Ortiz Alejandra Marcela, Chalup Laura, Silvestri María Celeste, Seijo Guillermo, Lavia Graciela Inés
CONICET-UNNE, Fac. Cs. Agrarias, Instituto de Botánica del Nordeste, Sargento Cabral 2131, C.C. 209, 3400 Corrientes, Argentina.
Universidad Nacional del Chaco Austral, UNCAUS, Comandante Fernandez 755, 3700, Pcia. Roque Sáenz Peña, Chaco, Argentina.
An Acad Bras Cienc. 2023 Apr 17;95(2):e20210162. doi: 10.1590/0001-3765202320210162. eCollection 2023.
The rhizoma peanut (Arachis glabrata Benth., section Rhizomatosae) is a tetraploid perennial legume. Although several A. glabrata cultivars have been developed as forage and ornamental turf, the origin and genomic constitution of this species are still unknown. In this study, we evaluated the affinity between the genomes of A. glabrata and the probable diploid donors of the sections Rhizomatosae, Arachis, Erectoides and Procumbentes by genomic in situ hybridization (GISH). Single GISH analyses detected that species of the sections Erectoides (E2 subgenome) and Procumbentes (E3 subgenome) were the diploid species with the highest degree of genomic affinity with A. glabrata. Based on single GISH experiments and DNA sequence similarity, three species -A. duranensis, A. paraguariensis subsp. capibarensis, and A. rigonii-, which showed the most uniform and brightest hybridization patterns and lowest genetic distance, were selected as probes for double GISH experiments. Double GISH experiments showed that A. glabrata is constituted by four identical or very similar chromosome complements. In these assays, A. paraguariensis subsp. capibarensis showed the highest brightness onto A. glabrata chromosomes. Thus, our results support the autopolyploid origin of A. glabrata and show that the species with E2 subgenome are the most probable ancestors of this polyploid legume forage.
根茎花生（Arachis glabrata Benth.，根茎花生组）是一种四倍体多年生豆科植物。尽管已经培育出了几种根茎花生品种用作饲料和观赏草坪，但该物种的起源和基因组构成仍然未知。在本研究中，我们通过基因组原位杂交（GISH）评估了根茎花生基因组与根茎花生组、花生组、直立花生组和匍匐花生组可能的二倍体供体之间的亲缘关系。单基因组原位杂交分析检测到，直立花生组（E2亚基因组）和匍匐花生组（E3亚基因组）的物种是与根茎花生基因组亲缘关系程度最高的二倍体物种。基于单基因组原位杂交实验和DNA序列相似性，选择了三个杂交模式最一致、最亮且遗传距离最短的物种——A. duranensis、A. paraguariensis subsp. capibarensis和A. rigonii——作为双基因组原位杂交实验的探针。双基因组原位杂交实验表明，根茎花生由四个相同或非常相似的染色体组构成。在这些分析中，A. paraguariensis subsp. capibarensis在根茎花生染色体上显示出最高的亮度。因此，我们的结果支持根茎花生的同源多倍体起源，并表明具有E2亚基因组的物种是这种多倍体豆科饲料最可能的祖先。
