Resistant Ones Research Articles

Experimental and producer-reported data quantify the value of foliar fungicide to winter wheat and its dependency on genotype and environment in the U.S. central Great Plains

• We quantified the yield benefits of fungicide to wheat using plot and survey data. • Fungicide yield benefits (7.8 ± 15 %) were greater in wetter growing seasons. • Susceptible genotypes benefited more from fungicides (17 %) than resistant ones (6 %). • Fungicides improved stability and modified environment-adaptability of genotypes. • Fungicide yield benefits were greater (31 %) in the survey data. Foliar fungicides can account for a large portion of the yield gap in winter wheat ( Triticum aestivum L.); however, their impacts on yield have been inconsistent in rainfed environments. We compiled a database of replicated field experiments and producer-reported fungicide and yield data from commercial fields to quantify the effects of fungicide application on winter wheat yield and yield stability. The database of field experiments (i.e., canopy level) included 56 non-inoculated environments spanning 12 growing seasons in eight Kansas locations, and was restricted to field experiments with direct comparisons between a foliar fungicide between Zadoks 40–55 and a side-by-side untreated control, resulting in 393 mean yield comparisons resulting from 3226 yield observations. The producer survey included genotype and fungicide management data from 654 commercial Kansas wheat fields cultivated across three growing seasons. Grain yield and weather conditions in the experimental and producer-reported database were similar, with seasonal precipitation ranging from ˜150 to 1035 mm and average grain yield of ˜3900 kg ha −1 with a ˜7000 kg ha −1 range. Foliar fungicide application resulted in 7.8 % average yield gain in the canopy-level data, ranging from −27 % to +97 %. Yield differences due to fungicide were strongly related to precipitation and to the ratio of precipitation and reference evapotranspiration (WS:WD) during the spring in the experimental data. Grain yield responsiveness to fungicide associated with the responsiveness of green canopy cover, kernel weight, biomass, and harvest index. Analysis of covariance suggested that grain yield usually decreased with increases in disease susceptibility in the absence of foliar fungicides; however, yield-disease relationships were either neutral or positive in the presence of fungicides. Average yield gain for resistant varieties was ˜166 kg ha −1 (5.6 %), which was lower than for intermediate (˜199 kg ha −1 ; 6.9 %) or susceptible genotypes (˜598 kg ha −1 ; 16.9 %). Foliar fungicides increased yield stability across genotypes at the canopy level and at the commercial field level. In the commercial-field level data, 53 % of the fields received foliar fungicide, with higher frequency in growing seasons with greater WS:WD (which were also higher yielding). The use of foliar fungicides was associated with improved yields and interacted with genotype’s resistance level to stripe rust and with growing seasons’ WS:WD. This work quantified and explained the yield benefits of foliar fungicide, and characterized its dependency on genotype-specific disease resistance and environmental conditions both at the canopy- and commercial field-levels.

Front Cover: Platinum Cyclooctadiene Complexes with Activity against Gram‐positive Bacteria (ChemMedChem /2021)

The Front Cover shows the protagonist of our recent work, platinum. Although well-known for its immense contribution to chemotherapy in the form of cisplatin, this transition metal has only sparingly been explored for antimicrobial applications so far. In our work we describe its excellent in vitro antibacterial activity against Gram-positive strains, including drug resistant ones. Cover design by Dr. Angelo Frei. More information can be found in the Communication by Angelo Frei, Mark A. T. Blaskovich et al.

P-088: Indirubin-3’-monoxime acts as an alternative proteasome inhibitor and confers new regimens for the treatment of Multiple Myeloma

<h3>Background</h3> Multiple myeloma (MM) is still an incurable malignancy of plasma cells. Despite the therapeutic benefit of the proteasome inhibitor (PI) bortezomib, drug resistance still accounts for majority of tumor relapses and cancer-related death in MM patients. Thus, exploring the mechanism underlying BTZ resistance and investigating a novel treatment strategy are urgent requisites for clinical practise. Indirubin-3'-monoxime (Id-3) is an active ingredient of a traditional Chinese medicine. <h3>Method</h3> In the present study, we firstly investigated Id-3 effects on myeloma treatment in patient primary samples and myeloma cell lines. We also investigated the molecular mechanism of Id-3 treatment on MM cells via in vivo and in vitro study. <h3>Results</h3> We first reported that Id-3 is an effective cytotoxicity agentia against MM cells growth by inducing the MM cells apoptosis. Id-3 treatment also effectively induces the cell death in bortezomib-resistant MM cell lines and primary myeloma patient samples. Stringently, we found there is a synergistic anti-MM effect between Id-3 and bortezomib. The treatment with lower dosage combination of Id-3 and bortezomib exhibited a notably inhibition of the growth of myeloma cells both in xenograft mouse model and MM-PDX model. Mechanism study revealed that Id-3 treatment efficiently inhibited the chymotrypsin-like and caspase-like activity of proteasome in MM cells. The level of the proteasome 11s activator, PA200 (PSME4) and PA28y (PSME3) was significantly down-regulated both in mRNA and protein level. GEO datasets analysis showed that the high levels of PSME4 and PSME3 were over-expressed in relapsed patients and MM cell lines which correlated with the drug-resistance of MM cells. Kaplan-Meier analysis showed that patients with high-levels of PSME3 or PSME4 had the shortened survival. Knocking-down the level of PSME4 or PSME3 by shRNA noteworthy inhibited the cell growth and enhanced the sensitivity to bortezomib of MM cells. In vivo study also found that down-regulated the level of PSME3 or PSME4 can suppress the proliferation of MM cells and prolong the survival of MM-bearing mouse. <h3>Conclusions</h3> Taken together, our study supported that Id-3 is an effective agentia against the survival of MM cells both in bortezomib-sensitive and -resistance ones. We further identified that the 11s proteasome activators, PSME3 and PSME4, were down-regulated effectively by Id-3 treatment. High-levels of PSME3 or PSME4 were correlated with the inferior outcome of MM patients. Down-regulating PSME3 and PSME4 by Id-3 or shRNA could efficiently suppressed the growth of MM cells and improve the survival of MM-bearing mice. Our study provides the rational evidence for the clinical application of Id-3 in the treatment of MM.

'Resistance Mixtures' Reduce Insect Herbivory in Strawberry (Fragaria vesca) Plantations.

The transition toward more sustainable plant protection with reduced pesticide use is difficult, because there is no “silver bullet” available among nonchemical tools. Integrating several plant protection approaches may thus be needed for efficient pest management. Recently, increasing the genetic diversity of plantations via cultivar mixing has been proposed as a possible method to reduce pest damage. However, previous studies have not addressed either the relative efficiency of exploiting cultivar mixing and intrinsic plant herbivore resistance or the potential utility of combining these approaches to increase cropping security. Here, using a full factorial experiment with 60 woodland strawberry plots, we tested for the relative and combined effect of cultivar mixing and intrinsic plant resistance on herbivore damage and yield. The experiment comprised two levels of diversity (“high” with 10 varieties and “low” with two varieties) and three levels of resistance (“resistant” comprising only varieties intrinsically resistant against strawberry leaf beetle Galerucella tenella; “susceptible” with susceptible varieties only; and “resistance mixtures” with 50:50 mixtures of resistant and susceptible varieties). The experiment was carried out over two growing seasons. Use of resistant varieties either alone or intermixed with susceptible varieties in “resistance mixtures” reduced insect herbivory. Interestingly, resistant varieties not only reduced the mean damage in “resistance mixtures” by themselves being less damaged, but also protected intermixed susceptible varieties via associational resistance. The effect of higher genetic diversity was less evident, reducing herbivory only at the highest level of herbivore damage. In general, herbivory was lowest in plots with high diversity that included at least some resistant varieties and highest in low diversity plots consisting only of susceptible varieties. Despite this, no significant difference in yield (fruit biomass) was found, indicating that strawberry may be relatively tolerant. Our results demonstrate that combined use of high genetic diversity and resistant varieties can help reduce pest damage and provide a useful tool for sustainable food production. “Resistance mixtures” may be particularly useful for sensitive food crops where susceptible varieties are high yielding that could not be completely replaced by resistant ones.

Прогноз развития корневых гнилей и перспективный материал яровой мягкой пшеницы селекции ФАНЦ Северо-Востока

Abstract. The aim of the study is to predict the level of damage to the root system of spring soft wheat by fusarium infection in the conditions of the Kirov region and to identify promising disease-resistant lines. Methods. The object of research was 146 lines of spring soft wheat of the FARC of the North-East selection, which were sown annually against an infections background of fusarium root rot. Results. As a result of many years of research (2004-2006 u 2009˗2020) it was found that a high level of infection of plants of spring soft wheat by root rot was observed in years with an average daily air temperature in the first decade of July in the range from 15 to 23 °C and precipitation in the first decade of august of 30 or more millimeters. A rectilinear regression equation was obtained that reflects the quantitative variability of the disease development indicator from the total year of the weather index. A retrospective analysis of the expected (according to the forecast) and actual development of fusarium root rot on spring wheat showed a fairly high level of coincidence of the date obtained (67 %). Among the promising spring soft wheat lines of the FARC of the North-East selection, 3 (E-310, U-163 and T-79) with resistance to root rot were identified. Combining high resistance to the fusarium root rot and the yield of significantly higher than the standards, the breeding line E-310 can be recommended for transfer to variety testing. The selected highly and moderately resistant lines can be used in further breeding as sources of resistance to the disease. The decrease in grain weight from 1 m2 in susceptible lines compared to resistant ones was on average 83.4 g. The degree of development of the disease in plants affected the yield and weight of grain to a greater extent (d = 15.3 and 11.0 % respectively). In midseason lines the damage and development of root rot was 77.5 and 82.9 % respectively, determined by the duration of the “stands – heading” period. In early maturing lines showed a positive significant correlation between the duration of the “stands – heading” period and the development of root rot (r = +0.66).

Cyclic nucleotide gated channel genes (CNGCs) in Rosaceae: genome-wide annotation, evolution and the roles on Valsa canker resistance.

In Rosaceae, tandem duplication caused the drastic expansion of CNGC gene family Group I. The members MdCN11 and MdCN19 negatively regulate Valsa canker resistance. Apple (Malus domestica) and pear (Pyrus bretschneideri and P. communis) are important fruit crops in Rosaceae family but are suffering from threats of Valsa canker. Cyclic nucleotide-gated ion channels (CNGCs) take crucial roles in plant immune responses. In the present study, a total of 355 CNGCs was identified from 8 Rosaceae plants. Based on phylogenetic analysis, 540 CNGCs from 18 plants (8 in Rosaceae and 10 others) could be divided into four groups. Group I was greatly expanded in Rosaceae resulted from tandem duplications. A large number of cis-acting regulatory elements (cis-elements) responsive to signals from multiple stresses and hormones were identified in the promoter regions of CNGCs in Malus spp. and Pyrus spp. Expressions of most Group I members were obviously up-regulated in Valsa canker susceptible varieties but not in the resistant ones. Furthermore, overexpression of the MdCN11 and MdCN19 in both apple fruits and 'Duli' (P. betulifolia) suspension cells compromised Valsa canker resistance. Overexpression of MdCN11 induced expression of hypersensitive response (HR)-related genes. In conclusion, tandem duplication resulted in a drastic expansion of CNGC Group I members in Rosaceae. Among these, MdCN11 and MdCN19 negatively regulate the Valsa canker resistance via inducting HR.

Spatiotemporal Changes in Varietal Resistance to Wheat Yellow Rust in France Reveal an Increase in Field Resistance Level During the Period 1985-2018.

Monitoring spatiotemporal changes in varietal resistance and understanding its drivers seem essential to managing plant diseases but require having access to the genetic basis of disease resistance and to its deployment. In this study, we focused on yellow rust (Puccinia striiformis f. sp. tritici) for three decades in France, by using field adult plant resistance levels, Yr race-specific resistance genes of varieties, presence of Puccinia striiformis f. sp. tritici pathotypes and their virulence profiles, and systematic surveys of the acreages of bread wheat varieties available at a yearly survey time and at a district level. Based on these data, we studied spatiotemporal changes in varietal resistance over the period from 1985 to 2018 in 54 French administrative districts (hereafter "departments") by using a set of relevant indicators weighted by the relative acreage proportion of the varieties sown at the department level. Our analyses revealed an increase in varietal resistance over decades that would be due to the accumulation of both quantitative resistance and different race-specific resistance genes. We suggest that, beyond breeders, several actors, including examination offices, agricultural advisory services, and farmers, may have had a substantial influence on these spatiotemporal changes, promoting more resistant varieties and the rapid replacement of newly susceptible varieties by still resistant ones at the beginning of each epidemic.

Specific phenotypic, genomic, and fitness evolutionary trajectories toward streptomycin resistance induced by pesticide co-stressors in Escherichia coli

To explore how co-occurring non-antibiotic environmental stressors affect evolutionary trajectories toward antibiotic resistance, we exposed susceptible Escherichia coli K-12 populations to environmentally relevant levels of pesticides and streptomycin for 500 generations. The coexposure substantially changed the phenotypic, genotypic, and fitness evolutionary trajectories, resulting in much stronger streptomycin resistance (>15-fold increase) of the populations. Antibiotic target modification mutations in rpsL and rsmG, which emerged and dominated at late stages of evolution, conferred the strong resistance even with less than 1% abundance, while the off-target mutations in nuoG, nuoL, glnE, and yaiW dominated at early stages only led to mild resistance (2.5–6-fold increase). Moreover, the strongly resistant mutants exhibited lower fitness costs even without the selective pressure and had lower minimal selection concentrations than the mildly resistant ones. Removal of the selective pressure did not reverse the strong resistance of coexposed populations at a later evolutionary stage. The findings suggest higher risks of the selection and propagation of strong antibiotic resistance in environments potentially impacted by antibiotics and pesticides.

Single nucleotide polymorphisms, gene expression and serum profile of immune and antioxidant markers associated with postpartum disorders susceptibility in Barki sheep

The objective of this study was to explore the immunological and antioxidant alterations associated with ovine postpartum disorders. Blood samples were collected from 90 adult Barki ewes and allocated into three equal-sized groups (30 ewes each): control group (CG), inflammatory postpartum disorders group (IPG) and non-inflammatory postpartum disorders group (NIPG). PCR-DNA sequencing approach was carried out for TLR4 (256-bp) and SOD (456-bp) genes, and nucleotide sequence variations were noticed to be associated with postpartum disorders resistance/susceptibility. Gene expression profile was also evaluated and levels of IL5, IL6, IL1-ß, TNF alpha, TLR4 and Tollip were significantly up-regulated in ewes affected with postpartum disorders than resistant ones, while SOD and CAT genes pattern elicited an opposite trend. Exploring serum profile also showed a significant increase of IL-1α, IL-1β, IL-6, TNF-α, MDA and NO in IPG compared to their correspond values in NIPG and CG. However, serum levels of IL-10, CAT, GSH and GPx were significantly decreased. This study highlights that SNPs in TLR4 and SOD genes could be genetic markers for postpartum disorders resistance/susceptibility in Barki ewes. Gene expression alongside serum profiles of antioxidant markers could also be used to follow-up the immune status of ewes to build up an effective management protocol.

Sensitivity assessment to azamethiphos by time-to-response bioassay and biomarkers in the sea louse Caligus rogercresseyi

Delousing drugs have been intensively applied to salmon farming as the main method to control lice infestations. Hence, early detection of changes in the susceptibility status is crucial to control and prevent the spread of drug resistance. This study aimed to assess the sensitivity to azamethiphos in the sea louse based on the time-to-response method coupled with gene biomarkers related to drug response (ET50-PCR). Four populations of the sea lice C. rogercresseyi with contrasting sensitivity to azamethiphos drug were used to validate this assay. For those populations, EC50 and ET50 indexes were tested. Additionally, the transcription expression of 20 candidate genes related to drug response were also evaluated. Lower ET50 indexes were observed for susceptible lice populations compared with resistant ones. Moreover, gene expression analysis evidenced three genes: cytochrome p450, long non-coding RNAs 8967 and 532, as good candidate biomarkers for drug sensitivity testing. The study provides novel knowledge to assess delousing drug sensitivity by ET50-PCR bioassay in Chilean salmonid farms.

Volatile compounds from plum genotypes with different levels of resistance to leaf scald disease

AbstractPlum leaf scald (PLS) is the main obstacle to plum expansion in Brazil. This disease is caused by Xylella fastidiosa, which colonizes the foregut of xylem‐sap feeding insects and the xylem of the plants. Breeding programmes identified new plum genotypes that showed no leaf scald symptoms in the field and remained negative for X. fastidiosa for at least 10 years. However, the mechanisms that confer this resistance are not fully elucidated. One hypothesis is the emission of volatile organic compounds by the host. Therefore, we investigated the volatile compound profile from six plum genotypes with different resistance levels to PLS. Thirty‐nine compounds were identified. The major constituents in the plum volatile extract were phytol (46.76%) and limonene (2.48%). Cultivar Laetitia presented the highest total alkane content, Simka showed the highest alcohol content, while Fortune and SC13 exhibited the highest concentration of ketones. Cedrol was not detected in susceptible genotypes but was found in the resistant ones, SC7 and SC15. (E,E)‐α‐farnesene was detected in high concentrations in Fortune but was not found in SC13 and SC15. According to principal components analysis, genotypes were divided into four groups based on the similarity of the volatile profile: 1: Fortune and Laetitia; 2: Simka and SC13; 3: SC7; and 4: SC15. This is the first description of leaf volatile chemical components of Prunus salicina, and the putative factor related to resistance in SC7 and SC15 is discussed. We also propose a terpene pathway of the main volatile compounds found.

Screening for M220 mutation in azole-resistant Aspergillus fumigatus isolates from clinical and environmental specimens in Cuba

Aspergillosis is a fungal disease caused by different Aspergillus species and have high morbidity/mortality rates. Aspergillus fumigatus is the main aetiological agent related to most of Aspergillus infections. The use of triazoles is recommended as first line of treatment, however, the reports of azole-resistant A. fumigatus due to mutations in CYP51 have increased around the world. The goals were to determine the antifungal susceptibility patterns for triazoles in thirty A. fumigatus isolates from clinical and environmental samples and to detect mutation M220 in the resistant ones. Determination of minimum inhibitory concentrations of every isolate was performed by using the Etest commercial method for itraconazole, voriconazole and posaconazole. For the resistant isolates, a PCR was performed for amplifying a 173 bp fragment of cyp51A and the resulting amplicons were sequenced. Nine out of 30 isolates were resistant to itraconazole and none were resistant to voriconazole or posaconazole. The alignment of sequences with a CYP51 A. fumigatus wild type strain did not show any modifications at codon 220. Other molecular mechanisms of resistance are probably related to the resistant phenotypes isolated.

Biodiversity of Fusarium oxysporum Isolated from Diseased Chickpea and Detection of Resistance Sources to Some Egyptian Chickpea Cultivars

Fusarium wilt caused by Fusarium oxysporum (Fo) is the maximum critical soil borne diseases of chickpea in Egypt and many other countries in the world. Sixteen F. oxysporum(Fo) isolates were collected from 9 Governorates in Egypt isolated from wilted chickpea plants. Identification of these isolates was achieved by variation in morphological characters i.e., growth rate, growth habits, pigments, sporulation, and the morphological identifications were further confirmed by molecular method using specific ITS primers. Virulence of these isolates was classified as high virulence (Fo7, Fo8 and Fo10), moderate (Fo2, Fo3, Fo6, Fo9, Fo11, Fo13, Fo14, Fo15 and Fo16) and low (Fo1, Fo4, Fo5, Fo12). Host response of chickpea cultivars infected with Fo7 showed a moderate resistance (Giza-2 and Giza-531) and susceptible ones (Giza-195, Giza-1 and Giza-88). Mechanism underline induce disease resistance revealed that resistant chickpea cultivars contained high activities peroxidase, polyphenol oxidase, catalase, Phenylalanine ammonia lyase and Phenolic compounds than susceptible cultivars.

Intrinsic and Chemotherapeutic Stressors Modulate ABCC-Like Transport in Trypanosoma cruzi.

Trypanosoma cruzi is the etiologic agent for Chagas disease, which affects 6–7 million people worldwide. The biological diversity of the parasite reflects on inefficiency of benznidazole, which is a first choice chemotherapy, on chronic patients. ABC transporters that extrude xenobiotics, metabolites, and mediators are overexpressed in resistant cells and contribute to chemotherapy failure. An ABCC-like transport was identified in the Y strain and extrudes thiol-conjugated compounds. As thiols represent a line of defense towards reactive species, we aimed to verify whether ABCC-like transport could participate in the regulation of responses to stressor stimuli. In order to achieve this, ABCC-like activity was measured by flow cytometry using fluorescent substrates. The present study reveals the participation of glutathione and ceramides on ABCC-like transport, which are both implicated in stress. Hemin modulated the ABCC-like efflux which suggests that this protein might be involved in cellular detoxification. Additionally, all strains evaluated exhibited ABCC-like activity, while no ABCB1-like activity was detected. Results suggest that ABCC-like efflux is not associated with natural resistance to benznidazole, since sensitive strains showed higher activity than the resistant ones. Although benznidazole is not a direct substrate, ABCC-like efflux increased after prolonged drug exposure and this indicates that the ABCC-like efflux mediated protection against cell stress depends on the glutathione biosynthesis pathway.

Growth and survival characteristics of Salmonella enterica regarding antibiotic resistance phenotypes

Salmonella enterica is a foodborne pathogen that can cause zoonotic diseases. The aggravation of antibiotic resistant S. enterica has drawn wide attention. Understanding the behavior of antibiotic-resistant pathogens along food chain is important to risk assessment. The objective of this study was to describe the growth and survival characteristics of S. enterica strains and evaluate the correlation with the strains’ antibiotic resistance phenotypes. Strains isolated from food (n = 16), clinic (n = 8) and standard strain (n = 2) of various antibiotic resistant phenotypes were selected, of which half strains were S. Typhimurium and half were S. Enteritidis. The growth parameters under different temperatures (25, 30, 35 °C) were obtained by time-to-detection (TTD) method, the survival characteristics were evaluated by the viability after exposed to heat (55, 57.5, 60 °C) and acid (HCl, pH = 3.0). It was observed that the antibiotic-resistant strains were more heat sensitive than antibiotics-sensitive ones, although the difference was significant only at 57.5 °C. The multi-antibiotics resistant strains showed significant higher acid resistance than antibiotics resistant ones. No significant differences were observed on growth and inactivation characteristics between strains of different origins or serotypes. This study provides useful information for understanding the correlation of antibiotic resistance phenotypes with growth and survival characteristics in S. enterica.

A review on nanostructured silver as a basic ingredient in medicine: physicochemical parameters and characterization.

Recent studies with silver nanoparticles (AgNPs) and the history of silver metal as a broad-spectrum bactericidal and virucidal agent, places silver as one of the future biocidal candidates in the field of nanomedicine to eliminate bacteria and viruses, especially multidrug resistant ones. In this review, we have described the various morphologies of AgNPs and correlated the enhanced bactericidal activity with their prominent {111} facets. In addition to prioritizing the characterization we have also discussed the importance of quantifying AgNPs and silver ion content (Ag+) and their different mechanisms at the chemical, biological, pharmacological, and toxicological levels. The mechanism of action of AgNPs against various bacteria and viruses including the SARS-CoV-2 was analyzed in order to understand its effectiveness as an antimicrobial agent with therapeutic efficacy and low toxicity. Further, there is the need to characterize AgNPs and quantify the content of free Ag+ for the implementation of new systematic studies of this promising agent in nanomedicine and in clinical practice.

Variation of Glucosinolate Contents in Clubroot-Resistant and -Susceptible Brassica napus Cultivars in Response to Virulence of Plasmodiophora brassicae.

The present study investigated the changes in total and individual glucosinolates (GSLs) in roots and leaves of different clubroot-resistant and -susceptible oilseed rape cultivars following artificial inoculation with Plasmodiophora brassicae isolates with different virulence. The results showed significant differences in clubroot incidence and severity as well as in the amount of total and individual glucosinolates between oilseed rape cultivars in response to virulence of the pathogen. Single among with total aliphatic and total indolic glucosinolate contents were significantly lower in leaves of susceptible cultivars compared to resistant ones due to the infection. Similarly, single and total aliphatic as well as indolic glucosinolate contents in roots were lower in susceptible cultivars compared to resistant cultivars analyzed. The different isolates of P. brassicae seem to differ in their ability to reduce gluconasturtiin contents in the host. The more aggressive isolate P1 (+) might be able to suppress gluconasturtiin synthesis of the host in a more pronounced manner compared to the isolate P1. A possible interaction of breakdown products of glucobrassicin with the auxin receptor transport inhibitor response 1 (TIR1) is hypothesized and its possible effects on auxin signaling in roots and leaves of resistant and susceptible cultivars is discussed. A potential interplay between aliphatic and indolic glucosinolates that might be involved in water homeostasis in resistant cultivars is explained.

Mitigation of bacterial spot disease induced biotic stress in Capsicum annuum L. cultivars via antioxidant enzymes and isoforms

Bacterial spot, caused by a group of Xanthomonads (Xanthomonas spp.), is a devastating disease. It can adversely affect the Capsicum annum productivity. Scientists are working on the role of antioxidants to meet this challenge. However, research is lacking on the role of antioxidant enzymes and their isoforms in the non-compatible pathogen and host plant interaction and resistance mechanisms in capsicum varieties. The present study was conducted to ascertain the defensive role of antioxidant enzymes and their isoforms in chilli varieties Hybrid, Desi, Serrano, Padron, and Shehzadi against bacterial spot disease-induced Xanthomonas sp. The seedlings were inoculated with bacterial pathogen @ 107 CFU/mL, and samples were harvested after regular intervals of 24 h for 4 days followed by inoculation. Total plant proteins were extracted in phosphate buffer and quantified through Bradford assay. The crude protein extracts were analyzed through quantitative enzymatic assays in order to document activity levels of various antioxidant enzymes, including peroxidase (POD), Catalase (CAT), Ascorbate peroxidase (APX), and Superoxide dismutase (SOD). Moreover, the profiles appearance of these enzymes and their isoforms were determined using native polyacrylamide gel electrophoresis (PAGE) analysis. These enzymes exhibited maximum activity in Hybrid (HiR) cultivar followed by Desi (R), Serrano (S), Padron, and Shehzadi (HS). Both the number of isoforms and expression levels were higher in highly resistant cultivars compared to susceptible and highly susceptible cultivars. The induction of POD, CAT, and SOD occurs at the early stages of growth in resistant Capsicum cultivars. At the same time, APX seems to make the second line of antioxidant defense mechanisms. We found that modulating antioxidant enzymes and isoforms activity at the seedling stage was an important mechanism for mitigating plant growth inhibition in the resistant ones.

Search for the parent material of spring soft wheat resistant to septoria tritici blotch and analysis of the trait inheritance

In 2017-2020 in the conditions of Kirov region there were studied 143 varieties, 115 perspective lines and 28 hybrids of the first generation of spring soft wheat according to the degree of resistance to septoria tritici blotch against the background of the natural development of infection. It has been established that development of the disease significantly increased with a decrease in air temperature during the «seedling-tillering» phase (r = -0.83…-0.96) and an increase in the amount of precipitation during «shooting» phase (r = +0.87…+0.90). Resistance to septoria tritici blotch was shown by 16.1 % collection samples. A significant (r = -0.83) decrease in yield by an average of 19 % in susceptible samples compared to resistant ones was revealed. The greatest breeding and immunological value were represented by the varieties of Russian selection: Tobolskaya, Tyumenskaya 29, Moskovskaya 35 and МIS, among which the early variety MIS was tolerant to septoria tritici blotch. Thirteen lines resistant to septoria tritici blotch were identified from the new breeding material. The varieties selected for resistance to septoria tritici blotch were used in hybridization. In F1hybrids domination and overdomination in the inheritance of resistance to septoria tritici blotch prevailed, as well as weight of 1000 grains and yield per 1 m2. Among them, 8 hybrids F1 with the highest values of the dominance indices were identified. It has been established, that inheritance of resistance to septoria tritici blotch, weight of 1000 grains and yield of hybrids F1 occurs both in the maternal and paternal lines. The greatest immunological effect was obtained when using the varieties Daria (Russia) and Epos (Germany). The most productive hybrids were the variety Daria, taken as both a maternal and paternal form, as well as when using the Egisar 29 (Russia) variety as a maternal form.

Immunological detection of AcAMP antimicrobial peptide secreted by Aspergillus clavatus.

Background and Objectives:Aspergillus clavatus antimicrobial peptide (AcAMP) is a fungi-derived peptide with a broad spectrum of activity against pathogenic bacteria and fungi. Natural antimicrobial peptides, including AcAMP, have attracted many attentions in the development of new natural antibiotics against pathogenic bacteria, especially multidrug resistant ones.Materials and Methods:In the present study, acamp gene was codon-optimized and chemically synthesized in pUC57 cloning vector, subcloned into pET28a (+) expression vector and transferred into competent Escherichia coli BL21 (DE3) cells. The expression of AcAMP was induced by addition of Isopropyl β- d-1-thiogalactopyranoside (IPTG) and the expressed peptide was purified by Ni-NTA. BALB/c mice were immunized with the purified peptide and the ability of the immunized mice sera for the detection of the native AcAMP secreted by A. clavatus IRAN 142C was examined through ELISA and Western blotting techniques.Results:Both ELISA and Western blotting demonstrated the ability of the sera of the immunized mice to detect the native AcAMP.Conclusion:The results of the present work show that the raised antibody against recombinant AcAMP can be used to detect AcAMP peptide, an issue which paves the way to develop detection kits for the detection of AcAMP-producing organisms, purification of this valuable peptide for further investigations.