Multiple models for Rosaceae genomics

Abstract

The plant family Rosaceae consists of over 100 genera and 3,000 species that include many important fruit, nut, ornamental, and wood crops. Members of this family provide high-value nutritional foods and contribute desirable aesthetic and industrial products. Most rosaceous crops have been enhanced by human intervention through sexual hybridization, asexual propagation, and genetic improvement since ancient times, 4,000 to 5,000 B.C. Modern breeding programs have contributed to the selection and release of numerous cultivars having significant economic impact on the U.S. and world markets. In recent years, the Rosaceae community, both in the United States and internationally, has benefited from newfound organization and collaboration that have hastened progress in developing genetic and genomic resources for representative crops such as apple (Malus spp.), peach (Prunus spp.), and strawberry (Fragaria spp.). These resources, including expressed sequence tags, bacterial artificial chromosome libraries, physical and genetic maps, and molecular markers, combined with genetic transformation protocols and bioinformatics tools, have rendered various rosaceous crops highly amenable to comparative and functional genomics studies. This report serves as a synopsis of the resources and initiatives of the Rosaceae community, recent developments in Rosaceae genomics, and plans to apply newly accumulated knowledge and resources toward breeding and crop improvement.

Figure 1.

Representative rosaceous crops exhibiting diversity of fruit types: A, P. persica, peach, fleshy drupe; B, P. armeniaca, apricot, fleshy drupe; C, M. ×domestica, apple, pome; D, F. ×ananassa, strawberry, achenes; E, R. ×hybrida, rose, achene; F, Pyrus communis, pear, pome; G, P. avium, sweet cherry, fleshy drupe; H, P. domestica, plum, fleshy drupe; I, Rubus idaeus, raspberry, drupelets.

Figure 2.

Phylogenetic tree of Rosaceae, based on the multi-gene analysis by Potter et al. (2007) and modified from their figure 4. Positions of several economically important genera are indicated, and a hypothesis for the evolution of fruit types, based on parsimony optimization of that character, is represented by the different colors of the branches. The three subfamilies recognized by Potter et al. (2007) are shown on the right margin. Dry, Dryadoideae. The tree was rooted with representatives of the family Rhamnaceae (Rh).

Figure 3.

Map comparison between Prunus (Joobeur et al., 1998) and Malus (Maliepaard et al., 1998). Prunus linkage groups are noted with G and Malus groups as L followed by a number. Only linkage groups with two or more common markers have been included. Markers in parenthesis in Prunus correspond to approximate positions deduced from other maps. Incomplete linkage groups are indicated by two parallel oblique lines.