Caracterização molecular e análise da expressão de membros da família gênica PR-1 em tomateiro

• Autor(a) principal: Guimarães, Gustavo Augusto Moreira
• Data de Publicação: 2007
• Tipo de documento: Dissertação
• Idioma: por
• Título da fonte: LOCUS Repositório Institucional da UFV
• Texto Completo: http://locus.ufv.br/handle/123456789/4802
• topic: Tomate - Genética; Tomate - Resistência a doenças e pragas; Genética molecular; Regulação de expressão gênica; Tomato - Genetics; Tomato - Resistance to diseases and pests; Molecular genetics; Regulation of gene expression; CNPQ::CIENCIAS AGRARIAS::AGRONOMIA::FITOTECNIA::MELHORAMENTO VEGETAL

The plants resist to the infection caused by pathogens using constitutive and induced defenses. The induced defense is activated by the plants when they recognize general elicitors and effector proteins. This recognition leads to the rapid activation of the defense responses, including the synthesis of Pathogenesis-related proteins - PR proteins. There are 17 known PR-protein families (PR-1 to PR-17) that are expressed in response to pathogens and/or chemical inductors. The genes that codes for PR-1 proteins share a high sequence identity and are used as markers of the systemic acquired resistance (SAR). However the biochemical function of these proteins is still unknown. Antimicrobial activities were reported only for basic PR-1 proteins. PR-1 genes are members of gene families in many plant species. Based on sequence analysis of sequences deposited in public database the following possible PR-1 gene family members from tomato plant were identified: PR-1aP4 (accession numbers AJ011520 and M69247); P1p14 (Y08804, M69248 and 68738); PR1A1 (X71592); PR1A2 (Y08844); PR1D (AJ001627) in the NCBI database and two unigenes sequences from the Solanaceae Genomics Network database, SGN-U213451 and SGN- U220473. The genes PR-1aP4 and P1p14 and the unigenes SGN-U213451 and SGN-U220473 encode basic PR-1 proteins and the genes PR1A1, PR1A2 and PR1D encode acid proteins. The gene represented by the unigene SGN-U213451 seems encode the P14c protein, that has a reported antimicrobial activity and until this moment is not in the databases. In this work were developed essays to detect the expression of PR-1 family members by real-time PCR. The analyzed genes can be distinguished by their quantitative and qualitative expression pattern. PR-1aP4, P1p14, PR1A1 and the SGN-U213451 had a higher level of expression in younger leaves in response to A. solani; while, the gene PR1A2 was more induced in the older leaves of these plants, where severity of the disease is greater. The gene represented by the SGN-U220473 did not show induction by A. solani. The P1p14 and PR1A2 expression was induced by benzothiadiazole (commercial product Bion) and jasmonic acid, respectively. Lower gene expression levels were obtained with chemical induction showing that more refined kinetic induction essays of PR-1 genes of the tomato plant in response to chemical inductors are needed in order to establish which specific signaling molecule is able to trigger the expression of each family member.