@article{b4fbdc1b5b1d46009489e1d55a3375bd,
title = "Combined drought and bark beetle attacks deplete non-structural carbohydrates and promote death of mature pine trees",
abstract = "How carbohydrate reserves in conifers respond to drought and bark beetle attacks are poorly understood. We investigated changes in carbohydrate reserves and carbon-dependent diterpene defences in ponderosa pine trees that were experimentally subjected to two levels of drought stress (via root trenching) and two types of biotic challenge treatments (pheromone-induced bark beetle attacks or inoculations with crushed beetles that include beetle-associated fungi) for two consecutive years. Our results showed that trenching did not influence carbohydrates, whereas both biotic challenges reduced amounts of starch and sugars of trees. However, only the combined trenched-bark beetle attacked trees depleted carbohydrates and died during the first year of attacks. While live trees contained higher carbohydrates than dying trees, amounts of constitutive and induced diterpenes produced did not vary between live and beetle-attacked dying trees, respectively. Based on these results we propose that reallocation of carbohydrates to diterpenes during the early stages of beetle attacks is limited in drought-stricken trees, and that the combination of biotic and abiotic stress leads to tree death. The process of tree death is subsequently aggravated by beetle girdling of phloem, occlusion of vascular tissue by bark beetle-vectored fungi, and potential exploitation of host carbohydrates by bark beetle symbionts as nutrients.",
keywords = "Dendroctonus spp., Pinus ponderosa, diterpene resin acids, soluble sugars, starch, tree increment cores",
author = "Nadir Erbilgin and Leila Zanganeh and Klutsch, {Jennifer G.} and Chen, {Shih hsuan} and Shiyang Zhao and Guncha Ishangulyyeva and Burr, {Stephen J.} and Monica Gaylord and Richard Hofstetter and Ken Keefover-Ring and Raffa, {Kenneth F.} and Thomas Kolb",
note = "Funding Information: Canadian Network for Research and Innovation in Machining Technology, Natural Sciences and Engineering Research Council of Canada; USDA National Institute of Food and Agriculture, Grant/Award Number: 230732 Funding information Funding Information: This field work was supported by McIntire-Stennis Program project accession no. 230732 from the USDA National Institute of Food and Agriculture. John Kaplan, Ansley Roberts, Teresa Reyes and Patrick Dunn provided valuable help in the field; A Roberts and T Reyes were supported by the Hooper Undergraduate Research Program at Northern Arizona University and the National Science Foundation Research Experience for Undergraduates Program, respectively. The Northern Arizona University Centennial Forest provided the study site. NSERC to NE supported all the work at the University of Alberta. Non-structural carbohydrate and diterpene analyses were conducted in Erbilgin lab (https://sites.ualberta.ca/~erbilgin/). Funding Information: This field work was supported by McIntire‐Stennis Program project accession no. 230732 from the USDA National Institute of Food and Agriculture. John Kaplan, Ansley Roberts, Teresa Reyes and Patrick Dunn provided valuable help in the field; A Roberts and T Reyes were supported by the Hooper Undergraduate Research Program at Northern Arizona University and the National Science Foundation Research Experience for Undergraduates Program, respectively. The Northern Arizona University Centennial Forest provided the study site. NSERC to NE supported all the work at the University of Alberta. Non‐structural carbohydrate and diterpene analyses were conducted in Erbilgin lab ( https://sites.ualberta.ca/~erbilgin/ ). Publisher Copyright: {\textcopyright} 2021 John Wiley & Sons Ltd.",
year = "2021",
month = dec,
doi = "10.1111/pce.14197",
language = "English (US)",
volume = "44",
pages = "3636--3651",
journal = "Plant Cell and Environment",
issn = "0140-7791",
publisher = "Wiley-Blackwell",
number = "12",
}