PCR-RFLP of the ribosomal DNA internal transcribed spacers (ITS) provides markers for the A and B genomes in Musa L.

Abstract

Musa acuminata Colla (AA genomes) and Musa balbisiana Colla (BB genomes) are the diploid ancestors of modern bananas that are mostly diploid or triploid cultivars with various combinations of the A and B genomes, including AA, AAA, BB, AAB and ABB. The objective of this study was to identify molecular markers that will facilitate discrimination of the A and B genomes, based on restriction-site variations in the internal transcribed spacers (ITS) of the nuclear ribosomal RNA genes. The ITS regions of seven M. acuminata and five M. balbisiana accessions were each amplified by PCR using specific primers. All accessions produced a 700-bp fragment that is equivalent in size to the ITS of most plants. This fragment was then digested with ten restriction enzymes ( AluI, CfoI, DdeI, HaeIII, HinfI, HpaII, MspI, RsaI, Sau3AI and TaqI) and fractionated in 2% agarose gels, stained with ethidium bromide and visualized under UV light. The RsaI digest revealed a single 530-bp fragment unique to the A genome and two fragments of 350-bp and 180-bp that were specific to the B genome. A further 56 accessions representing AA, AAA, AAB, AB and ABB cultivars, and synthetic hybrids, were amplified and screened with RsaI. All accessions with an exclusively A genome showed only the 530-bp fragment, while accessions having only the B-genome lacked the 530-bp fragment but had the 350-bp and 180-bp fragments. Interspecific cultivars possessed all three fragments. The staining intensity of the B-genome markers increased with the number of B-genome complements. These markers can be used to determine the genome constitution of Musa accessions and hybrids at the nursery stage, and, therefore, greatly facilitate genome classification in Musa breeding.

SCAR Marker for the A Genome of Bananas (Musa spp. L.) Supports Lack of Differentiation between the A and B Genomes

“…The findings may imply that there is recombination between the A and B genomes. While the implication in previous studies (Heslop-Harrison & Schwarzacher, 2007;Howell, Newbury, Swennen, Whithers, & Ford-Lloyd, 1994;Nwakanma, Pillay, Okoli, & Tenkouano, 2003;Nair, Teo, & Schwarzacher, Heslop-Harisson, 2005) alluded marked differentiation of the A and B genomes, the SC3 primers developed in this study from the A genome do not suggest such a differentiation. Evidence for the lack of complete differentiation of the A and B genomes of banana does exist in the literature (Ortiz & Vuylsteke, 1994;Osuji, Harrison, Crouch, & Heslop-Harrison, 1997;D'Hont, Paget-Goy, Escoute, & Carreel, 2000;Khayat, 2004;Boonruangrod, Desai, Fluch, Berenyi, & Burg, 2008;Jeridi et al, 2011Jeridi et al, , 2012Cizkova et al, 2013;De Jesus et al, 2013).…”

Spore germination and early gametophyte development of Platycerium wandae (Polypodiaceae) from Papua, Indonesia

“…Morphological traits and molecular methods can be used to identify the genomic groups of bananas. Various levels of ploidy and genomic constitution of bananas include diploid (AA, BB, AB; 2n= 2x= 22); triploid (AAA, AAB, ABB; 2n= 3x= 33); and tetraploid (AAAA, AAAB, AABB, ABBB; 2n= 4x= 44) (Simmonds, 1959;Doležel et al 1994;Pillay et al 2000;Valmayor 2000;Daniells et al 2001;Wong et al 2002;Nwakanma et al 2003;De Jesus et al 2013;Hapsari et al 2015b). …”

Variabilidade genética e estimativa da taxa de cruzamento do pinhão manso (Jatropha curcas L.) empregando marcadores moleculares

“…Para que um marcador molecular seja considerado um marcador genético ele deve possuir um comportamento mendeliano, onde os alelos de cada loco segregam na meiose e que os alelos de locos distintos são herdados de forma independente (FERREIRA et al, 2007 A amplificação, restrição e seqüenciamento da região ITS têm sido utilizadas com sucesso para a caracterização da diversidade genética, análises filogenéticas e estudos taxonômicos (HSIAO et al, 1994;AKAGI et al, 1997;CORDEIRO et al, 2003;NWAKANMA et al, 2003;SHU-PING et al, 2007;BECHARA et al, 2010;FUKUNAGA et al, 2011). Para o pinhão manso, Sudheer Pamidimarri et al (2009a) utilizaram sequências do DNA ribossomal (ITS) para analisar filogeneticamente o gênero Jatropha.…”

“…Estudos de comparação da sequência das regiões ITS do rDNA foram utilizados para avaliar as relações filogenéticas em vários níveis taxonômicos e também para descrever a estrutura genética das populações (WHITE et al, 1990;FIGUEIRA et al, 1994;HSIAO et al, 1994;AKAGI et al, 1997;CORDEIRO et al, 2003;NWAKANMA et al, 2003;SHU-PING et al, 2007;SUDHEER PAMIDIMARRI et al, 2009a …”

“…A amplificação, restrição e sequenciamento das regiões ITS têm sido utilizadas para as análises filogenéticas e estudos taxonômicos de espécies como trigo, cana-deaçúcar, arroz, amendoim e painço (HSIAO et al, 1994;AKAGI et al, 1997;CORDEIRO et al, 2003;NWAKANMA et al, 2003;SHU-PING et al, 2007;BECHARA et al, 2010;FUKUNAGA et al, 2011). Para o pinhão manso, Sudheer Pamadimarri et al (2009a) utilizaram sequências do DNA ribossomal (ITS) para estudar filogeneticamente o gênero Jatropha, onde concluíram que as regiões gênicas ribossomais podem contribuir para estudos intra-específicos e biogeográfica, além de abrir caminho para estudos sobre a evolução da família Euphorbiaceae.…”