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Plant susceptibility to pathogens is usually considered from the perspective of the loss of resistance. However, susceptibility cannot be equated with plant passivity since active host cooperation may be required for the pathogen to propagate and cause disease. This cooperation consists of the induction of reactions called susceptible responses that transform a plant from an autonomous biological unit into a component of a pathosystem. Induced susceptibility is scarcely discussed in the literature (at least compared to induced resistance) although this phenomenon has a fundamental impact on plant-pathogen interactions and disease progression. This review aims to summarize current knowledge on plant susceptible responses and their regulation. We highlight two main categories of susceptible responses according to their consequences and indicate the relevance of susceptible response-related studies to agricultural practice. We hope that this review will generate interest in this underestimated aspect of plant-pathogen interactions.

We have studied the spontaneous comminution of cast materials consisting of a Mn-doped Cr2AlC MAX phase and chromium, manganese, and aluminum carbides and aluminides. The materials were prepared in the form of ingots by self-propagating high-temperature synthesis (SHS) in a 3-L reactor at an argon pressure p = 5 MPa. The starting mixtures consisted of manganese(IV) oxide, chromium(III) oxide, aluminum (ASD-1), and carbon. The presence of aluminum carbide (Al4C3) in a cast material has been shown to lead to spontaneous comminution of the cast material (without mechanical or chemical influences) into powders with a crystalline particle size under 100 μm. The particle size reduction has been shown to result from reaction between aluminum carbide and atmospheric moisture. The synthesized materials have been characterized by X-ray diffraction and X-ray microanalysis, and we have studied structural and phase states of particles of the desired products obtained as a result of self-comminution of a cast SHS material.

A material based on a (VCr)2AlC solid solution has been obtained for the first time by self-propagating high-temperature synthesis from a powder reaction mixture of vanadium(V) and chromium(III) oxides with aluminum and carbon (graphite). The synthesized material has been studied by X-ray diffraction and microstructural analyses. It has been shown that the product also contains vanadium and chromium carbides and intermetallics. The presence of these phases seems to be associated with the nonequilibrium character of the synthesis process due to a short “lifetime” of melt and its fast cooling and crystallization. The synthesized material is an electrical conductor, which demonstrates a metallic character of conductivity throughout the entire measured temperature range of 300–1300 K. The room-temperature specific resistance of the composite material based on a (Cr,V)2AlC solid solution is 1.14 µΩ m, which is higher than the specific resistance of the materials based on the Cr2AlC and V2AlC MAX phases. The microhardness of the synthesized material is 6.9 GPa.

–A material based on the V2AlC MAX phase has been obtained for the first time by the method of self-propagating high-temperature synthesis (SHS) using a reaction mixture of vanadium oxide(V) and (IV) powders with aluminum and carbon (graphite). The obtained material was characterized by X-ray diffraction and energy-dispersive X-ray spectroscopy. The Rietveld method was used to perform quantitative analysis. The synthesized material based on the V2AlC MAX phase is an electrical conductor that demonstrates the metallic behavior of conductivity in the entire measured temperature range of 300–1300 K in the vacuum of 2 × 10–3 Pa. It has been suggested that the V2AlC phase makes a decisive contribution to the electrical resistance of the synthesized material that may be caused by the formation of V2AlC nanolaminate grains contacting with each other in the bulk of the material.

Experimental data are presented on the high-temperature synthesis of cast composite materials in the Cr–Al–C system with different relative amounts of the MAX phase Cr2AlC and chromium carbides and aluminides. The experiments were carried out in multipurpose self-propagating high-temperature synthesis (SHS) reactors at an argon pressure p = 5 MPa. The starting mixtures consisted of calcium chromate (CaCrO4), aluminum (ASD-1), and carbon powders. It has been shown that varying the percentage of carbon in the starting mixture may have a significant effect on the synthesis process and the phase composition and microstructure of the final products. It has been found that, in the case of the stoichiometric starting mixture composition, the synthesis yields cast composite materials consisting predominantly of the MAX phase Cr2AlC and containing the lower chromium carbide Cr7C3 and the chromium aluminide Cr5Al8. The addition of excess (superstoichiometric) carbon to the starting mixture leads to an increase in the percentage of the MAX phase Cr2AlC in the synthesis product, disappearance of the chromium aluminide Cr5Al8, and the formation of the higher chromium carbide Cr3C2 instead of the lower carbide. The final synthesis products have been characterized by X-ray diffraction and local microstructural analysis. The structure and composition of the synthesis products obtained under various conditions have been determined.

A cast material based on the Nb2AlC MAX phase was obtained by SHS metallurgy. Synthesis was carried out from the Nb2O5– Al–C mixture with a high-energy CaO2–Al additive. Thermodynamic calculation results correlate well with experimental data. It was found that the CaO2–Al additive content has a substantial effect on the thermodynamic parameters and phase composition of the final product. It was shown that synthesis from the specified mixtures passed in a stationary mode with steady combustion wave. Increasing the additive content leads to increasing combustion rate (from 6 to 12 mm/s), and product yield to ingot increases (from 30 to 47 %) up to 15 wt.% of the additive and then decreases. Variation in the composition of initial mixtures can provide a significant impact on both synthesis parameters and final product phase composition. Optimal conditions of material synthesis to ensure maximum yield of the Nb2AlC MAX phase in the ingot composition were determined. The liquid phase lifetime during synthesis is a determining factor influencing the Nb2AlC content in the final product. It is shown that the maximum Nb2AlC phase amount (67 wt.%) is reached with 15 wt.% of the high-energy additive in the initial charge.

Soft rot Pectobacteriaceae (SRP) are ubiquitous on earth as there are records of findings from all continents where host plants are grown. This chapter describes information on soft rot diseases on these continents. For some countries, detailed information is provided by local experts on the SRP present, their economic damage, and the management strategies applied for their control. The focus of the chapter is mainly on SRP as causative agents of potato blackleg, although in specific cases details are provided on SRP in other host plants. In Europe, the SRP cause important economic losses mainly on potato, with most species described in the literature being found. In Latin America significant losses are also reported due to potato diseases caused by various Dickeya and Pectobacterium species, while in Australia and Oceania, recent outbreaks of D. dianthicola in potato have resulted in high economic losses. In Asia, however, SRP cause economic losses mainly in vegetable crops other than potato, while in North America SRP cause diseases on a wide range of crops (including potato and ornamental plants) in both field and storage. In Africa SRP are only known to occur in 17 of the 54 African countries but where it is known, potato is the most affected crop.

Snow mold is a severe plant disease caused by psychrophilic or psychrotolerant fungi, of which Microdochium species are the most harmful. A clear understanding of Microdochium biology has many gaps, the pathocomplex and its dynamic are poorly characterized, virulence factors are unknown, genome sequences are not available, and the criteria of plant snow mold resistance are not elucidated. Our study aimed to identify comprehensive characteristics of a local community of snow mold-causing Microdochium species colonizing a particular crop culture. By using the next-generation sequencing (NGS) technique, we characterized fungal and bacterial communities of pink snow mold-affected winter rye (Secale cereale) plants within a given geographical location shortly after snowmelt. Twenty-one strains of M. nivale were isolated, classified on the basis of internal transcribed spacer 2 (ITS2) region, and characterized by morphology, synthesis of extracellular enzymes, and virulence. Several types of extracellular enzymatic activities, the level of which had no correlations with the degree of virulence, were revealed for Microdochium species for the first time. Our study shows that genetically and phenotypically diverse M. nivale strains simultaneously colonize winter rye plants within a common area, and each strain is likely to utilize its own, unique strategy to cause the disease using &ldquo, a personal&rdquo, pattern of extracellular enzymes.

A series of novel 4-aminobenzofuroxan derivatives containing aromatic/aliphatic amines fragments was achieved via aromatic nucleophilic substitution reaction of 4,6-dichloro-5-nitrobenzofuroxan. The quantum chemistry calculations were performed to identify the factors affecting the regioselectivity of the reaction. The formation of 4-substituted isomer is favored both by its greater stability and the lower activation barrier. Antimicrobial activity of the obtained compounds has been evaluated and some of them were found to suppress effectively bacterial biofilm growth. Fungistatic activity of 4-aminobenzofuroxans were tested on two genetically distinct isolates of M. nivale. The effect of some benzofuroxan derivatives is likely to be more universal against different varieties of M. nivale compared with benzimidazole and carbendazim. Additionally, their anti-cancer activity in vitro has been tested. 4-aminofuroxans possessing aniline moiety showed a high selectivity towards MCF-7 and M-HeLa tumor cell lines. Moreover, they exhibit a significantly lower toxicity towards normal liver cells compared to Doxorubicin and Tamoxifen. Thus, benzofuroxans containing aromatic amines fragments in their structure are promising candidates for further development both as anti-cancer and anti-microbial agents.