Positive Selection of Squalene Synthase in Cucurbitaceae Plants

Triterpenoid saponins are secondary metabolites synthesized through isoprenoid pathways in plants. Cucurbitaceae represent an important plant family in which many species contain cucurbitacins as secondary metabolites synthesized through isoprenoid and triterpenoid pathways. Squalene synthase (SQS)...

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Main Authors: Jieying Qian, Yong Liu, Chengtong Ma, Naixia Chao, Qicong Chen, Yangmei Zhang, Yu Luo, Danzhao Cai, Yaosheng Wu
Format: Article
Language:English
Published: Wiley 2019-01-01
Series:International Journal of Genomics
Online Access:http://dx.doi.org/10.1155/2019/5913491
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author Jieying Qian
Yong Liu
Chengtong Ma
Naixia Chao
Qicong Chen
Yangmei Zhang
Yu Luo
Danzhao Cai
Yaosheng Wu
author_facet Jieying Qian
Yong Liu
Chengtong Ma
Naixia Chao
Qicong Chen
Yangmei Zhang
Yu Luo
Danzhao Cai
Yaosheng Wu
author_sort Jieying Qian
collection DOAJ
description Triterpenoid saponins are secondary metabolites synthesized through isoprenoid pathways in plants. Cucurbitaceae represent an important plant family in which many species contain cucurbitacins as secondary metabolites synthesized through isoprenoid and triterpenoid pathways. Squalene synthase (SQS) is required for the biosynthesis of isoprenoids, but the forces driving the evolution of SQS remain undetermined. In this study, 10 SQS cDNA sequences cloned from 10 species of Cucurbitaceae and 49 sequences of SQS downloaded from GenBank and UniProt databases were analyzed in a phylogenetic framework to identify the evolutionary forces for functional divergence. Through phylogenetic construction and positive selection analysis, we found that SQS sequences are under positive selection. The sites of positive selection map to functional and transmembrane domains. 180L, 189S, 194S, 196S, 265I, 289P, 389P, 390T, 407S, 408A, 410R, and 414N were identified as sites of positive selection that are important during terpenoid synthesis and map to transmembrane domains. 196S and 407S are phosphorylated and influence SQS catalysis and triterpenoid accumulation. These results reveal that positive selection is an important evolutionary force for SQS in plants. This provides new information into the molecular evolution of SQS within the Cucurbitaceae family.
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spelling doaj-art-5479289433324b979ffef8b5ecd3d86b2025-08-20T02:05:45ZengWileyInternational Journal of Genomics2314-436X2314-43782019-01-01201910.1155/2019/59134915913491Positive Selection of Squalene Synthase in Cucurbitaceae PlantsJieying Qian0Yong Liu1Chengtong Ma2Naixia Chao3Qicong Chen4Yangmei Zhang5Yu Luo6Danzhao Cai7Yaosheng Wu8Key Laboratory of Biological Molecular Medicine Research of Guangxi Higher Education, Department of Biochemistry and Molecular Biology, Guangxi Medical University, Nanning, Guangxi 530021, ChinaSchool of Pharmacy, Guangdong Medical University, Dongguan, Guangdong 523808, ChinaKey Laboratory of Biological Molecular Medicine Research of Guangxi Higher Education, Department of Biochemistry and Molecular Biology, Guangxi Medical University, Nanning, Guangxi 530021, ChinaKey Laboratory of Biological Molecular Medicine Research of Guangxi Higher Education, Department of Biochemistry and Molecular Biology, Guangxi Medical University, Nanning, Guangxi 530021, ChinaKey Laboratory of Biological Molecular Medicine Research of Guangxi Higher Education, Department of Biochemistry and Molecular Biology, Guangxi Medical University, Nanning, Guangxi 530021, ChinaKey Laboratory of Biological Molecular Medicine Research of Guangxi Higher Education, Department of Biochemistry and Molecular Biology, Guangxi Medical University, Nanning, Guangxi 530021, ChinaKey Laboratory of Biological Molecular Medicine Research of Guangxi Higher Education, Department of Biochemistry and Molecular Biology, Guangxi Medical University, Nanning, Guangxi 530021, ChinaKey Laboratory of Biological Molecular Medicine Research of Guangxi Higher Education, Department of Biochemistry and Molecular Biology, Guangxi Medical University, Nanning, Guangxi 530021, ChinaKey Laboratory of Biological Molecular Medicine Research of Guangxi Higher Education, Department of Biochemistry and Molecular Biology, Guangxi Medical University, Nanning, Guangxi 530021, ChinaTriterpenoid saponins are secondary metabolites synthesized through isoprenoid pathways in plants. Cucurbitaceae represent an important plant family in which many species contain cucurbitacins as secondary metabolites synthesized through isoprenoid and triterpenoid pathways. Squalene synthase (SQS) is required for the biosynthesis of isoprenoids, but the forces driving the evolution of SQS remain undetermined. In this study, 10 SQS cDNA sequences cloned from 10 species of Cucurbitaceae and 49 sequences of SQS downloaded from GenBank and UniProt databases were analyzed in a phylogenetic framework to identify the evolutionary forces for functional divergence. Through phylogenetic construction and positive selection analysis, we found that SQS sequences are under positive selection. The sites of positive selection map to functional and transmembrane domains. 180L, 189S, 194S, 196S, 265I, 289P, 389P, 390T, 407S, 408A, 410R, and 414N were identified as sites of positive selection that are important during terpenoid synthesis and map to transmembrane domains. 196S and 407S are phosphorylated and influence SQS catalysis and triterpenoid accumulation. These results reveal that positive selection is an important evolutionary force for SQS in plants. This provides new information into the molecular evolution of SQS within the Cucurbitaceae family.http://dx.doi.org/10.1155/2019/5913491
spellingShingle Jieying Qian
Yong Liu
Chengtong Ma
Naixia Chao
Qicong Chen
Yangmei Zhang
Yu Luo
Danzhao Cai
Yaosheng Wu
Positive Selection of Squalene Synthase in Cucurbitaceae Plants
International Journal of Genomics
title Positive Selection of Squalene Synthase in Cucurbitaceae Plants
title_full Positive Selection of Squalene Synthase in Cucurbitaceae Plants
title_fullStr Positive Selection of Squalene Synthase in Cucurbitaceae Plants
title_full_unstemmed Positive Selection of Squalene Synthase in Cucurbitaceae Plants
title_short Positive Selection of Squalene Synthase in Cucurbitaceae Plants
title_sort positive selection of squalene synthase in cucurbitaceae plants
url http://dx.doi.org/10.1155/2019/5913491
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