Transcriptome profile of Carrizo citrange roots in response to <i>Phytophthora parasitica</i> infection

<i>Phytophthora parasitica</i> is one of the most widespread <i>Phytophthora</i> species, which is known to cause root rot, foot rot/gummosis and brown rot of fruits in citrus. In this study, we have analyzed the transcriptome of a commonly used citrus rootstock Carrizo citrange in response to <i>P. parasitica</i> infection using the RNA-seq technology. In total, we have identified 6692 differentially expressed transcripts (DETs) among <i>P. parasitica</i>-inoculated and mock-treated roots. Of these, 3960 genes were differentially expressed at 24 h post inoculation and 5521 genes were differentially expressed at 48 h post inoculation. Gene ontology analysis of DETs suggested substantial transcriptional reprogramming of diverse cellular processes particularly the biotic stress response pathways in Carrizo citrange roots. Many <i>R</i> genes, transcription factors, and several other genes putatively involved in plant immunity were differentially modulated in citrus roots in response to <i>P. parasitica</i> infection. Analysis reported here lays out a strong foundation for future studies aimed at improving resistance of citrus rootstocks to <i>P. parasitica</i>.