Li Xueting, Huang Fei, Chai Jin, Wang Qiusong, Yu Fan, Huang Yongji, Wu Jiayun, Wang Qinnan, Xu Liangnian, Zhang Muqing, Deng Zuhu
National Engineering Research Center for Sugarcane, Fujian Agriculture and Forestry University, Fuzhou, 350002, Fujian, China.
Guangdong Key Laboratory of Sugarcane Improvement and Biorefinery, Guangdong Provincial Bioengineering Institute, Guangzhou, China.
BMC Plant Biol. 2021 Mar 16;21(1):139. doi: 10.1186/s12870-021-02911-z.
In recent years, sugarcane has attracted increasing attention as an energy crop. Wild resources are widely used to improve the narrow genetic base of sugarcane. However, the infertility of F hybrids between Saccharum officinarum (S. officinarum) and Erianthus arundinaceus (E. arundinaceus) has hindered sugarcane breeding efforts. To discover the cause of this infertility, we studied the hybridization process from a cytological perspective.
We examined the meiotic process of pollen mother cells (PMCs) in three F hybrids between S. officinarum and E. arundinaceus. Cytological analysis showed that the male parents, Hainan 92-77 and Hainan 92-105, had normal meiosis. However, the meiosis process in F hybrids showed various abnormal phenomena, including lagging chromosomes, micronuclei, uneven segregation, chromosome bridges, and inability to form cell plates. Genomic in situ hybridization (GISH) showed unequal chromatin distribution during cell division. Interestingly, 96.70% of lagging chromosomes were from E. arundinaceus. Furthermore, fluorescence in situ hybridization (FISH) was performed using 45S rDNA and 5S rDNA as probes. Either 45S rDNA or 5S rDNA sites were lost during abnormal meiosis, and results of unequal chromosomal separation were also clearly observed in tetrads.
Using cytogenetic analysis, a large number of meiotic abnormalities were observed in F. GISH further confirmed that 96.70% of the lagging chromosomes were from E. arundinaceus. Chromosome loss was found by further investigation of repeat sequences. Our findings provide insight into sugarcane chromosome inheritance to aid innovation and utilization in sugarcane germplasm resources.
近年来，甘蔗作为一种能源作物受到越来越多的关注。野生资源被广泛用于改善甘蔗狭窄的遗传基础。然而，甘蔗（Saccharum officinarum）和斑茅（Erianthus arundinaceus）之间F代杂种的不育性阻碍了甘蔗育种工作。为了找出这种不育性的原因，我们从细胞学角度研究了杂交过程。
我们研究了甘蔗和斑茅之间三个F代杂种花粉母细胞（PMC）的减数分裂过程。细胞学分析表明，雄性亲本海南92-77和海南92-105减数分裂正常。然而，F代杂种的减数分裂过程表现出各种异常现象，包括染色体滞后、微核、分离不均、染色体桥以及无法形成细胞板。基因组原位杂交（GISH）显示细胞分裂过程中染色质分布不均。有趣的是，96.70%的滞后染色体来自斑茅。此外，以45S rDNA和5S rDNA为探针进行荧光原位杂交（FISH）。在异常减数分裂过程中，45S rDNA或5S rDNA位点丢失，并且在四分体中也清楚地观察到染色体分离不均的结果。
通过细胞遗传学分析，在F代中观察到大量减数分裂异常。GISH进一步证实96.70%的滞后染色体来自斑茅。通过对重复序列的进一步研究发现了染色体丢失现象。我们的研究结果为甘蔗染色体遗传提供了见解，有助于甘蔗种质资源的创新和利用。
