{"title":"Association of Dryocola boscaweniae, Gibbsiella greigii and Gibbsiella quercinecans with oak decline in Iran","authors":"Mohammad-Hossein Araeinejhad, Nargues Falahi Chrakhabi, Heshmat Rahimian, Carrie Brady","doi":"10.1007/s10342-024-01658-0","DOIUrl":null,"url":null,"abstract":"<p>Tree decline is described as the loss in tree vigor and increased mortality initiated by climate change events, and also involves pathogens and pests. Stem bleeding and bark canker of oak (<i>Quercus castaneifolia</i>) were observed in Mazandaran and Golestan forests during summer 2020–2021. Symptoms included cracks in the outer bark, stem tissue necrosis, bleeding, dark exudate and dark brown lesions in the inner bark. Eighty-nine strains with a metallic green sheen pigment were isolated on eosin methylene blue agar. The pathogenicity of all strains recovered in this study was assessed on oak seedlings and acorns. Forty-four strains produced rotting on oak acorns 2 weeks after inoculation. Inoculation of six representative strains on oak seedlings resulted in twig dieback of the plants after 4 weeks. Strains were negative for Gram reaction, oxidase and levan formation from sucrose. The <i>gyrB</i> and <i>infB</i> gene sequence similarity values of strains were 98.87–99.57% with the type strain of <i>Gibbsiella quercinecans</i>, 98.66–98.86% with the type strain of <i>Gibbsiella greigii</i> and 99.46–99.64% with the type strain of <i>Dryocola boscaweniae</i>. In the phylogenetic tree based on concatenated sequences of <i>gyrB</i> and <i>infB</i> genes or each gene individually, the strains were divided into three clusters containing the type strains of <i>G. quercinecans</i>, <i>G. greigii</i> and <i>D. boscaweniae</i>, each with high bootstrap support and confirming their identity as belonging to these three species. To the best of our knowledge, this is the first report of oak bacterial canker caused by <i>D. boscaweniae</i>, <i>G. greigii</i> and <i>G. quercinecans</i> in Iran and the first report of <i>D. boscaweniae</i> associated with oak decline symptoms.</p>","PeriodicalId":11996,"journal":{"name":"European Journal of Forest Research","volume":null,"pages":null},"PeriodicalIF":2.6000,"publicationDate":"2024-02-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"European Journal of Forest Research","FirstCategoryId":"97","ListUrlMain":"https://doi.org/10.1007/s10342-024-01658-0","RegionNum":2,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q1","JCRName":"FORESTRY","Score":null,"Total":0}
引用次数: 0
Abstract
Tree decline is described as the loss in tree vigor and increased mortality initiated by climate change events, and also involves pathogens and pests. Stem bleeding and bark canker of oak (Quercus castaneifolia) were observed in Mazandaran and Golestan forests during summer 2020–2021. Symptoms included cracks in the outer bark, stem tissue necrosis, bleeding, dark exudate and dark brown lesions in the inner bark. Eighty-nine strains with a metallic green sheen pigment were isolated on eosin methylene blue agar. The pathogenicity of all strains recovered in this study was assessed on oak seedlings and acorns. Forty-four strains produced rotting on oak acorns 2 weeks after inoculation. Inoculation of six representative strains on oak seedlings resulted in twig dieback of the plants after 4 weeks. Strains were negative for Gram reaction, oxidase and levan formation from sucrose. The gyrB and infB gene sequence similarity values of strains were 98.87–99.57% with the type strain of Gibbsiella quercinecans, 98.66–98.86% with the type strain of Gibbsiella greigii and 99.46–99.64% with the type strain of Dryocola boscaweniae. In the phylogenetic tree based on concatenated sequences of gyrB and infB genes or each gene individually, the strains were divided into three clusters containing the type strains of G. quercinecans, G. greigii and D. boscaweniae, each with high bootstrap support and confirming their identity as belonging to these three species. To the best of our knowledge, this is the first report of oak bacterial canker caused by D. boscaweniae, G. greigii and G. quercinecans in Iran and the first report of D. boscaweniae associated with oak decline symptoms.
期刊介绍:
The European Journal of Forest Research focuses on publishing innovative results of empirical or model-oriented studies which contribute to the development of broad principles underlying forest ecosystems, their functions and services.
Papers which exclusively report methods, models, techniques or case studies are beyond the scope of the journal, while papers on studies at the molecular or cellular level will be considered where they address the relevance of their results to the understanding of ecosystem structure and function. Papers relating to forest operations and forest engineering will be considered if they are tailored within a forest ecosystem context.