Identification and Functional Characterization of Acyl-ACP Thioesterases B (GhFatBs) Responsible for Palmitic Acid Accumulation in Cotton Seeds
In spite of increasing use in the food industry, high relative levels of palmitic acid (C16:0) in cottonseed oil imposes harmful effects on human health when overconsumed in the diet. The limited understanding of the mechanism in controlling fatty acid composition has become a significant obstacle f...
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MDPI AG
2022-10-01
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| Series: | International Journal of Molecular Sciences |
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| author | Baoling Liu Yan Sun Xiaodan Wang Jinai Xue Jiping Wang Xiaoyun Jia Runzhi Li |
| author_facet | Baoling Liu Yan Sun Xiaodan Wang Jinai Xue Jiping Wang Xiaoyun Jia Runzhi Li |
| author_sort | Baoling Liu |
| collection | DOAJ |
| description | In spite of increasing use in the food industry, high relative levels of palmitic acid (C16:0) in cottonseed oil imposes harmful effects on human health when overconsumed in the diet. The limited understanding of the mechanism in controlling fatty acid composition has become a significant obstacle for breeding novel cotton varieties with high-quality oil. Fatty acyl–acyl carrier protein (ACP) thioesterase B (FatBs) are a group of enzymes which prefer to hydrolyze the thioester bond from saturated acyl-ACPs, thus playing key roles in controlling the accumulation of saturated fatty acids. However, FatB members and their roles in cotton are largely unknown. In this study, a genome-wide characterization of FatB members was performed in allotetraploid upland cotton, aiming to explore the GhFatBs responsible for high accumulations of C16:0 in cotton seeds. A total of 14 <i>GhFatB</i> genes with uneven distribution on chromosomes were identified from an upland cotton genome and grouped into seven subfamilies through phylogenetic analysis. The six key amino acid residues (Ala, Trys, Ile, Met, Arg and Try) responsible for substrate preference were identified in the N-terminal acyl binding pocket of GhFatBs. RNA-seq and qRT-PCR analysis revealed that the expression profiles of <i>GhFatB</i> genes varied in multiple cotton tissues, with eight <i>GhFatBs</i> (<i>GhA/D-FatB3</i>, <i>GhA/D-FatB4</i>, <i>GhA/D-FatB5</i>, and <i>GhA/D-FatB7</i>) having high expression levels in developing seeds. In particular, expression patterns of <i>GhA-FatB3</i> and <i>GhD-FatB4</i> were positively correlated with the dynamic accumulation of C16:0 during cotton seed development. Furthermore, heterologous overexpression assay of either <i>GhA-FatB3</i> or <i>GhD-FatB4</i> demonstrated that these two GhFatBs had a high substrate preference to 16:0-ACP, thus contributing greatly to the enrichment of palmitic acid in the tested tissues. Taken together, these findings increase our understanding on fatty acid accumulation and regulation mechanisms in plant seeds. <i>GhFatBs</i>, especially <i>GhA-FatB3</i> and <i>GhD-FatB4</i>, could be molecular targets for genetic modification to reduce palmitic acid content or to optimize fatty acid profiles in cotton and other oil crops required for the sustainable production of healthy edible oil. |
| first_indexed | 2024-03-09T19:01:31Z |
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| spelling | doaj.art-5194d010078c4be3a388d4bafee85df62023-11-24T04:57:28ZengMDPI AGInternational Journal of Molecular Sciences1661-65961422-00672022-10-0123211280510.3390/ijms232112805Identification and Functional Characterization of Acyl-ACP Thioesterases B (GhFatBs) Responsible for Palmitic Acid Accumulation in Cotton SeedsBaoling Liu0Yan Sun1Xiaodan Wang2Jinai Xue3Jiping Wang4Xiaoyun Jia5Runzhi Li6College of Agriculture, Shanxi Agricultural University, Jinzhong 030801, ChinaCollege of Agriculture, Shanxi Agricultural University, Jinzhong 030801, ChinaCollege of Agriculture, Shanxi Agricultural University, Jinzhong 030801, ChinaCollege of Agriculture, Shanxi Agricultural University, Jinzhong 030801, ChinaCollege of Agriculture, Shanxi Agricultural University, Jinzhong 030801, ChinaCollege of Life Sciences, Shanxi Agricultural University, Jinzhong 030801, ChinaCollege of Agriculture, Shanxi Agricultural University, Jinzhong 030801, ChinaIn spite of increasing use in the food industry, high relative levels of palmitic acid (C16:0) in cottonseed oil imposes harmful effects on human health when overconsumed in the diet. The limited understanding of the mechanism in controlling fatty acid composition has become a significant obstacle for breeding novel cotton varieties with high-quality oil. Fatty acyl–acyl carrier protein (ACP) thioesterase B (FatBs) are a group of enzymes which prefer to hydrolyze the thioester bond from saturated acyl-ACPs, thus playing key roles in controlling the accumulation of saturated fatty acids. However, FatB members and their roles in cotton are largely unknown. In this study, a genome-wide characterization of FatB members was performed in allotetraploid upland cotton, aiming to explore the GhFatBs responsible for high accumulations of C16:0 in cotton seeds. A total of 14 <i>GhFatB</i> genes with uneven distribution on chromosomes were identified from an upland cotton genome and grouped into seven subfamilies through phylogenetic analysis. The six key amino acid residues (Ala, Trys, Ile, Met, Arg and Try) responsible for substrate preference were identified in the N-terminal acyl binding pocket of GhFatBs. RNA-seq and qRT-PCR analysis revealed that the expression profiles of <i>GhFatB</i> genes varied in multiple cotton tissues, with eight <i>GhFatBs</i> (<i>GhA/D-FatB3</i>, <i>GhA/D-FatB4</i>, <i>GhA/D-FatB5</i>, and <i>GhA/D-FatB7</i>) having high expression levels in developing seeds. In particular, expression patterns of <i>GhA-FatB3</i> and <i>GhD-FatB4</i> were positively correlated with the dynamic accumulation of C16:0 during cotton seed development. Furthermore, heterologous overexpression assay of either <i>GhA-FatB3</i> or <i>GhD-FatB4</i> demonstrated that these two GhFatBs had a high substrate preference to 16:0-ACP, thus contributing greatly to the enrichment of palmitic acid in the tested tissues. Taken together, these findings increase our understanding on fatty acid accumulation and regulation mechanisms in plant seeds. <i>GhFatBs</i>, especially <i>GhA-FatB3</i> and <i>GhD-FatB4</i>, could be molecular targets for genetic modification to reduce palmitic acid content or to optimize fatty acid profiles in cotton and other oil crops required for the sustainable production of healthy edible oil.https://www.mdpi.com/1422-0067/23/21/12805cotton (<i>Gossypium hirsutum</i>)acyl-ACP thioesterase (FatBs)substrate specificitypalmitic acid (C16:0)expression patternheterologous expression assay |
| spellingShingle | Baoling Liu Yan Sun Xiaodan Wang Jinai Xue Jiping Wang Xiaoyun Jia Runzhi Li Identification and Functional Characterization of Acyl-ACP Thioesterases B (GhFatBs) Responsible for Palmitic Acid Accumulation in Cotton Seeds International Journal of Molecular Sciences cotton (<i>Gossypium hirsutum</i>) acyl-ACP thioesterase (FatBs) substrate specificity palmitic acid (C16:0) expression pattern heterologous expression assay |
| title | Identification and Functional Characterization of Acyl-ACP Thioesterases B (GhFatBs) Responsible for Palmitic Acid Accumulation in Cotton Seeds |
| title_full | Identification and Functional Characterization of Acyl-ACP Thioesterases B (GhFatBs) Responsible for Palmitic Acid Accumulation in Cotton Seeds |
| title_fullStr | Identification and Functional Characterization of Acyl-ACP Thioesterases B (GhFatBs) Responsible for Palmitic Acid Accumulation in Cotton Seeds |
| title_full_unstemmed | Identification and Functional Characterization of Acyl-ACP Thioesterases B (GhFatBs) Responsible for Palmitic Acid Accumulation in Cotton Seeds |
| title_short | Identification and Functional Characterization of Acyl-ACP Thioesterases B (GhFatBs) Responsible for Palmitic Acid Accumulation in Cotton Seeds |
| title_sort | identification and functional characterization of acyl acp thioesterases b ghfatbs responsible for palmitic acid accumulation in cotton seeds |
| topic | cotton (<i>Gossypium hirsutum</i>) acyl-ACP thioesterase (FatBs) substrate specificity palmitic acid (C16:0) expression pattern heterologous expression assay |
| url | https://www.mdpi.com/1422-0067/23/21/12805 |
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