Functional characterization of a HD-ZIP IV transcription factor NtHDG2 in regulating flavonols biosynthesis in Nicotiana tabacum
Functional characterization of a HD-ZIP IV transcription factor NtHDG2 in regulating flavonols biosynthesis in Nicotiana tabacum
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HD-ZIP IV 转录因子 NtHDG2 在调节烟草黄酮醇生物合成中的功能表征
DOI：
10.1016/j.plaphy.2019.11.033
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发表时间：
2020
影响因子：
6.5
通讯作者：
Jun Yang
中科院分区：
文献类型：
--
作者：
Zhong Wang;Shanshan Wang;Yansong Xiao;Zefeng Li;Mingzhu Wu;Xiaodong Xie;Hongguang Li;Wenjun Mu;Feng Li;Pingping Liu;Ran Wang;Jun Yang
HD-ZIP Ⅳ转录因子已在许多植物中被鉴定并鉴定出功能。然而，尚未分离到烟草HD-ZIP IV基因，并且尚不清楚HD-ZIP IV基因是否参与控制植物中黄酮醇的积累。本研究克隆了烟草HD ZIP基因NtHDG 2，该基因属于HD ZIP家族的第IV类，NtHDG 2-GFP融合蛋白定位于细胞核。进一步观察到NtHDG 2过表达植株叶片中黄酮醇类化合物的含量增加到野生型植株的1.9-4.5倍，而NtHDG 2-RNAi植株中黄酮醇类化合物的含量则降低到野生型植株的20.9%-52.7%。NtHDG 2显著诱导了1个调控基因NtMYB 12和3个结构基因NtPAL、NtF 3 ′H、NtF 3 GT的转录。然而，黄酮醇合成抑制因子NtNAC 002的转录水平在NtHDG 2过表达的细胞中也显著上调，而在RNAi细胞中则显著下调，表明HDG 2作为一个复杂的调控网络调控黄酮醇的合成。此外，NtHDG 2基因的异位表达促进了几个AP 2/ERF基因的转录，包括NtERF 1 -5、NtERF 109、NtDREB 1和NtCIPK 11，这些基因参与调控根的发育和对非生物胁迫的抗性。我们的研究结果揭示了HD-ZIP IV转录因子在类黄酮生物合成中的新功能，并表明HD-ZIP IV成员可能在植物抵抗非生物胁迫中发挥重要作用。NtHDG 2基因为通过遗传操作提高烟草叶片中黄酮醇含量提供了一个很有前途的靶基因。
The HD-ZIP Ⅳ transcription factors have been identified and functional characterized in many plant species. However, no tobacco HD-ZIP IV gene has been isolated, and it is not yet known whether HD-ZIP IV genes are involved in controlling flavonols accumulation in plants. Here, we cloned a HD ZIP gene namedNtHDG2fromNicotiana tabacum, which belongs to the class IV of HD-ZIP family, and the NtHDG2-GFP fusion protein is localized to the nucleus. We further observed that the flavonols contents in theNtHDG2overexpression leaves increase to 1.9–4.5 folds of that in WT plants, but in theNtHDG2-RNAiplants the flavonols contents reduce to 20.9%–52.7% of that in WT plants. The transcriptions of one regulatory geneNtMYB12, and three structural genes (NtPAL,NtF3′H,NtF3GT), contributing to flavonols biosynthesis, were significantly induced by NtHDG2. However, the transcription level ofNtNAC002, a flavonols biosynthesis repressor, was also significantly up-regulated inNtHDG2-overexpression lines, but significantly down-regulated in the RNAi lines, indicating that HDG2 regulates the synthesis of flavonols as a complex regulatory network. Moreover, ectopic expression ofNtHDG2gene promoted the transcription of several AP2/ERFgenes, includingNtERF1-5,NtERF109,NtDREB1, andNtCIPK11, which participate in regulating root development and resistance to abiotic stresses. Our findings reveal the new function of HD-ZIP IV transcription factors in flavonoids biosynthesis, and indicate that HD-ZIP IV members may play an important role in plant resistance to abiotic stress. TheNtHDG2gene provides a promising target for genetically manipulating to increase the amounts of flavonols in tobacco leaves.