Chaves Ana Luisa Arantes, Carvalho Pedro Henrique Mendes, Ferreira Marco Tulio Mendes, Benites Flávio Rodrigo Gandolfi, Techio Vânia Helena
Department of Biology (DBI), Plant Cytogenetics Laboratory, Federal University of Lavras (UFLA), P.O. Box 3037, Lavras, Minas Gerais State, Brazil.
Empresa Brasileira de Pesquisa Agropecuária, Embrapa Gado de Leite, Juiz de Fora, Minas Gerais State, Brazil.
Protoplasma. 2022 Jul;259(4):999-1011. doi: 10.1007/s00709-021-01716-z. Epub 2021 Oct 28.
Polyploidy is the main mechanism for chromosome number variation in Cynodon. Taxonomic boundaries are difficult to define and, although phylogenetic studies indicate that some species are closely related, the degree of genomic similarity remains unknown. Furthermore, the Cynodon species classification as auto or allopolyploids is still controversial. Thus, this study aimed to investigate the genomic constitution in diploid and polyploid species using different approaches of genomic in situ hybridization (GISH). To better understand the hybridization events, we also investigated the occurrence of unreduced gametes in C. dactylon diploid pollen grains. We suggest a genomic nomenclature of diploid species as DD, DD, and DD for C. dactylon, C. incompletus, and C. nlemfuensis, and DDDD and DDDD for the segmental allotetraploids of Cynodon dactylon and C. transvaalensis, respectively. Furthermore, an evolutionary proposal was built based on our results and previous data from other studies, showing possible crosses that may have occurred between Cynodon species.
多倍体是狗牙根属植物染色体数目变异的主要机制。分类界限难以界定，尽管系统发育研究表明一些物种亲缘关系密切，但基因组相似程度仍不清楚。此外，狗牙根属物种是同源多倍体还是异源多倍体的分类仍存在争议。因此，本研究旨在利用不同的基因组原位杂交（GISH）方法研究二倍体和多倍体物种的基因组组成。为了更好地理解杂交事件，我们还研究了狗牙根二倍体花粉粒中未减数配子的发生情况。我们建议将二倍体物种的基因组命名为：狗牙根、不完全狗牙根和恩勒富狗牙根分别为DD、DD和DD，狗牙根和德兰士瓦狗牙根的节段异源四倍体分别为DDDD和DDDD。此外，基于我们的研究结果和其他研究的先前数据，构建了一个进化模型，展示了狗牙根属物种之间可能发生的杂交。
