Historical phenological responses in apple tree to contrasting warming contexts may clarify future crucial responses in Europe

National audienc

Target enrichment sequencing coupled with GWAS identifies MdPRX10 as a candidate gene in the control of budbreak in apple

The timing of floral budbreak in apple has a significant effect on fruit production and quality. Budbreak occurs as a result of a complex molecular mechanism that relies on accurate integration of external environmental cues, principally temperature. In the pursuit of understanding this mechanism, especially with respect to aiding adaptation to climate change, a QTL at the top of linkage group (LG) 9 has been identified by many studies on budbreak, but the genes underlying it remain elusive. Here, together with a dessert apple core collection of 239 cultivars, we used a targeted capture sequencing approach to increase SNP resolution in apple orthologues of known or suspected A. thaliana flowering time-related genes, as well as approximately 200 genes within the LG9 QTL interval. This increased the 275 223 SNP Axiom® Apple 480 K array dataset by an additional 40 857 markers. Robust GWAS analyses identified MdPRX10, a peroxidase superfamily gene, as a strong candidate that demonstrated a dormancy-related expression pattern and down-regulation in response to chilling. In-silico analyses also predicted the residue change resulting from the SNP allele associated with late budbreak could alter protein conformation and likely function. Late budbreak cultivars homozygous for this SNP allele also showed significantly up-regulated expression of C-REPEAT BINDING FACTOR (CBF) genes, which are involved in cold tolerance and perception, compared to reference cultivars, such as Gala. Taken together, these results indicate a role for MdPRX10 in budbreak, potentially via redox-mediated signaling and CBF gene regulation. Moving forward, this provides a focus for developing our understanding of the effects of temperature on flowering time and how redox processes may influence integration of external cues in dormancy pathways

Historical phenological responses in apple to contrasting warming contexts may clarify future crucial responses in Europe

UMR AGAP - équipe AFEF - Architecture et fonctionnement des espèces fruitièresPhenological responses to warming in temperate fruit trees have rarely been investigated in contrasting warming contexts. This framework is appropriate for highlighting varying responses that would combine chill accumulation declines and heat accumulation increases. A comprehensive overview of historical responses might clarify crucial future responses in the warmest European regions. To examine this issue, a dataset was constituted in apple from flowering dates collected for main BBCH stages in contrasting temperate regions of Western Europe and in different mild regions (Northern Morocco, Southern Brazil). Multiple change-point models were applied to series of flowering date, flowering duration and temperature, aiming to statistically analyse both flowering responses and temperature changes. Modelling of flowering date was used to understand the determinisms of warming responses. In addition, regional differences in dormancy dynamic were characterized by forcing tests. Statistical analysis provided an overview of flowering date responses at global scale, highlighting flowering advances, mainly in Europe and Morocco, but also stationary flowering date series in Brazilian and French Mediterranean regions. Modelling analysis supported the notion that flowering advances are due to heat accumulation increases, explained by marked warming during ecodormancy. Later dormancy releases due to chill declines were also supported in Europe and may explain, in long term, stationary flowering dates in the French Mediterranean region. While the flowering duration series were stationary whatever the region, the flowering duration was far longer in Moroccan and Brazilian regions compared to European. This was linked to contrasting differences in dormancy dynamic observed between these mild and temperate regions. Dormancy release was inadequate in mild due to poor chill accumulation, leading to extended flowering durations. Since later dormancy releases would already have significant impacts on flowering date in Europe, new crucial warming responses, such as extended flowering durations, could be experienced especially in Mediterranean regions in near future

Predicting flowering in apple with near-infrared spectrometry (NIRS) to improve orchard yield

International audienc

A COMPARISON BETWEEN PLANT COMMUNITY COMPOSITION AND BOTANICAL SPECIESGATHERED BY HONEY BEES IN A CULTIVATED LANDSCAPE OF WESTERN FRANCE

International audienc

A COMPARISON BETWEEN PLANT COMMUNITY COMPOSITION AND BOTANICAL SPECIESGATHERED BY HONEY BEES IN A CULTIVATED LANDSCAPE OF WESTERN FRANCE

International audienc

Characterization of dormancy-associated and flowering-time related mads-box transcription factors in apple

National audienceDormancy is an adaptive mechanism that enables plants to survive unfavorable climatic conditions. The production of temperate fruits, such as apple (Malus x domestica Borkh.), is closely related to bud dormancy, which is triggered by exposure to cold. Therefore, the predicted impact of the ongoing climate changes will result in difficulties for apple production. The present work aims to prospect and characterize genes encoding Dormancy-Associated (DAM) and flowering-time related MADS-box transcription factors in the dormancy process of apple. On one hand, we are exploring the allelic variation present in genes involved in bud dormancy and flowering control in an apple core collection. We have developed a target capture sequencing approach and used it for genome-wide association studies (GWAS). On the other hand, we are identifying protein-protein interactions between DAM and flowering-time proteins by yeast-two-hybrid and searching for their transcriptional targets. By making use of these approaches, we have re-defined and narrow down genomic regions associated to bud dormancy. Additionally, we have identified potential transcriptional complexes containing DAM and flowering-time related proteins that act in apple bud dormancy. These studies contribute to better characterize key processes in dormancy molecular control, as well as to identify possible biotechnological resources for breeding programs

Correlating the pollens gathered by Apis mellifera with the landscape features in western France

Honey bee health depends on various factors, including the availability of food resources and chronic exposure to toxins in the foraging area.These parameters can be evaluated using indicators based on either pollen gathered to the hive or landscape features of the foraging area, including the structure, land use, or density of such specific landscape elements as hedgerows.This study examines the correlation between the diversity of pollens gathered and the landscape features in a 3-km radius using Geographic Information System technology. Palynological analyses were performed on pollen pellets collected from sixteen apiaries in western France during one year. Richness, diversity and similarity indices were calculated for land-cover features and palynological data and then compared. The land-cover analyses permitted the identification of three different landscape contexts (hedgerow, cultivated, and urban landscapes). Although the palynological profiles were highly diverse, some taxa were conserved between hives. The flower richness was greater in the apiaries from urban landscapes than in apiaries from rural landscapes, regardless of the dominant land-cover.The statistical analysis did not associate a specific flora with a specific landscape. However, it was possible to distinguish the pollen gathered by bees in urban landscapes and from pollen collected in rural area