Poster: Vegetative development

Abs # 322: Sequencing and Analysis of the Peach EVG Locus

Presenter:	Bielenberg, Douglas G., dbielen@clemson.edu
Authors	Bielenberg, Douglas G. (A)   Wang, Ying  (A)   Reighard, Gregory L (A)   Scorza, Ralph  (C)   Abbott, Albert G (B)
Affiliations:	(A): Horticulture, Clemson University (B): Genetics, Biochemistry & Life Science Studies, Clemson University (C): Genetic Improvement of Fruit Crops, Appalachian Fruit Research Station

'Evergrowing' (EVG) peach is one of only two described mutants affecting winter dormancy in woody perennial trees. The 'Evergrowing' peach mutant does not set terminal buds, cease new leaf growth, or enter into a dormant resting phase in response to winter conditions. The EVG mutation segregates as a single recessive gene, and we previously created a local genetic linkage map around EVG using AFLP and SSR markers. Here we report the physical mapping, sequencing, and analysis of a 55-kb region of the EVG locus. A physical map of the EVG region was created using a bacterial artificial chromosome (BAC) library. Two SSR markers that flank the EVG locus, pchgms40 and pchgms41, were isolated from a single BAC clone. This BAC was completely sequenced by the use of a transposon insertion system in combination with direct BAC sequencing and primer walking through overlapping subclones. Sequence analysis of this BAC predicted a number of putative genes. Six of these putative genes were represented by a cluster of tandem duplicated MADS-box transcription factors similar to those involved in the vernalization pathways of Arabidopsis. Additionally there is a Ca²⁺ binding protein of unknown function. Other potential open reading frames in the region did not have homology to known proteins. Our initial Southern analyses suggested that the EVG mutation is a substantial (>40 kb) deletion of a region that contains multiple gene candidates for the EVG mutation. The deletion was bracketed using RFLP analysis and this analysis showed that the deletion is contained within a segment of the genome no greater than 120 kb.