Organization and diversity of resistance genes in Musa sp. genome with respect to disease resistance and biotic stress

Azhar Mohamad am214(a) and Pat Heslop-Harrison

Bananas and plantains ( Musa sp.) are very important crops and the largest perennial herbs in tropical and subtropical regions for food but their taxonomic complexity has never been fully resolved and understood, and only now are we starting to understand their complement of genes.

Azhar Mohamad is a Ph.D. student under the supervision of Prof Pat J.S. Heslop Harrison. Currently, he works as researcher at Malaysian Institute for Nuclear Technology Research (MINT) , MALAYSIA. His research work is related to plant disease resistance genes (R-genes) in Musa sp. that encode proteins with leucine rich repeats (LRR) and nucleotide binding site (NBS) domains. These domain clusters consist of TIR domain (homology to Drosophila Toll and mammalian Interleukin-1 receptor), coiled-coil (CC) structure near the N terminus (sometimes form of leucine zipper-LZ) and/or trans-membrane protein (TM) and believed participates in signalling transduction for primarily elicitor recognition.

Our objectives are to design degenerate oligo PCR primers which can be used as COS (conserved orthologue synteny) markers to isolate, characterize and understand diversity and evolution of TIR, CC, LRR, NBS-LRR motifs which might lead us to their important roles in the plant resistance genes. As genomes of all eukaryotic species consist of single-copy, middle repetitive and high copy number sequences, hybridization blots of plant DNA and fluorescent in situ hybridization will help to understand the pattern, structure, organization and distribution of the genes in plant genomes. The sequences will be used to study dispersion in BAC clones and expected to give important information for understanding the marker systems and making further assessment of plant genome evolution especially for resistance genes.

These studies are important to identify the nature and diversity of the resistance gene domains in Musa and to look at their evolutionary and functional relationships across the sequences in the MIPS-Sputnik EST database available through Musa Genomic Consortium and genomic clones from diploid A, B genome and hybrids of Musa accessions.

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