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Molecular study of the effect of bud carbon status on dormancy cycle regulation in apple tree
Reference
1572527438
Deadline for applications
11/20/2019
Date of publication
10/31/2019

Details

Details on the type of contract
Internship
Duration of contract
6 months
Beginning
01/20/2020

Remuneration
According to the regulations in force for 2020 (around 580 € / month)
Professional field
Biology

Assignment

Name of unit of assignment
UMR1334 AGAP Amélioration Génétique et Adaptation des Plantes méditerranéennes et Tropicales
Address of unit of assignment
INRA - Campus Supagro Montpellier 2 place Viala 34060 MONTPELLIER CEDEX 2
Website of unit of assignment
http://umr-agap.cirad.fr/
Region of assignment
Occitanie

Description

Working environment

The AFEF team is focused on the study of the phenotypic variability of vegetative and reproductive development in perennial fruit species. In particular, we are interested in understanding the molecular control of the dormancy cycle in apple tree (Malus × domestica Borkh.) (Allard et al., 2016). Dormancy is an adaptive mechanism that enables plants to survive unfavorable climatic conditions, for example during winter, and allows budbreak (and flowering) to occur only when the conditions are more permissive, typically in spring. It was proposed that dormancy cycle in temperate trees is divided in three phases: paradormancy, endodormancy and ecodormancy (Falavigna et al., 2018). The duration and intensity of these phases is affected by different internal and external factors, such as bud carbon (sugar) status and temperature, respectively (Falavigna et al., 2018; Legave et al., 2013). Indeed, it was observed in our team that carbon reserves of the tree in spring and summer of a given year influences the timing of budbreak in the year after. In turn, carbon status is highly dependent on the presence of fruits, as they are strong sugar sinks. Thus, we have hypothesized that fruits could have a significant effect on dormancy cycle control by affecting sugar accessibility in the buds. To explore this question, the selected student will analyze the effect of apple fruits on the temporal expression pattern of sugar and dormancy-related genes and micro RNAs (miRNAs) in buds during the winter dormancy cycle. These data will be used to build a molecular pathway that, together with sugar content measurements and climatic data, will be integrated in Function-Structure Plant Models (FSPM) to predict dormancy cycle progression and budbreak.

 

1) monitoring apple dormancy dynamics by using physiological tests i.e. Tabuenca test (Malagi et al., 2015); 2) sampling apple buds in field during the dormancy cycle, 3) isolation of RNA and small RNAs and synthesis of cDNA, 4) quantification of candidate genes and miRNAs expression by RT-qPCR, using an optimized method for miRNAs analyses (Androvic et al., 2017), 5) analysis of the results and elaboration of a model to explain the molecular control of the dormancy cycle in apple to be integrated in FSPM.

  

Activities :

 

- Sample collection and management.

- Isolation of RNA and small RNA using commercial kits.

- Quantification and quality control of RNA and small RNA using NanoQuant and Agilent 4200 TapeSation.

- Utilisation of a LightCycler 480 Instrument for RT-qPCR experiments.

- Statistical analyses of the results.

Publications  :

Allard A., Bink M.C.A.M., Martinez S., Kelner J.-J., Legave J.-M., di Guardo M., Di Pierro E.A., Laurens F., van de Weg E.W., et Costes E. 2016. Detecting QTLs and putative candidate genes involved in budbreak and flowering time in an apple

Androvic, P., Valihrach, L., Elling, J., Sjoback, R., and Kubista, M. (2017). Two-tailed RT-qPCR: a novel method for highly accurate miRNA quantification. Nucleic Acids Res 45, e144. doi:10.1093/nar/gkx588.

Cornille A., Giraud T., Marinus J. M. Smulders, Isabel Roldàn-Ruiz, Gladieux P. The domestication and evolutionary ecology of apples (2014) Trends in Genetics doi:10.1016/j.tig.2013.10.002

Falavigna V. da S., Guitton B., Costes E., et Andrés F. 2019. I Want to (Bud) Break Free: The Potential Role of DAM and SVP-Like Genes in Regulating Dormancy Cycle in Temperate Fruit Trees. Frontiers in Plant Science. 9, p. 1990

Legave J.M., Blanke M., Christen D., Giovannini D., Mathieu V., et Oger R. 2013. A comprehensive overview of the spatial and temporal variability of apple bud dormancy release and blooming phenology in Western Europe. International Journal of Biometeorology. 57(2), p. 317-331.

Malagi, G., Sachet, M. R., Citadin, I., Herter, F. G., Bonhomme, M., Regnard, J.-L., et al. (2015). The comparison of dormancy dynamics in apple trees grown under temperate and mild winter climates imposes a renewal of classical approaches. Trees 29, 1365–1380. doi:10.1007/s00468-015-1214-3.

Training and skills required

PROFILE REQUIRED:

 - Master 1 on plant functional biology or related

- Knowlegde on plant molecular biology

- Operational competences: experience in lab work.

- Languages : English

Contact

Name
Fernando ANDRES-LALAGUNA / Evelyne COSTES
Telephone
+ 33 4 67 61 59 23 / + 33 4 67 61 75 08
Email
fernando.andres-lalaguna@inra.fr ; evelyne.costes@inra.fr