Differential expression of genes identified from Poncirus trifoliata tissue inoculated with CTV through EST analysis and in silico hybridization

Abstract

Citrus is the most important fruit crop in Brazil and Citrus tristeza virus (CTV) is considered one of the most important pathogens of citrus. Most citrus species and varieties are susceptible to CTV infection. However, Poncirus trifoliata, a close relative of citrus, is resistant to the virus. In order to better understand the responses of citrus plants to the infection of CTV, we constructed expressed sequence tag (EST) libraries with tissues collected from Poncirus trifoliata plants, inoculated or not with Citrus tristeza virus at 90 days after inoculation, grafted on Rangpur lime rootstocks. We generated 17,867 sequence tags from Poncirus trifoliata inoculated (8,926 reads) and not (8,941 reads) with a severe CTV isolate. A total of 2,782 TCs (Tentative Consensi sequences) were obtained using both cDNA libraries in a single clusterization procedure. By the in silico hybridization approach, 289 TCs were identified as differentially expressed in the two libraries. A total of 121 TCs were found to be overexpressed in plants infected with CTV and were grouped in 12 primary functional categories. The majority of them were associated with metabolism and defense response. Some others were related to lignin, ethylene biosynthesis and PR proteins. In general, the differentially expressed transcripts seem to be somehow involved in secondary plant response to CTV infection.

In silico analysis of the grapefruit sRNAome, transcriptome and gene regulation in response to CTV-CDVd co-infection

“…Many diverse “genes” were found differentially regulated in response CTV-CDVd co-infection across both grapefruit varieties. Similar to the results of previous studies on the infection of either CTV [ 53 – 57 ] or CDVd [ 58 ] in different citrus species and in P. trifoliata , grapefruit metabolic, disease response, structural and phytohormone-related pathways seem to be affected by the co-infection. Genes with known involvement in plant disease responses were mostly grouped into leucine-rich repeat (which include tobacco mosaic virus resistance protein N-like) and ankyrin repeat-containing protein coding genes.…”

Germin and Germin-like Proteins: Evolution, Structure, and Function

“…The predicted amino acid sequence of the cDNA clone exhibited a high sequence similarity to a GLP, and was classified as belonging to a new family of PR proteins, 'PR-16' (see also van Loon et al, 2006). More recently, Cristofani-Yaly et al (2007) constructed expressed sequence tag (EST) libraries with tissues collected from Poncirus trifoliata plants, inoculated or not with citrus tristeza virus, and found a GLP among the genes upregulated at 90 d after inoculation (see also Gandía et al, 2007). Similar results have been reported for Capsicum chinense plants infected with pepper mild mottle virus (PMMoV) (Elvira et al, 2008) and pepper Huasteco yellow vein virus (PHYVV) (Gasca-González et al, 2008).…”

Co-infection of Sweet Orange with Severe and Mild Strains of Citrus tristeza virus Is Overwhelmingly Dominated by the Severe Strain on Both the Transcriptional and Biological Levels

“…Understanding host responses to infection by pathogens facilitates the understanding of plant–pathogen interactions and also provides insights for new control strategies. Changes in the transcriptomes of susceptible Mexican lime (Gandía et al, 2007 ; Liu et al, 2012 ; Yang et al, 2013 ) and sweet orange (Cheng et al, 2016 ) and resistant trifoliate orange (Cristofani-Yaly et al, 2007 ) in response to the infection by mild or severe CTV strains have been well documented. Changes in gene expression in resistant, tolerant, and susceptible hosts in response to CTV were also compared to huanglongbing (HLB; Bowman and Albrecht, 2015 ).…”