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Description:
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Background: Prunus fruit development, growth, ripening, and senescence includes major
biochemical and sensory changes in texture, color, and flavor. The genetic dissection of these
complex processes has important applications in crop improvement, to facilitate maximizing and
maintaining stone fruit quality from production and processing through to marketing and
consumption. Here we present an integrated fruit quality gene map of Prunus containing 133 genes
putatively involved in the determination of fruit texture, pigmentation, flavor, and chilling injury
resistance.
Results: A genetic linkage map of 211 markers was constructed for an intraspecific peach (Prunus
persica) progeny population, Pop-DG, derived from a canning peach cultivar 'Dr. Davis' and a fresh
market cultivar 'Georgia Belle'. The Pop-DG map covered 818 cM of the peach genome and
included three morphological markers, 11 ripening candidate genes, 13 cold-responsive genes, 21
novel EST-SSRs from the ChillPeach database, 58 previously reported SSRs, 40 RAFs, 23 SRAPs, 14
IMAs, and 28 accessory markers from candidate gene amplification. The Pop-DG map was co-linear
with the Prunus reference T x E map, with 39 SSR markers in common to align the maps. A further
158 markers were bin-mapped to the reference map: 59 ripening candidate genes, 50 coldresponsive
genes, and 50 novel EST-SSRs from ChillPeach, with deduced locations in Pop-DG via
comparative mapping. Several candidate genes and EST-SSRs co-located with previously reported
major trait loci and quantitative trait loci for chilling injury symptoms in Pop-DG.
Conclusion: The candidate gene approach combined with bin-mapping and availability of a
community-recognized reference genetic map provides an efficient means of locating genes of
interest in a target genome. We highlight the co-localization of fruit quality candidate genes with
previously reported fruit quality QTLs. The fruit quality gene map developed here is a valuable tool
for dissecting the genetic architecture of fruit quality traits in Prunus crops. |
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