Plant & Animal Genomes XIV Conference

January 14-18, 2006
Town & Country Convention Center
San Diego, CA

Unique Mitochondrial Genetics Of Cucumis

Michael J Havey¹ , Grzegorz Bartoszewski² , Jason Lilly¹ , Young Hoon Park¹ , Stefan Malepszy²

¹  USDA-ARS and Department of Horticulture, University of Wisconsin, Madison, WI 53706 USA

²  Department of Plant Genetics, Breeding and Biotechnology, Warsaw Agricultural University, 02-787 Warsaw, Poland

The Cucumis mitochondrial (mt) genome is unique for its enormous size and paternal transmission. Recombination among inverted and direct repeats in the cucumber mt DNA produce paternally transmitted mosaic (MSC) phenotypes with altered mt gene expression. We used MSC to reveal phenotypic variation affecting mitochondrial-genome transmission in cucumber. Plant Introductions of cucumber were crossed as the female with MSC16. Wild-type F1 progenies were observed at high frequencies in F1 families from 10 PIs, with the greatest proportions being from PI 401734. Polymorphisms near the mitochondrial cox1 gene and JLV5 region revealed that wild-type hybrid progenies possessed the wild-type mt DNA from the male parent. F2, F3, and backcross progenies from non-mosaic F1 plants from PI 401734 x MSC16 were testcrossed with MSC16 as the male parent to reveal segregation of a nuclear locus (Psm for Paternal sorting of mitochondria) controlling sorting of mitochondrial DNA from the paternal parent. Psm is a unique locus at which the maternal genotype conditions sorting of paternally transmitted mitochondrial DNA.