Gene expression changes in leaves of Citrus sinensis (L.) Osbeck infected by Citrus tristeza virus

ABSTRACT

Transcriptional changes between Citrus tristeza virus (CTV) inoculated- and mock inoculated- sweet orange ‘Jincheng’ (Citrus sinensis Osbeck cv. ‘Jincheng’) leaves were compared using microarrays. A total of 2400 differentially expressed genes (DEGs, fold change ≥ 2), 1557 (64.85%) up-regulated and 843 (35.15%) down-regulated, were obtained. Data mining revealed that CTV infection enhanced the transcription of genes involved in cell wall metabolism, plant defense, and material transport while it decreased the expression of protein synthesis and cytokinin metabolism-related genes. CTV infection strongly affected pathways involved in light reaction, starch and sucrose metabolism, lipid metabolism, and hormone metabolism. Secondary metabolism pathways including terpenoids, phenylpropanoids, flavonoids and alkaloid metabolism were also greatly influenced. Notably, several gibberellin (GA)-regulated genes were significantly induced by CTV. Quantitative real-time polymerase chain reaction (qRT-PCR) was applied to confirm the expression changes of 13 DEGs detected by microarray analysis. Our data described the early molecular changes of sweet orange in response to CTV infection and should provide informative suggestions for transgene selection of citrus genetic breeding.

KEYWORDS:

• Citrus tristeza virus (CTV)
• differentially expressed genes (DEGs)
• microarray
• plant–pathogen interaction

Acknowledgements

We are thankful to Dr. Powell of the US Horticultural Research Laboratory for his advice and help in revising the manuscript. We are also thankful to Dr. Yan Zhou of Southwest University for kindly giving us branches carrying severe CTV strain TR-L514.

Disclosure statement

No potential conflict of interest was reported by the authors.

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Additional information

Funding

This work was supported by the International Science & Technology Cooperation Program of China [grant number 2012DFA30610], the National Natural Science Foundation of China [grant number 31572113], and Guangdong Provincial Science and Technology Programs [grant numbers 2014B070706018, 2013B090700007 and 2014B020202009].