| Title: | High-quality evergreen azalea genome reveals tandem duplication-facilitated low-altitude adaptability and floral scent evolution |
| Author(s): | Wang X; Gao Y; Wu X; Wen X; Li D; Zhou H; Li Z; Liu B; Wei J; Chen F; Chen F; Zhang C; Zhang L; Xia Y; |
| Address: | "Genomics and Genetic Engineering Laboratory of Ornamental Plants, College of Agriculture and Biotechnology, Zhejiang University, Hangzhou, China. Fujian Provincial Key Laboratory of Haixia Applied Plant Systems Biology, Key Laboratory of Ministry of Education for Genetics & Breeding and Multiple Utilization of Crops, College of life science, Fujian Agriculture and Forestry University, Fuzhou, China. The Southwest China of Germplasm Bank of Wild Species, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming, China. Research & Development Center, Hangzhou Landscaping Incorporated, Hangzhou, China. College of Horticulture, Nanjing Agricultural University, Nanjing, China. Department of Plant Sciences, University of Tennessee, Knoxville, TN, USA" |
| ISSN/ISBN: | 1467-7652 (Electronic) 1467-7644 (Print) 1467-7644 (Linking) |
| Abstract: | "Azalea belongs to Rhododendron, which is one of the largest genera of flowering plants and is well known for the diversity and beauty in its more than 1000 woody species. Rhododendron contains two distinct groups: the most high-altitude and a few low-altitude species; however, the former group is difficult to be domesticated for urban landscaping, and their evolution and adaptation are little known. Rhododendron ovatum has broad adaptation in low-altitude regions but possesses evergreen characteristics like high-altitude species, and it has floral fragrance that is deficient in most cultivars. Here we report the chromosome-level genome assembly of R. ovatum, which has a total length of 549 Mb with scaffold N50 of 41 Mb and contains 41 264 predicted genes. Genomic micro-evolutionary analysis of R. ovatum in comparison with two high-altitude Rhododendron species indicated that the expansion genes in R. ovatum were significantly enriched in defence responses, which may account for its adaptability in low altitudes. The R. ovatum genome contains much more terpene synthase genes (TPSs) compared with the species that lost floral fragrance. The subfamily b members of TPS are involved in the synthesis of sesquiterpenes as well as monoterpenes and play a major role in flora scent biosynthesis and defence responses. Tandem duplication is the primary force driving expansion of defence-responsive genes for extensive adaptability to the low-altitude environments. The R. ovatum genome provides insights into low-altitude adaptation and gain or loss of floral fragrance for Rhododendron species, which are valuable for alpine plant domestication and floral scent breeding" |
| Keywords: | Altitude Flowers/genetics Odorants Phylogeny Plant Breeding *Rhododendron/genetics Rhododendron ovatum Azalea adaptability defence response floral scent tandem duplication terpene synthase (TPS); |
| Notes: | "MedlineWang, Xiuyun Gao, Yuan Wu, Xiaopei Wen, Xiaohui Li, Danqing Zhou, Hong Li, Zheng Liu, Bing Wei, Jianfen Chen, Fei Chen, Feng Zhang, Chengjun Zhang, Liangsheng Xia, Yiping eng Research Support, Non-U.S. Gov't England 2021/08/11 Plant Biotechnol J. 2021 Dec; 19(12):2544-2560. doi: 10.1111/pbi.13680. Epub 2021 Aug 21" |
