于大巴黎的一家实验室目前拟招收一名中国籍博士生，奖学金数额约为1200欧元/月，为期最长4年。有关情况如下（英文），具备生物学方面最好是植物生物学方面研究生学历的学生如感兴趣，请尽快尽快将简历邮件至：[email protected]。
PhD proposal
Title
Contact information: [email protected]
Laboratory name Institut des Sciences du Végétal - Team ‘Legume rootarchitecture’
Laboratory web site http://www.isv.cnrs-gif.fr/isv/veranglais/research/ffa/ffa.html
Leguminous plants have the ability toestablish a symbiotic association with some rhizobial bacteria able to convertatmospheric nitrogen (N2) into ammonia for the benefit of the host plant. Thisplant-microbe interaction leads to the formation on plant roots of new organscalled nodules where bacteria are hosted in a suitable environment to reduce N2 (Crespi and Frugier,2008). This association therefore allows legumes to grow in soil deprived ofnitrogen and to produce protein-rich grains at low-cost since legumecultivation does not require use of nitrogen fertilizers.
Nodule formation is triggered following amolecular dialogue between host legumes root and soil bacteria from the Rhizobiumgenus (Crespi and Frugier, 2008). Flavonoids released by the root chemicallyattract Rhizobium and activate the bacterial production of Nod factor signalingmolecules. These compounds, once perceived by root hairs, trigger two processesoccurring simultaneously and which are both required for the emergence offunctional nodules: bacterial infection and nodule organogenesis.
Nod factors interact with plant hormonesignaling pathway to promote nodule development and particularly with the cytokininsignalling pathway (Frugier et al., 2008).
In our lab, we have shown that the specificinactivation of the Medicago truncatula cytokinin receptor MtCRE1 largelyinhibited nodule formation (Gonzalez-Rizzo et al., 2006; Plet et al., 2011).Analysis of Mtcre mutant revealed that cytokinins act both in initial corticalcell division and later in indeterminate nodule meristem. Mtcre1 mutationimpaired also cytokinin regulations of several transcription factors criticalfor nodulation (Plet et al., 2011). Recently, we determined in vitro theconsensus sequence recognized by the response regulator MtRR1 largely expressedin roots. This sequence was then identified in the promoters of genes rapidlyregulated by cytokinins and new direct cytokinin targets corresponding to transcriptionfactors were demonstrated to be positively required in nodule formation (Arielet al., 2012).
The PhD proposal follows the researches we areconducting on the role of cytokinin signalling in Medicago truncatulanodulation. The main objective will be to identify new components regulatingcytokinin signalling pathway in legume roots. This objective will be achievedusing an integrated approach: genetics to determine the role in nodulation andcytokinin signalling (Medicago truncatula insertional mutants are alreadyavailable in the lab), in situ hybridization and immunohistolocalization to follow spatial andtemporal regulation, biochemistry to study cytokinin and Nod factor regulation(especially postranslational modifications), high-throughput transcriptomicsforthe identification of transcriptional network and promoter targets (RNA seq,ChIP seq).
