activity of HEMA1 and CHLI1 was significantly enhanced by CmMYC2.

Key words: Chrysanthemum, flower color, chlorophyll, transcription factor, CmMYC2

中图分类号:

S682.11

陈思嘉, 王焕, 李蕊蕊, 王卓异, 罗靖, 王彩云. 菊花CmMYC2在舌状花绿色性状形成过程中的功能研究[J]. 园艺学报, 2022, 49(11): 2377-2387.

CHEN Sijia, WANG Huan, LI Ruirui, WANG Zhuoyi, LUO Jing, WANG Caiyun. Characterization of CmMYC2 in Formation of Green Color in Ray Florets of Chrysanthemum[J]. Acta Horticulturae Sinica, 2022, 49(11): 2377-2387.

图/表 6

图1 菊花材料毛华菊、‘春晓’和‘绿安娜’中CmMYC2的表达分析和叶绿素含量测定毛华菊、‘春晓’和‘绿安娜’三种菊花材料的舌状花中的荧光定量PCR表达分析（A）;毛华菊、‘春晓’和‘绿安娜’三种材料的叶片中叶绿素含量（B）和CmMYC2的表达分析（C）。

Fig. 1 Expression analysis of CmMYC2 and content of chlorophyll in Chrysanthemum vestitum and C. morifolium‘Chunxiao’and‘Green anna’ Expression of CmMYC2 in ray florets in C. vestitum and C. morifolium ‘Chunxiao’and‘Green anna’（A）;Content of chlorophyll（B）and expression of CmMYC2（C）in leaves of C. vestitum and C. morifolium‘Chunxiao’and‘Green anna’.

图2 ABA处理对菊花‘绿扣’表型（A、B）、叶绿素含量（C）和CmMYC2及叶绿素合成相关基因表达（D）的影响

Fig. 2 Effects of ABA treatment on Chrysanthemum morifolium‘Lükou’phenotype（A，B），chlorophyll content（C），CmMYC2 and chlorophyll synthesis related gene expression（D）

图3 菊花‘绿扣’CmMYC2过表达表型（A）、叶绿素含量（B）和CmMYC2的相对表达量（C）

Fig. 3 Phenotype（A），chlorophyll content（B）and relative expression of CmMYC2（C）in CmMYC2 overexpression and Super1300 control samples of Chrysanthemum morifolium‘Lükou’

图4 菊花‘绿扣’CmMYC2过表达样本中叶绿素合成相关基因表达分析

Fig. 4 Expression of chlorophyll synthesis related genes in CmMYC2 overexpression and Super1300 control samples of Chrysanthemum morifolium‘Lükou’

图5 菊花‘绿扣’CmMYC2过表达样本中叶绿素循环和降解相关基因表达分析

Fig. 5 Analysis of chlorophyll cycling- and degradation-related gene expression in CmMYC2 overexpression and Super1300 control samples of Chrysanthemum morifolium‘Lükou’

图6 CmMYC2对叶绿素合成基因启动子活性的调节 A. CmMYC2对HEMA1，CHLI1和PORA1启动子的瞬时转录激活分析;B. HEMA1、CHLI1和PORA1启动子中的MYC结合位点。矩形和三角形分别代表+链或-链上的结合位点。

Fig. 6 Regulation of promoter activity of chlorophyll synthesis gene by CmMYC2 A. Transient transactivation assays of HEMA1，CHLI1 and PORA1 promoters by CmMYC2;B. MYC binding sites in the promoters of HEMA1，CHLI1 and PORA1. Rectangles and triangles represent the binding sites on the + or - chains，respectively.

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