title: Transcriptional profiling of canker-resistant transgenic sweet orange (Citrus sinensis Osbeck) constitutively overexpressing a spermidine synthase gene.
abstract: Citrus canker disease caused by Xanthomonas citri subsp. citri (Xcc) is one of the most devastating diseases affecting the citrus industry worldwide. In our previous study, the canker-resistant transgenic sweet orange (Citrus sinensis Osbeck) plants were produced via constitutively overexpressing a spermidine synthase. To unravel the molecular mechanisms underlying Xcc resistance of the transgenic plants, in the present study global transcriptional profiling was compared between untransformed line (WT) and the transgenic line (TG9) by hybridizing with Affymetrix Citrus GeneChip. In total, 666 differentially expressed genes (DEGs) were identified, 448 upregulated, and 218 downregulated. The DEGs were classified into 33 categories after Gene ontology (GO) annotation, in which 68 genes are in response to stimulus and involved in immune system process, 12 genes are related to cell wall, and 13 genes belong to transcription factors. These genes and those related to starch and sucrose metabolism, glutathione metabolism, biosynthesis of phenylpropanoids, and plant hormones were hypothesized to play major roles in the canker resistance of TG9. Semiquantitative RT-PCR analysis showed that the transcript levels of several candidate genes in TG9 were significantly higher than in WT both before and after Xcc inoculation, indicating their potential association with canker disease.
authors.affiliation: Key Laboratory of Horticultural Plant Biology (MOE), College of Horticulture and Forestry Sciences, Huazhong Agricultural University, Wuhan 430070, China.
authors.forename: Xing-Zheng
authors.initials: XZ
authors.lastname: Fu
authors.forename: Ji-Hong
authors.initials: JH
authors.lastname: Liu
mesh_terms: D002473:Cell Wall / Q000378:metabolism; D002957:Citrus / Q000235:genetics* / Q000382:microbiology; D017931:DNA Primers; D060467:Disease Resistance / Q000235:genetics; D020869:Gene Expression Profiling; D018506:Gene Expression Regulation, Plant; D005818:Genetic Engineering; D020411:Oligonucleotide Array Sequence Analysis; D010935:Plant Diseases / Q000235:genetics* / Q000382:microbiology; D018515:Plant Leaves / Q000378:metabolism; D030821:Plants, Genetically Modified / Q000235:genetics / Q000382:microbiology; D011436:Spermidine Synthase / Q000235:genetics* / Q000378:metabolism; D013312:Stress, Physiological; D014157:Transcription Factors / Q000378:metabolism; D059467:Transcriptome; D014974:Xanthomonas
chemical_list: D017931:DNA Primers; D014157:Transcription Factors; D011436:Spermidine Synthase