RESUMEN
BACKGROUND: Pathogen perception by plants is mediated by plasma membrane-localized immune receptors that have varied extracellular domains. Lectin receptor kinases (LecRKs) are among these receptors and are subdivided into 3 classes, C-type LecRKs (C-LecRKs), L-type LecRKs (L-LecRKs) and G-type LecRKs (G-LecRKs). While C-LecRKs are represented by one or two members in all plant species investigated and have unknown functions, L-LecRKs have been characterized in a few plant species and have been shown to play roles in plant defense against pathogens. Whereas Arabidopsis G-LecRKs have been characterized, this family of LecRKs has not been studied in tomato. RESULTS: This investigation updates the current characterization of Arabidopsis G-LecRKs and characterizes the tomato G-LecRKs, using LecRKs from the monocot rice and the basal eudicot columbine to establish a basis for comparisons between the two core eudicots. Additionally, revisiting parameters established for Arabidopsis nomenclature for LecRKs is suggested for both Arabidopsis and tomato. Moreover, using phylogenetic analysis, we show the relationship among and between members of G-LecRKs from all three eudicot plant species. Furthermore, investigating presence of motifs in G-LecRKs we identified conserved motifs among members of G-LecRKs in tomato and Arabidopsis, with five present in at least 30 of the 38 Arabidopsis members and in at least 45 of the 73 tomato members. CONCLUSIONS: This work characterized tomato G-LecRKs and added members to the currently characterized Arabidopsis G-LecRKs. Additionally, protein sequence analysis showed an expansion of this family in tomato as compared to Arabidopsis, and the existence of conserved common motifs in the two plant species as well as conserved species-specific motifs.
Asunto(s)
Proteínas de Arabidopsis/clasificación , Arabidopsis/enzimología , Proteínas de Plantas/clasificación , Proteínas Quinasas/clasificación , Receptores de Superficie Celular/clasificación , Solanum lycopersicum/enzimología , Secuencias de Aminoácidos , Aquilegia/enzimología , Aquilegia/genética , Arabidopsis/genética , Proteínas de Arabidopsis/química , Proteínas de Arabidopsis/genética , Proteínas de Arabidopsis/metabolismo , Dominio Catalítico , Mapeo Cromosómico , Solanum lycopersicum/genética , Familia de Multigenes , Oryza/enzimología , Oryza/genética , Filogenia , Proteínas de Plantas/química , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Proteínas Quinasas/química , Proteínas Quinasas/genética , Proteínas Quinasas/metabolismo , Receptores de Superficie Celular/química , Receptores de Superficie Celular/genética , Receptores de Superficie Celular/metabolismo , Terminología como AsuntoRESUMEN
We have isolated a cDNA encoding the Delta(8) sphingolipid desaturase from the plant Aquilegia vulgaris L. via a PCR-based strategy using primers designed to target the conserved histidine box regions of microsomal desaturases. The function of the cDNA was confirmed by expression in the yeast, Saccharomyces cerevisiae. Analysis of the long-chain sphingoid bases as their dinitrophenyl derivatives by reverse-phase HPLC demonstrated the accumulation of cis - and trans -desaturated sphingoid bases which were not present in the wild-type yeast cells. The Delta(8) desaturated products co-eluted with known Delta(8)-desaturated phytosphingenine and the molecular mass of these products was confirmed by liquid chromatography-MS. The Delta(8) long-chain base desaturase was also able to desaturate dihydrosphingosine substrates. This is the first report of the functional characterization of an A. vulgaris gene product.
