Institute of Experimental Botany AS CR
We are Discovering the Plant World

Šafář, Jan; Noa-Carrazana, J. C.; Vrána, Jan; Bartoš, Jan; Alkhimova, Olena; Lheureux, F.; Šimková, Hana; Caruana, M. L.; Doležel, Jaroslav; Piffanelli, P.
GENOME 47: 1182-1191, 2004

Keywords: bacterial artificial chromosome library; banana; BAC-FISH
Abstract: The first bacterial artificial chromosome (BAC) library of the banana species Musa balbisiana žPisang Klutuk WulungŽ (PKW BAC library) was constructed and characterized. One improved and one novel protocol for nuclei isolation were employed to overcome problems caused by high levels of polyphenols and polysaccharides present in leaf tissues. The use of flow cytometry to purify cell nuclei eliminated contamination with secondary metabolites and plastid DNA. Furthermore, the usefulness of the inducible pCC1BAC vector to obtain a higher amount of BAC DNA was demonstrated. The PKW BAC library represents nine haploid genome equivalents of M. balbisiana and its mean insert size is 135 kb. It consists of two sublibraries, of which the first one (SN sublibrary with 24 960 clones) was prepared according to an improved standard nuclei isolation protocol, whereas the second (FN sublibrary with 11 904 clones) was obtained from flow-sorted nuclei. Screening with 12 RFLP probes, which were genetically anchored to 8 genetic linkage groups of the banana species Musa acuminata, revealed an average of 11 BAC clones per probe, thus confirming the genome coverage estimated based on the insert size, as well as a high level of conservation between the two species of Musa. Localization of selected BAC clones to mitotic chromosomes using FISH indicated that the BAC library represented a useful resource for cytogenetic mapping. As the first step in map-based cloning of a genetic factor that is involved in the activation of integrated pararetroviral sequences of Banana streak virus (BSV), the BSV expressed locus (BEL) was physically delimited. The PKW BAC library represents a publicly available tool, and is currently used to reveal the integration and activation mechanisms of BSV sequences and to study banana genome structure and evolution. IEB authors: Jan Bartoš, Jaroslav Doležel, Jan Šafář, Hana Šimková