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Huang H, Ji H, Ju S, Lin W, Li J, Lv X, Lin L, Guo L, Qiu D, Yan J, Ma X. Pantranscriptome combined with phenotypic quantification reveals germplasm kinship and regulation network of bract color variation in Bougainvillea. Front Plant Sci 2022; 13:1018846. [PMID: 36466294 PMCID: PMC9713818 DOI: 10.3389/fpls.2022.1018846] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 08/14/2022] [Accepted: 10/07/2022] [Indexed: 06/17/2023]
Abstract
Bracts are the metamorphic non-flower organ in angiosperm plants. The variation of the color and shape of bracts was found to be neo-functionalized (i.e., similar to petals), garnering research interest as a pollinator attractor. Bougainvillea is known for its specialized, large, and colorful bracts, which contrast with its tiny colorless flowers. As a plant whose bracts vary greatly in terms of coloration, the molecular mechanisms for Bougainvillea bract coloration and polychroism are largely unknown. The lack of genomic information for Bougainvillea largely hinders studies into the evolution and genetic basis of bract color variation. In this study, a pan-transcriptome of bracts obtained from 18 Bougainvillea glabra accessions was employed to investigate the global population-level germplasm kinship and the gene regulation network for bract color variation. Our results showed that the bracts of B. glabra accessions have largely differentiated International Commission on Illumination (CIE) L-a-b values. Moreover, germplasm kinship detected using principal component analysis, phylogeny, and admixture analysis showed three optimal subgroups, two of them distinctly clustered, which were not directly correlated with bract color variation at the population level. Differentially expressed genes (DEGs) between accessions of high vs. low L-a-b values revealed several considerable upregulated genes related to bract color L-a-b variation. A weighted gene co-expression network was constructed, and eight co-expressed regulation modules were identified that were highly correlated with variation in bract CIE L-a-b color values. Several candidate DEGs and co-expressed hub genes (e.g., GERD, SGR, ABCA3, GST, CYP76AD1, CYP76C, and JAZ) that were tightly associated with bract color variation were eventually determined responsible for L-a-b colorations, which might be the core regulation factors contributing to the B. glabra bract color variation. This study provides valuable insights into the research on germplasm kinship, population-level pan-transcriptome expression profiles, and the molecular basis of color variation of key innovative bracts in horticultural Bougainvillea.
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Affiliation(s)
- Huaxing Huang
- Center for Genomics and Biotechnology, School of Future Technology, Haixia Institute of Science and Technology, Fujian Agriculture and Forestry University, Fuzhou, China
- Yuanshan Institute of Bougainvillea in Longhai, Zhangzhou, China
| | - Hongli Ji
- Vegetable and Flower Institute, Jiangxi Academy of Agricultural Sciences, Nanchang, China
| | - Song Ju
- Center for Genomics and Biotechnology, School of Future Technology, Haixia Institute of Science and Technology, Fujian Agriculture and Forestry University, Fuzhou, China
- College of Forestry, Fujian Agriculture and Forestry University, Fuzhou, China
| | - Wei Lin
- College of Forestry, Fujian Agriculture and Forestry University, Fuzhou, China
| | - Jing Li
- Center for Genomics and Biotechnology, School of Future Technology, Haixia Institute of Science and Technology, Fujian Agriculture and Forestry University, Fuzhou, China
- College of Horticulture, Fujian Agriculture and Forestry University, Fuzhou, China
| | - Xuanrui Lv
- Center for Genomics and Biotechnology, School of Future Technology, Haixia Institute of Science and Technology, Fujian Agriculture and Forestry University, Fuzhou, China
- College of Life Sciences, Fujian Agriculture and Forestry University, Fuzhou, China
| | - Lixian Lin
- Center for Genomics and Biotechnology, School of Future Technology, Haixia Institute of Science and Technology, Fujian Agriculture and Forestry University, Fuzhou, China
- College of Life Sciences, Fujian Agriculture and Forestry University, Fuzhou, China
| | - Lijin Guo
- International Magnesium Institute, School of Future Technology, Haixia Institute of Science and Technology, Fujian Agriculture and Forestry University, Fuzhou, China
| | - Dongliang Qiu
- College of Horticulture, Fujian Agriculture and Forestry University, Fuzhou, China
| | - Jianyong Yan
- Yuanshan Institute of Bougainvillea in Longhai, Zhangzhou, China
| | - Xiaokai Ma
- Center for Genomics and Biotechnology, School of Future Technology, Haixia Institute of Science and Technology, Fujian Agriculture and Forestry University, Fuzhou, China
- Key Laboratory of Orchid Conservation and Utilization of National Forestry and Grassland Administration at College of Landscape Architecture, Fujian Agriculture and Forestry University, Fuzhou, China
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