title: Histology and cell wall biochemistry of stone cells in the physical defence of conifers against insects.
abstract: Conifers possess an array of physical and chemical defences against stem-boring insects. Stone cells provide a physical defence associated with resistance against bark beetles and weevils. In Sitka spruce (Picea sitchensis), abundance of stone cells in the cortex of apical shoots is positively correlated with resistance to white pine weevil (Pissodes strobi). We identified histological, biochemical and molecular differences in the stone cell phenotype of weevil resistant (R) or susceptible (S) Sitka spruce genotypes. R trees displayed significantly higher quantities of cortical stone cells near the apical shoot node, the primary site for weevil feeding. Lignin, cellulose, xylan and mannan were the most abundant components of stone cell secondary walls, respectively. Lignin composition of stone cells isolated from R trees contained a higher percentage of G-lignin compared with S trees. Transcript profiling revealed higher transcript abundance in the R genotype of coumarate 3-hydroxylase, a key monolignol biosynthetic gene. Developing stone cells in current year apical shoots incorporated fluorescent-tagged monolignol into the secondary cell wall, while mature stone cells of previous year apical shoots did not. Stone cell development is an ephemeral process, and fortification of shoot tips in R trees is an effective strategy against insect feeding.
authors.affiliation: Michael Smith Laboratories, University of British Columbia, 2185 East Mall, Vancouver, BC, Canada, V6T 1Z4.
authors.forename: Justin G A
authors.initials: JG
authors.lastname: Whitehill
authors.affiliation: Michael Smith Laboratories, University of British Columbia, 2185 East Mall, Vancouver, BC, Canada, V6T 1Z4.
authors.forename: Hannah
authors.initials: H
authors.lastname: Henderson
authors.affiliation: Department of Botany, University of British Columbia, 6270 University Boulevard, Vancouver, BC, Canada, V6T 1Z4.
authors.forename: Mathias
authors.initials: M
authors.lastname: Schuetz
authors.affiliation: Department of Wood Science, University of British Columbia, 2424 Main Mall, Vancouver, BC, Canada, V6T 1Z4.
authors.forename: Oleksandr
authors.initials: O
authors.lastname: Skyba
authors.affiliation: Michael Smith Laboratories, University of British Columbia, 2185 East Mall, Vancouver, BC, Canada, V6T 1Z4.
authors.forename: Macaire Man Saint
authors.initials: MM
authors.lastname: Yuen
authors.affiliation: British Columbia Ministry of Forests, Lands, and Natural Resource Operations, Victoria, BC, Canada, V8W 9C2.
authors.forename: John
authors.initials: J
authors.lastname: King
authors.affiliation: Department of Botany, University of British Columbia, 6270 University Boulevard, Vancouver, BC, Canada, V6T 1Z4.
authors.forename: A Lacey
authors.initials: AL
authors.lastname: Samuels
authors.affiliation: Department of Wood Science, University of British Columbia, 2424 Main Mall, Vancouver, BC, Canada, V6T 1Z4.
authors.forename: Shawn D
authors.initials: SD
authors.lastname: Mansfield
authors.affiliation: Michael Smith Laboratories, University of British Columbia, 2185 East Mall, Vancouver, BC, Canada, V6T 1Z4.|Department of Botany, University of British Columbia, 6270 University Boulevard, Vancouver, BC, Canada, V6T 1Z4.|Department of Forest and Conservation Sciences, University of British Columbia, 2424 Main Mall, Vancouver, BC, Canada, V6T 1Z4.
authors.forename: Jörg
authors.initials: J
authors.lastname: Bohlmann
mesh_terms: D000818:Animals; D050260:Carbohydrate Metabolism; D002473:Cell Wall / Q000378:metabolism*; D005838:Genotype; D060434:Herbivory; D008031:Lignin / Q000096:biosynthesis; D010641:Phenotype; D028222:Picea / Q000235:genetics / Q000378:metabolism / Q000648:ultrastructure*; D048889:Weevils
chemical_list: D008031:Lignin
keywords: bark beetle; fluorescent-tagged coniferyl alcohol; lignin; plant insect interaction; plant resistance; secondary cell wall; spruce