Nitric Oxide role in rice root formation and development exposed to viable and autoclaved mycorrhizal spores

Giulia Raffaele ¹, Marilena Ronzan ², Emanuela Del Dottore ³, Barbara Mazzolai ³

Istituto Italiano di Tecnologia & Università di Napoli Federico II ¹, Istituto Italiano di Tecnologia ², Istituo Italiano di Tecnologia ³

Nitric oxide (NO) is a reactive nitrogen species involved with various signalling processes in the plant responses to biotic stresses. Nowadays, it is evident that NO is accumulated during the interaction with rhizobia bacteria (Berger et al., 2020) and arbuscular mycorrhizal fungi (Martínez‐Medina et al., 2019). However, its specific role remains unclear. This study aims to elucidate the role of NO in the early stages of the interaction between Oryza sativa L. and Rhizophagus irregularis (MUCL 41833), focusing on its influence on the formation and development of large lateral roots, which are preferentially colonised during the AM symbioses (Chiu et al., 2022). Experiments were conducted using a treated group with viable and autoclaved spores, as well as a control group. Three replicates of the experiment were carried out. Nitric oxide was detected through DAF-FM specific dye seven days post-inoculation. The NO endogenous signal was located in the root primordia and the internal tissues of the large lateral roots in the treated group with viable spores, whereas it was not detected in the roots of the autoclaved spores and control group. These results suggest that nitric oxide plays a role in the development of the root primordia and large lateral roots following arbuscular mycorrhizal fungi perception. Further research will be essential to determine the nitric oxide signal pathways and clarify its interaction with other molecules during the mycorrhizal pre-symbiotic phase. Bibliography BERGER, A., GUINAND, S., BOSCARI, A., PUPPO, A. & BROUQUISSE, R. (2020) Medicago truncatula Phytoglobin 1.1 controls symbiotic nodulation and nitrogen fixation via the regulation of nitric oxide concentration. New Phytologist 227, 84–98. CHIU, C.H., ROSZAK, P., ORVOŠOVÁ, M. & PASZKOWSKI, U. (2022) Arbuscular mycorrhizal fungi induce lateral root development in angiosperms via a conserved set of MAMP receptors. Current Biology 32, 4428-4437.e3. MARTÍNEZ‐MEDINA, A., PESCADOR, L., FERNÁNDEZ, I., RODRÍGUEZ‐SERRANO, M., GARCÍA, J.M., ROMERO‐PUERTAS, M.C. & POZO, M.J. (2019) Nitric oxide and phytoglobin PHYTOGB1 are regulatory elements in the Solanum lycopersicum – Rhizophagus irregularis mycorrhizal symbiosis. New Phytologist 223, 1560–1574.

Main author career stage: PhD student

Contribution type: Talk

First choice session: 4. Structure, physiology, and development

Second choice session: 2. Ecology