Wax apple, also known as water apple, belongs to the Myrtaceae family, Syzygium genus, and is a tropical evergreen tree. Widely cultivated in regions such as Guangxi, Hainan, Guangdong, Yunnan, and Taiwan in China. The wax apple fruit has a crispy and tender texture, with a sweet and refreshing taste, abundant moisture, low calories, and rich in dietary fiber, making it highly nutritious. As an emerging tropical fruit, wax apple has a short cultivation history and limited distribution, resulting in lagging basic research. The lack of a cultivated wax apple genome sequence and related genetic studies seriously hinder the breeding progress of wax apple.
Recently, a research team from Hainan University published a paper in "Horticultural Research," using the Black Diamond variety of wax apple as the research subject. They utilized long-read sequencing technology to assemble the diploid wax apple genome, resulting in a 676.1 megabase genome with 11 chromosomes. Genome annotation revealed 45,914 coding genes, with a GC content of 40.87% and repetitive sequences accounting for 51.27%.
Phylogenetic analysis indicated that wax apple diverged from its close relatives approximately 15 million years ago. Karyotype analysis revealed that the ancestor of wax apple experienced a common whole-genome duplication event in the Myrtaceae family around 65 million years ago.
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Identification of key genes involved in lotus fruit development and assembly of the lotus genome
The research team conducted transcriptome sequencing on lotus fruit samples at different developmental stages and in various organs, including small fruits at 20 days, small fruits at 40 days, medium fruits at 60 days, medium fruits at 75 days, large fruits at 95 days, large fruits at 110 days, mature fruits at 120 days, functional leaves, flowers, and stems. Through time trend analysis, key gene modules consistent with lotus fruit development and maturation trends were identified, with the top three weighted NAC transcription factors being highlighted. By integrating co-expression networks, heatmap visualization, and evolutionary analysis, it was further confirmed that three NAC transcription factors, Ssam8.1288 (SsNAC106), Ssam8.1083 (SsNAC105), and Ssam7.3635 (SsNAC94), are the most important regulatory genes involved in lotus fruit maturation and development.
In conclusion, this study utilized novel long-read sequencing technology to obtain a high-quality reference genome sequence for lotus, laying the foundation for genetic research and gene discovery in lotus and opening up new avenues for molecular breeding of lotus.
Related paper: https://doi.org/10.1093/hr/uhae025
