Disease Resistance Mechanisms Research Articles

Peptide-Drug Conjugates: An Emerging Direction for the Next Generation of Peptide Therapeutics.

Building on recent advances in peptide science, medicinal chemists have developed a hybrid class of bioconjugates, called peptide-drug conjugates, that demonstrate improved efficacy compared to peptides and small molecules independently. In this Perspective, we discuss how the conjugation of synergistic peptides and small molecules can be used to overcome complex disease states and resistance mechanisms that have eluded contemporary therapies because of their multi-component activity. We highlight how peptide-drug conjugates display a multi-factor therapeutic mechanism similar to that of antibody-drug conjugates but also demonstrate improved therapeutic properties such as less-severe off-target effects and conjugation strategies with greater site-specificity. The many considerations that go into peptide-drug conjugate design and optimization, such as peptide/small-molecule pairing and chemo-selective chemistries, are discussed. We also examine several peptide-drug conjugate series that demonstrate notable activity toward complex disease states such as neurodegenerative disorders and inflammation, as well as viral and bacterial targets with established resistance mechanisms.

Response of bacterial community metabolites to bacterial wilt caused by Ralstonia solanacearum: a multi-omics analysis.

The soil microbial community plays a critical role in promoting robust plant growth and serves as an effective defence mechanism against root pathogens. Current research has focused on unravelling the compositions and functions of diverse microbial taxa in plant rhizospheres invaded by Ralstonia solanacearum, however, the specific mechanisms by which key microbial groups with distinct functions exerttheir effects remain unclear. In this study, we employed a combination of amplicon sequencing and metabolomics analysis to investigate the principal metabolic mechanisms of key microbial taxa in plant rhizosphere soil. Compared to the healthy tobacco rhizosphere samples, the bacterial diversity and co-occurrence network of the diseased tobacco rhizosphere soil were significantly reduced. Notably, certain genera, including Gaiella, Rhodoplanes, and MND1 (Nitrosomonadaceae), were found to be significantly more abundant in the rhizosphere of healthy plants than in that of diseased plants. Eight environmental factors, including exchangeable magnesium, available phosphorus, and pH, were found to be crucial factors influencing the composition of the microbial community. Ralstonia displayed negative correlations with pH, exchangeable magnesium, and cation exchange flux, but showed a positive correlation with available iron. Furthermore, metabolomic analysis revealed that the metabolic pathways related to the synthesis of various antibacterial compounds were significantly enriched in the healthy group. The correlation analysis results indicate that the bacterial genera Polycyclovorans, Lysobacter, Pseudomonas, and Nitrosospira may participate in the synthesis of antibacterial compounds. Collectively, our findings contribute to a more in-depth understanding of disease resistance mechanisms within healthy microbial communities and provide a theoretical foundation for the development of targeted strategies using beneficial microorganisms to suppress disease occurrence.

Transcriptomic-Proteomic Analysis Revealed the Regulatory Mechanism of Peanut in Response to Fusarium oxysporum.

Peanut Fusarium rot, which is widely observed in the main peanut-producing areas in China, has become a significant factor that has limited the yield and quality in recent years. It is highly urgent and significant to clarify the regulatory mechanism of peanuts in response to Fusarium oxysporum. In this study, transcriptome and proteome profiling were combined to provide new insights into the molecular mechanisms of peanut stems after F. oxysporums infection. A total of 3746 differentially expressed genes (DEGs) and 305 differentially expressed proteins (DEPs) were screened. The upregulated DEGs and DEPs were primarily enriched in flavonoid biosynthesis, circadian rhythm-plant, and plant-pathogen interaction pathways. Then, qRT-PCR analysis revealed that the expression levels of phenylalanine ammonia-lyase (PAL), chalcone isomerase (CHI), and cinnamic acid-4-hydroxylase (C4H) genes increased after F. oxysporums infection. Moreover, the expressions of these genes varied in different peanut tissues. All the results revealed that many metabolic pathways in peanut were activated by improving key gene expressions and the contents of key enzymes, which play critical roles in preventing fungi infection. Importantly, this research provides the foundation of biological and chemical analysis for peanut disease resistance mechanisms.

Host-pathogen interaction between pitaya and Neoscytalidium dimidiatum reveals the mechanisms of immune response associated with defense regulators and metabolic pathways

BackgroundUnderstanding how plants and pathogens regulate each other's gene expression during their interactions is key to revealing the mechanisms of disease resistance and controlling the development of pathogens. Despite extensive studies on the molecular and genetic basis of plant immunity against pathogens, the influence of pitaya immunity on N. dimidiatum metabolism to restrict pathogen growth is poorly understood, and how N. dimidiatum breaks through pitaya defenses. In this study, we used the RNA-seq method to assess the expression profiles of pitaya and N. dimidiatum at 4 time periods after interactions to capture the early effects of N. dimidiatum on pitaya processes.ResultsThe study defined the establishment of an effective method for analyzing transcriptome interactions between pitaya and N. dimidiatum and to obtain global expression profiles. We identified gene expression clusters in both the host pitaya and the pathogen N. dimidiatum. The analysis showed that numerous differentially expressed genes (DEGs) involved in the recognition and defense of pitaya against N. dimidiatum, as well as N. dimidiatum’s evasion of recognition and inhibition of pitaya. The major functional groups identified by GO and KEGG enrichment were responsible for plant and pathogen recognition, phytohormone signaling (such as salicylic acid, abscisic acid). Furthermore, the gene expression of 13 candidate genes involved in phytopathogen recognition, phytohormone receptors, and the plant resistance gene (PG), as well as 7 effector genes of N. dimidiatum, including glycoside hydrolases, pectinase, and putative genes, were validated by qPCR. By focusing on gene expression changes during interactions between pitaya and N. dimidiatum, we were able to observe the infection of N. dimidiatum and its effects on the expression of various defense components and host immune receptors.ConclusionOur data show that various regulators of the immune response are modified during interactions between pitaya and N. dimidiatum. Furthermore, the activation and repression of these genes are temporally coordinated. These findings provide a framework for better understanding the pathogenicity of N. dimidiatum and its role as an opportunistic pathogen. This offers the potential for a more effective defense against N. dimidiatum.

Genetic Mechanisms of Crop Disease Resistance: New Advances in GWAS

Genetic Mechanisms of Crop Disease Resistance: New Advances in GWAS

Unravelling the Functional Role of GthGAPC2 in Cotton's Defense Against Verticillium dahliae through Proteome

AbstractCotton (Gossypium spp.) is an economically important crop, but its productivity is often hindered by the soil‐borne pathogen Verticillium dahliae. This study aimed to investigate the response of cotton roots to V. dahliae infection by analysing the proteome of Gossypium thurberi (resistant) and Gossypium raimondii (susceptible) at 0 h, 24 h, and 48 h post‐infection. Through weighted protein coexpression network analysis, fifteen hub proteins crucial for defense against V. dahliae were identified. Expression analysis revealed the pivotal role of GthGAPC2, encoding GLYCERALDEHYDE‐3‐PHOSPHATE DEHYDROGENASE 2, in conferring resistance to V. dahliae in cotton. Virus‐induced gene Silencing (VIGS) of GthGAPC2 increased susceptibility to V. dahliae, which was supported by oxidant and antioxidant enzyme activities. Furthermore, GthGAPC2 silencing influenced lignin content, indicating its involvement in lignin biosynthesis regulation. Transient overexpression of GthGAPC2 in tobacco supported its role in cell death processes. Subcellular localization studies showed predominant nuclear localization of GthGAPC2. Overexpression of GthGAPC2 in Arabidopsis also confirms its significant role in V. dahliae resistance. These findings shed light on the molecular mechanisms of disease resistance in Gossypium thurberi. Identification of GthGAPC2, as a key protein involved in V. dahliae resistance, and its functional implications can aid breeding strategies for enhancing cotton's disease resistance.

Intercropping and appropriate nitrogen application control faba bean Fusarium wilt by improving physiological and biochemical resistance and protein expression of faba bean

AbstractThis study set up four nitrogen application levels (0, 45, 90 and 135 kg/ha) and two planting systems (faba bean monocropping and faba bean and wheat intercropping) to investigate the incidence of faba bean Fusarium wilt under different treatments and determine the resistance enzyme activities and gene expression, protein expression, and other indexes of faba bean plants. At all N levels, faba bean and wheat intercropping controlled faba bean Fusarium wilt by decreasing the content of hydrogen peroxide and superoxide anion in faba bean roots, increasing the enzyme activity and gene expression of the superoxide dismutase and the gene expression of pathogenesis‐related protein 1 (VfPR1), VfPR2, VfPR5 and VfPR10 disease resistance proteins in the roots, with the most significant effects at the N2 level (90 kg/ha). Further investigation of the impact of intercropping on faba bean roots using the N2 treatment showed that faba bean–wheat intercropping upregulated 288 proteins and downregulated 179 proteins compared with monocropping, and the functions of the upregulated proteins were mainly related to energy metabolism, antioxidant enzymes, stress and DNA repair. GO functional analysis showed that the upregulated proteins were mainly focused on the involvement in amide biological processes. KEGG enrichment analysis revealed that faba bean–wheat intercropping upregulated proteins involved in glutathione metabolism and ascorbic acid metabolism. In summary, at the N2 level, faba bean–wheat intercropping effectively mitigated root oxidative stress by enhancing antioxidant and disease resistance mechanisms in faba bean roots.

How to Manage Philadelphia-Positive Acute Lymphoblastic Leukemia in Resource-Constrained Settings.

Recent studies have indicated that more than half of adult patients newly diagnosed with Ph+ ALL can now achieve a cure. However, determining the most suitable protocol for less-resourced settings can be challenging. In these situations, we must consider the potential for treatment toxicity and limited access to newer agents and alloSCT facilities. Currently, it is advisable to use less intensive induction regimens for Ph+ ALL. These regimens can achieve high rates of complete remission while causing fewer induction deaths. For consolidation therapy, chemotherapy should remain relatively intensive, with careful monitoring of the BCR-ABL1 molecular transcript and minimal residual disease. AlloSCT may be considered, especially for patients who do not achieve complete molecular remission or have high-risk genetic abnormalities, such as IKZF1-plus. If there is a loss of molecular response, it is essential to screen patients for ABL mutations and, ideally, change the TKI therapy. The T315I mutation is the most common mechanism for disease resistance, being targetable to ponatinib. Blinatumomab, a bispecific antibody, has shown significant synergy with TKIs in treating this disease. It serves as an excellent salvage therapy, aside from achieving outstanding results when incorporated into the frontline.

Red and Blue Light Induce Soybean Resistance to Soybean Mosaic Virus Infection through the Coordination of Salicylic Acid and Jasmonic Acid Defense Pathways.

Soybean mosaic virus (SMV) seriously harms soybean quality and yield. In order to understand the effect of a heterogeneous light environment on the disease resistance of intercropped soybeans, we simulated three kinds of light environments to learn the effects of white light, blue light, and far-red light on the SMV resistance of soybeans. The results showed that compared with the control, SMV-infected soybeans showed dwarfing and enhanced defense. The symptoms of leaves under red and blue light were less severe than those under white light, the virus content of infected plants was about 90% lower than under white light, the activity of antioxidant enzymes increased, and the accumulation of reactive oxygen species decreased. The oxidation damage in SMV-infected soybeans was serious under far-red light. Transcriptome data showed that the biostimulatory response, plant-pathogen interaction, and plant hormone signaling pathway gene expression of SMV-infected soybeans were significantly up-regulated under red light compared with the control. Compared with the control, the genes in the biostimulatory response, calcium ion binding, carbohydrate-binding, mitogen-activated protein kinase (MAPK) signaling, and plant-pathogen interaction pathways, were significantly up-regulated in SMV-infected soybeans under blue light. In far-red light, only 39 genes were differentially expressed in SMV-infected soybeans compared with the control, and most of the genes were down-regulated. Compared with the control, the up-regulation of the salicylic acid (SA) pathway defense gene in SMV-infected soybeans under red light was higher than under other light treatments. Compared with the control, the up-regulation of the jasmonic acid (JA) and ethylene (ET) pathway defense genes in SMV-infected soybeans under blue light was higher than under other light treatments. Compared with the control, most defense-related genes in the SA and JA pathways were inhibited in SMV-infected soybeans under far-red light, while genes in the ET pathway were significantly up-regulated. These results will advance our understanding of the disease resistance mechanism of intercropping soybeans in a heterogeneous light environment and provide new ideas for the prevention and control of viral diseases.

Research Progress in the Mechanisms of Resistance to Biotic Stress in Sweet Potato.

Sweet potato (Ipomoea batatas (L.) Lam.) is one of the most important food, feed, industrial raw materials, and new energy crops, and is widely cultivated around the world. China is the largest sweet potato producer in the world, and the sweet potato industry plays an important role in China's agriculture. During the growth of sweet potato, it is often affected by biotic stresses, such as fungi, nematodes, insects, viruses, and bacteria. These stressors are widespread worldwide and have severely restricted the production of sweet potato. In recent years, with the rapid development and maturity of biotechnology, an increasing number of stress-related genes have been introduced into sweet potato, which improves its quality and resistance of sweet potato. This paper summarizes the discovery of biological stress-related genes in sweet potato and the related mechanisms of stress resistance from the perspectives of genomics analysis, transcriptomics analysis, genetic engineering, and physiological and biochemical indicators. The mechanisms of stress resistance provide a reference for analyzing the molecular breeding of disease resistance mechanisms and biotic stress resistance in sweet potato.

Research progress on the resistance mechanism of host pine to pine wilt disease

AbstractPine wilt disease, caused by Bursaphelenchus xylophilus, is a major quarantine forest disease that has resulted in massive economic losses as well as ecological disaster. Therefore, it is imperative to study the defence response mechanism of host pine trees to infection by B. xylophilus to understand further the internal causes of pine tree death and to find control strategies. For many years, systematic research has been carried out on the pathophysiological response of pine trees to pine wilt disease. However, due to the complexity of the occurrence and development of pine wilt disease, the specific response mechanisms of different tree species have remained unclear. This paper attempts to provide an overview of the resistance mechanism of host pine trees against B. xylophilus infection through the perspectives of histopathological characteristics, physiological and biochemical responses, and molecular response mechanisms, which provide a theoretical reference for further investigating the disease resistance mechanism of pine trees to pine wilt disease and lay the foundation for the prevention and quarantine of pine wilt disease.

Phenyllactic acid treatment for controlling anthracnose disease (Colletotrichum musae) and preserving banana fruit quality during storage

Banana is considered climacteric fruit that undergoes rapid post-harvest senescence, making it highly susceptible to diseases such as anthracnose, leading to a decline in quality. To address this issue, researchers investigated the effects of phenyllactic acid (PLA), a novel natural bio-preservative with broad-spectrum antibacterial properties, on banana fruit after harvesting. The study revealed that PLA treatment resulted in improved attributes of postharvest quality, including reduced changes in peel color, soluble solids concentration, and firmness. Additionally, respiratory rate, ethylene release, and disease index were significantly decreased, indicating that the fruit's physiological processes were better regulated. Furthermore, PLA treatment enhanced the activity of disease-resistant enzymes β-1,3-glucanase and chitinase, and upregulated the expression of pathogenesis-related genes. Importantly, PLA demonstrated its efficacy in suppressing the growth of anthracnose-causing fungi (Colletotrichum musae) and reducing disease severity on harvested fruit. In conclusion, PLA treatment shows promise as a new approach to maintain the freshness and quality of harvested banana fruit by reducing disease development, regulating physiological processes, and enhancing disease resistance mechanisms.

177 Functional Annotation of an Array of Immune Cells and Various Tissues in the Chicken

Abstract Infection and disease negatively affect performance, growth, and health in production animals and has major economic impacts on commercial poultry production. Regulatory elements control the expression of genes and consequently phenotype. Epigenetic modifications such as histone tail modifications and DNA methylation are not only key to the regulation of unique transcriptome patterns, these modifications are indispensable as genome annotators to uncover cell- and tissue-specific regulatory elements. The objectives of our current projects are to leverage transcriptomic and epigenomic methods to annotate transcripts, coding and noncoding, and cis-regulatory elements in the chicken genome, including promoters, enhancers and insulators. In addition, we are employing single-cell sequencing to characterize new or rare cell populations in tissues relevant to production and investigate underlying mechanisms of disease resistance to pathogens. The transcriptome of a number of important cells and tissues has been analyzed, including immune, intestinal and reproductive. The animal procedure was approved and conducted according to guidelines established by the Western University of Health Sciences, Pomona, California (WesternU) Institutional Animal Care and Use Committee. Cell and tissue collection, processing and bioinformatic analysis for transcriptome studies were performed as described in Overbey et al. (2021; Frontiers Genetics). Single-cell studies were performed as described in Sparling et al. (2022; Journal of Immunology) using the 10x Genomics platform. Results for the transcriptome studies show that in the immune cells, many DEGs were mostly involved in cellular processes relating to differentiation and cell metabolism as well as basic functions of immune cells such as cell adhesion and signal transduction. This was to be expected, as there was no explicit immunological stimulus involved. Nevertheless, it was notable that DEGs in the comparison between bursa and thymus that were upregulated in the thymus were related to T cell differentiation and maturation. On the other hand, genes differentially upregulated in B cell vs Bursa or Bursa vs Thymus, are mostly involved in B cell development and differentiation, or activation. Genes differentially regulated in B cells and monocytes are involved in specific functions of the cell types. In the intestinal tissues, we were able to correlate most of the differential expressed genes to metabolic processes related to nutrient digestion and absorption. Several genes in the distal part of the intestine were particularly implicated in vitamin metabolism. Genes involved in energy metabolism are also abundant in the cecum, which suggests that microbial contribution of energy production in the intestine is especially important. Finally, single cell studies on the chicken shell gland are ongoing, but we found differences in cellular populations and gene expression dependent on the chicken haplotype profiled and differences in expression of Ig-like receptors that need to be further explored.

Control strategies for 2.3.4.4 highly pathogenic avian influenza virus - From vaccines to host disease resistance. Proceeding of The First International Avian Influenza Summit, University of Arkansas- October 16-17, 2023"

Avian influenza virus (AIV) is a highly contagious and lethal disease that can have major impacts on the global poultry industry and food supply. While more frequent in Asia and Europe, highly pathogenic avian influenza virus (HPAIV) outbreaks have traditionally been rare in the U.S. However, in recent years, the U.S. has seen an increase in the incidence of HPAIV outbreaks in wild birds and commercial poultry. In 2014/2015 and in 2021/2022, outbreaks of HPAIV subtype H5NX clade 2.3.4.4 resulted in the death and destruction of over 50 million birds, each costing billions of dollars to the U.S. economy. Here, we present a comprehensive overview of control strategies against the 2.3.4.4 HPAI virus, encompassing both vaccination approaches and host-driven disease resistance mechanisms. The first section outlines the advancements in vaccine development tailored specifically for the 2.3.4.4 HPAI subtype. Through a critical analysis of experimental studies and field trials, we discuss the efficacy, safety, and cross-protection capabilities of various vaccine formulations, including inactivated whole-virus vaccines, vector-based platforms, and novel recombinant technologies. Furthermore, this section explores the challenges associated with vaccine design, including strain diversity, antigenic differences, and logistical hurdles in large-scale vaccination campaigns. The second section delves into host-centric strategies aimed at enhancing natural resistance against 2.3.4.4 HPAI virus infections. Because vaccines are not currently approved for use in the U.S., control strategies for HPAIV are dependent on biosecurity and culling of infected flocks. New strategies for HPAIV control based on gene editing of poultry species could offer solutions for disease control. Two different strategies for improving disease resistance to HPAIV are based on enhancing the innate immunity of the bird and targeting the viral RNA genome inside the cell. By harnessing genetic engineering techniques, including CRISPR/Cas-9 or -13, natural resistance to avian influenza can be achieved in poultry. Taken together, we will examine the current basis of control strategies for the 2.3.4.4 HPAI virus, offering insights into the strengths and limitations of both vaccination and novel gene-editing technologies to enhance host disease resistance to HPAI. By expanding our toolbox, this work contributes to the ongoing efforts to mitigate the impact of 2.3.4.4 HPAI on global poultry industries and public health.

Transgenic Mice Expressing Functional TCRs Specific to Cardiac Myhc-α 334-352 on Both CD4 and CD8 T Cells Are Resistant to the Development of Myocarditis on C57BL/6 Genetic Background.

Myocarditis is a predominant cause of congestive heart failure and sudden death in children and young adolescents that can lead to dilated cardiomyopathy. Lymphocytic myocarditis mediated by T cells can result from the recognition of cardiac antigens that may involve CD4 or CD8 T cells or both. In this report, we describe the generation of T cell receptor (TCR) transgenic mice on a C57BL/6 genetic background specific to cardiac myosin heavy chain (Myhc)-α 334-352 and make the following observations: First, we verified that Myhc-α 334-352 was immunogenic in wild-type C57BL/6 mice and induced antigen-specific CD4 T cell responses despite being a poor binder of IAb; however, the immunized animals developed only mild myocarditis. Second, TCRs specific to Myhc-α 334-352 in transgenic mice were expressed in both CD4 and CD8 T cells, suggesting that the expression of epitope-specific TCR is common to both cell types. Third, although T cells from naïve transgenic mice did not respond to Myhc-α 334-352, both CD4 and CD8 T cells from animals immunized with Myhc-α 334-352 responded to the peptide, indicating that antigen priming is necessary to break tolerance. Fourth, although the transgenic T cells could produce significant amounts of interferon-γ and interleukin-17, the immunized animals developed only mild disease, indicating that other soluble factors might be necessary for developing severe myocarditis. Alternatively, the C57BL/6 genetic background might be a major contributing factor for resistance to the development of myocarditis. Taken together, our model permits the determination of the roles of both CD4 and CD8 T cells to understand the disease-resistance mechanisms of myocarditis in a single transgenic system antigen-specifically.

Evaluation of reference genes for accurate normalization of qPCR data under biotic stresses in mulberry (Morus indica L.)

Biotic stresses adversely affect the leaf quality as well as the yield of mulberry (Morus spp.) which is used to feed mulberry silkworm (Bombyx mori L.). The different biotic stresses which are of economic importance in mulberry are tukra caused by mealybug insect, root knot disease by nematode, powdery mildew, and root rot by fungi. Reverse transcription-quantitative PCR (RT-qPCR) is a preferred technique to assess the transcript abundance of target genes associated with the diseases using a suitable reference gene as a normalizer. However, no study has been conducted to identify suitable reference genes during different biotic stresses in mulberry. In the present work, six candidate reference genes were quantified through qPCR during different biotic stresses in mulberry and their stability was compared using geNorm, NormFinder and RefFinder algorithms. The analysis of data revealed that actin was the preferred gene during root rot and root knot nematode infection for normalizing gene expression. Ubiquitin gene was the best-scoring gene for mealybug infestation resulting in tukra disease. PP2A (Protein phosphatase 2A) and RPL3 (60S ribosomal protein L3) were highly stable expressing genes during powdery mildew fungi infection. In the combined analysis of all tested biotic stresses, actin gene was the most preferred one followed by ubiquitin and PP2A as reference genes. This study identified the best scoring reference genes in various biotic stresses which will contribute for the precise quantification of target genes by RT-qPCR in mulberry as a tool to unravel the disease resistance mechanism.

Biological control of gentian spot blight by the combination of endophytic fungi fermentation broth and traditional Chinese medicine extractions

Gentian spot blight is a disease that decreases yields. Soil treatment can improve both plant growth and resistance to this disease. We investigated the effectiveness of endophytic fungi fermentation broth combined with traditional Chinese medicine (TCM) extractions in the biological control of gentian spot blight. We tested the anti-pathogen and growth-promoting properties of the endophytic fungi 3714, 272 fermentation broth, and 12 different TCM extractions in various solvents alone or in combination. The experiment was conducted in the field by treating gentian with various mixtures and examining their effect in controlling gentian spot blight. The combination of TCM water extractions and endophytic fungi fermentation broth, Anemarrhena asphodeloides Bge (ZM), ZM-272, Cnidium monnieri (L.). Cuss. (SCZ)-3714 and ZM-SCZ-3714 significantly controlled gentian spot blight at a control rate of more than 70%. Analyses of physiological and biochemical indexes, defense enzymes, soil enzymes, and soil properties suggest a mechanism for disease resistance and growth promotion. Specifically, different combination generally increases the number of microorganisms and soil enzyme activities in the rhizosphere of gentian, resulting in improvements in the accumulation of nutrients in soil, as well as the living environment of plants. The accumulation of nutrients in soil was improved by activating defense enzymes. The levels of secondary metabolites such as gentiopicrin increased, thus improving the disease resistance of gentian. Disease resistance was accomplished by directly suppressing the pathogen causing gentian spot blight on the surface of gentian plants and in the soil. These results provide a theoretical foundation for the biological control of gentian spot blight.

The role of WRKY transcription factors, FaWRKY29 and FaWRKY64, for regulating Botrytis fruit rot resistance in strawberry (Fragaria × ananassa Duch.)

BackgroundThe cultivated strawberry (Fragaria × ananassa Duch.) is one of the most economically important horticultural crops worldwide. Botrytis fruit rot (BFR) caused by the necrotrophic fungal pathogen Botrytis cinerea is the most devasting disease of cultivated strawberries. Most commercially grown strawberry varieties are susceptible to BFR, and controlling BFR relies on repeated applications of various fungicides. Despite extensive efforts, breeding for BFR resistance has been unsuccessful, primarily due to lack of information regarding the mechanisms of disease resistance and genetic resources available in strawberry.ResultsUsing a reverse genetics approach, we identified candidate genes associated with BFR resistance and screened Arabidopsis mutants using strawberry isolates of B. cinerea. Among the five Arabidopsis T-DNA knockout lines tested, the mutant line with AtWRKY53 showed the greatest reduction in disease symptoms of BFR against the pathogen. Two genes, FaWRKY29 and FaWRKY64, were identified as orthologs in the latest octoploid strawberry genome, ‘Florida Brilliance’. We performed RNAi-mediated transient assay and found that the disease frequencies were significantly decreased in both FaWRKY29- and FaWRKY64-RNAi fruits of the strawberry cultivar, ‘Florida Brilliance’. Furthermore, our transcriptomic data analysis revealed significant regulation of genes associated with ABA and JA signaling, plant cell wall composition, and ROS in FaWRKY29 or FaWRKY64 knockdown strawberry fruits in response to the pathogen.ConclusionOur study uncovered the foundational role of WRKY transcription factor genes, FaWRKY29 and FaWRKY64, in conferring resistance against B. cinerea. The discovery of susceptibility genes involved in BFR presents significant potential for developing resistance breeding strategies in cultivated strawberries, potentially leveraging CRISPR-based gene editing techniques.

Transcriptome analysis reveals mechanisms of the disease resistance in postharvest kiwifruit induced by Meyerozyma caribbica

Meyerozyma caribbica, an antagonistic yeast, effectively controls the postharvest blue mold decay of kiwifruit. Our previous study explored the mechanism of M. caribbica inhibiting the postharvest blue mold in kiwifruit at the physiological level, but its molecular mechanism is still unknown. This study investigated the related molecular mechanisms of disease-resistance in kiwifruits induced by M. caribbica based on transcriptome analysis. In addition, the effects of M. caribbica on the natural decay and storage quality of postharvest kiwifruit were investigated. The research showed that M. caribbica could reduce natural decay during kiwifruit storage without an apparent adverse effect on quality. The transcriptome analysis of postharvest kiwifruit found that there were 2916 DEGs, of which 1986 were up-regulated and 930 were down-regulated. KEGG pathway analysis showed that the plant-pathogen interaction pathway, glycolysis/gluconeogenesis pathway, flavonoid biosynthesis pathway, glutathione metabolism pathway and phenylpropane biosynthesis pathway were associated with the enhancement of kiwifruit resistance. The analysis of related metabolic pathways and functional analysis of related DEGs showed that M. caribbica could improve the expression of genes related to kiwifruit resistance, which are associated with induction of fruit resistance, mediated substance transport, improvement of cell wall strength, enhancement of plant antioxidant capacity, signal transduction and secondary metabolite synthesis, etc. These results provide a reference for future research on the use of antagonistic yeasts to prevent and control postharvest diseases of fruits and vegetables, and provide a theoretical basis for the practical application of antagonistic yeasts.

Identification of propranolol and derivatives that are chemical inhibitors of phosphatidate phosphatase as potential broad-spectrum fungicides

Plant diseases cause enormous economic losses in agriculture and threaten global food security, and application of agrochemicals is an important method of crop disease control. Exploration of disease-resistance mechanisms and synthesis of highly bioactive agrochemicals are thus important research objectives. Here, we show that propranolol, a phosphatidate phosphatase (Pah) inhibitor, effectively suppresses fungal growth, sporulation, sexual reproduction, and infection of diverse plants. The MoPah1 enzyme activity of the rice blast fungus Magnaporthe oryzae is inhibited by propranolol. Alterations in lipid metabolism are associated with inhibited hyphal growth and appressorium formation caused by propranolol in M. oryzae. Propranolol inhibits a broad spectrum of 12 plant pathogens, effectively inhibiting infection of barley, wheat, maize, tomato, and pear. To improve antifungal capacity, we synthesized a series of propranolol derivatives, one of which shows a 16-fold increase in antifungal ability and binds directly to MoPah1. Propranolol and its derivatives can also reduce the severity of rice blast and Fusarium head blight of wheat in the field. Taken together, our results demonstrate that propranolol suppresses fungal development and infection through mechanisms involved in lipid metabolism. Propranolol and its derivatives may therefore be promising candidates for fungicide development.