Plant pathogens pose a significant threat to agricultural productivity and food security worldwide. The use of traditional chemical pesticides for plant disease management raises concerns due to the emergence of pesticide resistance and their potential adverse effects on human health and the environment. As a result, there is a growing interest in exploring alternative approaches for plant disease control. This review provides an overview of the antimicrobial potential of some plant-derived compounds, including essential oils, plant extracts, wastes and their major constituents, against plant pathogenic bacteria. The antimicrobial activity is attributed to the diverse chemical composition of these plant-derived compounds and their ability to target multiple cellular processes in pathogens’ cells. Furthermore, the review explores the use of some antagonistic bacteria and fungi as control tools. These beneficial microorganisms have shown promising results in suppressing the growth of plant pathogens through various mechanisms such as competition, antibiosis and induced systemic resistance. This review discusses the advantages and limitations of using plant-derived compounds and antagonistic microorganisms for plant disease management. Moreover, it highlights the need for further research to optimize their efficacy, develop sustainable formulations and evaluate their performance under field conditions.

The purpose of the study is to investigate the possibility of using wine industry wastes, such as red and white grape bagasse, to produce bacterial cellulose (BC) instead of using a costly commercial medium. BC was produced using grape bagasse as a carbon source replacement and the sole nutrient in the medium. The BC films were evaluated for their productivity and water-holding capacity. The BC films were also investigated for their morphology using scanning electron microscopy (SEM), their viscoelastic properties using dynamic mechanical analysis (DMA), and their chemical composition using Fourier-transform infrared spectroscopy (FTIR). Although the use of grape bagasse as the sole nutrient was successful in the preparation of BC, the BC films had inferior viscoelastic properties to other produced BC films. White grape bagasse proved to be an excellent carbon substitute as the production of BC and its water-holding capacity were five times higher and the produced BC films were up to 72% more flexible than the bacterial cellulose produced using standard HS medium.

High-throughput sequencing (HTS), more specifically RNA sequencing of plant tissues, has become an indispensable tool for plant virologists to detect and identify plant viruses. During the data analysis step, plant virologists typically compare the obtained sequences to reference virus databases. In this way, they are neglecting sequences without homologies to viruses, which usually represent the majority of sequencing reads. We hypothesized that traces of other pathogens might be detected in this unused sequence data. In the present study, our goal was to investigate whether total RNA-seq data, as generated for plant virus detection, is also suitable for the detection of other plant pathogens and pests. As proof of concept, we first analyzed RNA-seq datasets of plant materials with confirmed infections by cellular pathogens in order to check whether these non-viral pathogens could be easily detected in the data. Next, we set up a community effort to re-analyze existing Illumina RNA-seq datasets used for virus detection to check for the potential presence of non-viral pathogens or pests. In total, 101 datasets from 15 participants derived from 51 different plant species were re-analyzed, of which 37 were selected for subsequent in-depth analyses. In 29 of the 37 selected samples (78%), we found convincing traces of non-viral plant pathogens or pests. The organisms most frequently detected in this way were fungi (15/37 datasets), followed by insects (13/37) and mites (9/37). The presence of some of the detected pathogens was confirmed by independent (q)PCRs analyses. After communicating the results, 6 out of the 15 participants indicated that they were unaware of the possible presence of these pathogens in their sample(s). All participants indicated that they would broaden the scope of their bioinformatic analyses in future studies and thus check for the presence of non-viral pathogens. In conclusion, we show that it is possible to detect non-viral pathogens or pests from total RNA-seq datasets, in this case primarily fungi, insects, and mites. With this study, we hope to raise awareness among plant virologists that their data might be useful for fellow plant pathologists in other disciplines (mycology, entomology, bacteriology) as well.

The phylogeny, identification, and characterization of 33 B. cereus sensu lato isolates originating from 17 agricultural soils from 11 countries were analyzed on the basis of whole genome sequencing. Phylogenetic analyses revealed all isolates are divided into six groups, which follows the generally accepted phylogenetic division of B. cereus sensu lato isolates. Four different identification methods resulted in a variation in the identity of the isolates, as none of the isolates were identified as the same species by all four methods—only the recent identification method proposed directly reflected the phylogeny of the isolates. This points to the importance of describing the basis and method used for the identification. The presence and percent identity of the protein product of 19 genes potentially involved in pathogenicity divided the 33 isolates into groups corresponding to phylogenetic division of the isolates. This suggests that different pathotypes exist and that it is possible to differentiate between them by comparing the percent identity of proteins potentially involved in pathogenicity. This also reveals that a basic link between phylogeny and pathogenicity is likely to exist. The geographical distribution of the isolates is not random: they are distributed in relation to their division into the six phylogenetic groups, which again relates to different ecotypes with different temperature growth ranges. This means that we find it easier to analyze and understand the results obtained from the 33 B. cereus sensu lato isolates in a phylogenetic, patho-type and ecotype-oriented context, than in a context based on uncertain identification at the species level.

Root-knot nematodes (Meloidogyne spp.) are important pests of many cultivated plants. Recently, the most efficient chemical control products (e.g. methyl bromide) have now been restricted due to their toxic characteristics. Research on agents that work against root-knot nematodes and do not have a detrimental impact on the environment is becoming increasingly important. Advances in the last decades produced quite a number of biocontrol products that are already marketed. Some of the well-accepted commercial products contain bacteria Bacillus firmus and Pasteuria penetrans, and fungus Purpureocillium lilacinus. In this review we summarize the antagonistic activity of bacteria and fungi, with their advantages and limitations in biocontrol of root-knot nematodes.

Strains of Pseudomonas savastanoi pv. savastanoi (Pss), isolated from infected olive trees (Olea europaea L.) in three European countries (Croatia, Slovenia and Portugal) were identified and characterised according to their colony morphology, physiological and biochemical features. According to the LOPAT scheme, 38.6% of Pss isolates were grouped in the Ib cluster. The Portuguese Pss strains were fully consistent with the typical LOPAT profile for this bacterium. Conversely, most Slovenian Pss strains showed delayed oxidase activity, whilst Croatian Pss strains did not produce any fluorescent pigment when grown in vitro. For Pss molecular identification, both end-point and real-time PCR were used, as well as MALDI–TOF, which was additionally used for proteomic analysis and the subsequent species identification of a number of strains that showed deviations from expected LOPAT results. Pss was confirmed as a causal agent of olive knot disease in 46.6% of olive orchards screened. Overall, these data suggests a possible correlation of certain Pss features with the geographical origin and the ecological niche of Pss isolates.