Versatility of germin-like proteins in their sequences, expressions, and functions

Abstract

Germin-like proteins (GLPs) are evolutionary conserved ubiquitous plant glycoproteins belonging to the cupin superfamily. A large number of GLP family members have been identified from different higher and lower plant species, and those have been classified into different subfamilies. Although three histidine residues (H) and one glutamate residue (E) in germin box B and C were conserved among all the GLP subfamily members, how the sequences of one subfamily member differ from the other is unclear. Progress in the field of genomics, transcriptomics, and proteomics has made it possible to understand the variation at gene level among different GLP members from diverse genera and also their biological significances. GLPs from different plant species were found to have various enzymatic properties including oxalate oxidase (OxO), superoxide dismutase (SOD), ADP glucose pyrophosphatase/phosphodiesterase (AGPPase), and polyphenol oxidase (PPO) activities. 'Omics' study demonstrated the expression as well as involvement of GLP family members in almost every part of higher plants as well as in lower plants. Additionally, GLPs from different species were reported to be involved in biotic as well as abiotic stresses and also in the growth and development. This review describes the present research status of GLPs from different plant species, their expressions, and functional significances. Sequence variation was detected among GLP subfamily members at the amino acid level, and based on the sequence variation and phylogenetic analyses, two new GLP subfamilies have been proposed in this review.

In silico analysis of transcription factor binding sites in promoters of germin-like protein genes in rice

“…GERs and GLPs constitute a diverse and ubiquitous families of plant glycoproteins known as the cupin superfamily which is involved in many developmental and stress related processes [2]. They possess a single or combination of enzymatic activities, including oxalate oxidase (OXO), superoxide dismutase (SOD), ADP glucose pyrophosphatase/phosphodiesterase (AGPPase) and polyphenol oxidase (PPO), which either act as structural proteins or participate in signal transduction through their receptor function [3]. A GLP from wheat leaf apoplast was reported for its ability to in-hibit serine protease [4].…”

Narrow-Leafed Lupin (Lupinus angustifolius) β1- and β6-Conglutin Proteins Exhibit Antifungal Activity, Protecting Plants against Necrotrophic Pathogen Induced Damage from Sclerotinia sclerotiorum and Phytophthora nicotianae

“…Identified from germinating wheat embryos, the wheat germin protein exhibits oxalate oxidase activity, catalyzing the conversion of oxalates (the conjugate base of oxalic acid) into CO 2 and H 2 O 2 (Woo et al, 2000; Pan et al, 2007). Other enzymatic properties of germins or germin-like proteins include superoxide dismutase (SOD) activity, ADP glucose pyrophosphatase/phosphodiesterase activity or polyphenol oxidase (PPO) activity (reviewed in Barman and Banerjee, 2015). Over-expression of germin in several plant species can lead to increased resistance to fungal pathogens such as S. sclerotiorum (Donaldson et al, 2001; Dong et al, 2008; Walz et al, 2008), and the over-expression of a germin-like oxalate oxidase in rice or sunflowers lead to increased resistance, respectively, against R. solani (Molla et al, 2013) or both R. solani and S. sclerotiorum (Beracochea et al, 2015).…”

Identification of a xylem sap germin-like protein and its expression under short-day and non-freezing low-temperature conditions in poplar root

“…The bold characters indicate the cupin conserved domain according to the Pfam website. Using the Clustal W software, the sequence was aligned with the closest homologs in cotton, grapevine and Arabidopsis (GrGLP14: gi823124638, VvGER3: gi526118118, AtGLP9: gi15233510), belonging to the GER 7 clade, and with wheat oxalate oxidase (TaGermin GF-2.8: gi121129), belonging to the GER 1 clade, in the germin-like protein family (Barman and Banerjee 2015). Identical amino acid residues are indicated by asterisks, strongly similar sequences by two dots, and weakly similar sequences by one dot.…”

“…GLPs are functionally and taxonomically diverse (Dunwell et al 2008). The GLP with high sequence similarity to PtXSP24 belongs to the GER 7 clade of the GLP family (Barman and Banerjee 2015). The closest homologs in cotton, grapevine and Arabidopsis (GrGLP14: gi823124638, VvGER3: gi526118118, AtGLP9: gi15233510), which belong to the GER 7 clade, and wheat oxalate oxidase (TaGermin GF-2.8: gi121129), which belongs to the GER 1 clade, were aligned using the ClustalW software ( Figure 1B).…”

“…PtXSP24, which belongs to the GER 7 subfamily of GLP, has homologs in cotton, grapevine and Arabidopsis (GrGLP14, VvGER3 and AtGLP9, respectively) (Barman and Banerjee 2015). Although wheat germin was originally found to have oxalate oxidase activity (Lane et al 1993), it was revealed to be a bifunctional enzyme, which also exhibits superoxide dismutase activity (Dunwell et al 2008;Woo et al 2000).…”