Biology subjects

Grolimund, D.

Publications and source records attributed to Grolimund, D..

2 recordsLinked to original sources

bioRxiv2020

Arabidopsis thaliana Zn2+-efflux ATPases HMA2 and HMA4 are required for resistance to the necrotrophic fungus Plectosphaerella cucumerina BMM

O_LIZinc is an essential nutrient at low concentrations, but toxic at slightly higher ones. This could be used by plants to fight pathogens colonization. C_LIO_LIElemental distribution in Arabidopsis thaliana leaves inoculated with the necrotrophic fungus Plectosphaerella cucumerina BMM (PcBMM) was determined and compared to mock-inoculated ones. Infection assays were carried out in wild type and long-distance zinc trafficking double mutant hma2hma4, defective in root-to-shoot zinc partitioning. Expression levels of genes involved in zinc homeostasis or in defence phytohormone-mediated pathways were determined. C_LIO_LIZinc and manganese levels increased at the infection site. Zinc accumulation was absent in hma2hma4. HMA2 and HMA4 transcription levels were upregulated upon PcBMM inoculation. Consistent with a role of these genes in plant immunity, hma2hma4 mutants were more susceptible to PcBMM infection, phenotype rescued upon zinc supplementation. Transcript levels of genes involved in the salicylic acid, ethylene and jasmonate pathways were constitutively upregulated in hma2hma4 plants. C_LIO_LIThese data are consistent with a role of zinc in plant immunity not only of hyperaccumulator plants, but also of plants containing ordinary levels of zinc. This new layer of immunity seems to run in parallel to the already characterized defence pathways, and its removal has a direct effect on pathogen resistance. C_LI

plant biology↗

bioRxiv2017

Medicago truncatula Zinc-Iron Permease6 provides zinc to rhizobia-infected nodule cells

AbstractZinc is a micronutrient required for symbiotic nitrogen fixation. It has been proposed that in model legume Medicago truncatula, zinc is delivered in a similar fashion as iron, i.e. by the root vasculature into the nodule and released in the infection/differentiation zone. There, zinc transporters must introduce this element into rhizobia-infected cells to metallate the apoproteins that use zinc as a cofactor. MtZIP6 (Medtr4g083570) is a M. truncatula Zinc-Iron Permease (ZIP) that is expressed only in roots and nodules, with the highest expression levels in the infection/differentiation zone. Immunolocalization studies indicate that it is located in the plasma membrane of rhizobia-infected cells in the nodule. Down-regulating MtZIP6 expression levels with RNAi does not result in any strong phenotype when plants are being watered with mineral nitrogen. However, these silenced plants displayed severe growth defects when they depended on nitrogen fixed by their nodules, as a consequence of the loss of 80% of their nitrogenase activity. The reduction of this activity was not the result of iron not reaching the nodule, but an indirect effect of zinc being retained in the infection/differentiation zone and not reaching the cytosol of rhizobia-infected cells. These data are consistent with a model in which MtZIP6 would be responsible for zinc uptake by rhizobia-infected nodule cells in the infection/differentiation zone.

plant biology↗