Phylogenetic insight into subgenera Idaeobatus and Malachobatus (Rubus, Rosaceae) inferring from ISH analysis

Abstract

BackgroundRubus is a large and taxonomically complex genus exhibiting agamospermy, polyploidy and frequent hybridization. The objective of this work was to elucidate rDNA disrtibution pattern and investigate genomic composition of polyploids in 16 Rubus taxa (2n = 2x, 3x, 4x, 8x) of two subgenera Idaeobatus and Malachobatus by ISH method.ResultsThe basic Rubus genome had one 45S rDNA locus, and all the polyploids (except R. setchuenensis) had the expected multiples of this number. Diploid and tetraploid Rubus taxa carried two 5S rDNA, whereas the triploid and octoploid species only had three. The duplicated 45S rDNA sites tended to be conserved, whereas those of 5S rDNA tended to be eliminated after polyploidization. The accession R03-20 was an autotriploid R. parvifolius, while R03-27 and R03-57 were naturally-occurred triploid hybrids between R. parvifolius and R. coreanus. GISH results suggested that R. parvifolius had close relationship with polyploids from Malachobatus.ConclusionsThe polyploids from Malachobatus were probable allopolyploid. In addition, Rubus parvifolius might be involved in hybridization, polyploidization and speciation of some Idaeobatus and Malachobatus species.

Major structural genomic alterations can be associated with hybrid speciation inAegilops markgrafii(Triticeae)

“…Introgressive hybridization, as an important evolutionary force, was suggested by E. Anderson in 1949. Since then, many events of natural introgression through interspecific hybridization have been proven for a wide range of plant species, insects and fish (Rieseberg and Wendel, ; Baack and Rieseberg, ; Gaines et al ., ; Chen and Yu, ; Cornille et al ., ; Wang et al ., ). The Triticeae was actively involved in interspecific hybridization, because many grasses are allopolyploids (Tsunewaki, ; Kilian et al ., ; Feldman and Levy, ).…”

Target Capture Sequencing Unravels Rubus Evolution

“…Varying intra-and interspecific ploidy levels (diploid, 2n = 2x = 14 to dodecaploid, 2n = 12x = 84, plus aneuploids), and hybridization (Jennings, 1988;Thompson, 1995;Thompson, 1997;Alice et al, 2001;Sochor et al, 2015;Wang et al, 2015) make phylogenetic estimation challenging. Focke's worldwide taxonomic treatment of Rubus (Focke, 1910;Focke, 1911;Focke, 1914), defined 12 subgenera ( Table 1).…”

“…Species from Dalibardastrum and Idaeobatus were nested within the paraphyletic Malachobatus. These authors hypothesized that the allopolyploid species in Malachobatus may be derived from crosses between Idaeobatus and Cylactis species (Wang et al, 2015;Wang et al, 2016). Idaeobatus was polyphyletic with members in four clades.…”

The fate of ribosomal RNA genes in spontaneous polyploid dogrose hybrids [Rosa L. sect. Caninae (DC.) Ser.] exhibiting non‐symmetrical meiosis

“…Fragaria L., Malus L., Rosa ). The fate of rDNA loci has been documented in several polyploid rosaceous genera reporting either the persistence of progenitor rDNA loci regions, for example in Rubus L. (Chen et al ., ; Wang et al ., ) and Sanguisorba L. (Mishima et al ., ), or frequent losses, for example in Fragaria (Liu and Davis, ). In Rosa , one 35S rDNA locus per genome and several small 5S loci have been detected in diploid species (Ma et al ., ; Fernandez‐Romero et al ., ; Lim et al ., ; Kirov et al ., ).…”