Genomic relationships of the polyploid rhizoma peanut (Arachis glabrata Benth .) inferred by genomic in situ hybridization (GISH)

ALEJANDRA ORTIZ; CHALUP LAURA; CELESTE SILVESTRI; GUILLERMO SEIJO; GRACIELA LAVIA

ANAIS DA ACADEMIA BRASILEIRA DE CIENCIAS.

ACAD BRASILEIRA DE CIENCIAS

Año: 2023

0001-3765

The rhizoma peanut (Arachis glabrata Benth., section Rhizomatosae) is a tetraploidperennial legume. Although several A. glabrata cultivars have been developed as forageand ornamental turf, the origin and genomic constitution of this species are stillunknown. In this study, we evaluated the affinity between the genomes of A. glabrataand the probable diploid donors of the sections Rhizomatosae, Arachis, Erectoides andProcumbentes by genomic in situ hybridization (GISH). Single GISH analyses detectedthat species of the sections Erectoides (E2 subgenome) and Procumbentes (E3subgenome) 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. capibariensis, and A. rigonii-, whichshowed the most uniform and brightest hybridization patterns and lowest geneticdistance, were selected as probes for double GISH experiments. Double GISHexperiments showed that A. glabrata is constituted by four identical or very similarchromosome complements. In these assays, A. paraguariensis subsp. capibariensis showed the highest brightness onto A. glabrata chromosomes. Thus, our results supportthe autopolyploid origin of A. glabrata and show that the species with E2 subgenome are the most probable ancestors of this polyploid legume forage.