A Small Cellulose-Binding-Domain Protein (CBD1) in Phytophthora is Highly Variable in the Non-binding Amino Terminus

Abstract

The small cellulose-binding-domain protein CBD1 is tightly bound to the cellulosic cell wall of the plant pathogenic stramenopile Phytophthora infestans. Transgene expression of the protein in potato plants also demonstrated binding to plant cell walls. A study was undertaken using 47 isolates of P. infestans from a worldwide collection, along with 17 other Phytophthora species and a related pathogen Plasmopara halstedii, to determine if the critical cell wall protein is subject to amino acid variability. Within the amino acid sequence of the secreted portion of CBD 1, encoded by the P. infestans isolates, 30 were identical with each other, and with P. mirabilis. Four isolates had one amino acid difference, each in a different location, while one isolate had two amino acid substitutions. The remaining 13 isolates had five amino acid changes that were each in identical locations (D17/G, D31/G, I32/S, T43/A, and G50/A), suggesting a single origin. Comparison of P. infestans CBD1 with other Phytophthora species identified extensive amino acid variation among the 60 amino acids at the amino terminus of the protein, and a high level of conservation from G61, where the critical cellulose-binding domain sequences begin, to the end of the protein (L110). While the region needed to bind to cellulose is conserved, the region that is available to interact with other cell wall components is subject to considerable variation, a feature that is evident even in the related genus Plasmopara. Specific changes can be used in determining intra- and inter-species relatedness. Application of this information allowed for the design of species-specific primers for PCR detection of P. infestans and P. sojae, by combining primers from the highly conserved and variable regions of the CBD1 gene.Electronic supplementary materialThe online version of this article (doi:10.1007/s00284-017-1315-x) contains supplementary material, which is available to authorized users.

Phage‐based technologies for highly sensitive luminescent detection of foodborne pathogens and microbial toxins: A review

“…Endolysin can then pass through these pores to reach the cell wall (Roach & Donovan, 2015; Yan et al., 2019). Endolysin encoded by a Gram‐positive bacterial DNA phage includes a highly conserved N‐terminal domain (catalytic domain) that determines the catalytic activity of the enzyme and a variable C‐terminal domain (cell‐binding domain) that determines the cell binding site (Jones & Perez, 2017; Loessner, 2005; Santos et al., 2019; Sim et al., 2017). Most catalytic domains utilize N‐acetylmuramyl‐ l alanine amidase (abbreviated as amidase) to interact with carbohydrate residues on peptidoglycans, especially N‐acetylglucosamine (GlcNAc) residues at C4 of the polyphosphate ribose phosphoric subunit (Lenz et al., 2016).…”