Mutational analysis indicates that abnormalities in rhizobial infection and subsequent plant cell and bacteroid differentiation in pea (Pisum sativum) nodules coincide with abnormal cytokinin responses and localization
Open Access
- 21 March 2020
- journal article
- research article
- Published by Oxford University Press (OUP) in Annals of Botany
- Vol. 125 (6), 905-923
- https://doi.org/10.1093/aob/mcaa022
Abstract
Background and Aims: Recent findings indicate that Nod factor signalling is tightly interconnected with phytohormonal regulation that affects the development of nodules. Since the mechanisms of this interaction are still far from understood, here the distribution of cytokinin and auxin in pea (Pisum sativum) nodules was investigated. In addition, the effect of certain mutations blocking rhizobial infection and subsequent plant cell and bacteroid differentiation on cytokinin distribution in nodules was analysed. Methods: Patterns of cytokinin and auxin in pea nodules were profiled using both responsive genetic constructs and antibodies. Key Results: In wild-type nodules. cytokinins were found in the meristem, infection zone and apical part of the nitrogen fixation zone, whereas auxin localization was restricted to the meristem and peripheral tissues. We found significantly altered cytokinin distribution in sym33 and sym40 pea mutants defective in IPD3/CYCLOPS and ETD transcription factors, respectively. In the sym33 mutants impaired in bacterial accommodation and subsequent nodule differentiation, cytokinin localization was mostly limited to the meristem. In addition, we found significantly decreased expression of LOG1 and A-type RR11 as well as KNOX3 and NIN genes in the sym33 mutants, which correlated with low cellular cytokinin levels. In the sym40 mutant, cytokinins were detected in the nodule infection zone but, in contrast to the wild type, they were absent in infection droplets. Conclusions: In conclusion, our findings suggest that enhanced cytokinin accumulation during the late stages of symbiosis development may be associated with bacterial penetration into the plant cells and subsequent plant cell and bacteroid differentiation.Keywords
Funding Information
- Russian Science Foundation (16-16-10043)
This publication has 85 references indexed in Scilit:
- Two Direct Targets of Cytokinin Signaling Regulate Symbiotic Nodulation in Medicago truncatulaPlant Cell, 2012
- A Phylogenetic Strategy Based on a Legume-Specific Whole Genome Duplication Yields Symbiotic Cytokinin Type-A Response RegulatorsPlant Physiology, 2011
- MicroRNAs in the Rhizobia Legume SymbiosisPlant Physiology, 2009
- CYCLOPS, a mediator of symbiotic intracellular accommodationProceedings of the National Academy of Sciences of the United States of America, 2008
- EFD Is an ERF Transcription Factor Involved in the Control of Nodule Number and Differentiation inMedicago truncatulaPlant Cell, 2008
- Cytokinins Act Directly on Lateral Root Founder Cells to Inhibit Root InitiationPlant Cell, 2007
- Cytokinins Determine Arabidopsis Root-Meristem Size by Controlling Cell DifferentiationCurrent Biology, 2007
- TheMedicago truncatulaCRE1 Cytokinin Receptor Regulates Lateral Root Development and Early Symbiotic Interaction withSinorhizobium melilotiPlant Cell, 2006
- RNAi Phenotypes and the Localization of a Protein::GUS Fusion Imply a Role for Medicago truncatula PIN Genes in NodulationJournal of Plant Growth Regulation, 2006
- Analysis of Relative Gene Expression Data Using Real-Time Quantitative PCR and the 2−ΔΔCT MethodMethods, 2001