Genomes, diversity and resistance gene analogues in Musa species.

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TitleGenomes, diversity and resistance gene analogues in Musa species.
Publication TypeJournal Article
Year of Publication2008
AuthorsAzhar M, Heslop-Harrison JS
JournalCytogenet Genome Res
Date Published2008
KeywordsAmino Acid Motifs, Base Sequence, Consensus Sequence, DNA, Plant, DNA Primers, Genetic Variation, Genome, Plant, Molecular Sequence Data, Musa, Phylogeny, Plant Diseases, Plant Proteins, Sequence Homology, Amino Acid, Species Specificity

<p>Resistance genes (R genes) in plants are abundant and may represent more than 1% of all the genes. Their diversity is critical to the recognition and response to attack from diverse pathogens. Like many other crops, banana and plantain face attacks from potentially devastating fungal and bacterial diseases, increased by a combination of worldwide spread of pathogens, exploitation of a small number of varieties, new pathogen mutations, and the lack of effective, benign and cheap chemical control. The challenge for plant breeders is to identify and exploit genetic resistances to diseases, which is particularly difficult in banana and plantain where the valuable cultivars are sterile, parthenocarpic and mostly triploid so conventional genetic analysis and breeding is impossible. In this paper, we review the nature of R genes and the key motifs, particularly in the Nucleotide Binding Sites (NBS), Leucine Rich Repeat (LRR) gene class. We present data about identity, nature and evolutionary diversity of the NBS domains of Musa R genes in diploid wild species with the Musa acuminata (A), M. balbisiana (B), M. schizocarpa (S), M. textilis (T), M. velutina and M. ornata genomes, and from various cultivated hybrid and triploid accessions, using PCR primers to isolate the domains from genomic DNA. Of 135 new sequences, 75% of the sequenced clones had uninterrupted open reading frames (ORFs), and phylogenetic UPGMA tree construction showed four clusters, one from Musa ornata, one largely from the B and T genomes, one from A and M. velutina, and the largest with A, B, T and S genomes. Only genes of the coiled-coil (non-TIR) class were found, typical of the grasses and presumably monocotyledons. The analysis of R genes in cultivated banana and plantain, and their wild relatives, has implications for identification and selection of resistance genes within the genus which may be useful for plant selection and breeding and also for defining relationships and genome evolution patterns within the genus using the multi-copy and variable resistance genes.</p>

Alternate JournalCytogenet. Genome Res.
PubMed ID18544928
Showing 14 of 14 accessions
Accession Name Pictures Accession number Species / Group SubSpecies / SubGroup Origin Collection Available for distribution
Musa ornata ITC0370 ornata subsp. ornata Unknown ITC
Schizocarpa ITC1002 schizocarpa Unknown Papua New Guinea ITC
Schizocarpa ITC0852 schizocarpa Unknown Papua New Guinea ITC
Agutay ITC1028 acuminata Unknown Unknown ITC
Calcutta 4 ITC0249 acuminata subsp. burmannicoides Unknown ITC
Musa textilis ITC1072 textilis subsp. textilis Unknown ITC
Malaccensis ITC0250 acuminata subsp. malaccensis Unknown ITC
Paliama ITC0766 acuminata subsp. banksii Unknown ITC
Musa textilis ITC0539 textilis subsp. textilis Unknown ITC
Tani ITC1120 balbisiana Unknown Unknown ITC
Long Tavoy ITC0283 acuminata subsp. burmannica Unknown ITC
Musa velutina ITC0638 velutina subsp. velutina Unknown ITC
Honduras ITC0247 balbisiana Unknown Unknown ITC
Schizocarpa ITC0599 schizocarpa Unknown Papua New Guinea ITC