Development and Characterization of SN1 Transgenic Wheat Plants with Enhanced Resistance to Rhizoctonia cerealis and Bipolaris sorokiniana

Nanoparticles in association with antimicrobial peptides (NanoAMPs) as a promising combination for agriculture development

Antimicrobial peptides are small molecules, up to 10 kDa, present in all kingdoms of life, including in plants. Several studies report that these molecules have a broad spectrum of activity, including antibacterial, antifungal, antiviral, and insecticidal activity. Thus, they can be employed in agriculture as alternative tools for phytopathogen and pest control. However, the application of peptides in agriculture can present challenges, such as loss of activity due to degradation of these molecules, off-target effects, and others. In this context, nanotechnology can offer versatile structures, including metallic nanoparticles, liposomes, polymeric nanoparticles, nanofibers, and others, which might act both in protection and in release of AMPs. Several polymers and biomaterials can be employed for the development of nanostructures, such as inorganic metals, natural or synthetic lipids, synthetic and hybrid polymers, and others. This review addresses the versatility of NanoAMPs (Nanoparticles in association with antimicrobial peptides), and their potential applications in agribusiness, as an alternative for the control of phytopathogens in crops.

Potato Snakin-1: an antimicrobial player of the trade-off between host defense and development

Snakin-1 (SN1) from potato is a cysteine-rich antimicrobial peptide with high evolutionary conservation. It has 63 amino acid residues, 12 of which are cysteines capable of forming six disulfide bonds. SN1 localizes in the plasma membrane, and it is present mainly in tissues associated with active growth and cell division. SN1 is active in vitro against bacteria, fungus, yeasts, and even animal/human pathogens. It was demonstrated that it also confers in vivo protection against commercially relevant pathogens in overexpressing potato, wheat, and lettuce plants. Although researchers have demonstrated SN1 can disrupt the membranes of E. coli, its integral antimicrobial mechanism remains unknown. It is likely that broad-spectrum antimicrobial activity is a combined outcome of membrane disruption and inhibition of intracellular functions. Besides, in potato, partial SN1 silencing affects cell division, leaf metabolism, and cell wall composition, thus revealing additional roles in growth and development. Its silencing also affects reactive oxygen species (ROS) and ROS scavenger levels. This finding indicates its participation in redox balance. Moreover, SN1 alters hormone levels, suggesting its involvement in the complex hormonal crosstalk. Altogether, SN1 has the potential to integrate development and defense signals directly and/or indirectly by modulating protein activity, modifying hormone balance and/or participating in redox regulation. Evidence supports a paramount role to SN1 in the mechanism underlying growth and immunity balance. Furthermore, SN1 may be a promising candidate in preservation, and pharmaceutical or agricultural biotechnology applications.

Antifungal and antimicrobial proteins and peptides of potato (Solanum tuberosum L.) tubers and their applications

Potato proteins are well known for their nutritional, emulsifying, foaming, gel forming or antioxidant properties that all make from them valuable protein source for food industry. Antifungal, antimicrobial and also antiviral properties, described for potato proteins in the review, enrich the possibilities of potato protein usage. Potato proteins were divided into patatin, protease inhibitors and fraction of other proteins that also included, besides others, proteins involved in potato defence physiology. All these proteins groups provide proteins and peptides with antifungal and/or antimicrobial actions. Patatins, obtained from cultivars with resistance to Phytophthora infestans, were able to inhibit spore germination of this pathogen. Protease inhibitors represent the structurally heterogeneous group with broad range of antifungal and antimicrobial activities. Potato protease inhibitors I and II reduced the growth of Phytophthora infestans, Rhizoctonia solani and Botrytis cinerea or of the fungi of Fusarium genus. Members of Kunitz family (proteins Potide-G, AFP-J, Potamin-1 or PG-2) were able to inhibit serious pathogens such as Staphylococcus aureus, Listeria monocytogenes, Escherichia coli or Candida albicans. Potato snakins, defensins and pseudothionins are discussed for their ability to inhibit serious potato fungi as well as bacterial pathogens. Potato proteins with the ability to inhibit growth of pathogens were used for developing of pathogen-resistant transgenic plants for crop improvement. Incorporation of potato antifungal and antimicrobial proteins in feed and food products or food packages for elimination of hygienically risk pathogens brings new possibility of potato protein usage.

Characterization of a novel seed protein of Prosopis cineraria showing antifungal activity

An antifungal protein with a molecular mass of 38.6 kDa was isolated from the seed of Prosopis cineraria. The protein was purified using ammonium sulphate precipitation, ion exchange chromatography and gel filtration. The antifungal activity of purified protein was retained up to 50 °C for 10 min. The MALDI TOF mass spectroscopy revealed 15 assorted peptides. The molecular weight of the antifungal protein is different from antifungal proteins reported in seeds of other leguminous plants. The purified protein exerted antifungal activity against post-harvest fruit fungal pathogens Lasiodiplodia theobromae and Aspergillus fumigatus, isolated from the rotten fruits. The antifungal properties of this novel antifungal protein can be potentially exploited to manage post-harvest fungal disease of fruits through alternative means to reduce use of hazardous chemicals.

Plant antifungal proteins and their applications in agriculture

Fungi are far more complex organisms than viruses or bacteria and can develop numerous diseases in plants that cause loss of a substantial portion of the crop every year. Plants have developed various mechanisms to defend themselves against these fungi which include the production of low-molecular-weight secondary metabolites and proteins and peptides with antifungal activity. In this review, families of plant antifungal proteins (AFPs) including defensins, lectins, and several others will be summarized. Moreover, the application of AFPs in agriculture will also be analyzed.