|Bartoszewski, Grzegorz - UNIV OF WISCONSIN|
|Lilly, Jason - BOYCE THOMPSON INST, NY|
|Malepszy, Stefan - WARSAW AG UNIV, POLAND|
Submitted to: Cucurbitaceae Proceedings
Publication Type: Proceedings
Publication Acceptance Date: July 12, 2002
Publication Date: December 15, 2002
Citation: Bartoszewski, G., Lilly, J.W., Malepszy, S., Havey, M.J. 2002. Rearrangements in the cucumber mitochondrial genome associated with the msc phenotype. Cucurbitaceae Proceedings. Technical Abstract: The mitochondrial genome of cucumber is unique because of its huge size and paternal transmission. Passage of cucumber through tissue culture produces plants with a strong mosaic (MSC) phenotype on cotyledons and leaves. Independent MSC mutant lines have been produced after passage through tissue culture and regeneration. The genetic bases of these MSC mutant lines are unknown. Hybridizations of 15 cosmids covering the entire mitochondrial genome of Arabidopsis thaliana to DNAs of MSC16, wild type cucumbers, and two wild-type lines lines derived from the same tissue culture experiment that produced MSC16 were completed. Two rearrangements were revealed near the rrn5/rrn18 and nad5-exon2 coding regions. However these two changes were found in the wild type tissue culture derived lines and were not associated with the MSC phenotype. We identified a 16-kb deletion (JLV5-DEL) in the mitochondrial genome shared among three independently derived MSC lines. We isolated and sequenced a genomic clone from MSC16 carrying the front junction of this deleted region. A rearrangement likely caused the deletion and placed an rpl5 coding region adjacent to the front junction of the deletion. Northern analyses revealed numerous rpl5 transcripts; one transcript of 7.5 kb was present in wild-type cucumber and almost absent in MSC16 line. Two wild-type lines derived from the same tissue culture experiment that produced MSC16 possessed different DNA next to the junction point. Therefore, the rearrangement involving the rpl5 gene and the JLV5 deletion is strongly associated with the MSC phenotype.