24 Feb Oferta de Doctorado en Francia, French National Institute for Agronomic Research
PHD offer in FRANCE
Following French President’s visit to Mexico in 2014, agreements have been signed between both Countries to strengthen scientific exchanges.
CONACYT is offering PhD fellowships for students wishing to come to France.
The PhD subject below has been submitted to the CONACYT PhD fellowship program.
CONACYT is giving high propriety to several areas of research, including “Aprovechamento y proteccion de ecosistemas y de la biodiversidad”
INRA UR AGPF
French National Institute for Agronomic Research Forest Tree Genetics, Physiology and Breeding Unit
Orléans – FRANCE (100 km South of Paris)
Contact person: Dr Arnaud DOWKIW [email protected]
Breeding to save a tree species from a disease: quantifying and understanding the genetic variability of Fraxinus excelsior for susceptibility to Hymenoscyphus fraxineus.
Because they are long-lived species, trees are subjected to many biotic and abiotic stresses. While native pests can have effects on local or large areas, yet they do not cause species extinction. In contrast, exotic pests can threaten the continued existence of a species if the species lacks non-host or exapted resistance. Among the 11 major tree pests and pathogens reviewed in Boyd et al. (Science 2013), five have been introduced from Asia (including the Citrus greening disease which is now affecting Mexico).
Among those five, two are threatening Ash (Fraxinus) either in Northern America (insect: Agrilus Planipennis) or in Europe (fungus: Hymenoscyphus fraxineus). Severe dieback of European common ash (Fraxinus excelsior) due to H. fraxineus was first reported in Poland and Lithuania in the early 1990s. Since then, the pathogen infected at least 26 countries with its current South-Western limit now in Central France. The observed symptoms have long been thought to result from a combination of disease outbreaks due to climate change or to the emergence of new pathogens and vectors. It was fourteen years after the first reports that an ascomycete was finally identified as the primary causal agent. Recent data indicate that the fungus is an invasive pest in Europe and most probably originates from Asia.
Consequences of the disease can be severe. In Lithuania, 10 years after the first report, over 30,000 ha of common ash stands were reported to be affected and mortality was estimated to be 60% state wide. In some parts of North-Eastern France, only 3% of the trees remained completely healthy 2 years after the first reports. Fraxinus excelsior is distributed all over France. It is the fifth broadleave species in terms of acreage and the main component of several ecosystems. The disease is thus considered a major threat for the species and for all associated species and environments.
Breeding for better levels of resistance is the most ecologically and economically suitable strategy for forest trees. However, the prerequisite for such strategy is the existence of sufficient genetic variation for resistance to the disease in the host species. There are some indications that such variation exists in F. excelsior and that it is heritable.
This PhD will aim at a better understanding of the genetic variability in F. excelsior for susceptibility to H. fraxineus. Most specifically, it will focus on decomposing this genetic variability into individual, familial and population levels but – and more challenging – into:
– Different resistance responses linked to the different symptoms induced by the disease (crown vs. trunk symptoms)
– Resistance vs. avoidance, especially by studying the relationship between phenology (budflush, leaf senescence) and susceptibility
This work will benefit from the expertise of the UAGPF INRA laboratory in terms of tree biology, phytopathology and breeding. A valuable amount of data is already available from a network of field experiments representing more than 30, 000 trees originating from several European countries.
The candidate will collect additional data from some of these field experiments while selected material from already existing datasets will serve for more detailed investigations. Depending on the candidate’s skills and centers of interest, these investigations will be more focused on breeding strategies, phytopathology (symptoms), biochemical (infra-red spectrometry) or implementation of molecular tools.
The applicant must have adequate theoretical knowledge in genetics and plant breeding. Very basic knowledge in plant pathology is sufficient. Most important is the desire to learn and understand and the ability to communicate, be autonomous and work in team. Although recommended, speaking French is not compulsory. Candidates will be asked to learn French during their stay in order to facilitate everyday life in the lab. English must be spoken fluently.