Molecular and phylogenetic characterization of the sieve element occlusion gene family in Fabaceae and non-Fabaceaeplants

BMC Plant Biology

Research Article

Gundula A Noll¹  Steffen Nordzieke¹  Stephan B Jekat²  Boris Rüping²  Boje Müller²  Antonia M Ernst²  Dirk Prüfer²  Anna R Reineke³  Erich Bornberg-Bauer³ 

[1] Institut für Biochemie und Biotechnologie der Pflanzen, Westfälische Wilhelms-Universität Münster, D-48143, Hindenburgplatz 55, Münster, Germany;Institut für Biochemie und Biotechnologie der Pflanzen, Westfälische Wilhelms-Universität Münster, D-48143, Hindenburgplatz 55, Münster, Germany;Fraunhofer Institute for Molecular Biology and Applied Ecology (IME), D-52074, Forckenbeckstraße 6, Aachen, Germany;Institut für Evolution und Biodiversität, Westfälische Wilhelms-Universität Münster, D-48149, Hüfferstraße 1, Münster, Germany;

关键词: Sieve Element;    Conserve Domain Database;    Genome Duplication Event;    Sieve Plate;    Genomic Synteny;   

DOI  :  10.1186/1471-2229-10-219

 received in 2010-01-15, accepted in 2010-10-08,  发布年份 2010

来源: Springer

【 摘 要 】

BackgroundThe phloem of dicotyledonous plants contains specialized P-proteins (phloem proteins) that accumulate during sieve element differentiation and remain parietally associated with the cisternae of the endoplasmic reticulum in mature sieve elements. Wounding causes P-protein filaments to accumulate at the sieve plates and block the translocation of photosynthate. Specialized, spindle-shaped P-proteins known as forisomes that undergo reversible calcium-dependent conformational changes have evolved exclusively in the Fabaceae. Recently, the molecular characterization of three genes encoding forisome components in the model legume Medicago truncatula (MtSEO1, MtSEO2 and MtSEO3; SEO = sieve element occlusion) was reported, but little is known about the molecular characteristics of P-proteins in non-Fabaceae.ResultsWe performed a comprehensive genome-wide comparative analysis by screening the M. truncatula, Glycine max, Arabidopsis thaliana, Vitis vinifera and Solanum phureja genomes, and a Malus domestica EST library for homologs of MtSEO1, MtSEO2 and MtSEO3 and identified numerous novel SEO genes in Fabaceae and even non-Fabaceae plants, which do not possess forisomes. Even in Fabaceae some SEO genes appear to not encode forisome components. All SEO genes have a similar exon-intron structure and are expressed predominantly in the phloem. Phylogenetic analysis revealed the presence of several subgroups with Fabaceae-specific subgroups containing all of the known as well as newly identified forisome component proteins. We constructed Hidden Markov Models that identified three conserved protein domains, which characterize SEO proteins when present in combination. In addition, one common and three subgroup specific protein motifs were found in the amino acid sequences of SEO proteins. SEO genes are organized in genomic clusters and the conserved synteny allowed us to identify several M. truncatula vs G. max orthologs as well as paralogs within the G. max genome.ConclusionsThe unexpected occurrence of forisome-like genes in non-Fabaceae plants may indicate that these proteins encode species-specific P-proteins, which is backed up by the phloem-specific expression profiles. The conservation of gene structure, the presence of specific motifs and domains and the genomic synteny argue for a common phylogenetic origin of forisomes and other P-proteins.

【 授权许可】

Unknown   
© Rüping et al; licensee BioMed Central Ltd. 2010. This article is published under license to BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.