There has been many recent studies on the use of microbial antagonists to control diseases incited by soilborne and airborne plant pathogenic bacteria and fungi, in an attempt to replace existing methods of chemical control and avoid extensive use of fungicides, which often lead to resistance in plant pathogens. In agriculture, plant growth-promoting and biocontrol microorganisms have emerged as safe alternatives to chemical pesticides. Streptomyces spp. and their metabolites may have great potential as excellent agents for controlling various fungal and bacterial phytopathogens. Streptomycetes belong to the rhizosoil microbial communities and are efficient colonizers of plant tissues, from roots to the aerial parts. They are active producers of antibiotics and volatile organic compounds, both in soil and in planta, and this feature is helpful for identifying active antagonists of plant pathogens and can be used in several cropping systems as biocontrol agents. Additionally, their ability to promote plant growth has been demonstrated in a number of crops, thus inspiring the wide application of streptomycetes as biofertilizers to increase plant productivity. The present review highlights Streptomyces spp.-mediated functional traits, such as enhancement of plant growth and biocontrol of phytopathogens.

The impact of disease outbreaks on the phytosanitary quality of seeds was investigated for two pathosystems: tomato– Xanthomonas vesicatoria and pepper– Xanthomonas euvesicatoria . This study, which was performed in Italy and Serbia, aimed to evaluate the season‐to‐season transmission of phytopathogenic regulated bacteria associated with phytosanitary risks posed by seeds produced in areas where bacterial infections are possible. For each pathosystem, field plots were experimentally inoculated to simulate an initial infection rate of 1%, 5% and 15%. The area under the disease progress curve ( AUDPC ) was calculated for each field plot, the seeds produced were analysed to determine the contamination level and rate, and the plant‐to‐seed transmission was evaluated by a seedling grow‐out ( SGO ) assay. To investigate transmission under field conditions, a second‐year experiment was performed, wherein seeds collected from the first year were used to establish new field plots. During the first growing season, AUDPC values were positively correlated with the percentages of initial infection for each pathosystem. Seed contamination levels in pepper ranged from 34 to 100 CFU g ⁻¹ , and the contamination rate ranged from 1.50% up to 3.17% for X. euvesicatoria , whereas processing and fresh market tomato seeds produced both in Italy and Serbia were not infected by X. vesicatoria . During SGO assays and the second cropping year, no symptoms were observed in either tomato or pepper plants. Therefore, the calculated pepper seed contamination rate for X. euvesicatoria appeared to be less than the threshold necessary to initiate a disease outbreak. Finally, all seeds obtained during the second cropping year were uninfected.

The seed industry plays a crucial role in global food production but it faces a persistent challenge in ensuring the health and quality of seeds, particularly those of tomato and pepper seeds, which represent key seed commodities on the global market. Seeds can serve as potential pathways for the introduction and dissemination of seed-borne bacteria, which may have devastating effects on crop yield, farmers’ remunerability, and food security. Therefore, fungicides and other antimicrobial compounds are extensively used to disinfect the seeds, thus increasing the input of chemicals in the agri-environment. In this review, we address aspects that connect disease epidemiology with seed infection and health, including seed contamination, endophytic colonization, and seed-borne infections. We focused on the main bacterial diseases affecting tomato and pepper seeds by discussing their official seed testing methods as requirements supporting a smooth seed trade. Moreover, we present a survey on the past and recent innovations for seed treatments, focusing on sustainable disinfection methods. Therefore, this review will be a short but indispensable guide for seed technologists and pathologists involved in the production of high-quality seeds, providing indications and suggestions to contrast seed-borne pathogen dissemination and avoid international controversies and complaints by phytosanitary authorities, extension services, and farmers.