Tomato polyphenol oxidase. Differential response of the polyphenol oxidase F promoter to injuries and wound signals

• Published in: Plant physiology (Bethesda) 1997-10, Vol.115 (2), p.409-418
• Main Authors: Thipyapong, P, Steffens, J.C
• Format: Article
• Language: English
• Subjects: ABIOTIC INJURIES; ACIDE JASMONIQUE; ACIDE SALICYLIQUE; ACIDO JASMONICO; ACIDO SALICILICO; ACTIVIDAD ENZIMATICA; ACTIVITE ENZYMATIQUE; AGENT PATHOGENE; ANATOMIA DE LA PLANTA; ANATOMIE VEGETALE; BACTERIOSE; BACTERIOSES; BACTERIOSIS; Biological and medical sciences; CATECHOL OXIDASE; CATECHOL OXYDASE; CATECOL OXIDASA; Cell Biology and Signal Transduction; CELL DIFFERENTIATION; CODE GENETIQUE; CODIGO GENETICO; CRECIMIENTO; CROISSANCE; DANOS MECANICOS; DEGAT MECANIQUE; DEVELOPMENTAL STAGES; DIFERENCIACION CELULAR; DIFFERENCIATION CELLULAIRE; DISEASE RESISTANCE; ENFERMEDADES FUNGOSAS; Enzymes; ENZYMIC ACTIVITY; ETAPAS DE DESARROLLO; ETHYLENE; ETILENO; EXPRESION GENICA; EXPRESSION DES GENES; FEUILLE; Fundamental and applied biological sciences. Psychology; FUNGAL DISEASES; GENE EXPRESSION; Generalities. Disease free stocks; GENETIC CODE; GENETIC REGULATION; GENETICA; GENETICS; GENETIQUE; GROWTH; HOJAS; INDUCTION; Inductive reasoning; Infections; JASMONIC ACID; LEAVES; Lesions; LYCOPERSICON ESCULENTUM; MALADIE FONGIQUE; MECHANICAL DAMAGE; Metabolism; ORGANISMOS PATOGENOS; Oxidases; PATHOGENS; Phytopathology. Animal pests. Plant and forest protection; PLANT ANATOMY; Plant physiology and development; Plants; Polyphenols; RESISTANCE AUX MALADIES; RESISTENCIA A LA ENFERMEDAD; SALICYLIC ACIDS; SINTOMAS; STADE DE DEVELOPPEMENT; STEMS; STRESS RESPONSE; SUSCEPTIBILITY; SYMPTOME; SYMPTOMS; TALLO; TIGE; TRANSCRIPCION; TRANSCRIPTION; Trichomes
• ISSN: 0032-0889; 1532-2548
• DOI: 10.1104/pp.115.2.409

Tomato (Lycopersicon esculentum Mill.) polyphenol oxidases (PPOs) are encoded by a seven-member gene family that exhibits complex patterns of differential expression during growth and differentiation. Antisense down-regulation of constitutive and induced PPO expression results in hypersusceptibility to pathogens, suggesting a critical role for PPO-mediated phenolic oxidation in plant defense. However, the nature and extent of PPO induction and its contribution to resistance are unclear. In this study we examined the inducibility of the tomato PPO gene family. In mature plants PPO transcript levels systemically increased in young leaves (nodes 1-3) when mature leaflets (node 5) were injured. Transcripts hybridizing to PPO E/F-specific probes were the predominant wound-induced PPO mRNAs in young leaves. Analysis of PPO promoter: GUS fusion constructs shows that mechanical wounding and infection by fungal and bacterial pathogens induced transcription of PPO F. Different injuries, salicylic acid, ethylene, and jasmonates elicited distinct, cell-specific and developmental stage-specific patterns of PPO F expression. Whereas jasmonates and mechanical wounding significantly induced PPO F only in young leaves (nodes 1-3), and ethylene induced PPO F only in older leaves (node 7), salicylic acid induced PPO F in stems and foliage at all developmental stages. These results demonstrate that cis-element(s) sufficient for PPO F inducibility reside in the 5' flanking region, and these elements are responsive to a broad range of signals