Analysis of the production of ethylene in 2,4-D resistant and sensitive biotypes of "Papaver rhoeas L."

Hasta el momento no se ha realizado ningún estudio en España a fin de indagar en los mecanismos de resistencia de “Papaver Rhoeas” al 2,4-D. En otros trabajos se ha demostrado como la producción de etileno está involucrada en la respuesta resistente de ciertas malas hierbas a auxinas sintéticas. En el presente estudio se ha observado que las plantas sensibles de amapola producen más etileno que las resistentes después de la aplicación de 2,4-D. Estos resultados podrían ayudar a comprender de mejor manera como ciertos biotipos son capaces de resistir a este producto.So far there has been none study in Spain to investigate the 2,4-D resistance mechanism of Papaver rhoeas. Other studies have shown how ethylene production is involved in the response of certain resistant weeds when they are sprayed with synthetic auxins. In the present study it was observed that sensitive corn poppy plants produce more ethylene than resistant one after 2,4-D application. These findings could help to understanding how certain biotypes are able to resist this product

Manipulating the taste-related composition of strawberry fruits (Fragaria x ananassa) from different cultivars using deficit irrigation

Demand and, consequently, production of strawberry fruits has increased over the past few years and, as a result, the water abstractions for cultivation of this fruit have risen considerably. To limit the amounts of water used for several horticultural crops, water deficit irrigation (DI) has been seen as a potential alternative for new cultivation systems. DI in strawberry fruits is generally associated with reduction in berry size and yield; however, a recent study demonstrated that DI on strawberry can increase the concentration of some taste- and health-related compounds in fruits from cv. Elsanta. Hence, the aim of the present study was to further corroborate such findings and to assess the response (and variability) among different strawberry cultivars (namely Christine, Elsanta, Florence, Sonata and Symphony) to imposed water-DI conditions. Water-DI affected both fruit physiology and biochemistry. Nevertheless, the response to drought stress was different for each of the cultivars tested. Plants from cvs. Elsanta, Sonata and Symphony showed a greater reduction in berry size, accompanied by a significant increase in dry matter content for fruit harvested from DI-treated plants. Concomitant to this, and where dry matter was increased, the concentrations of sugars and some acids were generally higher in DI-derived fruit. In contrast, cvs. Florence and Christine did not show significant variations in berry weight or any of the target analytes measured when grown under the conditions imposed in this study. The results presented herein suggest that reducing water irrigation between flower initiation and fruit harvest may be a viable technique for increasing the concentrations of taste-related compounds in cvs. Elsanta, Sonata and Symphony and it may not have a negative impact on overall fruit size of cvs. Christine and Florence

Molecular and biochemical differences underlying the efficacy of lovastatin in preventing the onset of superficial scald in a susceptible and resistant Pyrus communis L. cultivar

Riscaldo Superficiale, Pero, Frigoconservazione, Danno da freddo, Maturazione del frutto, AntiossidantiThe molecular and biochemical events underlying the onset of superficial scald in two pear cultivars with different susceptibility (‘Blanquilla’ and ‘Conference’) was investigated in fruit untreated and treated with lovastatin, 1-MCP or ethylene. ‘Conference’ pears were characterized by higher content of flavonols and linolenic acid (18:3), two metabolites related to chilling injury resistance. In this cultivar, the expression level of three genes belonging to the ascorbate glutathione pathway (APX, DHAR and MDHAR) were constitutively overexpressed, highlighting the role that endogenous antioxidant potential played in scald control. In the scaldsusceptible cultivar (‘Blanquilla’) the lovastatin treatment, in contrast to 1-MCP, effectively prevented superficial scald development and α-farnesene production without affecting fruit ripening. Moreover, lovastatin stimulated an increased production of ethanol and oleic + cis vaccenic acid (18:1), both compounds being also involved in cold stress tolerance. In both cultivars, and in contrast to 1-MCP, lovastatin did not impair the expression level of the genes devoted to ethylene production (ACO, ACS) and perception (ERS1, ERS2). As a consequence, the expression levels of the genes involved in texture modifications (PG1) and volatile emission (LOX, HPL, ADH and AAT) were maintained in lovastatin-treated samples allowing the fruit to reach an adequate final quality. The results from this study are discussed to highlight the complex regulatory network underlying superficial scald development in different pear cultivars

Investigation of the Transcriptomic and Metabolic Changes Associated With Superficial Scald Physiology Impaired by Lovastatin and 1-methylcyclopropene in Pear Fruit (Cv. "Blanquilla")

To elucidate the physiology underlying the development of superficial scald in pears, susceptible "Blanquilla" fruit was treated with different compounds that either promoted (ethylene) or repressed (1-methylcyclopropene and lovastatin) the incidence of this disorder after 4 months of cold storage. Our data show that scald was negligible for the fruit treated with 1-methylcyclopropene or lovastatin, but highly manifested in untreated (78% incidence) or ethylene-treated fruit (97% incidence). The comparison between the fruit metabolomic profile and transcriptome evidenced a distinct reprogramming associated with each treatment. In all treated samples, cold storage led to an activation of a cold-acclimation-resistance mechanism, including the biosynthesis of very-long-chain fatty acids, which was especially evident in 1-methylcyclopropane-treated fruit. Among the treatments applied, only 1-methylcyclopropene inhibited ethylene production, hence supporting the involvement of this hormone in the development of scald. However, a common repression effect on the PPO gene combined with higher sorbitol content was found for both lovastatin and 1-methylcyclopropene-treated samples, suggesting also a non-ethylene-mediated process preventing the development of this disorder. The results presented in this work represent a step forward to better understand the physiological mechanisms governing the etiology of superficial scald in pears