Current trends in management of bacterial pathogens infecting plants

Combat phytopathogenic bacteria employing Argirium-SUNCs: limits and perspectives

Bacterial plant diseases are difficult to control as the durability of deployed control measures is thwarted by continuous and rapid changing of bacterial populations. Although application of copper compounds to plants is the most widespread and inexpensive control measure, it is often partially efficacious for the frequent appearance of copper-resistant bacterial strains and it is raising concerns for the harmful effects of copper on environment and human health. Consequently, European Community included copper compounds in the list of substances candidates for substitution. Nanotechnologies and the application of nanoparticles seem to respond to the need to find new very effective and durable measures. We believe that Argirium-SUNCs®, silver ultra nanoclusters with an average size of 1.79 nm and characterized by rare oxidative states (Ag2+/3+), represent a valid candidate as a nano-bactericide in the control of plant bacterial diseases. Respect to the many silver nanoparticles described in the literature, Argirium-SUNCs have many strengths due to the reproducibility of the synthesis method, the purity and the stability of the preparation, the very strong (less than 1 ppm) antimicrobial, and anti-biofilm activities. In this mini-review, we provide information on this nanomaterial and on the possible application in agriculture. KEY POINTS: • Argirium-SUNCs have strong antimicrobial activities against phytopathogenic bacteria. • Argirium-SUNCs are a possible plant protection product. • Argirium-SUNCs protect tomato plants against bacterial speck disease.

The potential of bacteriocins and bacteriophages to control bacterial disease of crops with a focus on Xanthomonas spp

Crop production plays a crucial role in ensuring global food security and maintaining economic stability. The presence of bacterial phytopathogens, particularly Xanthomonas species (a key focus of this review), poses significant threats to crops, leading to substantial economic losses. Current control strategies, such as the use of chemicals and antibiotics, face challenges such as environmental impact and the development of antimicrobial resistance. This review discusses the potential of bacteriocins, bacterial-derived proteinaceous antimicrobials and bacteriophages, viruses that target bacteria as sustainable alternatives for effectively managing Xanthomonas diseases. We focus on the diversity of bacteriocins found within xanthomonads by identifying and predicting the structures of candidate bacteriocin genes from publicly available genome sequences using BAGEL4 and AlphaFold. Harnessing the power of bacteriocins and bacteriophages has great potential as an eco-friendly and sustainable approach for precision control of Xanthomonas diseases in agriculture. However, realising the full potential of these natural antimicrobials requires continued research, field trials and collaboration among scientists, regulators and farmers. This collective effort is crucial to establishing these alternatives as promising substitutes for traditional disease management methods.

Carbon nanotubes in plant dynamics: Unravelling multifaceted roles and phytotoxic implications

Carbon nanotubes (CNTs) have emerged as a promising frontier in plant science owing to their unique physicochemical properties and versatile applications. CNTs enhance stress tolerance by improving water dynamics and nutrient uptake and activating defence mechanisms against abiotic and biotic stresses. They can be taken up by roots and translocated within the plant, impacting water retention, nutrient assimilation, and photosynthesis. CNTs have shown promise in modulating plant-microbe interactions, influencing symbiotic relationships and mitigating the detrimental effects of phytopathogens. CNTs have demonstrated the ability to modulate gene expression in plants, offering a powerful tool for targeted genetic modifications. The integration of CNTs as sensing elements in plants has opened new avenues for real-time monitoring of environmental conditions and early detection of stress-induced changes. In the realm of agrochemicals, CNTs have been explored for their potential as carriers for targeted delivery of nutrients, pesticides, and other bioactive compounds. CNTs have the potential to demonstrate phytotoxic effects, detrimentally influencing both the growth and developmental processes of plants. Phytotoxicity is characterized by induction of oxidative stress, impairment of cellular integrity, disruption of photosynthetic processes, perturbation of nutrient homeostasis, and alterations in gene expression. This review aims to provide a comprehensive overview of the current state of knowledge regarding the multifaceted roles of CNTs in plant physiology, emphasizing their potential applications and addressing the existing challenges in translating this knowledge into sustainable agricultural practices.

Impact of biotic stresses on the Brassicaceae family and opportunities for crop improvement by exploiting genotyping traits

MAIN CONCLUSION

Utilizing RNAi, miRNA, siRNA, lncRNA and exploiting genotyping traits can help safeguard the food supply from illnesses and pest damage to Brassicas, as well as reduce yield losses caused by plant pathogens and insect pests. In the natural environment, plants face significant challenges in the form of biotic stress, due to various living organisms, leading to biological stress and a sharp decline in crop yields. To cope with these effects, plants have evolved specialized mechanisms to mitigate these challenges. Plant stress tolerance and resistance are influenced by genes associated with stress-responsive pathogens that interact with various stress-related signaling pathway components. Plants employ diverse strategies and mechanisms to combat biological stress, involving a complex network of transcription factors that interact with specific cis-elements to regulate gene expression. Understanding both plant developmental and pathogenic disease resistance mechanisms can allow us to develop stress-tolerant and -resistant crops. Brassica genus includes commercially important crops, e.g., broccoli, cabbage, cauliflower, kale, and rapeseed, cultivated worldwide, with several applications, e.g., oil production, consumption, condiments, fodder, as well as medicinal ones. Indeed, in 2020, global production of vegetable Brassica reached 96.4 million tones, a 10.6% rise from the previous decade. Taking into account their commercial importance, coupled to the impact that pathogens can have in Brassica productivity, yield losses up to 60%, this work complies the major diseases caused due to fungal, bacterial, viral, and insects in Brassica species. The review is structured into three parts. In the first part, an overview is provided of the various pathogens affecting Brassica species, including fungi, bacteria, viruses, and insects. The second part delves into the exploration of defense mechanisms that Brassica plants encounter against these pathogens including secondary metabolites, duplicated genes, RNA interference (RNAi), miRNA (micro-RNA), siRNA (small interfering RNA), and lncRNA (long non-coding RNA). The final part comprehensively outlines the current applications of CRISPR/Cas9 technology aimed at enhancing crop quality. Taken collectively, this review will contribute to our enhanced understanding of these mechanisms and their role in the development of resistance in Brassica plants, thus supporting strategies to protect this crucial crop.

Application of nanomaterials as potential quorum quenchers for disease: Recent advances and challenges

Chemical signal molecules are used by bacteria to interact with one another. Small hormone-like molecules known as autoinducers are produced, released, detected, and responded to during chemical communication. Quorum Sensing (QS) is the word for this procedure; it allows bacterial populations to communicate and coordinate group behavior. Several research has been conducted on using inhibitors to prevent QS and minimize the detrimental consequences. Through the enzymatic breakdown of the autoinducer component, by preventing the formation of autoinducers, or by blocking their reception by adding some compounds (inhibitors) that can mimic the autoinducers, a technique known as "quorum quenching" (QQ) disrupts microbial communication. Numerous techniques, including colorimetry, electrochemistry, bioluminescence, chemiluminescence, fluorescence, chromatography-mass spectroscopy, and many more, can be used to test QS/QQ. They all permit quantitative and qualitative measurements of QS/QQ molecules. The mechanism of QS and QQ, as well as the use of QQ in the prevention of biofilms, are all elaborated upon in this writing, along with the fundamental study of nanoparticle (NP)in QQ. Q.