AUTHOR=Chai Jin , Xue Li , Lei Jiawei , Yao Wei , Zhang Muqing , Deng Zuhu , Yu Fan 

TITLE=All nonhomologous chromosomes and rearrangements in Saccharum officinarum × Saccharum spontaneum allopolyploids identified by oligo-based painting

JOURNAL=Frontiers in Plant Science

VOLUME=14

YEAR=2023

URL=https://www.frontiersin.org/journals/plant-science/articles/10.3389/fpls.2023.1176914

DOI=10.3389/fpls.2023.1176914

ISSN=1664-462X

ABSTRACT=<p>Modern sugarcane cultivars (<italic>Saccharum</italic> spp., 2<italic>n</italic> = 100~120) are complex polyploids primarily derived from interspecific hybridization between <italic>S. officinarum</italic> and <italic>S. spontaneum</italic>. Nobilization is the theory of utilizing wild germplasm in sugarcane breeding, and is the foundation for utilizing <italic>S. spontaneum</italic> for stress resistance. However, the exact chromosomal transmission remains elusive due to a lack of chromosome-specific markers. Here, we applied chromosome-specific oligonucleotide (oligo)-based probes for identifying chromosomes 1-10 of the F<sub>1</sub> hybrids between <italic>S. officinarum</italic> and <italic>S. spontaneum</italic>. Then, <italic>S. spontaneum</italic>-specific repetitive DNA probes were used to distinguish <italic>S. spontaneum</italic> in these hybrids. This oligo- fluorescence <italic>in situ</italic> hybridization (FISH) system proved to be an efficient tool for revealing individual chromosomal inheritance during nobilization. We discovered the complete doubling of <italic>S. officinarum-</italic>derived chromosomes in most F<sub>1</sub> hybrids. Notably, we also found defective <italic>S. officinarum</italic>-derived chromosome doubling in the F<sub>1</sub> hybrid Yacheng75-4191, which exhibited 1.5n transmission for all nonhomologous chromosomes. Altogether, these results highlight the presence of variable chromosome transmission in nobilization between <italic>S. officinarum</italic> and <italic>S. spontaneum</italic>, including 1.5n + n and 2n + n. These findings provide robust chromosome markers for in-depth studies into the molecular mechanism underlying chromosome doubling during the nobilization, as well as tracing chromosomal inheritance for sugarcane breeding.</p>