A total of 34 apple (Malus × domestica Borkh.) cDNA libraries were constructed from root, leaf, bud, shoot, fl ower, and fruit tissues, at various developmental stages and/or under biotic or abiotic stress conditions, and of several genotypes. From these libraries, 190,425 clones were partially sequenced from the 5ʹ end and 42,619 clones were sequenced from the 3ʹ end, and a total of 182,241 high-quality expressed sequence tags (ESTs) were obtained. These coalesced into 23,442 tentative contigs and 9843 singletons, for a total of 33,825 apple unigenes. Functional annotation of this unigene set revealed an even distribution of apple sequences among the three main gene ontology categories. Of ~33,000 apple unigenes, 8437 (25%) had no detectable homologs (E >0.1) in the Arabidopsis genome. When the entire apple unigene set was compared with the entire citrus [Citrus sinensis (L.) Osbeck] unigene set and the poplar (Populus trichocarpa Torr. & Gray) predicted proteome, both members of the core eudicot and rosids clade, 13,521 of apple unigenes matched one or more sequences in citrus, while 25,817 had counterparts in the poplar protein database. Apple-Arabidopsis-citrus-poplar comparisons revealed closer evolutionary relationships between apple and poplar than with the other two species. Genes involved in basic metabolic pathways appear to be largely conserved among apple, citrus, poplar, and Arabidopsis.

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Fullerene C60 nanoparticles are being used in broad range of applications. It is important to assess their potential impacts in the environment. We evaluated the effects of C60 introduced as aqueous suspensions of nC60 aggregates of different particle size or via organic solvents on soils with different organic matter contents in this study. Impacts of the application were evaluated by measuring total microbial biomass, metabolic activity and bacterial community structure. Results show that nC60 aggregates, introduced as an aqueous suspension, had size-dependent effects on soil bacterial community composition in the low organic matter system, but induced minimal change in the microbial biomass and metabolic activity in soils with both high and low organic matter contents. Fullerene C60, co-introduced via an organic solvent, did not influence the response of soil microbes to the organic solvents. Our results suggest that nC60 aggregates of smaller size may have negative impact on soil biota and soil organic matter may play a key role in modulating the environmental effect of nanomaterials.