Homology-guided re-annotation improves the gene models of the alloploid Nicotiana benthamiana

Abstract

Nicotiana benthamiana is an important model organism and representative of the Solanaceae (Nightshade) family. N. benthamiana has a complex ancient allopolyploid genome with 19 chromosomes, and an estimated genome size of 3.1Gb. Several draft assemblies of the N. benthamiana genome have been generated, however, many of the gene-models in these draft assemblies appear incorrect. Here we present a nearly non-redundant database of 42,855 improved N. benthamiana gene-models. With an estimated 97.6% completeness, the new predicted proteome is more complete than the previous proteomes. We show that the database is more sensitive and accurate in proteomics applications, while maintaining a reasonable low gene number. As a proof-of-concept we use this proteome to compare the leaf extracellular (apoplastic) proteome to a total extract of leaves. Several gene families are more abundant in the apoplast. For one of these apoplastic protein families, the subtilases, we present a phylogenetic analysis illustrating the utility of this database. Besides proteome annotation, this database will aid the research community with improved target gene selection for genome editing and off-target prediction for gene silencing.