Disease Management Strategies Research Articles

OASL suppresses infectious bursal disease virus replication by targeting VP2 for degrading through the autophagy pathway.

OASL (2´,5´-oligadenylate synthetase-like protein) exhibits broad-spectrum antiviral effects against single-stranded RNA viruses in mammals, potentially serving as a promising target for novel antiviral strategies. However, its role in inhibiting the replication of double-stranded RNA viruses (dsRNA viruses), such as infectious bursal disease virus (IBDV), in avian species remains unclear. Our findings indicated a unique and potent defense mechanism of OASL against dsRNA viruses. It has been previously shown in mammals that OASL inhibits virus replication through increasing interferon production. The groundbreaking aspect of our study is the finding that OASL has the ability to interact with IBDV viral protein VP2 and target it for degradation and thus exerts its antiviral effect. Our results reveal the interaction between avian natural antiviral immune response and IBDV infection. Our study not only enhances our understanding of bird defenses against viral infections but can also inform strategies for poultry disease management.

Field response and genetic variability of elite spring bread wheat (Triticum aestivum L.) genotypes for septoria tritici blotch under natural infection in Northwest Ethiopia

AbstractFungal diseases cause significant yield loss to wheat production. Septoria tritici blotch (STB), caused by the ascomycete fungus Zymoseptoria trtici, is one of the major fungal diseases affecting wheat production worldwide. In Ethiopia, STB is a severe problem that causes significant yield loss in high and mid‐altitude wheat‐growing areas. The use of resistant varieties is one of the sustainable disease management strategies, particularly for resource‐poor farmers in developing countries. Two hundred and fifty bread wheat genotypes were evaluated to identify septoria tritici resistant genotypes and estimate the extent of genetic variability for resistance to STB and other economically important traits using alpha lattice design under natural infestation in two STB hotspot environments. Analysis of variance revealed highly significant differences among genotypes, environment, and genotype × environment interaction for all traits measured. The genetic coefficient of variance was lower than the phenotypic coefficient of variance for all traits studied, and both test environments showed the influence of the environment on trait expression. High and moderate heritability values were observed for the septoria disease severity parameters, indicating that the STB resistance trait was less influenced by the environment. The days to heading and plant height were inversely correlated with disease severity. This suggests that genotypes with tall plant height and long maturity period could be resistant to septoria tritici blotch through escape mechanisms. Four of the genotypes, namely, G‐215, G‐255, G‐257, and G‐258, were found to be resistant across all locations. These and other promising genotypes will be used in future breeding programmes to select or develop high‐yielding and STB‐resistant bread wheat genotypes that can be deployed in septoria tritici blotch‐prone areas. Highly susceptible genotypes will also be used as controls for STB resistance breeding programmes.

Role of Chitosan in Post Harvest Disease Management

Post harvest losses due to microbial spoilage remain a significant challenge in agriculture, affecting both food security and economic sustainability. Chitosan, a biopolymer derived from chitin, showed potential in recent years as a means of reducing post harvest diseases in fruits and vegetables. This review investigates into the complex role that chitosan plays in managing post harvest diseases. It emphasises the antimicrobial qualities, capacity to trigger defence mechanisms in plants, development of physical barriers, regulation of enzymatic activity, compatibility with biological control agents, and ecological sustainability of chitosan. Chitosan based treatments offer an environmentally sustainable approach to prolonging the period of the shelf life of produce by effectively preventing the growth of microbes, enhancing the plant's natural resistance to pathogens, and maintaining post harvest quality. Understanding the mechanisms underlying the efficacy of chitosan in disease management is essential for optimizing its application and integrating it into integrated disease management strategies in agricultural practices.

Immunoinformatics assisted profiling of West Nile virus proteome to determine immunodominant epitopes for the development of next-generation multi-peptide vaccine

Emerging infectious diseases represent a significant threat to global health, with West Nile virus (WNV) being a prominent example due to its potential to cause severe neurological disorders alongside mild feverish conditions. Particularly prevalent in the continental United States, WNV has emerged as a global concern, with outbreaks indicating the urgent need for effective prophylactic measures. The current problem is that the absence of a commercial vaccine against WNV highlights a critical gap in preventive strategies against WNV. This study aims to address this gap by proposing a novel, multivalent vaccine designed using immunoinformatics approaches to elicit comprehensive humoral and cellular immune responses against WNV. The objective of the study is to provide a theoretical framework for experimental scientists to formulate of vaccine against WNV and tackle the current problem by generating an immune response inside the host. The research employs reverse vaccinology and subtractive proteomics methodologies to identify NP_041724.2 polyprotein and YP_009164950.1 truncated flavivirus polyprotein NS1 as the prime antigens. The selection process for epitopes focused on B and T-cell reactivity, antigenicity, water solubility, and non-allergenic properties, prioritizing candidates with the potential for broad immunogenicity and safety. The designed vaccine construct integrates these epitopes, connected via GPGPG linkers, and supplemented with an adjuvant with the help of another linker EAAAK, to enhance immunogenicity. Preliminary computational analyses suggest that the proposed vaccine could achieve near-universal coverage, effectively targeting approximately 99.74% of the global population, with perfect coverage in specific regions such as Sweden and Finland. Molecular docking and immune simulation studies further validate the potential efficacy of the vaccine, indicating strong binding affinity with toll-like receptor 3 (TLR-3) and promising immune response profiles, including significant antibody-mediated and cellular responses. These findings present the vaccine construct as a viable candidate for further development and testing. While the theoretical and computational results are promising, advancing from in-silico predictions to a tangible vaccine requires comprehensive laboratory validation. This next step is essential to confirm the vaccine’s efficacy and safety in eliciting an immune response against WNV. Through this study, we propose a novel approach to vaccine development against WNV and contribute to the broader field of immunoinformatics, showcasing the potential to accelerate the design of effective vaccines against emerging viral threats. The journey from hypothesis to practical solution embodies the interdisciplinary collaboration essential for modern infectious disease management and prevention strategies.

Calcium signaling: Unveiling its role in disease control in plants

<p>Calcium signaling is a fundamental regulatory mechanism in plants, governing a myriad of physiological processes crucial for growth, development, and responses to environmental stimuli, including biotic stresses such as pathogen attack. Over the past decades, research into the intricate network of calcium signaling pathways has revealed its pivotal role in orchestrating plant defense mechanisms against a diverse array of pathogens. This review comprehensively examines the multifaceted roles of calcium ions in modulating plant immune responses, elucidating the molecular mechanisms underlying calcium-mediated signal transduction and its integration with other defense signaling pathways. We delve into the intricate crosstalk between calcium signaling and various hormonal pathways, reactive oxygen species (ROS) signaling, and secondary metabolite biosynthesis, highlighting the interconnectedness of these regulatory networks in shaping plant defense strategies. Furthermore, we explore the potential applications of calcium-based strategies for sustainable disease management in agriculture, including the use of calcium channel blockers, calcium chelators, and calcium-rich compounds as novel antimicrobial agents and priming agents for enhancing plant immunity. Challenges and future directions in the field are also discussed, aiming to advance our understanding of calcium signaling in plant-pathogen interactions and harness its potential for developing innovative approaches to combat plant diseases and ensure global food security. This review provides a comprehensive overview of the current state of knowledge regarding calcium signaling in plant disease control, offering valuable insights and perspectives for future research endeavors in this rapidly evolving field.<strong></strong></p>

Characterizing the Diversity of Oomycetes Associated with Diseased Cotton Seedlings in Alabama.

Many oomycete species are associated with the seedlings of crops, including upland cotton (Gossypium hirsutum L.), which leads to annual threats. The diversity of oomycete species in Alabama needs to be better understood since the last survey of oomycetes associated with cotton in Alabama was 20 years ago-before significant updates to taxonomy and improvements in identification of oomycetes using molecular tools. Our current study aimed to identify oomycetes associated with Alabama cotton seedlings, correlate diversity with soil edaphic factors, and assess virulence toward cotton seed. Thirty symptomatic cotton seedlings were collected independently from 25 fields in 2021 and 2022 2 to 4 weeks after planting. Oomycetes were isolated by plating root sections onto a semiselective medium. The internal transcribed spacer (ITS) region was sequenced to identify the resulting isolates. A seed virulence assay was conducted in vitro to verify pathogenicity, and 347 oomycete isolates were obtained representing 36 species. Northern Alabama soils had the richest oomycete communities and a greater silt and clay concentration than sandier soils in the central and southern coastal plains. Globisporangium irregulare and Phytophthora nicotianae were consistently recovered from cotton roots in both years. Globisporangium irregulare was pathogenic and recovered from all Alabama regions, whereas P. nicotianae was pathogenic but recovered primarily in areas with lower sand content in northern Alabama. Many oomycete species have not been previously reported in Alabama or the southeastern United States. Altogether, this knowledge will help facilitate effective management strategies for cotton seedling diseases caused by oomycetes in Alabama and the United States.

A Loop-Mediated Isothermal Amplification (LAMP) assay for the detection of Bremia lactucae in the field.

A real-time loop-mediated isothermal amplification (LAMP) assay for the detection of Bremia lactucae, the causal pathogen of Lettuce Downy Mildew (LDM), was developed and validated to aid in-field detection of airborne inoculum. Assay specificity was confirmed against a range of other pathogenic oomycete and fungal spp and sensitivity of the assay for the detection of DNA extracted from sporangia was evaluated. The B. lactucae LAMP assay reliably detected DNA equivalent to 1 spore/reaction (16.7 pg DNA/reaction). Following extraction of DNA from rotorod air-samplers to which sporangial suspensions were added, the assay reliably detected 25 sporangia/rotorod. Detection of airborne inoculum of B. lactucae collected through the season from air-samplers deployed in field plots infected with B. lactucae and also in commercial lettuce fields in Scotland over two growing seasons was assessed. The method can be deployed on samples collected from commercial lettuce production to inform disease management strategies and limit the use of unecessary prophylactic pesticide applications.

Viable protoplast isolation, organelle visualization and transformation of the globally distributed plant pathogen Phytophthora cinnamomi.

Phytophthora cinnamomi is an oomycete plant pathogen with a host range of almost 5000 plant species worldwide and therefore poses a serious threat to biodiversity. Omics technology has provided significant progress in our understanding of oomycete biology, however, transformation studies of Phytophthora for gene functionalisation are still in their infancy. Only a limited number of Phytophthora species have been successfully transformed and gene edited to elucidate the role of particular genes. There is a need to escalate our efforts to understand molecular processes, gene regulation and infection mechanisms of the pathogen to enable us to develop new disease management strategies. The primary obstacle hindering the advancement of transformation studies in Phytophthora is their challenging and unique nature, coupled with our limited comprehension of why they remain such an intractable system to work with. In this study, we have identified some of the key factors associated with the recalcitrant nature of P. cinnamomi. We have incorporated fluorescence microscopy and flow cytometry along with the organelle-specific dyes, fluorescein diacetate, Hoechst 33342 and MitoTracker™ Red CMXRos, to assess P. cinnamomi-derived protoplast populations. This approach has also provided valuable insights into the broader cell biology of Phytophthora. Furthermore, we have optimized the crucial steps that allow transformation of P. cinnamomi and have generated transformed isolates that express a cyan fluorescent protein, with a transformation efficiency of 19.5%. We therefore provide a platform for these methodologies to be applied for the transformation of other Phytophthora species and pave the way for future gene functionalisation studies.

Mitigating Emerging and Reemerging Diseases of Fruit and Vegetable Crops in a Changing Climate.

Fruit and vegetable crops are important sources of nutrition and income globally. Producing these high-value crops requires significant investment of often scarce resources, and, therefore, the risks associated with climate change and accompanying disease pressures are especially important. Climate change influences the occurrence and pressure of plant diseases, enabling new pathogens to emerge and old enemies to reemerge. Specific environmental changes attributed to climate change, particularly temperature fluctuations and intense rainfall events, greatly alter fruit and vegetable disease incidence and severity. In turn, fruit and vegetable microbiomes, and subsequently overall plant health, are also affected by climate change. Changing disease pressures cause growers and researchers to reassess disease management and climate change adaptation strategies. Approaches such as climate smart integrated pest management, smart sprayer technology, protected culture cultivation, advanced diagnostics, and new soilborne disease management strategies are providing new tools for specialty crops growers. Researchers and educators need to work closely with growers to establish fruit and vegetable production systems that are resilient and responsive to changing climates. This review explores the effects of climate change on specialty food crops, pathogens, insect vectors, and pathosystems, as well as adaptations needed to ensure optimal plant health and environmental and economic sustainability.

Morphological and Cultural Characterization of Sclerotium rolfsii Sacc on Chickpea and Its Management Using Combined Fungicide Molecules

Collar rot stands as a significant affliction of chickpea, attributed to the pathogen Sclerotium rolfsii. The current research investigated the morphological and cultural diversity among 10 isolates of S. rolfsii collected from major chickpea cultivation regions of Karnataka by assessing their growth rate, colony color and appearance, and features of Sclerotium including color, arrangement, and maturity days of Sclerotia were recored on two different media. The isolates BSR 2, BSR 5, BRS 9 and BSR 10 exhibited notably rapid growth on both Potato Dextrose Agar (PDA) and Corn meal Agar (CMA). Overall, the growth of these isolates appeared denser, indicating more substantial mycelial formation on PDA compared to CMA. These findings underscore the existence of variability among the isolates. In vitro evaluation of fungicides for the management of collar rot was evaluated using new combi fungicides. Among those Carbendazim 12% + Mancozeb 63% (0.15%), Hexaconazole 4% WP + Zineb 68%, Carboxin 37.5% + Thiram 37.5 %, Tricyclazole18 % + Mancozeb 62% WP, Captan 70% + Hexaconazole 5% WP at 0.05 per cent concentration showed cent per cent inhibition. Hence, these combi fungicides have been proven effective in suppressing the pathogen, making them valuable tools for implementing successful disease management strategies during the initial stages of crop growth.

Update on feline calicivirus: viral evolution, pathogenesis, epidemiology, prevention and control

Feline calicivirus (FCV) is a prevalent and impactful viral pathogen affecting domestic cats. As an RNA virus, FCV exhibits high mutability and genetic plasticity, enabling its persistence within cat populations. Viral genetic diversity is associated with a broad spectrum of clinical manifestations, ranging from asymptomatic infections and mild oral and upper respiratory tract diseases to the potential development of virulent systemic, and even fatal conditions. This diversity poses distinctive challenges in diagnosis, treatment, and prevention of diseases caused by FCV. Over the past four decades, research has significantly deepened understanding of this pathogen, with an emphasis on molecular biology, evolutionary dynamics, vaccine development, and disease management strategies. This review discusses various facets of FCV, including its genomic structure, evolution, innate immunity, pathogenesis, epidemiology, and approaches to disease management. FCV remains a complex and evolving concern in feline health, requiring continuous research to enhance understanding of its genetic diversity, to improve vaccine efficacy, and to explore novel treatment options.

TCF19 promotes cell proliferation and tumor formation in lung cancer by activating the Raf/MEK/ERK signaling pathway

ObjectiveThis study aimed to investigate TCF19′s role in lung cancer development, specifically its involvement in the RAF/MEK/ERK signaling pathway. MethodsLung cancer tissue analysis revealed significant TCF19 overexpression. In vitro experiments using A549 and Hop62 cells with TCF19 overexpression demonstrated enhanced cell growth. Transgenic mouse models confirmed TCF19′s role in primary tumor development. Transcriptome sequencing identified altered gene expression profiles, linking TCF19 to RAF/MEK/ERK pathway activation. Functional assays elucidated underlying mechanisms, revealing increased phosphorylation of Raf1, MEK1/2, and ERK1/2. Inhibiting RAF1 or ERK through shRaf1 or ERK inhibitor reduced cell cycle-related proteins and inhibited TCF19-overexpressing cell growth. ResultsTCF19 was identified as an oncogene in lung carcinoma, specifically impacting the RAF/MEK/ERK pathway. Elevated TCF19 levels in lung cancer suggest targeting TCF19 or its associated pathways as a promising strategy for disease management. ConclusionThis study unveils TCF19′s oncogenic role in lung cancer, emphasizing its modulation of the RAF/MEK/ERK pathway and presenting a potential therapeutic target for TCF19-overexpressing lung cancers.

Induction of volatile organic compounds in chrysanthemum plants following infection by Rhizoctonia solani.

This study investigated the effects of Rhizoctonia solani J.G. Kühn infestation on the volatile organic compound (VOC) emissions and biochemical composition of ten cultivars of chrysanthemum (Chrysanthemum × morifolium /Ramat./ Hemsl.) to bring new insights for future disease management strategies and the development of resistant chrysanthemum cultivars. The chrysanthemum plants were propagated vegetatively and cultivated in a greenhouse under semi-controlled conditions. VOCs emitted by the plants were collected using a specialized system and analyzed by gas chromatography/mass spectrometry. Biochemical analyses of the leaves were performed, including the extraction and quantification of chlorophylls, carotenoids, and phenolic compounds. The emission of VOCs varied among the cultivars, with some cultivars producing a wider range of VOCs compared to others. The analysis of the VOC emissions from control plants revealed differences in both their quality and quantity among the tested cultivars. R. solani infection influenced the VOC emissions, with different cultivars exhibiting varying responses to the infection. Statistical analyses confirmed the significant effects of cultivar, collection time, and their interaction on the VOCs. Correlation analyses revealed positive relationships between certain pairs of VOCs. The results show significant differences in the biochemical composition among the cultivars, with variations in chlorophyll, carotenoids, and phenolic compounds content. Interestingly, R. solani soil and leaf infestation decreased the content of carotenoids in chrysanthemums. Plants subjected to soil infestation were characterized with the highest content of phenolics. This study unveils alterations in the volatile and biochemical responses of chrysanthemum plants to R. solani infestation, which can contribute to the development of strategies for disease management and the improvement of chrysanthemum cultivars with enhanced resistance to R. solani.

Advancements in Crop Disease Detection: Analytical Methods for Recognizing Disease Stages through Leaf Analysis

Plant diseases have the potential to damage the livelihoods of farmers and impede their capacity to generate an adequate quantity of food. Diagnosis and early detection of plant diseases are critical for their effective management and control. Leaf analysis shows great potential as a method for forecasting disease stages due to its ability to detect subtle alterations in leaf physiology and appearance that may occur prior to the onset of conspicuous symptoms. By utilizing the algorithms of machine learning and deep learning, it is possible to classify characteristics extracted from photographs of leaves into distinct disease stages. Recent studies have demonstrated the potential of these algorithms, as they have achieved remarkable accuracy in disease stage prediction despite having limited training data. The integration of machine learning and deep learning techniques with foliage analysis holds promise for revolutionizing plant disease management through the provision of timely identification, accurate diagnosis, and customized treatment. In order to formulate efficacious disease management strategies, precise determination of the developmental stage of plant diseases is imperative. Scholars are presently devising novel approaches to identify the stages of plant diseases by employing diverse methodologies, including spectroscopy, machine learning, and image processing. This can benefit producers in substantial economic and environmental ways, as well as contribute to the improvement of food security. The primary investigation comprises an assortment of articles spanning the years 2014 to 2023. After evaluating various search strategies, a total of 117 research publications were identified, of which 43 were pertinent. The article examines numerous developments in deep learning research. In addition, it will facilitate the assessment of the present and prospective state of plant disease research by employing deep learning methodologies.

Harnessing Microbial Antagonists for Biological Control of Plant Pathogens: A Global Perspective

Reducing agricultural production inputs while maintaining a lucrative yield of high-quality goods is becoming more and more necessary as a result of the global sustainability agenda. Plant diseases pose a significant threat to productivity and product quality, yet many times there are no adequate measures available to control them. Consequently, research on substitute methods of crop protection has been mandated and has garnered significant interest from scholars around. A number of biological control agents (BCAs), including Bacillus, Pantoea, Streptomyces, Trichoderma, Clonostachys, Pseudomonas, Burkholderia, and specific yeasts, have been screened. Of these alternatives, biological controls through beneficial microorganisms have gained significant importance. BCAs, at the very least, support other sustainable disease management strategies like disease resistance and offer chances to control illnesses for whom alternative strategies are unfeasible or unobtainable. It is reasonable to anticipate that BCAs will be used more often to manage agricultural diseases in environmentally friendly ways.

Emerging Threat to Indian Agriculture: Fusarium incarnatum-equiseti Species Complex as a Novel Pathogen Imperiling Bajra, Cowpea, Finger Millet, Green gram, Moth Bean, and Soybean Crops

India, renowned for its diverse agro-climatic regions and agricultural legacy, relies on staple crops for sustenance. Cereals and Legumes, crucial to Indian agriculture and diet, contribute significantly to food security, economic prosperity, and environmental sustainability. Between August and October 2023, symptoms of grain/pod rot were observed in bajra, finger millet, cowpea, moth bean, green gram, and soybean crops in Uttarakhand. Based on morphological traits and the sequencing of the ITS (Internal Transcribed Spacer), rpb2 (RNA Polymerase II Second Largest Subunit), tef1 (Translation Elongation Factor 1-alpha) genes, the identified pathogens fall within the Fusarium incarnatum-equiseti species complex (FIESC). Pathogenicity tests confirmed the fulfillment of Koch's postulates, establishing the responsibility of the FIESC in grain/pod rot. This study unveils the first incidence of the FIESC causing grain/pod rot in bajra, cowpea, finger millet, soybean, green gram, and moth bean in India. Considering the economic importance of these crops, it is imperative to implement robust disease management strategies to alleviate the adverse effects of these pathogens on agricultural production. The findings underscore the necessity for continued research on emerging diseases to safeguard global crop production and food security.

SCOPE OF AYURVEDA IN THE MANAGEMENT OF KUSHTHA (SKIN DISEASES)

Background: Skin disorders are multi-faceted and may have their origin in allergy, autoimmunity, and hereditary. Ayurveda describes skin disorders under the umbrella of Kushtha, a disease characterized by the derangement of the skin. When we take into account the prevalence of different diseases, over 20% of all people seeking medical attention each year are suffering from skin disorders globally. Kushtha is categorized as Maha Kushtha and Kshudra Kushtha by all Acharyas depending on the severity of the symptoms and its prognosis. Many different etiological factors and disease management strategies are described in the Ayurvedic system of medicine. Aim: To assess the scope of Ayurveda in the management of skin diseases. Material & Methods: Different classical Ayurvedic texts, websites, journals and research articles were referred in the above context. Discussion & Conclusion: Kushtha arises from the vitiation of Tridosha and Twak, Rakta, Mamsa and Lasika. Thus the management for Kushtha is based on the involvement of Dosha and Dushya. Though some treatment modalities are condition-specific, the fundamental principle of treatment is consistent with all forms of Kushtha. Acharya have emphasized the significance of Shodhana (detoxification) therapy to eliminate the morbid Dosha from the body, and Raktamokshana to expel Dushita Rakta which is the key Dushya in the pathology of Kushtha. The Shamana (palliative) therapy comprises both internal and external medications viz. Rasa Aushadhi, Churna, Kwath, Asav, Arishta, Guggulu, Ghrita, and Malhara, Tail, Lepa. Dietary management, Dincharya, Ritucharya, Rasayana therapy, and Sadvritta are given immense importance in Ayurveda to preserve good health and prevention of diseases. This wholesome viewpoint of detoxification, palliative care and lifestyle modification needs to be analyzed to develop guidelines for the management of skin diseases based on Ayurveda principles.

First Report of Green Mould on Leaf of Phaseolus vulgaris Caused by Cladosporium tenuissimum in Liaoning, China.

Phaseolus vulgaris Linn. is a widely cultivated vegetable throughout the world. From spring 2019 to 2022, green mould symptoms were observed on leaves of P. vulgaris in the greenhouse in Liaoning, China, with disease incidence of 8-75% (plants) and 6-23% (leaves). Symptoms appeared as chlorotic lesions covered with dark green mould. The infections started at the apex or margin of the leaves and then spread inward with a characteristic "V" shape. Lesions exhibited curly morphology. 15 leaf samples with typical symptoms were collected from 5 different greenhouses. A total of 75 (5 replicates of each sample) leaf tissues (0.5 cm × 0.5 cm) were selected from the boundary between diseased and healthy parts. These samples were surface sterilized in 0.5% NaClO formin, rinsed 3 times in sterile distilled water and subsequently incubated at 28℃ on potato dextrose agar (PDA) supplemented with streptomycin (50 μg/ml). Numerous morphologically uniform colonies had been purified, with no other fungi observed. Afterwards, the strains were subcultured on malt extract agar (MEA). Colonies on MEA reached 70 to 80 mm diam after 14 days, smoke-grey to pale olivaceous-grey, woolly, sometimes radially wrinkled. The mycelia were pale olivaceous-grey, with hyphae measuring 1-5 μm wide (n = 20). The conidiophores were solitary or in groups of 2 to 5, and measured 50-280(-350) × 2.5-4 μm (n = 20), with 2-7 septa. The conidiogenous cells exhibited a cylindrical-oblong morphology and measured 10-44 × 5 μm (n = 20), with 0-2 septa, and the loci frequently thickened. The conidia were catenate in densely branched chains, ellipsoid to obovoid, smooth, and measured 2.5-5 × 2-3 μm (n = 50), with 0-4 septa. The morphological characteristics were similar to Cladosporium tenuissimum (Zhang 2003). The representative isolate KZ-19 was selected for molecular identification. The rDNA-ITS, translation elongation factor 1-α and actin genes were amplified, sequenced, and the resulting sequence data were submitted to GenBank (ITS: OQ931048; EF-1α: OQ954495; ACT: OQ954496). The BLAST results exhibited a 99 to 100% similarity with the sequences of C. tenuissimum type strain CBS 125995(ITS: HM148197; EF-1α: HM148442; ACT: HM148687). Furthermore, a multi-locus phylogenetic tree was constructed using the PhyloSuite (v 1. 2. 2) software, which revealed that the strains were most closely related to C. tenuissimum (Zhang et al. 2020). Based on both morphological and molecular characteristics, KZ-19 was finally identified as C. tenuissimum (Bensch 2012). Pathogenicity testing was performed on healthy 1-month-old P. vulgaris plants by inoculating the spore suspension (1×106 conidia/ml) of KZ-19 onto leaf surfaces, while control plants were simulated inoculated with sterile water, and five pots were used for each treatment. The test was performed under field conditions of 16-28°C (temperature) and 24-56% (relative humidity). Chlorotic lesions became evident within 2 days of inoculation, followed by the appearance of green mold on leaves after 7 days. No symptoms were observed in the control group. To fulfill Koch's postulates, the pathogen was re-isolated from three inoculated leaves. The morphological identification of re-isolated pathogens was similar to that of originally isolated pathogens. No infection was observed in non-inoculated control. To the best of our knowledge, this is the first report of C. tenuissimum causing green mould on P. vulgaris. As a ubiquitous saprobic hyphomycete, C. tenuissimum has been implicated in leaf mold in Punica granatum and Trifolium repens, larch bud blight, and strawberry blossom blight in previous years (He et al. 1987; Zhang et al. 2003; Zheng et al. 2010; Nam et al. 2015), presenting a potential threat to numerous crops. Therefore, an investigation of its distribution and pathogenic potential is essential in addition to the development of effective disease management strategies.

Homobrassinolide Delays Huanglongbing Progression in Newly Planted Citrus (Citrus sinensis) Trees.

Huanglongbing (HLB), or citrus greening, is a devastating disease impacting citrus trees worldwide, with severe effects particularly noted in Florida. Current strategies to combat HLB focus on aggressive replanting, despite the high susceptibility of young trees to infection. In this context, it is critical to explore agronomic practices that can enhance the health and resistance of young citrus trees to HLB. Here, we demonstrate that treatment with homobrassinolide (HBr), a type of brassinosteroid, in newly planted citrus (Citrus sinensis) trees can delay HLB infection and improve tree health amidst the high psyllid pressure conditions endemic to Florida. Our study reveals a significant reduction in HLB infection rates in HBr-treated trees compared to control trees, with only 25% of treated trees testing positive for HLB by six months, in contrast to 100% infection in untreated trees. This delay in infection may be attributed to HBr inducing an immune response and negatively impacting psyllid performance, as subsequently demonstrated in a greenhouse experiment. Our findings suggest that HBr applications could serve as a viable strategy to enhance the resilience of citrus production against HLB, underscoring the need for further investigation into their mechanisms of action and potential role in a comprehensive pest and disease management strategy.

Bacillus thuringiensis promotes systemic immunity in tomato, controlling pests and pathogens and promoting yield

AbstractPlant pathogens and pests pose an increasing threat to worldwide food security. To improve and strengthen food security under increasingly difficult environmental, economic, and geopolitical conditions, the prospect of using microbial biocontrol agents becomes increasingly desirable. One of the most studied, and commercially used, biopesticide microorganisms is the entomopathogenic, gram-positive, soil bacterium Bacillus thuringiensis (Bt). While Bt has been known for many years as an insecticidal microorganism and used extensively in agriculture, its possible anti-phytopathogen and plant growth-promoting activities have received comparatively limited attention thus far. Here, we examine the ability of Bt to promote systemic immunity in tomato plants. We investigate how Bt influences plant immunity and disease resistance against several fungal and bacterial plant pathogens, as well as several arthropod pests. In order to determine which component of Bt (i.e., Bt spores or pure crystals) is responsible for the observed effects on pathogens or pests, we dissected the different fractions present in a commercial preparation and assessed their effects on pest and pathogen control. As previously reported in the Bt literature, our results indicate that proteins produced by Bt are likely the primary acting components against pests. In the case of pathogens, however, it appears that both the Bt spores and proteins directly act against pathogens such as the fungus Botrytis cinerea. Bt Spores and produced proteins also both induce plant immunity. Understanding the different Bt mode of action mechanisms will help in developing cost-effective and safe plant protection strategies for enhancing food security. Taken together, our findings suggest that Bt could be used in broad-spectrum pest and disease management strategies. Pending validation in agricultural settings, Bt products on the market could have additional uses in sustainable pest management and plant growth promotion.