文献类型：期刊文献

英文题名：Fungal pathogens of canker disease trigger canopy dieback in poplar saplings by inducing functional failure of the phloem and cambium and carbon starvation in the xylem

作者：Xing, Junchao[1] Li, Ping[1] Zhang, Yinan[1] Li, Jinxin[1] Liu, Ya[2] Lachenbruch, Barbara[3] Su, Xiaohua[4] Zhao, Jiaping[1]

第一作者：Xing, Junchao

通信作者：Zhao, JP[1];Su, XH[2]|[a0005bccc5d7b21323380]赵嘉平;

机构：[1]Chinese Acad Forestry, Forestry Inst New Technol, State Key Lab Tree Genet & Breeding, Beijing, Peoples R China;[2]Chinese Acad Forestry, Res Inst Forest Ecol Environm & Protect, Beijing, Peoples R China;[3]Oregon State Univ, Dept Forest Ecosyst & Soc, Corvallis, OR 97331 USA;[4]Chinese Acad Forestry, Res Inst Forestry, State Key Lab Tree Genet & Breeding, Beijing, Peoples R China

年份：2020

卷号：112

外文期刊名：PHYSIOLOGICAL AND MOLECULAR PLANT PATHOLOGY

收录：;Scopus(收录号：2-s2.0-85089509552);WOS:【SCI-EXPANDED(收录号:WOS:000591329500003)】；

基金：This work was supported by Central Public-interest Scientific Institution Basal Research Fund of China (CAFYBB2014MA012 and CAFYBB2018ZY001-6 to JZ) and USDA National Institute of Food and Agriculture, McIntire Stennis project, (1002808 to BL). The funders have no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.

语种：英文

外文关键词：Poplar canker diseases; Gas exchange; Non-structural carbohydrates; Girdling and inoculation system; Carbon starvation

摘要：Tree canker diseases are mainly caused by necrotrophic fungal pathogens, which induce canker lesions, wilting, or dieback in many species. We hypothesized that canker-associated canopy dieback is related to functional failure of the phloem and cambium, carbon starvation and/or hydraulic failure. Using a girdling and inoculation system, we evaluated gas exchange and hydraulic parameters, concentrations of non-structural carbohydrates (NSCs), leaf characteristics, stem phenotyping and symptoms of 6-month-old poplar saplings with Botryosphaeria or Valsa canker disease. Pathogen inoculations inhibited callus formation and phloem regeneration and altered the physiological parameters, water potential, NSC content in stems, and symptoms on leaves and stems, while the girdling-only control did not. Results suggest that the functional and structural integrity of the phloem and cambium play crucial roles in the pathogenesis of canker disease. Botryosphaeria canker decreased photosynthetic rate (-54% to-75%), stomatal conductance (-71% to-80%) and transpiration rate (-58% to-66%), while Valsa canker decreased photosynthetic rate (-53% to-83%), stomatal conductance (-71% to-87%) and transpiration rate (-53% to-76%) at 20, 25, and 30 days after inoculation. Results suggest that the two fungal pathogens induce carbon starvation by inhibiting photosynthesis. The leaf water potential was higher and the change in specific hydraulic conductivity was smaller in the canker region than in the adjacent regions, while the NSC content was lower in the region below cankers than above them, suggesting that the fungal pathogens caused poplar canopy dieback by initially inducing carbon starvation, not hydraulic failure.