Comprehensive analysis of sucrolytic enzyme gene families in carnation (Dianthus caryophyllus L.)
Comprehensive analysis of sucrolytic enzyme gene families in carnation (Dianthus caryophyllus L.)
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DOI：
10.1016/j.phytochem.2020.112607
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发表时间：
2021-03-27
期刊：
影响因子：
3.8
通讯作者：
Tsuzuki, Chie
中科院分区：
文献类型：
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作者：
Harada, Taro;Horiguchi, Itsuku;Tsuzuki, Chie
蔗糖在植物的生长和对环境的反应中起着至关重要的作用，包括在观赏植物中。在切花采后处理过程中，蔗糖降解是细胞间和细胞内碳分配的重要过程，影响花的开放和衰老，进而影响花的品质。然而，关于观赏花卉蔗糖降解的分子基础，可以被两种蔗糖分解酶催化，转化酶(INV)和蔗糖合成酶(SUS)，从过去的报道中没有得到完整的信息。本研究表明，蔗糖对香石竹(Diantus caryophyllus L.)小花增加了花瓣中的淀粉含量，同时伴随着液泡INV(VIN)活性的降低和SUS活性的增加。然而，低氧处理降低了香石竹花瓣的蔗糖含量和细胞壁INV(CWIN)活性。在利用香石竹基因组数据库进行的电子分析中，鉴定出6个CWIN、3个VIN、8个细胞质INV(CIN)和5个SUS基因。实时荧光定量RT-PCR分析证实，这些基因在香石竹花瓣对蔗糖和低氧处理的响应中存在差异表达，部分与酶活性的变化相对应。与香石竹中已报道的SUS基因DcSUS1(Dca4507.1)相反，DcSUS2(Dca22218.1)是一个未知的香石竹SUS基因，在低氧条件下表达增强，类似于酒精脱氢酶基因DcADH1(Dca18671.1)。这些结果表明，香石竹花瓣中的糖代谢受到环境提示的调节，伴随着一组蔗糖裂解酶的活性和基因表达的调节。
Sucrose plays crucial roles in growth and responses of plants to the environment, including those in ornamental species. During post-harvest handling of cut flowers, sucrose degradation is an essential process of inter- and intra-cellular carbon partitioning affecting flower opening and senescence and, subsequently, flower quality. However, complete information about the molecular basis of sucrose degradation in ornamental flowers, which can be catalyzed by two kinds of sucrolytic enzymes, invertase (INV), and sucrose synthase (SUS), is not available from past reports. The present study shows that sucrose treatment of carnation (Dianthus caryophyllus L.) florets increased starch content in petals, accompanied by decreased vacuolar INV (VIN) activity and increased SUS activity. However, hypoxic treatment of carnation florets decreased sucrose content and cell-wall INV (CWIN) activity in petals. In silico analysis using the carnation genome database identified six CWIN, three VIN, eight cytoplasmic INV (CIN), and five SUS genes. Real-time RT-PCR analysis confirmed that these genes are differentially expressed in carnation petals in response to sucrose and hypoxic treatments, partially corresponding to the changes in enzyme activities. In contrast to DcSUS1 (Dca4507.1), a SUS gene already reported in carnation, which showed preferential expression under aerated conditions, the expression of DcSUS2 (Dca22218.1), an undescribed carnation SUS gene, was enhanced under hypoxia similarly to an alcohol dehydrogenase gene DcADH1 (Dca18671.1). These results suggest that sugar metabolism in carnation petals is regulated in response to environmental cues, accompanied by modulated activities and gene expression of a set of sucrolytic enzymes.