Leibniz Institute of Plant Genetics and Crop Plant Research (IPK), Gatersleben, 06466, Stadt Seeland, Germany.
Biology Department, Dalat University, District 8, Dalat City, Lamdong Province, Vietnam.
Chromosoma. 2021 Mar;130(1):15-25. doi: 10.1007/s00412-020-00749-2. Epub 2021 Jan 14.
Duckweeds represent a small, free-floating aquatic family (Lemnaceae) of the monocot order Alismatales with the fastest growth rate among flowering plants. They comprise five genera (Spirodela, Landoltia, Lemna, Wolffiella, and Wolffia) varying in genome size and chromosome number. Spirodela polyrhiza had the first sequenced duckweed genome. Cytogenetic maps are available for both species of the genus Spirodela (S. polyrhiza and S. intermedia). However, elucidation of chromosome homeology and evolutionary chromosome rearrangements by cross-FISH using Spirodela BAC probes to species of other duckweed genera has not been successful so far. We investigated the potential of chromosome-specific oligo-FISH probes to address these topics. We designed oligo-FISH probes specific for one S. intermedia and one S. polyrhiza chromosome (Fig. 1a). Our results show that these oligo-probes cross-hybridize with the homeologous regions of the other congeneric species, but are not suitable to uncover chromosomal homeology across duckweeds genera. This is most likely due to too low sequence similarity between the investigated genera and/or too low probe density on the target genomes. Finally, we suggest genus-specific design of oligo-probes to elucidate chromosome evolution across duckweed genera.
浮萍是单子叶植物泽泻目中浮萍科的一个小型漂浮水生植物家族，是开花植物中生长最快的植物。浮萍科由五个属（紫萍属、无根萍属、浮萍属、沃氏萍属和大藻属）组成，其基因组大小和染色体数目有所不同。紫萍是第一个被测序的浮萍属植物基因组。两个浮萍属物种（紫萍和青萍）都有细胞遗传学图谱。然而，到目前为止，使用浮萍 BAC 探针进行种间交叉 FISH 还未能成功阐明染色体同源性和进化过程中的染色体重排。我们研究了使用染色体特异性寡核苷酸-FISH 探针解决这些问题的潜力。我们设计了针对一个青萍和一个紫萍染色体的寡核苷酸-FISH 探针（图 1a）。我们的结果表明，这些寡核苷酸探针与其他同属种的同源区域发生交叉杂交，但不适合揭示浮萍属植物之间的染色体同源性。这很可能是由于所研究的属之间的序列相似性太低，或者目标基因组上的探针密度太低。最后，我们建议针对特定属设计寡核苷酸探针，以阐明浮萍属植物之间的染色体进化。
