Influence of pea genotype on root associated fluorescent pseudomonads, consequences for plant iron nutrition

Archive ouverte

Lurthy, Tristan | Avoscan, Laure | Lemaître, Jean-Paul, J.-P. | Barraud, Catherine | Lemanceau, Philippe | Mazurier, Sylvie

Edité par CCSD -

prod 2019-99c SPE EA BIOmE INRA GENOSOL DOCT. International audience. Pea has a high potential in agroecology because of its ability to fix atmospheric nitrogen and in Human nutrition because of the high aminoacid content of its grains. However, pea may suffer from a susceptibility to iron deficiency in calcareous soils. This susceptibility varies depending on cultivars. Pseudomonad siderophores, pyoverdines (pvd), were shown to promote iron nutrition in Arabidopsis and tobacco. Thus, we hypothesize that variations in iron susceptibility between pea cultivars could be related to differences in their ability to recruit fluorescent pseudomonad (fp) contributing to siderophore-mediated iron nutrition. Our aims were to compare i) the impact of a susceptible (S) and a tolerant (T) cultivar of pea on fp biodiversity with a focus on their pvd, and in return ii) the impact of the corresponding bacteria and pvd on pea iron nutrition. The strategy consisted in cultivating S & T pea cultivars in a calcareous soil (low iron bioavailability). fp associated with roots of S & T and corresponding pvd were compared. In return, representative pvd from fp associated with S and T were tested for i) their effect on the transcription of genes involved in plant iron uptake and homeostasis (rt-qPCR) and ii) their impact on plant growth, iron content and ionome (HRICP-MS). Differences recorded between fp associated with T and S roots were related to i) their low susceptibility to Fe deficiency and ii) their pvd types as characterized by isoelectrofocalisation. Representatives of major pvd types impacted differently S & T for i) iron content, plant ionome and growth of pea and ii) the transcription of genes involved in plant iron metabolism. The results obtained support the principle of an extended phenotype in which associated bacteria contribute to plant nutrition, showing the importance to consider root microbiota to develop strategies aiming at overcoming iron susceptibility in pea. Further studies are in progress to unravel the mechanisms implied.

• Description
• Sujet/Public
• Outil
• Outil d'anticipation
• Mémoire et thèse
• Gestion