Genome‐Wide Screening for Lectin Motifs in Arabidopsis thaliana

Abstract

For more than three decades, served as a model for plant biology research. At present only a few protein families have been studied in detail in . This study focused on all sequences with lectin motifs in the genome of . Based on amino acid sequence similarity (BLASTp searches), 217 putative lectin genes were retrieved belonging to 9 out of 12 different lectin families. The domain organization and genomic distribution for each lectin family were analyzed. Domain architecture analysis revealed that most of these lectin gene sequences are linked to other domains, often belonging to protein families with catalytic activity. Many protein domains identified are known to play a role in stress signaling and defense, suggesting a major contribution of the putative lectins in development and plant defense. This genome-wide screen for different lectin motifs will help to unravel the functional characteristics of lectins. In addition, phylogenetic trees and WebLogos were created and showed that most lectin sequences that share the same domain architecture evolved together. Furthermore, the amino acids responsible for carbohydrate binding are largely conserved. Our results provide information about the evolutionary relationships and functional divergence of the lectin motifs in .

A glycoform of the secreted purple acid phosphatase AtPAP26 co‐purifies with a mannose‐binding lectin (AtGAL1) upregulated by phosphate‐starved Arabidopsis

“…AtPAP26‐S2 isolated from the CCF of the −Pi cells appeared to be purified to electrophoretic homogeneity following lectin affinity chromatography on Con‐A Sepharose (Figure a). However, peptide mass fingerprinting by MALDI‐TOF MS of the excised 55‐kDa protein‐staining and anti‐AtPAP26 immunoreactive polypeptide obtained following Con‐A chromatography (Figure a) indicated that it was a mixture of AtPAP26 (At5g34850) and a member of Arabidopsis ' GNA (mannose‐binding) lectin family (Eggermont et al, ) encoded by gene loci At1g78850. Phenyl Superose FPLC of the pooled Con‐A fractions resolved a pair of protein peaks that both migrated as 55‐kDa polypeptides following SDS‐PAGE of the respective pooled fractions (Figure b,c); they were identified as At1g78850 and AtPAP26 following MALDI‐TOF MS analysis (Table S4).…”

“…Phenyl Superose FPLC of the pooled Con‐A fractions resolved a pair of protein peaks that both migrated as 55‐kDa polypeptides following SDS‐PAGE of the respective pooled fractions (Figure b,c); they were identified as At1g78850 and AtPAP26 following MALDI‐TOF MS analysis (Table S4). We have designated At1g78850 as AtGAL1 (i.e., G NA A pple L ectin‐ 1 ) because it belongs to the GNA domain lectin family (Eggermont et al, ) and has been annotated as a “D‐mannose binding lectin with an apple‐like carbohydrate‐binding domain” (www.araport.org/search/thalemine/at1g78850).…”

“…The Arabidopsis lectin superfamily is encoded by over 200 genes classified into 12 different families, in which AtGAL1 belongs to the GNA family with 49 members (Eggermont et al, ; Van Damme et al, ). GNA‐related lectins show exclusive specificity towards high‐mannose N‐glycans (Van Damme et al, ).…”

“…Most plant lectins are so‐called “chimerolectins” that contain at least one functional domain in addition to their carbohydrate‐binding domain. Members of the GNA lectin family are no exception because they also contain S‐locus glycoprotein, S‐locus receptor kinase, protein kinase, and/or apple domains (Eggermont et al, ).…”

“…Sequences of Arabidopsis GNA family members (Eggermont, Verstraeten, & Van Damme, ) were obtained from Tair and UniProt and aligned in MUSCLE 3.8 using ClustalW. These were used to construct a maximum likelihood tree in MEGA 7.0 using WAG model with the gamma distributed with invariant sites (G + l) and the partial deletion options.…”