Here we report the first part of a study on the correlation between variations in non-coding DNA sequences, i.e. promoters, and the level of gene expression in a group of genes coding for pathogenesis-related (PR) proteins, known to play a crucial role in host-pathogen interaction both at the local and the systemic level, with the aim of developing markers for tolerance/resistance to disease. Promoters of PR-genes have been shown to contain sequences involved in the induction of gene expression upon wounding and after treatment with ethylene, methyl jasmonate, salicylic acid or other elicitors. In particular, the so-called PR box or GCC box is found in many plant defense-related genes promoters, including the promoters of many basic PR proteins. Based on these data, we have chosen two genes whose promoters contain one or more GCC boxes, i.e. endochitinase and osmotin. Moreover, as PR-1 gene is considered to be a marker for Systemic Acquired Resistance (SAR), two PR-1 genes differentially regulated during the hypersensitive response and development have been included: PR1a2, whose expression is costitutive, and PR1b1 that is induced by pathogen attack, salicylic acid and ethylene precursors. The study has been carried out on 14 Lycopersicon esculentum cultivars known to be susceptible or resistant to pathogens, as well as on the wild species L. pennellii, L. pimpinellifolium and L. peruvianum. Primers for PCR amplification have been designed on the promoter sequences found in GenBank, the reverse primer being anchored in the coding region to increase specificity. Amplified sequences have been cloned, sequenced and aligned in order to detect the presence of polymorphisms. Preliminary data show that both single nucleotide polymorphisms (SNPs) and variations in microsatellite length can be detected in the promoters of the above mentioned genes, the sequences of the wild species showing the highest variability.
Promoter analysis of pathogenesis-related genes in resistant and susceptible tomato cultivars and Lycopersicon wild species / S. Sorace; M. Gori; P. Bettini. - ELETTRONICO. - Proceedings of the XLVI Italian Society of Agricultural Genetics - SIGA Annual Congress:(2002), pp. 4.31-4.31. (Intervento presentato al convegno XLVI Convegno Annuale Società Italiana di Genetica Agraria (S.I.G.A.) tenutosi a Giardini Naxos (ME), Italy nel 18-21/09/2002).
Promoter analysis of pathogenesis-related genes in resistant and susceptible tomato cultivars and Lycopersicon wild species
GORI, MASSIMO;BETTINI, PRISCILLA PAOLA
2002
Abstract
Here we report the first part of a study on the correlation between variations in non-coding DNA sequences, i.e. promoters, and the level of gene expression in a group of genes coding for pathogenesis-related (PR) proteins, known to play a crucial role in host-pathogen interaction both at the local and the systemic level, with the aim of developing markers for tolerance/resistance to disease. Promoters of PR-genes have been shown to contain sequences involved in the induction of gene expression upon wounding and after treatment with ethylene, methyl jasmonate, salicylic acid or other elicitors. In particular, the so-called PR box or GCC box is found in many plant defense-related genes promoters, including the promoters of many basic PR proteins. Based on these data, we have chosen two genes whose promoters contain one or more GCC boxes, i.e. endochitinase and osmotin. Moreover, as PR-1 gene is considered to be a marker for Systemic Acquired Resistance (SAR), two PR-1 genes differentially regulated during the hypersensitive response and development have been included: PR1a2, whose expression is costitutive, and PR1b1 that is induced by pathogen attack, salicylic acid and ethylene precursors. The study has been carried out on 14 Lycopersicon esculentum cultivars known to be susceptible or resistant to pathogens, as well as on the wild species L. pennellii, L. pimpinellifolium and L. peruvianum. Primers for PCR amplification have been designed on the promoter sequences found in GenBank, the reverse primer being anchored in the coding region to increase specificity. Amplified sequences have been cloned, sequenced and aligned in order to detect the presence of polymorphisms. Preliminary data show that both single nucleotide polymorphisms (SNPs) and variations in microsatellite length can be detected in the promoters of the above mentioned genes, the sequences of the wild species showing the highest variability.
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