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Wang J, Xie W, Si F, He Z, Wang X, Shao S, Shi S, Guo Z. Evolution of sea-surfing plant propagule as revealed by the genomes of Heritiera mangroves. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2024; 117:432-448. [PMID: 37850375 DOI: 10.1111/tpj.16499] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/03/2023] [Revised: 08/13/2023] [Accepted: 10/04/2023] [Indexed: 10/19/2023]
Abstract
Coastal forests, such as mangroves, protect much of the tropical and subtropical coasts. Long-distance dispersal via sea-surfing propagules is essential for coastal plants, but the genomic and molecular basis of sea-surfing plant propagule evolution remains unclear. Heritiera fomes and Heritiera littoralis are two coastal plants with typical buoyant fruits. We de novo sequenced and assembled their high-quality genomes. Our phylogenomic analysis indicates H. littoralis and H. fomes originated (at ~6.08 Mya) just before the start of Quaternary sea-level fluctuations. Whole-genome duplication occurred earlier, permitting gene copy gains in the two species. Many of the expanded gene families are involved in lignin and flavonoid biosynthesis, likely contributing to buoyant fruit emergence. It is repeatedly revealed that one duplicated copy to be under positive selection while the other is not. By examining H. littoralis fruits at three different developmental stages, we found that gene expression levels remain stable from young to intermediate. However, ~1000 genes are up-regulated and ~ 3000 genes are down-regulated as moving to mature. Particularly in fruit epicarps, the upregulation of WRKY12 and E2Fc likely constrains the production of p-Coumaroyl-CoA, the key internal substrate for lignin biosynthesis. Hence, to increase fruit impermeability, methylated lignin biosynthesis is shut down by down-regulating the genes CCoAOMT, F5H, COMT, and CSE, while unmethylated lignins are preferentially produced by upregulating CAD and CCR. Similarly, cutin polymers and cuticular waxes accumulate with high levels before maturation in epicarps. Overall, our genome assemblies and analyses uncovered the genomic evolution and temporal transcriptional regulation of sea-surfing propagule.
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Affiliation(s)
- Jiayan Wang
- State Key Laboratory of Biocontrol, Guangdong Key Lab of Plant Resources, School of Life Sciences, Southern Marine Science and Engineering Guangdong Laboratory (Zhuhai), Sun Yat-Sen University, Guangzhou, Guangdong, China
| | - Wei Xie
- State Key Laboratory of Biocontrol, Guangdong Key Lab of Plant Resources, School of Life Sciences, Southern Marine Science and Engineering Guangdong Laboratory (Zhuhai), Sun Yat-Sen University, Guangzhou, Guangdong, China
- School of Life Sciences, Guizhou Normal University, Guiyang, Guizhou, China
| | - Fa Si
- State Key Laboratory of Biocontrol, Guangdong Key Lab of Plant Resources, School of Life Sciences, Southern Marine Science and Engineering Guangdong Laboratory (Zhuhai), Sun Yat-Sen University, Guangzhou, Guangdong, China
| | - Ziwen He
- State Key Laboratory of Biocontrol, Guangdong Key Lab of Plant Resources, School of Life Sciences, Southern Marine Science and Engineering Guangdong Laboratory (Zhuhai), Sun Yat-Sen University, Guangzhou, Guangdong, China
| | - Xinfeng Wang
- State Key Laboratory of Biocontrol, Guangdong Key Lab of Plant Resources, School of Life Sciences, Southern Marine Science and Engineering Guangdong Laboratory (Zhuhai), Sun Yat-Sen University, Guangzhou, Guangdong, China
| | - Shao Shao
- State Key Laboratory of Biocontrol, Guangdong Key Lab of Plant Resources, School of Life Sciences, Southern Marine Science and Engineering Guangdong Laboratory (Zhuhai), Sun Yat-Sen University, Guangzhou, Guangdong, China
| | - Suhua Shi
- State Key Laboratory of Biocontrol, Guangdong Key Lab of Plant Resources, School of Life Sciences, Southern Marine Science and Engineering Guangdong Laboratory (Zhuhai), Sun Yat-Sen University, Guangzhou, Guangdong, China
| | - Zixiao Guo
- State Key Laboratory of Biocontrol, Guangdong Key Lab of Plant Resources, School of Life Sciences, Southern Marine Science and Engineering Guangdong Laboratory (Zhuhai), Sun Yat-Sen University, Guangzhou, Guangdong, China
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Tan F, Li W, Feng H, Huang Y, Banerjee AK. Interspecific variation and phylogenetic relationship between mangrove and non-mangrove species of a same family (Meliaceae)-insights from comparative analysis of complete chloroplast genome. PeerJ 2023; 11:e15527. [PMID: 37397021 PMCID: PMC10309054 DOI: 10.7717/peerj.15527] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2022] [Accepted: 05/19/2023] [Indexed: 07/04/2023] Open
Abstract
The mahogany family, Meliaceae, contains 58 genera with only one mangrove genus: Xylocarpus. Two of the three species of the genus Xylocarpus are true mangroves (X. granatum and X. moluccensis), and one is a non-mangrove (X. rumphii). In order to resolve the phylogenetic relationship between the mangrove and non-mangrove species, we sequenced chloroplast genomes of these Xylocarpus species along with two non-mangrove species of the Meliaceae family (Carapa guianensis and Swietenia macrophylla) and compared the genome features and variations across the five species. The five Meliaceae species shared 130 genes (85 protein-coding genes, 37 tRNA, and eight rRNA) with identical direction and order, with a few variations in genes and intergenic spacers. The repetitive sequences identified in the rpl22 gene region only occurred in Xylocarpus, while the repetitive sequences in accD were found in X. moluccensis and X. rumphii. The TrnH-GUG and rpl32 gene regions and four non-coding gene regions showed high variabilities between X. granatum and the two non-mangrove species (S. macrophylla and C. guianensis). In addition, among the Xylocarpus species, only two genes (accD and clpP) showed positive selection. Carapa guianensis and S. macrophylla owned unique RNA editing sites. The above genes played an important role in acclimation to different stress factors like heat, low temperature, high UV light, and high salinity. Phylogenetic analysis with 22 species in the order Sapindales supported previous studies, which revealed that the non-mangrove species X. rumphii is closer to X. moluccensis than X. granatum. Overall, our results provided important insights into the variation of genetic structure and adaptation mechanism at interspecific (three Xylocarpus species) and intergeneric (mangrove and non-mangrove genera) levels.
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Affiliation(s)
- Fengxiao Tan
- College of Natural Resources and Environment, South China Agricultural University, Guangzhou, Guangdong, China
| | - Weixi Li
- School of Life Sciences, Sun Yat-Sen University, Guangzhou, Guangdong, China
| | - Hui Feng
- School of Life Sciences, Sun Yat-Sen University, Guangzhou, Guangdong, China
| | - Yelin Huang
- School of Life Sciences, Sun Yat-Sen University, Guangzhou, Guangdong, China
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Wang X, He Z, Guo Z, Yang M, Xu S, Chen Q, Shao S, Li S, Zhong C, Duke NC, Shi S. Extensive gene flow in secondary sympatry after allopatric speciation. Natl Sci Rev 2022; 9:nwac280. [PMID: 36694801 PMCID: PMC9869077 DOI: 10.1093/nsr/nwac280] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2022] [Revised: 12/04/2022] [Accepted: 12/10/2022] [Indexed: 12/15/2022] Open
Abstract
In the conventional view, species are separate gene pools delineated by reproductive isolation (RI). In an alternative view, species may also be delineated by a small set of 'speciation genes' without full RI, a view that has gained broad acceptance. A recent survey, however, suggested that the extensive literature on 'speciation with gene flow' is mostly (if not all) about exchanges in the early stages of speciation. There is no definitive evidence that the observed gene flow actually happened after speciation is completed. Here, we wish to know whether 'good species' (defined by the 'secondary sympatry' test) do continue to exchange genes and, importantly, under what conditions such exchanges can be observed. De novo whole-genome assembly and re-sequencing of individuals across the range of two closely related mangrove species (Rhizophora mucronata and R. stylosa) reveal the genomes to be well delineated in allopatry. They became sympatric in northeastern Australia but remain distinct species. Nevertheless, their genomes harbor ∼4000-10 000 introgression blocks averaging only about 3-4 Kb. These fine-grained introgressions indicate continual gene flow long after speciation as non-introgressable 'genomic islets,' ∼1.4 Kb in size, often harbor diverging genes of flower or gamete development. The fine-grained introgression in secondary sympatry may help settle the debate about sympatric vs. micro-allopatric speciation. In conclusion, true 'good species' may often continue to exchange genes but the opportunity for detection is highly constrained.
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Affiliation(s)
| | | | | | - Ming Yang
- Department of Laboratory Medicine & Pathology, University of Washington, Seattle, WA98195, USA
| | - Shaohua Xu
- State Key Laboratory of Biocontrol, Guangdong Key Laboratory of Plant Resources, School of Life Sciences, Southern Marine Science and Engineering Guangdong Laboratory (Zhuhai), Sun Yat-sen University, Guangzhou510275, China
| | - Qipian Chen
- State Key Laboratory of Biocontrol, Guangdong Key Laboratory of Plant Resources, School of Life Sciences, Southern Marine Science and Engineering Guangdong Laboratory (Zhuhai), Sun Yat-sen University, Guangzhou510275, China
| | - Shao Shao
- State Key Laboratory of Biocontrol, Guangdong Key Laboratory of Plant Resources, School of Life Sciences, Southern Marine Science and Engineering Guangdong Laboratory (Zhuhai), Sun Yat-sen University, Guangzhou510275, China
| | - Sen Li
- State Key Laboratory of Biocontrol, Guangdong Key Laboratory of Plant Resources, School of Life Sciences, Southern Marine Science and Engineering Guangdong Laboratory (Zhuhai), Sun Yat-sen University, Guangzhou510275, China
| | - Cairong Zhong
- Hainan Academy of Forestry (Hainan Academy of Mangrove), Haikou571100, China
| | - Norman C Duke
- Centre for Tropical Water and Aquatic Ecosystem Research, James Cook University, Townsville, QLD 4811, Australia
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