- Effects from climate change, adaptations and
greenhouse gas reduction at 2050

Abstract:

Atmospheric carbon dioxide (CO2) concentrations are among the chief factors shaping the mode and magnitude of interactions between plants and herbivorous insects. Here, we describe the first global analysis of systemic transcriptomic responses of grapevine Vitis vinifera plants to feeding of European grapevine moth Lobesia botrana larvae at future elevated CO2 concentrations. The study was conducted on mature, fruit-bearing grapevine plants under ambient and elevated CO2 concentrations in a grapevine free-air carbon dioxide enrichment (FACE) facility. Grapevine transcriptional response to herbivory was clearly dependent on phenological stage, with a higher number of differentially expressed genes identified at fruit development compared to berry ripening. At fruit development, more transcripts were differentially expressed as a response to herbivory under elevated compared to ambient CO2 concentrations. Classification of the respective transcripts revealed that in particular genes involved in metabolic pathways, biosynthesis of secondary metabolites and plant-pathogen interactions were significantly enriched. Most of these genes had similar expression patterns under both CO2 concentrations, with a higher fold-change under elevated CO2 concentrations. Differences in expression levels of a subset of herbivory responsive genes were further validated by RT-qPCR. Our study indicates that future elevated CO2 concentrations will affect interactions between grapevine plants and one of its key insect pests, with consequences for future relevance of L. botrana in worldwide viticulture.

Abstract:

We review direct and indirect effects of climate change on both the grapevine plant as a host for phytophagous insects, as well as on grape insect pests, their natural enemies and corresponding future grape plant protection strategies. Phenology, voltinism and distribution ranges are well known traits of many arthropods influenced by temperature as the key abiotic factor and thus by current and future climate change scenarios. Case studies of grapevine pests based on data from three decades point to clear changes in phenology of grape berry moths, shifts in distribution ranges of leafhoppers as vectors of grapevine diseases and range expansion of grapevine mealybugs. These case studies also illustrate the need to include data on putatively changed tri-trophic interactions in vineyards when predicting impacts of climate change on grapevine pest insects. Hence, future pest management strategies should be based on a sound set of field data obtained for both pests and antagonists under changed abiotic conditions, which can also build the basis for refining and extending currently existing models for forecasting population levels of respective insect pests.

Abstract:

Using barcoded pyrosequencing fungaland bacterial communities associated with grape berry clusters (Vitis viniferaL.) obtained from conventional, organic and biodynamic vine yard plots were investigated in two subsequent years at different stages during berry ripening. The four mosta bundant operational taxonomic units (OTUs) based on fungal ITS data were Botrytis cinerea, Cladosporium spp., Aureobasidium pullulans and Alternaria alternata which represented 57% and 47% of the total reads in 2010 and 2011, respectively. Members of the genera Sphingomonas, Gluconobacter, Pseudomonas, Erwinia, and Massilia constituted 67% of the total number of bacterial 16S DNA reads in 2010 samples and 78% in 2011 samples. Viticultural management system had no significant effect on abundance of fungi or bacteria in both years and at all three sampling dates. Exceptions were A.alternata and Pseudomonas spp. which were more abundant in the carposphere of conventional compared to biodynamic berries, as well as Sphingomonas spp. which was significantly less abundant on conventional compared to organic berries at an early ripening stage in 2011. In general,there were no significant differences in fungal and bacterial diversity indices or richness evident between management systems. No distinct fungal or bacterial communities were associated with the different maturation stages or management systems, respectively. An exception was the last stage of berry maturation in 2011, where the Simpson diversity index was significantly higher for fungal communities on biodynamiccompared to conventional grapes.Our study highlights the existence of complex and dynamic microbial communities in the grape cluster carposphere including both phytopathogenic and potentially antagonistic microorganisms that can have a significant impact on grape production. Such knowledge is particularly relevant for development, selection and application of effective control measures against economically important pathogens present in the grape carposphere.