ABSTRACT
Plants use volatile terpene compounds as odor cues for communicating with the environment. Fleshy fruits are particularly rich in volatiles that deter herbivores and attract seed dispersal agents. We have investigated how terpenes in citrus fruit peels affect the interaction between the plant, insects, and microorganisms. Because limonene represents up to 97% of the total volatiles in orange (Citrus sinensis) fruit peel, we chose to down-regulate the expression of a limonene synthase gene in orange plants by introducing an antisense construct of this gene. Transgenic fruits showed reduced accumulation of limonene in the peel. When these fruits were challenged with either the fungus Penicillium digitatum or with the bacterium Xanthomonas citri subsp. citri, they showed marked resistance against these pathogens that were unable to infect the peel tissues. Moreover, males of the citrus pest medfly (Ceratitis capitata) were less attracted to low limonene-expressing fruits than to control fruits. These results indicate that limonene accumulation in the peel of citrus fruit appears to be involved in the successful trophic interaction between fruits, insects, and microorganisms. Terpene down-regulation might be a strategy to generate broad-spectrum resistance against pests and pathogens in fleshy fruits from economically important crops. In addition, terpene engineering may be important for studying the basic ecological interactions between fruits, herbivores, and pathogens.
Subject(s)
Ceratitis capitata/physiology , Citrus sinensis/parasitology , Down-Regulation , Fruit/chemistry , Host-Pathogen Interactions , Odorants/analysis , Terpenes/metabolism , Acyclic Monoterpenes , Animals , Citrus sinensis/drug effects , Citrus sinensis/genetics , Citrus sinensis/microbiology , Cyclohexenes/pharmacology , Down-Regulation/drug effects , Feeding Behavior/drug effects , Feeding Behavior/physiology , Fruit/drug effects , Fruit/microbiology , Fruit/parasitology , Gene Expression Regulation, Plant/drug effects , Host-Pathogen Interactions/drug effects , Host-Pathogen Interactions/genetics , Limonene , Male , Molecular Sequence Data , Penicillium/drug effects , Penicillium/growth & development , Phenotype , Plant Diseases/genetics , Plant Diseases/microbiology , Plant Diseases/parasitology , Plants, Genetically Modified , Terpenes/pharmacology , Volatile Organic Compounds/analysisABSTRACT
Presents a study whose information was exposed as a poster at the Congress SEUP (Spanish Society of Emergencies in Pediatrics) in Gijón 2011. Labor has emerged as a result of observed differences in criteria in the taking of blood pressure between our neonatal unit nurses.
Subject(s)
Blood Pressure Determination/instrumentation , Blood Pressure Determination/methods , Equipment Design , Humans , InfantABSTRACT
Plant volatiles include terpenoids, which are generally involved in plant defense, repelling pests and pathogens and attracting insects for herbivore control, pollination and seed dispersal. Orange fruits accumulate the monoterpene limonene at high levels in the oil glands of their fruit peels. When limonene production was downregulated in orange fruits by the transgenic expression of a limonene synthase (CitMTSE1) in the antisense configuration, these fruits were resistant to the fungus Penicillium digitatum (Pers.) Sacc. and the bacterium Xanthomonas citri subsp. citri and were less attractive to the medfly pest Ceratitis capitata. These responses were reversed when the antisense transgenic orange fruits were treated with limonene. To gain more insight into the role of the limonene concentration in fruit responses to pests and pathogens, we attempted to overexpress CitMTSE1 in the sense configuration in transgenic orange fruits. Only slight increases in the amount of limonene were found in sense transgenic fruits, maybe due to the detrimental effect that excessive limonene accumulation would have on plant development. Collectively, these results suggest that when limonene reaches peak levels as the fruit develops, it becomes a signal for pest and pathogen attraction, which facilitate access to the fruit for pulp consumers and seed dispersers.
Subject(s)
Ceratitis capitata , Citrus sinensis/chemistry , Citrus sinensis/microbiology , Cyclohexenes/chemistry , Plant Diseases , Terpenes/chemistry , Animals , Citrus sinensis/genetics , Disease Resistance , Fruit/chemistry , Gene Expression Regulation, Plant , Intramolecular Lyases/genetics , Limonene , Penicillium/pathogenicity , Plants, Genetically Modified/chemistry , Plants, Genetically Modified/microbiologyABSTRACT
Se presenta un estudio parte de cuya información fue expuesta como póster en el congreso SEUP (Sociedad Española de Urgencias en Pediatría) en Gijón 2011. El trabajo ha surgido como consecuencia de observar diferencias de criterios en la toma de la presión arterial entre el personal de enfermería de nuestra unidad neonatal(AU)
Presents a study whose information was exposed as a poster at the Congress SEUP (Spanish Society of Emergencies in Pediatrics) in Gijón 2011. Labor has emerged as a result of observed differences in criteria in the taking of blood pressure between our neonatal unit nurses(AU)