Nitric Oxide Detoxification by Mesorhizobium loti Affects Root Nodule Symbiosis with Lotus japonicus

Hydrogen Sulphide: A Key Player in Plant Development and Stress Resilience

Based on the research conducted so far, hydrogen sulphide (H2S) plays a crucial role in the development and stress resilience of plants. H2S, which acts as a signalling molecule, responds to different stresses such as heavy metals, drought, and salinity, and it regulates various aspects of plant growth and development including seed germination, root development, stomatal movement, flowering, and fruit ripening. Additionally, H2S is involved in mediating legume-Rhizobium symbiosis signalling. It modulates plant responses to external environmental stimuli by interacting with other signalling molecules like phytohormones, nitric oxide, and reactive oxygen species. Furthermore, H2S exerts these regulations since it can modify protein functions through a reversible thiol-based oxidative posttranslational modification called persulfidation, particularly in stress response and developmental processes. As a result, H2S is recognised as an important emerging signalling molecule with multiple roles in plants. Research in this field holds promise for engineering stress tolerance in crops and may lead to potential biotechnological applications in agriculture and environmental management.

Defense and senescence interplay in legume nodules

Immunity and senescence play a crucial role in the functioning of the legume symbiotic nodules. The miss-regulation of one of these processes compromises the symbiosis leading to death of the endosymbiont and the arrest of the nodule functioning. The relationship between immunity and senescence has been extensively studied in plant organs where a synergistic response can be observed. However, the interplay between immunity and senescence in the symbiotic organ is poorly discussed in the literature and these phenomena are often mixed up. Recent studies revealed that the cooperation between immunity and senescence is not always observed in the nodule, suggesting complex interactions between these two processes within the symbiotic organ. Here, we discuss recent results on the interplay between immunity and senescence in the nodule and the specificities of this relationship during legume-rhizobium symbiosis.