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Differences in defence responses of Pinus contorta and Pinus banksiana to the mountain pine beetle fungal associate Grosmannia clavigera are affected by water deficit
Author(s) -
ArangoVelez Adriana,
El Kayal Walid,
Copeland Charles C. J.,
Zaharia L. Irina,
Lusebrink Inka,
Cooke Janice E. K.
Publication year - 2016
Publication title -
plant, cell and environment
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.646
H-Index - 200
eISSN - 1365-3040
pISSN - 0140-7791
DOI - 10.1111/pce.12615
Subject(s) - pinus contorta , mountain pine beetle , dendroctonus , biology , botany , xylem , inoculation , woody plant , ophiostoma , bark beetle , horticulture , ecology , curculionidae , fungus
We tested the hypotheses that responses to the mountain pine beetle fungal associate Grosmannia clavigera will differ between the evolutionarily co‐evolved host lodgepole pine ( Pinus contorta var. latifolia ) and the naïve host jack pine ( Pinus banksiana ) and that these responses will be influenced by water availability. G. clavigera inoculation resulted in more rapid stem lesion development in lodgepole than in jack pine; water deficit delayed lesion development in both species. Decreased hydraulic conductivity was observed in inoculated lodgepole pine seedlings, likely because of tracheid occlusion by fungal hyphae and/or metabolite accumulation. Drought but not inoculation significantly impacted bark abscisic acid levels. Jasmonic and salicylic acid were implicated in local and systemic responses of both species to G. clavigera , with salicylic acid appearing to play a greater role in jack pine response to G. clavigera than lodgepole pine. Water deficit increased constitutive levels and/or attenuated induced responses to G. clavigera for several monoterpenes in lodgepole but not jack pine. Instead, inoculation of well‐watered but not water deficit jack pine resulted in a greater number of xylem resin ducts. These findings reveal mechanisms underlying differences in G. clavigera ‐induced responses between lodgepole and jack pine hosts, and how water availability modulates these responses.