Expression and beta-glucan binding properties of Scots pine (Pinus sylvestris L.) antimicrobial protein (Sp-AMP)
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Expression and beta-glucan binding properties of Scots pine (Pinus sylvestris L.) antimicrobial protein (Sp-AMP). / Sooriyaarachchi, Sanjeewani; Jaber, Emad; Covarrubias, Adrian Suárez; Ubhayasekera, Wimal; Asiegbu, Frederick O; Mowbray, Sherry L.
In: Plant Molecular Biology, Vol. 77, No. 1-2, 17.05.2011, p. 33-45.Research output: Contribution to journal › Journal article › Research › peer-review
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TY - JOUR
T1 - Expression and beta-glucan binding properties of Scots pine (Pinus sylvestris L.) antimicrobial protein (Sp-AMP)
AU - Sooriyaarachchi, Sanjeewani
AU - Jaber, Emad
AU - Covarrubias, Adrian Suárez
AU - Ubhayasekera, Wimal
AU - Asiegbu, Frederick O
AU - Mowbray, Sherry L
N1 - Keywords: antimicrobial protein, Heterobasidion annosum, beta-(1,3)-glucan, chitin, inhibition, binding, homology modeling, Pinus sylvestris
PY - 2011/5/17
Y1 - 2011/5/17
N2 - Scots pine (Pinus sylvestris) secretes a number of small, highly-related, disulfide-rich proteins (Sp-AMPs) in response to challenges with fungal pathogens such as Heterobasidion annosum, although their biological role has been unknown. Here, we examined the expression patterns of these genes, as well as the structure and function of the encoded proteins. Northern blots and quantitative real time PCR showed increased levels of expression that are sustained during the interactions of host trees with pathogens, but not non-pathogens, consistent with a function in conifer tree defenses. Furthermore, the genes were up-regulated after treatment with salicylic acid and an ethylene precursor, 1-aminocyclopropane-1-carboxylic-acid, but neither methyl jasmonate nor H(2)O(2) induced expression, indicating that Sp-AMP gene expression is independent of the jasmonic acid signaling pathways. The cDNA encoding one of the proteins was cloned and expressed in Pichia pastoris. The purified protein had antifungal activity against H. annosum, and caused morphological changes in its hyphae and spores. It was directly shown to bind soluble and insoluble ß-(1,3)-glucans, specifically and with high affinity. Furthermore, addition of exogenous glucan is linked to higher levels of Sp-AMP expression in the conifer. Homology modeling and sequence comparisons suggest that a conserved patch on the surface of the globular Sp-AMP is a carbohydrate-binding site that can accommodate approximately four sugar units. We conclude that these proteins belong to a new family of antimicrobial proteins (PR-19) that are likely to act by binding the glucans that are a major component of fungal cell walls.
AB - Scots pine (Pinus sylvestris) secretes a number of small, highly-related, disulfide-rich proteins (Sp-AMPs) in response to challenges with fungal pathogens such as Heterobasidion annosum, although their biological role has been unknown. Here, we examined the expression patterns of these genes, as well as the structure and function of the encoded proteins. Northern blots and quantitative real time PCR showed increased levels of expression that are sustained during the interactions of host trees with pathogens, but not non-pathogens, consistent with a function in conifer tree defenses. Furthermore, the genes were up-regulated after treatment with salicylic acid and an ethylene precursor, 1-aminocyclopropane-1-carboxylic-acid, but neither methyl jasmonate nor H(2)O(2) induced expression, indicating that Sp-AMP gene expression is independent of the jasmonic acid signaling pathways. The cDNA encoding one of the proteins was cloned and expressed in Pichia pastoris. The purified protein had antifungal activity against H. annosum, and caused morphological changes in its hyphae and spores. It was directly shown to bind soluble and insoluble ß-(1,3)-glucans, specifically and with high affinity. Furthermore, addition of exogenous glucan is linked to higher levels of Sp-AMP expression in the conifer. Homology modeling and sequence comparisons suggest that a conserved patch on the surface of the globular Sp-AMP is a carbohydrate-binding site that can accommodate approximately four sugar units. We conclude that these proteins belong to a new family of antimicrobial proteins (PR-19) that are likely to act by binding the glucans that are a major component of fungal cell walls.
KW - Former Faculty of Pharmaceutical Sciences
U2 - 10.1007/s11103-011-9791-z
DO - 10.1007/s11103-011-9791-z
M3 - Journal article
C2 - 21584858
VL - 77
SP - 33
EP - 45
JO - Plant Molecular Biology
JF - Plant Molecular Biology
SN - 0167-4412
IS - 1-2
ER -
ID: 33874950