Comparative iTRAQ proteome and transcriptome analyses of sweet orange infected by "Candidatus Liberibacter asiaticus"

• Published in: Physiologia plantarum 2011-11, Vol.143 (3), p.235-245
• Main Authors: Fan, Jing, Chen, Chunxian, Yu, Qibin, Brlansky, Ronald H., Li, Zheng-Guo, Gmitter Jr, Frederick G.
• Format: Article
• Language: English
• Subjects: Bacterial plant pathogens; Biological and medical sciences; Chitinases - metabolism; Citrus sinensis - genetics; Copper - metabolism; DNA, Bacterial - analysis; Fundamental and applied biological sciences. Psychology; Gene Expression Profiling; Gene Expression Regulation, Plant; Lipoxygenase - metabolism; Phytopathology. Animal pests. Plant and forest protection; Plant Diseases - genetics; Plant Diseases - microbiology; Plant Leaves - chemistry; Plant physiology and development; Proteobacteria - physiology; Proteome; Superoxide Dismutase - metabolism; Zinc - metabolism
• ISSN: 0031-9317; 1399-3054
• DOI: 10.1111/j.1399-3054.2011.01502.x

Citrus Huanglongbing (HLB) has been threatening citrus production worldwide. In this study, a comparative proteomic approach was applied to understand the pathogenic process of HLB in affected sweet orange leaves. Using the isobaric tags for relative and absolute quantification (iTRAQ) technique, we identified 686 unique proteins in the mature leaves of both mock‐inoculated and diseased ‘Madam Vinous' sweet orange plants. Of the identified proteins, 20 and 10 were differentially expressed in leaves with and without symptoms of HLB (fold change > 2.5), respectively, compared with mock‐inoculated controls. Most significantly, upregulated proteins were involved in stress/defense response, such as four miraculin‐like proteins, chitinase, Cu/Zn superoxide dismutase and lipoxygenase. Microarray analysis also showed that stress‐related genes were significantly upregulated at the transcriptional level. For example, remarkable upregulations of miraculin‐like proteins and Cu/Zn superoxide dismutase transcripts were observed. Moreover, the transcriptional patterns of miraculin‐like protein 1 and Cu/Zn superoxide dismutase were examined at different stages of HLB disease development. Combined with the transcriptomic data, the proteomic data can provide an enhanced understanding of citrus stress/defense responses to HLB.