Meiotic configuration and rDNA distribution patterns in Six Rubus taxa

Published on Jun 07, 2018 12:55 PM

More than 200 Rubus species described so far have been
included in subgenera Idaeobatus and Malachobatus.
Tremendous amount of genetic diversity exists in Rubus
due to inter- or intra-species hybridization, polyploidization,
or agamospermy make it a typical taxonomically challenging
but genetically intriguing genus among land plants. In
present study, meiotic pairing behavior and the distribution
patterns of 45S and 5S ribosomal DNA (rDNA) arrays were
assessed by fluorescence in situ hybridization (FISH) in six
Rubus taxa with ploidy ranging from diploid (2n=14) to
octoploid (2n=56). At all ploidy levels, bivalent pairing is
the most predominant form in meiotic configuration. Very
few multivalents were observed in tetraploid or octoploid
samples. FISH analysis revealed two 45S rDNA sites in
each of the two diploid taxa. Each of the polyploids (2n=28)
studied had the expected multiples of this number except
the tetraploid R. setchuenensis (with only three sites). On
the contrary, both diploid and tetraploid taxa had two 5S
rDNA loci, while the octoploid R. buergeri carried only three
sites. Both meiotic behavior observations and FISH results
support that Rubus polyploids might be of allopolyploid in
origin.

Keywords: Rubus, meiotic pairing, fluorescence in situ hybridization (FISH), 45S/5SrDNA, polyploid origin

Info

Year: 2015
Volume: 75
Issue: 2
Article DOI: 10.5958/0975-6906.2015.00037.1
Print ISSN: 0019-5200
Online ISSN: 0975-6906

Authors

Qing Chen,Haoru Tang
Yan Wang, Hong Nan, Li Zhang and Xiaorong Wang

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