A plant chitinase controls cortical infection thread progression and nitrogen-fixing symbiosis
- Aarhus University, Denmark
- University of Copenhagen, Denmark
- The James Hutton Institute, United Kingdom
- Kazusa DNA Research Institute, Japan
- National Agriculture and Food Research Organization, Japan
- Cited 9
- Views 2,076
- Annotations
Abstract
Morphogens provide positional information and their concentration is key to the organized development of multicellular organisms. Nitrogen-fixing root nodules are unique organs induced by Nod factor-producing bacteria. Localized production of Nod factors establishes a developmental field within the root where plant cells are reprogrammed to form infection threads and primordia. We found that regulation of Nod factor levels by Lotus japonicus is required for the formation of nitrogen-fixing organs, determining the fate of this induced developmental program. Our analysis of plant and bacterial mutants shows that a host chitinase modulates Nod factor levels possibly in a structure-dependent manner. In Lotus, this is required for maintaining Nod factor signalling in parallel with the elongation of infection threads within the nodule cortex, while root hair infection and primordia formation are not influenced. Our study shows that infected nodules require balanced levels of Nod factors for completing their transition to functional, nitrogen-fixing organs.
Article and author information
Author details
Kasper Røjkjær Andersen
Funding
Danish Reasearch Foundation (DNRF79)
- Anna Malolepszy
- Simon Kelly
- Kasper Kildegaard Sørensen
- Christina Kalisch
- Zoltan Bozsoki
- Michael Panting
- Stig U Andersen
- Dorthe Bødker Jensen
- Maria Vinther
- Noor de Jong
- Lene Heegaard Madsen
- Kira Gysel
- Mette U Berentsen
- Michael Blaise
- Knud Jørgen Jensen
- Mikkel B Thygesen
- Niels Sandal
- Kasper Røjkjær Andersen
- Simona Radutoiu
China Scholarship Council (201604910506)
- Ke Tao
The funders had no role in study design, data collection and interpretation, or the decision to submit the work for publication.
Reviewing Editor
- Gary Stacey, University of Missouri, United States
Publication history
- Received: June 3, 2018
- Accepted: October 2, 2018
- Accepted Manuscript published: October 4, 2018 (version 1)
- Version of Record published: October 17, 2018 (version 2)
Copyright
© 2018, Malolepszy et al.
This article is distributed under the terms of the Creative Commons Attribution License permitting unrestricted use and redistribution provided that the original author and source are credited.
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Further reading
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- Microbiology and Infectious Disease
- Plant Biology
In plants, establishment of de novo DNA methylation is regulated by the RNA-directed DNA methylation (RdDM) pathway. RdDM machinery is known to concentrate in the Cajal body, but the biological significance of this localization has remained elusive. Here, we show that the antiviral methylation of the Tomato yellow leaf curl virus (TYLCV) genome requires the Cajal body in Nicotiana benthamiana cells. Methylation of the viral genome is countered by a virus-encoded protein, V2, which interacts with the central RdDM component AGO4, interfering with its binding to the viral DNA; Cajal body localization of the V2-AGO4 interaction is necessary for the viral protein to exert this function. Taken together, our results draw a long sought-after functional connection between RdDM, the Cajal body, and antiviral DNA methylation, paving the way for a deeper understanding of DNA methylation and antiviral defences in plants.
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- Cell Biology
- Plant Biology
TARGET OF RAPAMYCIN (TOR) is a protein kinase that coordinates eukaryotic metabolism. In mammals, TOR specifically promotes translation of ribosomal protein mRNAs when amino acids are available to support protein synthesis. The mechanisms controlling translation downstream from TOR remain contested, however, and are largely unexplored in plants. To define these mechanisms in plants, we globally profiled the plant TOR-regulated transcriptome, translatome, proteome, and phosphoproteome. We found that TOR regulates ribosome biogenesis in plants at multiple levels, but through mechanisms that do not directly depend on 5′ oligopyrimidine tract motifs (5′TOPs) found in mammalian ribosomal protein mRNAs. We then show that the TOR-LARP1-5′TOP signaling axis is conserved in plants and regulates expression of a core set of eukaryotic 5′TOP mRNAs, as well as new, plant-specific 5′TOP mRNAs. Our study illuminates ancestral roles of the TOR-LARP1-5′TOP metabolic regulatory network and provides evolutionary context for ongoing debates about the molecular function of LARP1.
