Molecular cytogenetic characterization and comparison of the two cultivated Canavalia species (Fabaceae)

By

She, Chao-Wen
Wei, Lin
Jiang, Xiang-Hui

Type

Article

Date of Publication

2017

Original Publication

Comparative cytogenetics : international journal of plant & animal cytogenetics, karyosystematics and molecular systematics

Volume

11

Series / Issue

Issue: 4

Pages

579-600

Subjects

45S rDNA , 5S rDNA , Canavalia cultivars , fluorochrome banding , in situ hybridization , karyotype

Contributed by

Pensoft Publishers

Language

English

Published by

St. Petersburg, Russia [Published] with technical support of Zoological Institute RAS [2007]-

Identifiers

DOI: https://doi.org/10.3897/compcytogen.v11i4.13604

 

Abstract

The two cultivated Canavalia (Adanson, 1763) species, Canavalia gladiata (N. J. von Jacquin, 1788) A. P. de Candolle, 1825 and Canavalia ensiformis (Linnaeus, 1753) A. P. de Candolle, 1825 are closely related based on morphological and molecular phylogenetic data. However, the similarities and differences in genome organization between them have not been evaluated at molecular cytogenetic level. Here, detailed karyotypes of both species were constructed using combined PI and DAPI (CPD) staining, rDNA-FISH and self-genomic in situ hybridization (sGISH). For further comparison, comparative genomic in situ hybridization (cGISH) and sequence analysis of 5S rDNA were applied. Their chromosomes were accurately identified by sGISH and rDNA-FISH signals. Both species had the karyotype formula 2n = 22 = 18m + 4m-SAT, but the karyotype of C. ensiformis was shorter and more asymmetric than that of C. gladiata. They displayed similar CPD bands at all 45S rDNA sites and centromeres. C. gladiata had ten centromeric 5S rDNA loci and two SC (secondary constriction)-associated 45S rDNA loci. C. ensiformis had nine centromeric and one interstitial 5S loci, two SC-associated and one proximal 45S loci. Their sGISH signal patterns displayed both basic similarities and distinct differences. Reciprocal cGISH generated prominent signals in all pericentromeric regions and 45S sites. There was lower level of sequence identity of the non-transcribed spacer between their 5S rDNA repeats. These data confirmed the evolutionary closeness between C. gladiata and C. ensiformis and demonstrated obvious differentiation between their genomes, and supported the opinion that C. ensiformis is more advanced in evolution than C. gladiata.