Comparative analysis of heterochromatin distribution in wild and cultivated Abelmoschus species based on fluorescent staining methods

Abstract

A comparative analysis of fluorochrome-binding pattern in nine taxa of Abelmoschus had shown that the type, amount and distribution pattern of heterochromatin were characteristic for each taxa. The fluorescent chromosome-binding sites obtained by chromomycin A3 (CMA) and 4',6-diamidino-2-phenylindole (DAPI) staining in all the nine species showed constitutive heterochromatin CMA(+), DAPI(+) and CMA(+)/DAPI(+). Large amount of heterozygosity was observed with regard to heterochromatin distribution pattern in all the taxa studied. The CMA(+)-binding sites are comparatively less than DAPI(+)-binding sites which is clearly evident as AT-rich regions are more than GC-rich regions in all the nine taxa analysed in Abelmoschus. These CMA(+) and DAPI(+)-binding sites apparently rise with the increased in chromosome numbers of the different species. This pattern of heterochromatin heterogeneity seems to be a general characteristic feature. Therefore, the differential pattern of distribution of GC- and AT-rich sequences might have played an important role in diversification of the genus Abelmoschus. Polyploidy is an important factor in the evolution of Abelmoschus and the sole reason for range in chromosome numbers in this genus. It may be noted that, though often, but not always, the increase of DNA is caused by an increase in the amount of heterochromatin, i.e. increase of non-coding sections indicating restructuring of the heterochromatin. Thus, cumulative small and direct numerical changes might have played a role in the speciation of Abelmoschus.

Complete chloroplast genomes of three important species, Abelmoschus moschatus, A. manihot and A. sagittifolius: Genome structures, mutational hotspots, comparative and phylogenetic analysis in Malvaceae

“…This genus was previously placed within Hibiscus, and subsequently isolated by taxonomists due to genetic differences [3]. As currently defined, genus Abelmoschus contains 11 species, 4 subspecies and 5 varieties [4], and displays a variable habit, from annual to perennial, herbs to shrubs, and is distributed in Asia, Australia and southwestern Africa [5]. Most members of this genus are economically important plants, and used in agriculture, food and medicines.…”

“…Patil et al found seed coat sculpturing and seed trichomes could be used as the diagnostic characters for many morphologically closely related species of Abelmoschus [5]. Fluorochrome-binding pattern of nine Abelmoschus species showed polyploidy was an important factor in the chromosome number variation and evolution in this genus [4]. Some researchers also used molecular markers to analyze genetic relationships of Abelmoschus, but most studied focused on genetic diversity within A. esculentus and A. manihot [2,7,9,18,19], molecular markers were relatively lacking in other species.…”