Characterisation of the double genome structure of modern sugarcane cultivars (Saccharum spp.) by molecular cytogenetics

Abstract

Cultivated sugarcane clones (Saccharum spp., 2n=100 to 130) are derived from complex interspecific hybridizations between the species S. officinarum and S. spontaneum. Using comparative genomic DNA in situ hybridization, we demonstrated that it is possible to distinguish the chromosomes contributed by these two species in an interspecific F1 hybrid and a cultivated clone, R570. In the interspecific F1 studied, we observed n + n transmission of the parental chromosomes instead of the peculiar 2n + n transmission usually described in such crosses. Among the chromosomes of cultivar R570 (2n = 107-115) about 10% were identified as originating from S. spontaneum and about 10% were identified as recombinant chromosomes between the two species S. officinarum and S. spontaneum. This demonstrated for the first time the occurrence of recombination between the chromosomes of these two species. The rDNA sites were located by in situ hybridization in these two species and the cultivar R570. This supported different basic chromosome numbers and chromosome structural differences between the two species and provided a first bridge between physical and genetical mapping in sugarcane.

A Review of Recent Molecular Genetics Evidence for Sugarcane Evolution and Domestication

“…As the region where North Indian and Chinese cultivars are encountered is outside the natural distribution range of S. robustum, the scenario of Brandes provides the simplest explanation of the data: Noble cultivars were transported by man to mainland Asia where they hybridized with local S. spontaneum. It is likely that resulting clones are first-generation hybrids because no -or very few-interspecific chromosome exchanges have been detected with GISH, in contrast with modern cultivars (D'Hont et al, 1996). Owing to mitochondrial haplotypes, it is most likely that, in all cases, Noble clones acted as females and S. spontaneum clones acted as males in founding crosses (D'Hont et al, 1993).…”

Use of simple sequence repeat markers for DNA fingerprinting and diversity analysis of sugarcane (Saccharum spp) cultivars resistant and susceptible to red rot

“…or S. barberi Jesw (Miller et al, 2005). Sugarcane cultivars have a complex, aneuploid and polyploid genome, which contains 100-120 chromosomes (D'Hont et al, 1996). Due to the complex nature of the genome, molecular analysis of sugarcane is not an easy task; however, different molecular techniques have been employed in sugarcane breeding and trait-related marker studies, including random amplified polymorphic DNA (RAPD) for genetic diversity (Harvey and Botha, 1996;Nair et al, 2002;Pan et al, 2003a), amplified fragment length polymorphism (AFLP) for genome mapping and QTL analysis of yield components (Hoarau et al, 2002;Lima et al, 2002), and restriction fragment length polymorphism (RFLP) in genetic diversity and genome complexity (Lu et al, 1994;Jannoo et al, 1999;Silva and Bressiani, 2005).…”

Use of differential levels of mean observed heterozygosity in microsatellite loci of commercial varieties of sugarcane (Saccharum spp)

“…Modern cultivars generally have between 100 and 130 chromosomes (Grivet and Arruda, 2002). In situ hybridization studies have suggested that modern cultivars inherit approximately 80% of their chromosomes entirely from S. officinarum, approximately 10% entirely from S. spontaneum, and approximately 10% as the result of recombination among the remaining ancestral species (D'Hont et al, 1996).…”