Rootstock-regulated gene expression patterns associated with fire blight resistance in apple

BMC Genomics

Research Article

Siela N Maximova¹  Robert M Crassweller¹  Philip J Jensen²  Timothy W McNellis²  Noemi Halbrendt³  Henry K Ngugi³  James W Travis³  Naomi Altman⁴  Craig Praul⁵  Izabela Makalowska⁶  Gennaro Fazio⁷ 

[1] Department of Horticulture, The Pennsylvania State University, 16802, University Park, PA, USA;Department of Plant Pathology, The Pennsylvania State University, 16802, University Park, PA, USA;Department of Plant Pathology, The Pennsylvania State University, 16802, University Park, PA, USA;The Pennsylvania State University Fruit Research and Extension Center, 17307, Biglerville, PA, USA;Department of Statistics, The Pennsylvania State University, 16802, University Park, PA, USA;Huck Institutes of the Life Sciences, The Pennsylvania State University, 16802, University Park, PA, USA;Institute of Molecular Biology and Biotechnology, Faculty of Biology, Adam Mickiewicz University, Poznan, Poland;USDA/ARS, Plant Genetics Research Unit, 14456, Geneva, NY, USA;

关键词: Apple Tree;    Stepwise Multiple Regression Analysis;    Fire Blight;    Apple Genome;    Susceptible Tree;   

DOI  :  10.1186/1471-2164-13-9

 received in 2011-07-08, accepted in 2012-01-09,  发布年份 2012

来源: Springer

【 摘 要 】

BackgroundDesirable apple varieties are clonally propagated by grafting vegetative scions onto rootstocks. Rootstocks influence many phenotypic traits of the scion, including resistance to pathogens such as Erwinia amylovora, which causes fire blight, the most serious bacterial disease of apple. The purpose of the present study was to quantify rootstock-mediated differences in scion fire blight susceptibility and to identify transcripts in the scion whose expression levels correlated with this response.ResultsRootstock influence on scion fire blight resistance was quantified by inoculating three-year old, orchard-grown apple trees, consisting of 'Gala' scions grafted to a range of rootstocks, with E. amylovora. Disease severity was measured by the extent of shoot necrosis over time. 'Gala' scions grafted to G.30 or MM.111 rootstocks showed the lowest rates of necrosis, while 'Gala' on M.27 and B.9 showed the highest rates of necrosis. 'Gala' scions on M.7, S.4 or M.9F56 had intermediate necrosis rates. Using an apple DNA microarray representing 55,230 unique transcripts, gene expression patterns were compared in healthy, un-inoculated, greenhouse-grown 'Gala' scions on the same series of rootstocks. We identified 690 transcripts whose steady-state expression levels correlated with the degree of fire blight susceptibility of the scion/rootstock combinations. Transcripts known to be differentially expressed during E. amylovora infection were disproportionately represented among these transcripts. A second-generation apple microarray representing 26,000 transcripts was developed and was used to test these correlations in an orchard-grown population of trees segregating for fire blight resistance. Of the 690 transcripts originally identified using the first-generation array, 39 had expression levels that correlated with fire blight resistance in the breeding population.ConclusionsRootstocks had significant effects on the fire blight susceptibility of 'Gala' scions, and rootstock-regulated gene expression patterns could be correlated with differences in susceptibility. The results suggest a relationship between rootstock-regulated fire blight susceptibility and sorbitol dehydrogenase, phenylpropanoid metabolism, protein processing in the endoplasmic reticulum, and endocytosis, among others. This study illustrates the utility of our rootstock-regulated gene expression data sets for candidate trait-associated gene data mining.

【 授权许可】

Unknown   
© Jensen et al; licensee BioMed Central Ltd. 2012. This article is published under license to BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.