image: Assembly and genomic features of Z. jujuba Mill. ‘Junzao’ (JZ) and a wild jujube accession (SZ). A Fruits of JZ and SZ. B, C Circos plot of JZ and SZ haplotype-resolved gap-free genomic features. (a) Chromosome length; (b) gene density along each chromosome (red, number of genes per 100 kb); (c) LTR/Gypsy element content; (d) LTR/Copia content; (e) repeat content along each chromosome; (f) GC content (nucleotides per megabase); (h) the innermost part of the plot represents the collinear relationship between the haplotype-resolved genomes. Using 1-Mb intervals, the TE density, Copia density, and Gypsy density were determined in the JZ and SZ genomes.
Credit: Horticulture Research
Unlocking the secrets of the Chinese jujube's evolution, a new study presents the most detailed genomic analysis to date. By assembling the haplotype-resolved T2T reference genomes of both wild and cultivated jujube, researchers have unveiled the genetic pathways behind the fruit's transformation. This work not only retraces the steps of domestication but also uncovers the molecular mechanisms governing key agronomic traits, setting a new benchmark for fruit tree research and breeding strategies.
Chinese jujube, known for its economic and nutritional significance, was domesticated from its wild ancestor. While previous studies have shed light on some aspects of its domestication, many genetic details remain unexplored. The jujube's transformation from a wild shrub with small, sour fruit to a cultivated tree with large, sweet fruit involved complex genetic changes. Due to these unanswered questions and the economic importance of jujube, a comprehensive genomic study was essential to uncover the detailed genetic mechanisms underlying its domestication. This necessity drove researchers to delve deeper into jujube’s genetic evolution.
A team of researchers from Northwest A&F University and Xinjiang Academy of Agricultural Sciences published a study (DOI: 10.1093/hr/uhae071) on March 7, 2024, in Horticulture Research. They report the assembly of haplotype-resolved genomes for the cultivated 'Junzao' jujube and its wild ancestor. This research reveals significant genetic variations that have shaped jujube's domestication.
The study successfully assembled the genomes of the cultivated jujube cultivar 'Junzao' and its wild relative 'Suanzao' using advanced sequencing technologies, achieving high-quality, haplotype-resolved assemblies. These genomes revealed significant structural variations, including large-scale inversions and translocations on chromosomes 1, 3, 4, and 12. Comparative genomic analyses showed that these variations affect numerous genes, particularly those involved in starch and sucrose metabolism, which are crucial for fruit sweetness. Additionally, the study identified new selection signals in regions associated with tissue development and pollination, highlighting the genetic pathways influenced by domestication. These findings provide a detailed genetic map, offering valuable insights into the evolutionary and domestication processes of jujube. The comprehensive data not only enhance the understanding of jujube's genetic diversity but also pave the way for targeted breeding strategies to improve fruit quality and other agronomic traits.
Dr. Jian Huang, a leading researcher, commented, "The haplotype-resolved genomes provide unprecedented clarity on the genetic underpinnings of jujube domestication. These high-quality genomes will be instrumental in breeding programs aimed at improving jujube fruit quality and resilience."
The insights gained from this study have significant implications for jujube breeding and agriculture. The identified genetic markers and structural variations can guide targeted breeding strategies to enhance desirable traits such as sweetness and drought resistance. Furthermore, the comprehensive genomic data serve as a valuable resource for future research in jujube and other related fruit trees.
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References
DOI
Original Source URL
https://doi.org/10.1093/hr/uhae071
Funding information
This work was supported by the earmarked fund of Xinjiang Jujube Industrial Technology System (XJCYTX-01), and the National Natural Science Foundation of China (grants 31870584 and 31860223).
About Horticulture Research
Horticulture Research is an open access journal of Nanjing Agricultural University and ranked number one in the Horticulture category of the Journal Citation Reports ™ from Clarivate, 2022. The journal is committed to publishing original research articles, reviews, perspectives, comments, correspondence articles and letters to the editor related to all major horticultural plants and disciplines, including biotechnology, breeding, cellular and molecular biology, evolution, genetics, inter-species interactions, physiology, and the origination and domestication of crops.
Journal
Horticulture Research
Subject of Research
Not applicable
Article Title
Haplotype-resolved T2T reference genomes for wild and domesticated accessions shed new insights into the domestication of jujube
Article Publication Date
7-Mar-2024
COI Statement
The authors declare that they have no competing interests.