Yu Fan, Zhao Xinwang, Chai Jin, Ding Xueer, Li Xueting, Huang Yongji, Wang Xianhong, Wu Jiayun, Zhang Muqing, Yang Qinghui, Deng Zuhu, Jiang Jiming
National Engineering Research Center for Sugarcane, Fujian Agriculture and Forestry University, Fuzhou, 350002, Fujian, China.
State Key Laboratory for Protection and Utilization of Subtropical Agro-bioresources, Guangxi University, Nanning, 530004, China.
New Phytol. 2022 Feb;233(4):1953-1965. doi: 10.1111/nph.17905. Epub 2021 Dec 24.
Karyotypes provide key cytogenetic information on the phylogenetic relationships and evolutionary origins in related eukaryotic species. Despite our knowledge of the chromosome numbers of sugarcane and its wild relatives, the chromosome composition and evolution among the species in the Saccharum complex have been elusive owing to the complex polyploidy and the large numbers of chromosomes of these species. Oligonucleotide-based chromosome painting has become a powerful tool of cytogenetic studies especially for plant species with large numbers of chromosomes. We developed oligo-based chromosome painting probes for all 10 chromosomes in Saccharum officinarum (2n = 8x = 80). The 10 painting probes generated robust fluorescence in situ hybridization signals in all plant species within the Saccharum complex, including species in the genera Saccharum, Miscanthus, Narenga and Erianthus. We conducted comparative chromosome analysis using the same set of probes among species from four different genera within the Saccharum complex. Excitingly, we discovered several novel cytotypes and chromosome rearrangements in these species. We discovered that fusion from two different chromosomes is a common type of chromosome rearrangement associated with the species in the Saccharum complex. Such fusion events changed the basic chromosome number and resulted in distinct allopolyploids in the Saccharum complex.
核型提供了有关相关真核物种系统发育关系和进化起源的关键细胞遗传学信息。尽管我们了解甘蔗及其野生近缘种的染色体数目，但由于这些物种复杂的多倍性和大量的染色体，甘蔗属复合体中各物种间的染色体组成和进化情况一直难以捉摸。基于寡核苷酸的染色体涂染已成为细胞遗传学研究的有力工具，特别是对于具有大量染色体的植物物种。我们为甘蔗（2n = 8x = 80）的所有10条染色体开发了基于寡核苷酸的染色体涂染探针。这10种涂染探针在甘蔗属复合体中的所有植物物种中均产生了强烈的荧光原位杂交信号，包括甘蔗属、芒属、河八王属和斑茅属的物种。我们使用同一组探针在甘蔗属复合体中四个不同属的物种间进行了比较染色体分析。令人兴奋的是，我们在这些物种中发现了几种新的细胞型和染色体重排。我们发现来自两条不同染色体的融合是与甘蔗属复合体中的物种相关的一种常见染色体重排类型。这种融合事件改变了基本染色体数，并在甘蔗属复合体中产生了独特的异源多倍体。
