Utility of blueberry-derived EST-PCR primers in related Ericaceae species

Expressed sequence tag-polymerase chain reaction (EST-PCR) markers for DNA fingerprinting and mapping in blueberry (Vaccinium sp.) had previously been developed from expressed sequence tags (ESTs) produced from a cDNA library, derived from RNA from floral buds of cold acclimated plants. Because EST-PCR markers are derived from gene coding regions, they are more likely to be conserved across populations and species than markers derived from random regions of DNA, such as randomly amplified polymorphic DNA (RAPD) or amplified fragment length polymorphism (AFLP) markers. In this study, we tested whether many of the EST-PCR primer pairs developed for blueberry are capable of amplifying DNA fragments in other members of the family Ericaceae. In addition, we cloned and sequenced a selection of 13 EST-PCR fragments to determine if they showed homology to the original blueberry cDNA clones from which the EST-PCR primer pairs were derived. Closely related cranberry genotypes (two wild selections of V. oxycoccus L. and two cultivars of V. macrocarpon Aiton, 'Early Black' and 'Stevens') and more distantly related rhododendron genotypes (one wild selection each of Rhododendron arboreum Marsh, R. maximum L., and R. ponticum L. and three complex species hybrids, 'Sonata', 'Grumpy Yellow', and 'Roseum elegans') were used. Of 26 primer pairs tested in cranberry, 23 (89%) resulted in successful amplification and eight of those (35%) amplified polymorphic fragments among the cranberry genotypes. Of 39 primer pairs tested in rhododendron, 29 (74%) resulted in successful amplification and 21 of those (72%) amplified polymorphic fragments among the rhododendron genotypes. Approximately 50% of the 13 sequenced EST-PCR fragments were found to be homologous to the original blueberry cDNA clones. These markers should be useful for DNA fingerprinting, mapping, and assessing genetic diversity within cranberry and rhododendron species. The markers which are shown to be homologous to the blueberry cDNA clones by DNA sequencing should also be useful for comparative mapping and genetic diversity studies between some genera of the family Ericaceae.