The Effects of the Microbial Biostimulants Approved by EU Regulation 2019/1009 on Yield and Quality of Vegetable Crops

Abstract

The use of microbial biostimulants such as plant growth-promoting rhizobacteria (PGPB) and arbuscular mycorrhizal fungi (AMF) has gained popularity in recent years as a sustainable approach to boost yield as well as the quality of produce. The beneficial effects of microbial biostimulants have been reported numerous times. However, information is missing concerning quantitative assessment of the overall impact of microbial biostimulants on the yield and quality of vegetable crops. Here we provide for the first time a comprehensive, semi-systematic review of the effects of microbial biostimulants allowed by Regulation (EU) 2019/1009, including microorganisms belonging to the AMF (phylum Glomeromycota), or to Azospirillum, Azotobacter and Rhizobium genera, on vegetable crops’ quality and yield, with rigorous inclusion and exclusion criteria based on the PRISMA method. We identified, selected and critically evaluated all the relevant research studies from 2010 onward in order to provide a critical appraisal of the most recent findings related to these EU-allowed microbial biostimulants and their effects on vegetable crops’ quality and yield. Moreover, we highlighted which vegetable crops received more beneficial effects from specific microbial biostimulants and the protocols employed for plant inoculation. Our study is intended to draw more attention from the scientific community to this important instrument to produce nutrient-dense vegetables in a sustainable manner. Finally, our semi-systematic review provides important microbial biostimulant application guidelines and gives extension specialists and vegetable growers insights into achieving an additional benefit from microbial biostimulant application.

Perspectives on the Use of Biopolymeric Matrices as Carriers for Plant-Growth Promoting Bacteria in Agricultural Systems

“…According to the European Union (EU) Regulation, only Rhizobium , Azospirillum , and Azotobacter genera have been approved to be used as biostimulants on the basis of Regulation (EU) 2019/1009 [ 66 , 67 ]. According to the EU Regulation, a fertilizing product can contain “microorganisms, including dead or empty-cell microorganisms and non-harmful residual elements of the media on which they were produced, which have undergone no other processing than drying or freeze drying.”…”

Iodine Biofortification and Seaweed Extract-Based Biostimulant Supply Interactively Drive the Yield, Quality, and Functional Traits in Strawberry Fruits

“…Numerous authors [ 5 , 8 , 9 , 10 , 11 , 12 , 13 , 14 ] report that primary and secondary metabolism, nutrient element modulation, phytotoxic substance accumulation, and biotic and abiotic stress tolerance are affected by either microbial or non-microbial biostimulants. Among those substances, seaweed extracts (SwE) are an imperative class, and their benefits are connected to enzymes involved in nitrogen and carbon metabolic pathways, glycolysis, and the Krebs cycle.…”

Do changes in Lactuca sativa metabolic performance, induced by mycorrhizal symbionts and leaf UV-B irradiation, play a role towards tolerance to a polyphagous insect pest?

“…Many microorganisms (e.g., arbuscular mycorrhizal fungi, AMF) can stimulate plant growth by facilitating the absorption of nutrients, enhancing the efficient use of soil natural resources, and promoting plant resistance to biotic and abiotic factors (Smith and Read 2008 ). In addition, AMF can alter plant secondary metabolism, leading to higher synthesis of antioxidant metabolites (Agnolucci et al 2020 ); as such, AMF are increasingly considered a biotechnological tool for the sustainable production of safe and healthy plant foods, especially horticultural crops (Zhu et al 2022 ; Messa & Savioli 2021 ; Fusco et al 2022 ). AMF-related effects on the plant are commonly beneficial for both the insect and the plant itself (Sharma et al 2017 ; Yu et al 2022 ).…”