Evaluación proteómica mediante geles bidimensionales en frutos de variedades tardías de Prunus Persica sometidas a tratamientos de postcosecha para prevenir el desarrollo de harinosidad
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2015
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es
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Universidad Andrés Bello
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Licencia CC
Licencia CC
Resumen
Chile es el principal exportador de duraznos y nectarines (Prunus persica) del hemisferio sur, sin embargo los mercados de destino son distantes. Estos frutos ablandan y se deterioran rápidamente a temperatura ambiente. Una estrategia utilizada para retrasar el ablandamiento durante el transporte de los frutos es el almacenamiento a bajas temperaturas (0°C). Sin embargo algunas variedades son susceptibles a sufrir desórdenes fisiológicos debido al almacenamiento prolongado en frío y en consecuencia desarrollan chilling injury (CI). Los principales síntomas del CI son harinosidad pardeamiento de la pulpa y enrojecimiento de la pulpa, los cuales disminuyen la calidad de los frutos. Con el objetivo de prolongar la vida de postcosecha y de prevenir el CI, se han aplicado tratamientos de postcosecha adicionales como atmósfera controlada (AC) y acondicionamiento de frutos (acondicionado), sin embargo los mecanismos moleculares asociados a estos tratamientos aún no están claros. Para entender dichos procesos, diseñamos un acercamiento proteómico mediante geles bidimensionales con el fin de detectar proteínas acumuladas diferencialmente en dos variedades de cosecha tardía, 'Red Pearl' (nectarin) y DU88 (durazno). El diseño experimental nos permitió comparar frutos firmes y blandos, con o sin almacenamiento refrigerado y tratamientos de postcosecha (AC y acondicionado) más almacenamiento refrigerado. Logramos detectar 53 y 66 spots acumulados diferencialmente en 'Red Pearl' y DU88 respectivamente. Algunos de estos spots fueron identificados mediante espectrometría de masas y clasificados por Gene Ontology (GO). Se encontraron proteínas con acumulación diferencial entre el almacenamiento refrigerado y los tratamientos de postcosecha en procesos relacionados con el metabolismo de la pared celular, respuesta a estrés y regulación redox. Además, se observaron diferencias entre variedades respecto a la acumulación de proteínas. En la variedad DU88 se observó mayor abundancia de las proteínas poligalacturonasa y expansina en frutos acondicionados y almacenados en frío en comparación a los no tratados, mientras que en ‘Red Pearl’ la superóxido dismutasa presentó mayores niveles de acumulación en frutos jugosos tratados con AC durante el almacenamiento en frío y con posterior maduración (Shelf life) comparación a los frutos almacenados en frío más Shelf life (harinosos). Estos resultados sugieren que serían diferentes los procesos moleculares regulados por AC y acondicionado.
Chile is the main exporter of peaches and nectarines (Prunus persica) of southern hemisphere, but their main destinations are distants. This fruits ripe and deteriorate quickly at ambient temperature. A strategy used to delay this ripening is cold storage (0°C). However some varieties are susceptible to physiological disorders due long storage at low temperatures and consequently develop chilling injury (CI). Typically, CI symptoms are mealiness, browning and flesh bleeding, which affects significantly fruit quality. Some additional postharvest treatments are used to extend postharvest life and prevent CI, like controlled atmosphere (CA) and conditioning, but the molecular mechanisms by which these treatments work are still unclear. To better understand these processes, we designed a 2-D proteomic approach to screen for differentially accumulated proteins in two late season varieties, ‘Red Pearl’ (nectarine) and DU88 (peach). Our experimental design allow us to compare fruits on ripening, after cold storage and fruits under postharvest treatments (CA and conditioning) plus cold storage. We detected 53 and 66 differentially accumulated spots in ‘Red Pearl’ and DU88 respectively. Some of these spots were identified by mass spectrometry, which were classified using Gene Ontology annotation (GO). Processes like cell wall metabolism, stress response and redox regulation were found to be different between cold storage and additional postharvest treatments. Some variances on spots accumulation between varieties were observed, such as more abundant polygalacturonase and expansin protein levels in conditioned fruit stored in cold condition plus shelf life (juicy) than just cold stored (mealy) in DU88. On the other hand in ‘Red Pearl’, superoxide dismutase showed increased levels in cold stored fruits with CA plus ripening (juicy) as compared to just cold stored and the ripen (mealy). These results suggest differences between both varieties with different molecular processes regulated by CA and conditioning.
Chile is the main exporter of peaches and nectarines (Prunus persica) of southern hemisphere, but their main destinations are distants. This fruits ripe and deteriorate quickly at ambient temperature. A strategy used to delay this ripening is cold storage (0°C). However some varieties are susceptible to physiological disorders due long storage at low temperatures and consequently develop chilling injury (CI). Typically, CI symptoms are mealiness, browning and flesh bleeding, which affects significantly fruit quality. Some additional postharvest treatments are used to extend postharvest life and prevent CI, like controlled atmosphere (CA) and conditioning, but the molecular mechanisms by which these treatments work are still unclear. To better understand these processes, we designed a 2-D proteomic approach to screen for differentially accumulated proteins in two late season varieties, ‘Red Pearl’ (nectarine) and DU88 (peach). Our experimental design allow us to compare fruits on ripening, after cold storage and fruits under postharvest treatments (CA and conditioning) plus cold storage. We detected 53 and 66 differentially accumulated spots in ‘Red Pearl’ and DU88 respectively. Some of these spots were identified by mass spectrometry, which were classified using Gene Ontology annotation (GO). Processes like cell wall metabolism, stress response and redox regulation were found to be different between cold storage and additional postharvest treatments. Some variances on spots accumulation between varieties were observed, such as more abundant polygalacturonase and expansin protein levels in conditioned fruit stored in cold condition plus shelf life (juicy) than just cold stored (mealy) in DU88. On the other hand in ‘Red Pearl’, superoxide dismutase showed increased levels in cold stored fruits with CA plus ripening (juicy) as compared to just cold stored and the ripen (mealy). These results suggest differences between both varieties with different molecular processes regulated by CA and conditioning.
Notas
Tesis (Magíster en Biotecnología)
Financiada por el proyecto FONDAP CRG 15090007.
Financiada por el proyecto FONDAP CRG 15090007.
Palabras clave
Proteómica, Duraznos, Calidad