Rhizobia are bacteria that exhibit both endophytic and free-living lifestyles. Endophytic rhizobial strains are widely known to infect leguminous host plants, while some do infect non-legumes. Infection of leguminous roots often results in the formation of root nodules. Associations between rhizobia and host plants may result in beneficial or non-beneficial effects. Such effects are linked to various biochemical changes that have far-reaching implications on relationships between host plants and the dependent multitrophic biodiversity. This paper explores relationships that exist between rhizobia and various plant species. Emphasis is on nutritional and phytochemical changes that occur in rhizobial host plants, and how such changes affect diverse consumers at different trophic levels. The purpose of this paper is to bring into context various aspects of such interactions that could improve knowledge on the application of rhizobia in different fields. The relevance of rhizobia in sustainable food systems is addressed in context.

Postharvest losses amongst small-scale farmers in developing countries are high due to inadequate resources and infrastructure. Among the various affected crops, tomatoes are particularly vulnerable; however, studies on postharvest losses of most fruits and vegetables are limited. Therefore, this study aimed to assess postharvest tomato losses under different production systems within the small-scale supply chain using the indirect assessment (questionnaires and interviews) and direct quantification of losses. Farmers reported tomato losses due to insects (82.35%), cracks, bruises, and deformities (70.58%), and diseases (64.71%). Chemical sprays were the main form of pest and disease control reported by all farmers. The direct quantification sampling data revealed that 73.07% of the tomatoes were substandard at the farm level, with 47.92% and 25.15% categorized as medium-quality and poor-quality, respectively. The primary contributors to the losses were decay (39.92%), mechanical damage (31.32%), and blotchiness (27.99%). Postharvest losses were significantly higher under open-field production systems compared to closed tunnels. The fungi associated with decay were mainly Geotrichum, Fusarium spp., and Alternaria spp. These findings demonstrate the main drivers behind postharvest losses, which in turn highlight the critical need for intervention through training and support, including the use of postharvest loss reduction technologies to enhance food security.

Introduction: Several postharvest strategies have been explored to prevent postharvest losses of fruit and vegetables in small-scale production environments that are caused by fungal spoilage during storage; however, the losses remain persistent. In the bell pepper industry for instance, approximately 40% of the total global production is lost annually, highlighting a need to understand pathogen dynamics at the preharvest stage that could contribute to tissue breakdown at storage. This study therefore aimed to explore fungal community shifts during bell pepper fruit development from flowering to storage.Methods: The samples of flowers, small fruits, mature fruits at harvest and storage were processed to identify the fungal composition using next-generation sequencing of the internal transcribed spacer region.Results: The results showed that bell pepper harbored 346 fungal genera across all fruit stages mainly from the phyla Ascomycota (83.9%) and Basidiomycota (15.3%). The fungal community comprised both pathogenic and beneficial taxa: Cladosporium, Alternaria, and Fusarium were among the most abundant probable pathogenic taxa, while Aureobasidium, Filobasidium, and Sampaiozyma represented potential biocontrol agents (BCAs). Trend and correlation analysis showed an antagonistic relationship between the BCAs and pathogenic fungi, possibly explaining their dynamic composition across the fruit stages.Discussion: The analysis showed interaction likelihood between pathogenic taxa, giving insights into co-infection, as well as among beneficial taxa with biocontrol potential, highlighting their synergistic effect against pathogens. Based on redundancy analysis, fruit physiological changes across the developmental stages may have accounted for approximately 8.53% of the total microbial variation observed and could favor growth of spoilage pathogens at storage. The overall analysis confirmed that primary infection at the early fruit developmental stage was the source of the bell pepper decay at postharvest. This highlights the critical need to refocus postharvest spoilage management on reducing preharvest infection, particularly those relating to quiescent infections. The antagonistic characteristics in the bell pepper mycobiome can be harnessed for the development of biocontrol consortia targeting dual/multiple infections. These findings offer a new approach to the management of postharvest losses while aligning with sustainable agricultural production and food security by promoting the use of naturally occurring beneficial microbes for crop protection.

Background: Though reported more than 100 years ago Huanglongbing (HLB)/citrus greening (CG), the disease remains of global phytosanitary importance. Methods: This study presents a systematic review of the disease from 1971 to 2024, based on the literature retrieved from the SCOPUS database. Results: The analysis reveals that far less has been published in the literature compared to other similar phytosanitary important citrus diseases, such as citrus black spot (CBS). Published research on HLB/CG only increased from the early 2000s despite HLB being first reported in 1919. Notable HLB research increase occurred after the first detection in the USA in 2005, coinciding with extensive funding and the adoption of more accurate molecular diagnostics. Conclusion: According to the analyzed data, the USA and China are the leading countries in publishing HLB research. Spain’s active involvement in HLB research, despite the disease not being reported there, highlights its regulatory and scientific significance. The review also showed that climate change may accelerate the spread of HLB pathogens and their vectors into new geographical regions. The notable lack of research from Africa highlights the need for increased financial support for scientists to focus on CG.