Enhancement of Clover (Trifolium alexandrinum L.) Shade Tolerance and Nitrogen Fixation under Dense Stands-Based Cropping Systems

Improving legumes crops’ performance under dense stands shade environment (e.g., intercropped oats–clover) is needed to promote agroecological practices. Previous studies have revealed that ethylene produced by plants standing conditions among other factors affect growth and reduce legumes’ ability fix nitrogen (N). Here, we identified a Pseudomonas thivervalensis strain T124 as high ACC deaminase-producing bacterium evaluated its potential alleviate the effects of reduced light (RL) exogenous applied (ethylene precursor) on clover development controlled field at oats intercrops. RL decreases root shoots biomass, whereas counteracted effects, enhancing tolerance shade. Exogenous chlorophyll content while inducing overaccumulation reactive oxygen species (H2O2 O2•−). ACC-elicited cellular stress was suppressed T124, suggesting role bacterial deaminase activity. Combined with Rhizobium leguminosarum T618 (the being able N in symbiosis clover), prevents early nodule senescence improving leghemoglobin reducing nitric oxide levels. Co-inoculation + increased shoot (+24%) more than alone. Field experiments intercropping Photosynthetic Active Radiation (PAR) top due oats, affecting photosynthesis assimilation. Interestingly, inoculation treatments, net photosynthetic rate (Anet) stomatal conductance (Gs) were found improve relative control treatments. Clover exhibits improved terms branching nodulation after inoculation. Most significant improvements occurred mixing two strains. Data suggest co-inoculation R. P. potentially interspecific competition between intercrops Our study competitive rhizobia PGPRs an eco-friendly approach systems’ performance.