ORCID Profile
0000-0002-6643-8019
Current Organisation
Aarhus University
Does something not look right? The information on this page has been harvested from data sources that may not be up to date. We continue to work with information providers to improve coverage and quality. To report an issue, use the Feedback Form.
Publisher: Springer Science and Business Media LLC
Date: 05-07-2021
Publisher: Oxford University Press (OUP)
Date: 04-12-2020
Abstract: Rhizobial infection of legume roots during the development of nitrogen-fixing root nodules can occur intracellularly, through plant-derived infection threads traversing cells, or intercellularly, via bacterial entry between epidermal plant cells. Although it is estimated that around 25% of all legume genera are intercellularly infected, the pathways and mechanisms supporting this process have remained virtually unexplored due to a lack of genetically amenable legumes that exhibit this form of infection. In this study, we report that the model legume Lotus japonicus is infected intercellularly by the IRBG74 strain, recently proposed to belong to the Agrobacterium clade of the Rhizobiaceae. We demonstrate that the resources available for L. japonicus enable insight into the genetic requirements and fine-tuning of the pathway governing intercellular infection in this species. Inoculation of L. japonicus mutants shows that Ethylene-responsive factor required for nodulation 1 (Ern1) and Leu-rich Repeat Receptor-Like Kinase (RinRK1) are dispensable for intercellular infection in contrast to intracellular infection. Other symbiotic genes, including nod factor receptor 5 (NFR5), symbiosis receptor-like kinase (SymRK), Ca2+/calmodulin dependent kinase (CCaMK), exopolysaccharide receptor 3 (Epr3), Cyclops, nodule inception (Nin), nodulation signaling pathway 1 (Nsp1), nodulation signaling pathway 2 (Nsp2), cystathionine-β-synthase (Cbs), and Vapyrin are equally important for both entry modes. Comparative RNAseq analysis of roots inoculated with IRBG74 revealed a distinctive transcriptome response compared with intracellular colonization. In particular, several cytokinin-related genes were differentially regulated. Corroborating this observation, cyp735A and ipt4 cytokinin biosynthesis mutants were significantly affected in their nodulation with IRBG74, whereas lhk1 cytokinin receptor mutants formed no nodules. These results indicate a differential requirement for cytokinin signaling during intercellular rhizobial entry and highlight distinct modalities of inter- and intracellular infection mechanisms in L. japonicus.
Publisher: Springer Science and Business Media LLC
Date: 08-03-2023
DOI: 10.1038/S41586-023-05791-5
Abstract: Increasing the proportion of locally produced plant protein in currently meat-rich diets could substantially reduce greenhouse gas emissions and loss of bio ersity 1 . However, plant protein production is h ered by the lack of a cool-season legume equivalent to soybean in agronomic value 2 . Faba bean ( Vicia faba L.) has a high yield potential and is well suited for cultivation in temperate regions, but genomic resources are scarce. Here, we report a high-quality chromosome-scale assembly of the faba bean genome and show that it has expanded to a massive 13 Gb in size through an imbalance between the rates of lification and elimination of retrotransposons and satellite repeats. Genes and recombination events are evenly dispersed across chromosomes and the gene space is remarkably compact considering the genome size, although with substantial copy number variation driven by tandem duplication. Demonstrating practical application of the genome sequence, we develop a targeted genotyping assay and use high-resolution genome-wide association analysis to dissect the genetic basis of seed size and hilum colour. The resources presented constitute a genomics-based breeding platform for faba bean, enabling breeders and geneticists to accelerate the improvement of sustainable protein production across the Mediterranean, subtropical and northern temperate agroecological zones.
Publisher: Wiley
Date: 20-05-2018
DOI: 10.1111/TPJ.13934
Abstract: Symbiotic nitrogen fixation in legumes requires nodule organogenesis to be coordinated with infection by rhizobia. The plant hormone auxin influences symbiotic infection, but the precise timing of auxin accumulation and the genetic network governing it remain unclear. We used a Lotus japonicus optimised variant of the DII-based auxin accumulation sensor and identified a rapid accumulation of auxin in the epidermis, specifically in the root hair cells. This auxin accumulation occurs in the infected root hairs during rhizobia invasion, while Nod factor application induces this response across a broader range of root hairs. Using the DR5 auxin responsive promoter, we demonstrate that activation of auxin signalling also occurs specifically in infected root hairs. Analysis of root hair transcriptome data identified induction of an auxin biosynthesis gene of the Tryptophan Amino-transferase Related (LjTar1) family following both bacteria inoculation and Nod factor treatment. Genetic analysis showed that both expression of the LjTar1 biosynthesis gene and the auxin response requires Nod factor perception, while common symbiotic pathway transcription factors are only partially required or act redundantly to initiate auxin accumulation. Using a chemical genetics approach, we confirmed that auxin biosynthesis has a functional role in promoting symbiotic infection events in the epidermis.
Publisher: Cold Spring Harbor Laboratory
Date: 23-12-2022
DOI: 10.1101/2022.12.23.521739
Abstract: Legume-rhizobium signaling during establishment of symbiotic nitrogen fixation restricts rhizobium colonization to specific cells. A limited number of root hair cells allow infection threads to form, and only a fraction of the epidermal infection threads progress to cortical layers to establish functional nodules. Here we use single-cell analysis to define the epidermal and cortical cell populations that respond to and facilitate rhizobium infection. We then identify high-confidence nodulation gene candidates based on their specific expression in these populations, pinpointing genes stably associated with infection across genotypes and time points. We show that one of these, which we name SYMRKL1 , encodes a protein with an ectodomain predicted to be nearly identical to that of SYMRK and is required for normal infection thread formation. Our work disentangles cellular processes and transcriptional modules that were previously confounded due to lack of cellular resolution, providing a more detailed understanding of symbiotic interactions.
Publisher: Oxford University Press (OUP)
Date: 21-07-2017
DOI: 10.1104/PP.17.00832
Publisher: Frontiers Media SA
Date: 02-08-2019
Publisher: Elsevier BV
Date: 09-2019
No related grants have been discovered for Marcin Nadzieja.