Visualization of the Crossroads between a Nascent Infection Thread and the First Cell Division Event in Phaseolus vulgaris Nodulation

• Published in: International journal of molecular sciences Vol. 23; no. 9; p. 5267
• Main Authors: Monroy-Morales, Elizabeth, Dávila-Delgado, Raúl, Ayala-Guzmán, Emmanuel, Gamboa-deBuen, Alicia, Sánchez-López, Rosana
• Format: Journal Article
• Language: English
• Published: Switzerland MDPI AG 09.05.2022; MDPI
• Subjects: Cell cycle; Cell Division; cell plate; Cell walls; Cyclin-dependent kinases; Cytokinesis; French beans; Genes; Genetic analysis; Hair; infection thread; Infections; Kinases; Legumes; Nitrogen; Nitrogen fixation; Nitrogenation; Nodulation; Nodules; nucleus; Organogenesis; Phaseolus - microbiology; Phaseolus vulgaris; Plant Proteins - genetics; Plant Root Nodulation; Plant Roots - genetics; Rhizobium - genetics; Root Nodules, Plant - microbiology; Stain; Symbiosis - genetics; Transcription factors; KNOLLE; infection thread; rhizobia; Phaseolus vulgaris; cell plate; cytokinesis; cell division; nucleus; nodulation
• ISSN: 1422-0067; 1661-6596; 1422-0067
• DOI: 10.3390/ijms23095267

The development of a symbiotic nitrogen-fixing nodule in legumes involves infection and organogenesis. Infection begins when rhizobia enter a root hair through an inward structure, the infection thread (IT), which guides the bacteria towards the cortical tissue. Concurrently, organogenesis takes place by inducing cortical cell division (CCD) at the infection site. Genetic analysis showed that both events are well-coordinated; however, the dynamics connecting them remain to be elucidated. To visualize the crossroads between IT and CCD, we benefited from the fact that, in nodulation, where the first division occurs in subepidermal cortical cells located underneath the infection site, we traced a strain expressing DsRed, the plant cytokinesis marker YFP- KNOLLE, a nuclear stain and cell wall auto-fluorescence. We found that the IT exits the root hair to penetrate an underlying subepidermal cortical (S-E) cell when it is concluding cytokinesis.