Developmental expression of glutathione-S-transferase in maize and its possible connection with herbicide tolerance

Summary Crop improvement for tolerance to specific herbicides is an important breeding target, since molecules performing well with regard to environmental safety are frequently not completely selective for crops. The glutathione (GSH)/glutathione-S-transferase (GST) system is a general mechanism of detoxification that in higher plants may confer tolerance to some herbicides. GSH level and GST activity were measured in different maize inbred lines, in the absence or in the presence of EPTC (a thiocarbamate) and of Alachlor (a chloroacetanilide); a wide genetic variability was observed for these parameters, which appear to be involved in plant tolerance to herbicides. Isozyme analysis was performed on roots, leaves, scutellum, pollen, coleoptile, mesocotyl of the same inbreds: it revealed the presence of many GST forms in maize, showing high polymorphism; they are controlled by at least five genes, the expression of which is developmentally regulated in the different tissues analyzed.     

Infestation potential of Dryocosmus kuriphilus Yasumatsu, 1951 (Hymenoptera: Cynipidae) in different natural populations of Castanea sativa Miller: an experimental ex situ test

The Asian chestnut gall wasp was accidentally introduced in Italy in 2002 and spread across Europe in the following years, becoming a serious threat for chestnut cultivations and rural economies of many countries. Exploring the variation in susceptibility of the host genetic resources is crucial to face the spreading of this pest. We used an experimental approach for testing the differential susceptibility within and between populations of European chestnut. For doing this, we compared both the infestation level and the rate of immune individuals in trees from populations of Spain, Italy, and Greece. We found that the level of infestation is not significantly different in the different provenances but that a higher rate of immune trees occur in Greece. Our results suggest that two different contingents of trees compose Greek populations: one major group of trees with the same susceptibility as the other populations and a second minor group of trees resistant to gall wasp infestation. Our data lay the basis for improving the currently adopted measures to mitigate gall wasp impacts.     

Assessment of Cyfluthrin commercial formulation on growth, photosynthesis and catalase activity of green algae

Aquatic environments of the pampasic region of Argentina are severely affected by agricultural contamination due to an increase in a glyphosate tolerant transgenic variety of soybean crops. The present study is aimed to determine the effects of a commonly used Cyfluthrin commercial formulation (CCF) on growth, some physiological and biochemical parameter of four species of green algae. Significant inhibition of algal growth was observed from 0.1 mg Cyf/l. 96 h IC₅₀ were between 0.92 and 4.85 mg Cyf/l. CCF caused algicidal effects. Photosynthesis was stimulated by 50% in Scenedesmus quadricauda cultures exposed to the lowest concentration (hormesis). Algal photosynthesis inhibition was observed at higher concentrations with IC₅₀ values between 1.7 and 8.9 mg Cyf/l. Similar toxicity endpoints were found as a consequence of applying the traditional methodology of short-term chronic toxicity test of 96 h of exposition and the methodology developed using the Clark type photosynthetic oxygen evolution method. CAT activity was significantly increased between 23% and 33% considering the four species, at a lower concentration than those affecting algal growth and photosynthesis, indicating a potential biomarker. Taking into account that the extent of the soybean crops in the region is about fourteen million hectares, the improvement and extension of environmental tools for early detection of the action of pesticides on this essential group of organisms are discussed.     

Model aging and oxidation effects on varietal, fermentative, and sulfur compounds in a dry botrytized red wine

From harvest until wine arrives to the consumer, oxygen plays a crucial role in the definition of the final aroma. In the present research, the effect of the model oxidative aging on a dry red Botrytis wine, such as Italian Amarone, was considered. Amarone wine was submitted to model oxidative aging and then analyzed with two different approaches (SPE-GC-MS and HS-SPME/GC-MS). The same sampling plan was adopted to study the model aging of the same Amarone wine in anaerobic conditions. The HS-SPME/GC-MS method was applied to investigate for the first time the effect of the oxidative aging on a vast number of fermentative sulfur compounds. This research highlighted peculiar evolutions for several volatile compounds. In particular, benzaldehyde showed a sensitive increment during the oxidative aging, with a rate much higher than that reported for non-Botrytis red wines. On the other hand, several sulfides (dimethyl sulfide, 3-(methylthio)-1-propanol, etc.) disappeared after just 15 days of oxidative aging. A wine oxidation marker such as 3-(methylthio)-propanal was not found in any of the oxidized wines; conversely methionol-S-oxide was tentatively identified. This evidence has not been mentioned in the literature. A possible involvement of grape withering process and Botrytis in these mechanisms was supposed: a dry red wine, produced from the same but without any grape withering process and Botrytis infection (e.g., Bardolino wine), was submitted to oxidative aging and analysis. This red wine showed an evolution similar to those reported in the literature for dry red wines but significantly different from the Amarone wine.     

Identification of <Emphasis Type="Italic">Pestalotiopsis bicilita,Diplodia seriata</Emphasis> and <Emphasis Type="Italic">Diaporthe eres</Emphasis> causing fruit rot in withered grapes in Italy

Pestalotiopsis biciliata, Diplodia seriata and Diaporthe eres were recovered from severely diseased bunches of withered grapes for Amarone wine production. To our knowledge this post-harvest disease has never been seen before in withered grapes. Fruit rot occurred with bunches containing decayed berries partially or totally covered by whitish mycelium. Morphological and phylogenetic analyses of fungal isolates from symptomatic fruits enabled species delimitation. Pathogenicity tests revealed that the three species are able to infect grape berries confirming that they are casual agents of fruit rot. This study provides preliminary insights on this post-harvest disease that might have important implications in grape quality.