In a previous research 23 genes, identified in Etrog citron in response to Citrus dwarfing viroid (CVd-III b) infection, were used as probes in Northern blot analysis to evaluate their expression level in sour orange seedlings inoculated with a severe SY isolate of Citrus tristeza virus found in Sicily (CTV S29). Seven of them,whose transcription was significantly altered were selected to evaluate their modulation in different citrus hosts inoculated with CTV S29., by reverse transcriptase quantitative real time PCR. In sour orange seedlings, quantitative real time PCR revealed that genes codifying for metallothionein (MT), regulator of gene silencing–calmodulin-like protein (rgs-CaM), suppressor of RNA silenc-ing, and CONSTANS-like (CLP) were up regulated, as observed in Northern blot analysis; in contrast, the expression of ethylene-responsive binding protein (EREBP) and peroxidase (PRX) genes showed a different behavior resulting down regulated. Alcohol dehydrogenase (ADH) and aminoacid permease (AP) genes, not detected by Northern, resulted to be down and up regulated, respec-tively. ADH and PRX genes, involved in general response to stress factors, ex-hibited the same pattern of expression (down regulation) in all citrus hosts tested. On the contrary, rgs-CaM, AP and CLP were down regulated in Etrog citron, grapefruit and sweet orange and over expressed in sour orange. Up regulation of EREBP occurred only in Etrog citron and in sweet orange, whereas MT is induced only in sour orange and sweet orange. Interestingly, CTV infection in Mexican lime as well as on sour orange seedling induced the down regulation of all the selected genes, but the rgs-CaM was drastically over expressed,.Since both hosts are susceptible to CTV S29 and showed very se-vere symptoms, the hypothesis is advanced that rgs-CaM may act as host spe-cific RNA silencing suppressor and CTV strongly induces its expression in sus-ceptible plants, evading RNA silencing activity.
Expression level of selected genes in different citrus species inoculated with a severe strain of Citrus Tristeza Virus
TESSITORI, MATILDE;LA ROSA, Rosa;
2010-01-01
Abstract
In a previous research 23 genes, identified in Etrog citron in response to Citrus dwarfing viroid (CVd-III b) infection, were used as probes in Northern blot analysis to evaluate their expression level in sour orange seedlings inoculated with a severe SY isolate of Citrus tristeza virus found in Sicily (CTV S29). Seven of them,whose transcription was significantly altered were selected to evaluate their modulation in different citrus hosts inoculated with CTV S29., by reverse transcriptase quantitative real time PCR. In sour orange seedlings, quantitative real time PCR revealed that genes codifying for metallothionein (MT), regulator of gene silencing–calmodulin-like protein (rgs-CaM), suppressor of RNA silenc-ing, and CONSTANS-like (CLP) were up regulated, as observed in Northern blot analysis; in contrast, the expression of ethylene-responsive binding protein (EREBP) and peroxidase (PRX) genes showed a different behavior resulting down regulated. Alcohol dehydrogenase (ADH) and aminoacid permease (AP) genes, not detected by Northern, resulted to be down and up regulated, respec-tively. ADH and PRX genes, involved in general response to stress factors, ex-hibited the same pattern of expression (down regulation) in all citrus hosts tested. On the contrary, rgs-CaM, AP and CLP were down regulated in Etrog citron, grapefruit and sweet orange and over expressed in sour orange. Up regulation of EREBP occurred only in Etrog citron and in sweet orange, whereas MT is induced only in sour orange and sweet orange. Interestingly, CTV infection in Mexican lime as well as on sour orange seedling induced the down regulation of all the selected genes, but the rgs-CaM was drastically over expressed,.Since both hosts are susceptible to CTV S29 and showed very se-vere symptoms, the hypothesis is advanced that rgs-CaM may act as host spe-cific RNA silencing suppressor and CTV strongly induces its expression in sus-ceptible plants, evading RNA silencing activity.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
