Transcriptional and protein structural characterization of homogentisate phytyltransferase genes in barley, wheat, and oat

BMC Plant Biology

Research

Taihe Xiang¹  Xiaoping Huang¹  Zhehao Chen¹  Zhanghui Zeng²  Ning Han³  Hongwu Bian³  Yong Jia⁴  Chengdao Li⁵ 

[1] College of Life and Environmental Sciences, Hangzhou Normal University, 311121, Hangzhou, China;College of Life and Environmental Sciences, Hangzhou Normal University, 311121, Hangzhou, China;Zhejiang Provincial Key Laboratory for Genetic Improvement and Quality Control of Medicinal Plants, 311121, Hangzhou, China;Institute of Genetic and Regenerative Biology, Key Laboratory for Cell and Gene Engineering of Zhejiang Province, College of Life Sciences, Zhejiang University, 310058, Hangzhou, China;Western Crops Genetic Alliance, Murdoch University, 6150, Murdoch, WA, Australia;State Agricultural Biotechnology Centre (SABC), College of Science, Health, Engineering and Education, Murdoch University, 6150, Murdoch, WA, Australia;Western Crops Genetic Alliance, Murdoch University, 6150, Murdoch, WA, Australia;State Agricultural Biotechnology Centre (SABC), College of Science, Health, Engineering and Education, Murdoch University, 6150, Murdoch, WA, Australia;Department of Primary Industry and Regional Development, Government of Western Australia, 6155, South Perth, WA, Australia;

关键词: Antioxidants;    Evolution;    Homogentisate phytyltransferase;    Protein structure modelling;    Substrate docking;    Transcriptome;    Tocopherols;    Vitamin E;   

DOI  :  10.1186/s12870-023-04535-x

 received in 2023-07-10, accepted in 2023-10-17,  发布年份 2023

来源: Springer

【 摘 要 】

BackgroundHomogentisate phytyltransferase (HPT) is the critical enzyme for the biosynthesis of tocopherols (vitamin E), which are the major lipid-soluble antioxidants and help plants adapt to various stress conditions. HPT is generally strictly conserved in various plant genomes; however, a divergent lineage HPT2 was identified recently in some Triticeae species. The molecular function and transcriptional profiles of HPT2 remain to be characterized.ResultsIn this study, we performed comprehensive transcriptome data mining of HPT1 and HPT2 in different tissues and stages of barley (Hordeum vulgare), wheat (Triticum aestivum), and oat (Avena sativa), followed by qRT-PCR experiments on HPT1 and HPT2 in different tissues of barley and wheat. We found that the common HPT1 genes (HvHPT1, TaHPT1s, and AsHPT1s) displayed a conserved transcriptional pattern in the three target species and were universally transcribed in various tissues, with a notable preference in leaf. In contrast, HPT2 genes (HvHPT2, TaHPT2, and AsHPT2) were specifically transcribed in spike (developmentally up-regulated) and shoot apex tissues, displaying a divergent tissue-specific pattern. Cis-regulatory elements prediction in the promoter region identified common factors related to light-, plant hormone-, low temperature-, drought- and defense- responses in both HPT1s and HPT2s. We observed the transcriptional up-regulation of HvHPT1 and HvHPT2 under various stress conditions, supporting their conserved function in environmental adaption. We detected a clear, relaxed selection pressure in the HPT2 lineage, consistent with the predicted evolution pattern following gene duplication. Protein structural modelling and substrate docking analyses identified putative catalytic amino acid residues for HvHPT1 and HvHPT2, which are strictly conserved and consistent with their function in vitamin E biosynthesis.ConclusionsWe confirmed the presence of two lineages of HPT in Triticeae and Aveninae, including hexaploid oat, and characterized their transcriptional profiles based on transcriptome and qRT-PCR data. HPT1s were ubiquitously transcribed in various tissues, whilst HPT2s were highly expressed in specific stages and tissue. The active transcription of HPT2s, together with its conserved cis-elements and protein structural features, support HPT2s’ role in tocopherol production in Triticeae. This study is the first protein structural analysis on the membrane-bound plant HPTs and provides valuable insights into its catalytic mechanism.

【 授权许可】

CC BY   
© The Author(s) 2023

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