Bioproducts of Pseudomonas chlororaphis suppress DMI fungicide-induced CsCYP51A and CsCYP51B gene expression in Colletotrichum siamense and generate synergistic effects with metconazole and propiconazole.

Mixtures of fungicides with different modes of action are commonly used as disease and resistance management tools, but little is known of mixtures of natural and synthetic products. In this study, mixtures of metabolites from the rhizobacterium Pseudomonas chlororaphis strain ASF009 formulated as Howler EVO with below label rates (50 µg/ml) of conventional sterol demethylation inhibitor (DMI) fungicides were investigated for control of anthracnose of cherry (Prunus avium) caused by Colletotrichum siamense. Howler mixed with metconazole or propiconazole synergistically reduced disease severity through lesion growth. Realtime PCR showed that difenoconazole, flutriafol, metconazole, and propiconazole induced the expression of DMI target genes CsCYP51A and CsCYP51B in C. siamense. The addition of Howler completely suppressed the DMI fungicide-induced expression of both CYP51 genes. We hypothesize that the downregulation of DMI fungicide-induced expression of the DMI target genes may, at least in part, explain the synergism observed in detached fruit assays.

Research on identification method of peanut pests and diseases based on lightweight LSCDNet model.

Timely and accurate identification of peanut pests and diseases, coupled with effective countermeasures, are pivotal for ensuring high-quality and efficient peanut production. Despite the prevalence of pests and diseases in peanut cultivation, challenges such as minute disease spots, the elusive nature of pests, and intricate environmental conditions often lead to diminished identification accuracy and efficiency. Moreover, continuous monitoring of peanut health in real-world agricultural settings demands solutions that are computationally efficient. Traditional deep learning models often require substantial computational resources, limiting their practical applicability. In response to these challenges, we introduce LSCDNet (Lightweight Sandglass and Coordinate Attention Network), a streamlined model derived from DenseNet. LSCDNet preserves only the transition layers to reduce feature map dimensionality, simplifying the model's complexity. The inclusion of a sandglass block bolsters features extraction capabilities, mitigating potential information loss due to dimensionality reduction. Additionally, the incorporation of coordinate attention addresses issues related to positional information loss during feature extraction. Experimental results showcase that LSCDNet achieved impressive metrics with an accuracy, precision, recall, and F1 score of 96.67%, 98.05%, 95.56%, and 96.79%, respectively, while maintaining a compact parameter count of merely 0.59M. When compared to established models such as MobileNetV1, MobileNetV2, NASNetMobile, DenseNet-121, InceptionV3, and Xception, LSCDNet outperformed with accuracy gains of 2.65%, 4.87%, 8.71%, 5.04%, 6.32%, and 8.2% respectively, accompanied by substantially fewer parameters. Lastly, we deployed the LSCDNet model on Raspberry Pi for practical testing and application, achieving an average recognition accuracy of 85.36%, thereby meeting real-world operational requirements.

Unraveling the Interplay: Soil Biogeochemical Factors Shaping the Efficacy of Anaerobic Soil Disinfestation in Suppressing Fusarium Root Rot of Strawberry.

Non-toxic alternatives to chemical soil fumigants for suppressing soilborne pathogens such as Fusarium oxysporum (Fo), one causative agent of strawberry black root rot complex prevalent in the southeastern U.S., are urgently needed. A promising alternative is anaerobic soil disinfestation (ASD), in which soil is amended with labile organic materials, irrigated to field capacity, and tarped to induce anaerobic fermentation for a brief period before planting. Pathogen-suppression mechanisms of ASD include anaerobic conditions and generation of reduced metal cations (Fe2+ and Mn2+) and volatile fatty acids (VFAs; e.g., acetic, n-butyric, isovaleric, and others). However, little is known about how the interaction between VFAs, reduced metals, soil texture, and liming influences suppression of Fo. We investigated Fo suppression by VFAs and reduced metal cations in both aqueous and soil-based incubation trials. Inoculum containing Fo chlamydospores was added to aqueous medium containing either 5 or 10 mmol/liter VFAs and either 0.01% or 0.05% (w/w) reduced metals. In soil-based incubations, chlamydospore-containing inoculum was applied to sandy, sandy loam, and silty clay soil saturated by solutions containing 10 or 20 mmol/liter VFAs with or without 0.05% (w/w) reduced metals. VFAs, particularly in combination with Fe2+ in aqueous solutions and Mn2+ in soils significantly reduced Fo viability. At the same time, liming and higher soil clay content reduced the effectiveness of VFAs and reduced metals for suppressing Fo, highlighting the influence of soil pH and soil texture on ASD effectiveness.

Influence of Propiconazole and Metconazole Formulations on Bacillus subtilis Vegetative Cell Growth and Disease Control of Fruit Crops.

Biological control agent Bacillus subtilis formulated as Theia is registered for control of fungal and bacterial diseases of fruit crops. Combinations of Theia and strategic concentrations of two demethylation inhibitor (DMI) fungicides were investigated to explore potential synergisms. Bacteria were cultured in nutrient broth and combined with technical grades and two formulations of propiconazole (emulsifiable concentrate [EC] and wettable powder) and metconazole (EC and water-dispersible granule) at 0, 10, 50, 100, and 150 µg/ml of active ingredient. After cocultivation, the optical density (OD600) and colony forming units (CFU/ml) were evaluated. In contrast to EC formulations, the wettable powder or water-dispersible granule formulations at 10 or 50 µg/ml of both DMIs did not affect vegetative cell growth. The mixture of Theia and each formulated DMI at 50 µg/ml of active ingredient resulted in a significant reduction of Monilinia fructicola lesion development on apple, Colletotrichum siamense lesion development on cherry, and Botrytis cinerea lesion development on cherry. The combination of Theia with EC formulations showed weaker disease reduction due to antagonism. Only Theia plus non-EC formulated propiconazole and metconazole significantly reduced brown rot disease incidence of apple compared with the respective solo treatments and anthracnose disease incidence of cherry compared with the untreated control. Our results indicated that at least some DMI fungicides possess bactericidal effects depending on the formulation and concentration. The combination of Theia with a lower-than-label-rate concentration (50 µg/ml) of the DMI fungicides propiconazole and metconazole showed potential for synergistic effects, especially when non-EC formulations were used.

The Nuances of Plant Disease Severity Estimation Using Quantitative Ordinal Scales-Lessons Learned over Four Decades.

We revisit the foundations of the Horsfall-Barratt (HB) scale, a widely cited and applied plant disease visual assessment tool introduced in 1945, a full 37 years prior to T. T. Hebert's 1982 critique that raised concerns regarding the scale's rationale, particularly its reliance on the Weber-Fechner law and visual perception assumptions. Although use of the HB scale and similar ordinal scales persists, comprehensive studies have revealed that direct visual estimation using percentage scales often proves more accurate and reliable. Challenges remain, such as biases due to estimator subjectivity and the potential for misclassification. The logarithmic assumptions of the HB scale have been debunked, and the importance of choosing appropriate interval sizes and numbers of classes in developing ordinal scales is emphasized. Analyzing ordinal scale data appropriately is crucial, and recent advances offer promising methods that reduce type II error rates. The closely related disease severity index is noted to have its shortcomings and potential for misuse. The letter underscores the need for continuous refinement and critical evaluation of disease assessment methodologies.

Validation of fungicide spray strategies and selection for fenhexamid resistance in Botrytis cinerea on greenhouse-grown grapevines.

In this study, in planta assays were conducted to assess the effects of fungicide spray tactics, such as the reduction of the labeled fungicide dose and mixture with a multi-site fungicide, on fungicide resistance selection and disease control using Vitis vinifera 'Cabernet Sauvignon' grown in a greenhouse for two years. The entire clusters were inoculated with B. cinerea isolates at varying frequencies of fenhexamid resistance, followed by fungicide sprays, disease and fenhexamid resistance investigations at critical phenological stages. Our findings indicate that the lower dose of the at-risk fungicide, fenhexamid, effectively managed fenhexamid resistance and disease as well as the higher, labeled dose. In addition, mixture with the multi-site fungicide captan generally resulted a net-positive effect on both resistance management and disease control.

Phytocytokine StPep1-secreting bacteria suppress potato powdery scab disease.

Powdery scab is an important potato disease caused by the soilborne pathogen Spongospora subterranea f. sp. subterranea. Currently, reliable chemical control and resistant cultivars for powdery scab are unavailable. As an alternative control strategy, we propose a novel approach involving the effective delivery of a phytocytokine to plant roots by the rhizobacterium Bacillus subtilis. The modified strain is designed to secrete the plant elicitor peptide StPep1. In our experiments employing a hairy root system, we observed a significant reduction in powdery scab pathogen infection when directly applying the StPep1 peptide. Furthermore, our pot assay, which involved pretreating potato roots with StPep1-secreting B. subtilis, demonstrated a substantial decrease in disease symptoms, including reduced root galling and fewer tuber skin scabs. These findings underscore the potential of engineered bacteria as a promising strategy for safeguarding plants against powdery scab.

Hiding in Plain Sight: A Widespread Native Perennial Harbors Diverse Haplotypes of 'Candidatus Liberibacter solanacearum' and Its Potato Psyllid Vector.

The unculturable bacterium 'Candidatus Liberibacter solanacearum' (CLso) is responsible for a growing number of emerging crop diseases. However, we know little about the diversity and ecology of CLso and its psyllid vectors outside of agricultural systems, which limits our ability to manage crop disease and understand the impacts this pathogen may have on wild plants in natural ecosystems. In North America, CLso is transmitted to crops by the native potato psyllid (Bactericera cockerelli). However, the geographic and host plant range of the potato psyllid and CLso beyond the borders of agriculture are not well understood. A recent study of historic herbarium specimens revealed that a unique haplotype of CLso was present infecting populations of the native perennial Solanum umbelliferum in California decades before CLso was first detected in crops. We hypothesized that this haplotype and other potentially novel CLso variants are still present in S. umbelliferum populations. To test this, we surveyed populations of S. umbelliferum in Southern California for CLso and potato psyllid vectors. We found multiple haplotypes of CLso and the potato psyllid associated with these populations, with none of these genetic variants having been previously reported in California crops. These results suggest that CLso and its psyllid vectors are much more widespread and diverse in North American natural plant communities than suggested by data collected solely from crops and weeds in agricultural fields. Further characterization of these apparently asymptomatic haplotypes will facilitate comparison with disease-causing variants and provide insights into the continued emergence and spread of CLso.

Antisense oligonucleotide as a new technology application for CsLOB1 gene silencing aiming citrus canker resistance.

Citrus canker disease, caused by Xanthomonas citri subsp. citri, poses a significant threat to global citrus production. The control of the disease in the field relies mainly on the use of conventional tools such as copper compounds, which are harmful to the environment and could lead to bacterial resistance. This scenario stresses the need for new and sustainable technologies to control phytopathogens, representing a key challenge in developing studies that translate basic into applied knowledge. During infection, X. citri subsp. citri secretes a transcriptional activator-like effector that enters the nucleus of plant cells, activating the expression of the canker susceptibility gene LATERAL ORGAN BOUNDARIES 1 (LOB1). In this study, we explored the use of antisense oligonucleotides (ASOs) with phosphorothioate modifications to transiently inhibit the gene expression of CsLOB1 in Citrus sinensis. We designed and validated three potential ASO sequences, which led to a significant reduction in disease symptoms compared to the control. The selected ASO3-CsLOB1 significantly decreased the expression level of CsLOB1 when delivered through two distinct delivery methods and the reduction of the symptoms ranged from approximately 15% to 83%. Notably, plants treated with ASO3 did not exhibit an increase in symptoms development over the evaluation period. This study highlights the efficacy of ASO technology, based on short oligonucleotide chemically modified sequences, as a promising tool for controlling phytopathogens without the need for genetic transformation or plant regeneration. Our results demonstrate the potential of ASOs as a biotechnological tool for the management of citrus canker disease.

Winter rye cover crops shelter competent squash phyllosphere bacteria to reduce Pseudomonas syringae pv. lachrymans growth and angular leaf spot symptoms.

Cover crops, a soil conservation practice, can contribute to reducing disease pressure caused by Pseudomonas syringae, considered one of the most important bacterial plant pathogens. We recently demonstrated that phyllosphere (leaf surface) bacterial community structure changed when squash (Cucurbita pepo) was grown with a rye (Secale cereale) cover crop treatment, followed by a decrease of angular leaf spot (ALS) disease symptoms on squash caused by P. syringae pv. lachrymans. Application of biocontrol agents is a known agricultural practice to mitigate crop losses due to microbial disease. In this study, we tested the hypothesis that some phyllosphere bacteria promoted when squash are grown on cover crops could be isolated and used as a biocontrol agent to decrease ALS symptoms. We grew squash during a two-year field experiment using four agricultural practices: bare soil, cover crops, chemically terminated cover crops, and plastic cover. We sampled squash leaves at 3 different dates each year and constructed a collection of cultivable bacterial strains isolated from squash leaves and rye cover crop material. Each isolated strain was identified by 16S rRNA gene sequencing and used in in vitro (Petri dish) pathogen growth and in vivo (greenhouse) symptom control assays. Four bacterial isolates belonging to the genera Pseudarthrobacter, Pseudomonas, Delftia and Rhizobium were shown to inhibit P. syringae pv. lachrymans growth and ALS symptom development. Strikingly, the symptom control efficacy of all strains was stronger on older leaves. This study sheds light on the importance of bacterial isolation from cover crops sources to promote disease control.

Drosophila hydei as a Potential Vector of Ceratocystis fimbriata, the Causal Agent of Sweetpotato Black Rot, in Storage Facilities.

Ceratocystis fimbriata, the causal agent of sweetpotato black rot, is a pathogen capable of developing and spreading within postharvest settings. A survey of North Carolina sweetpotato storage facilities was conducted to determine the arthropods present and identify potential vectors of C. fimbriata. Sixteen taxonomic categories were recovered, and the genus Drosophila (Diptera: Drosophilidae) accounted for 79% of individuals sampled, with Drosophila hydei being the most abundant species. Behavioral assays were conducted to determine if D. hydei is attracted to C. fimbriata-inoculated roots and if the pathogen could be recovered from external or internal surfaces of the insect. Flies were released in insect-trapping pitchers containing either C. fimbriata-inoculated or noninoculated roots or Petri dishes. No significant differences in fly number were detected in sweetpotato-baited pitchers; however, significant differences were found in the pitcher baited with a mature C. fimbriata culture. Flies were subjected to washes to determine if viable C. fimbriata was present (internally or externally); washes were plated onto carrot agar plates and observed for the presence of C. fimbriata colonies. Both external and internal washes had viable C. fimbriata inocula with no significant differences, and inoculated sweetpotatoes had a significantly higher number of flies carrying C. fimbriata. This study suggests that D. hydei can carry C. fimbriata from infected sweetpotatoes and move viable C. fimbriata inocula both externally and internally, making this the first report of any Drosophila sp. serving as a potential vector for the Ceratocystis genus.

Combining single-gene-resistant and pyramided cultivars of perennial crops in agricultural landscapes compromises pyramiding benefits in most production situations.

While resistant cultivars are valuable in safeguarding crops against diseases, they can be rapidly overcome by pathogens. Numerous strategies have been proposed to delay pathogen adaptation (evolutionary control), while still ensuring effective protection (epidemiological control). For perennial crops, multiple resistance genes can be deployed 1) in the same cultivar (pyramiding strategy), in single-gene-resistant cultivars grown 2) in the same field (mixture strategy) or 3) in different fields (mosaic strategy), or 4) in hybrid strategies that combine the three previous options. In addition, the spatial scale at which resistant cultivars are deployed can affect the plant-pathogens interaction: small fields are thought to reduce pest density and disease transmission. Here we used the spatially-explicit stochastic model landsepi to compare the evolutionary and epidemiological control across spatial scales and deployment strategies relying on two major resistance genes. Our results, broadly focused on resistance to downy mildew of grapevine, show that the evolutionary control provided by the pyramiding strategy is at risk when single-gene-resistant cultivars are concurrently planted in the landscape (hybrid strategies), especially at low mutation probability. Moreover, the effectiveness of pyramiding compared to hybrid strategies is influenced by whether the adapted pathogen pays a fitness cost across all hosts or only for unnecessary virulence, particularly when the fitness cost is high rather than intermediate. Finally, field size did not affect model outputs for a wide range of mutation probabilities and associated fitness costs. The socio-economic policies favoring the adoption of optimal resistant management strategies are discussed.

CbCyp51-mediated DMI resistance is modulated by codon bias.

Cercospora leaf spot (CLS), caused by the fungus Cercospora beticola, is the most destructive foliar disease of sugar beet worldwide. Resistance to the sterol demethylation inhibitor (DMI) fungicide tetraconazole has been previously correlated to synonymous and non-synonymous mutations in CbCyp51. Here, we extend these analyses to the DMI fungicides prothioconazole, difenoconazole, and mefentrifluconazole in addition to tetraconazole to confirm whether the synonymous and nonsynonymous mutations at amino acid positions 144 and 170 are associated with resistance to these fungicides. Nearly half of the 593 isolates of C. beticola collected in the Red River Valley of North Dakota and Minnesota in 2021 were resistant to all four DMIs. Another 20% were resistant to tetraconazole and prothioconazole, but sensitive to difenoconazole and mefentrifluconazole. A total of 13% of isolates were sensitive to all DMIs tested. We found five CbCyp51 haplotypes and associated them with phenotypes to the four DMIs. The most predominant haplotype (E170_A/ L144F_C) correlated to resistance to all four DMIs with up to 97.6% accuracy. The second most common haplotype (E170_A/L144) consisted of isolates associated with resistance phenotypes to tetraconazole and prothioconazole while also exhibiting sensitive phenotypes to difenoconazole and mefentrifluconazole with up to 98.4% accuracy. Quantitative PCR did not identify differences in CbCyp51 expression between haplotypes. This study gives an understanding for the importance of codon usage in fungicide resistance and provides crop management acuity for fungicide application decision-making.

Deep Learning Based Barley Disease Quantification for Sustainable Crop Production.

Net blotch disease caused by Drechslera teres is a major fungal disease that affects barley (Hordeum vulgare) plants and can result in significant crop losses. In this study, we developed a deep-learning model to quantify net blotch disease symptoms on different days post-infection on seedling leaves using Cascade R-CNN (Region-Based Convolutional Neural Networks) and U-Net (a convolutional neural network) architectures. We used a dataset of barley leaf images with annotations of net blotch disease to train and evaluate the model. The model achieved an accuracy of 95% for cascade R-CNN in net blotch disease detection and a Jaccard index score of 0.99, indicating high accuracy in disease quantification and location. The combination of Cascade R-CNN and U-Net architectures improved the detection of small and irregularly shaped lesions in the images at 4-days post infection, leading to better disease quantification. To validate the model developed, we compared the results obtained by automated measurement with a classical method (necrosis diameter measurement) and a pathogen detection by real-time PCR. The proposed deep learning model could be used in automated systems for disease quantification and to screen the efficacy of potential biocontrol agents to protect against disease.

Plant-Derived, Nodule-Specific Cysteine-Rich Peptides as a Novel Source of Biopesticides for Controlling Citrus Greening Disease.

Nodule-specific cysteine-rich (NCR) peptides, encoded in the genome of the Mediterranean legume Medicago truncatula (barrelclover), are known to regulate plant-microbe interactions. A subset of computationally derived 20-mer peptide fragments from 182 NCR peptides was synthesized to identify those with activity against the unculturable vascular pathogen associated with citrus greening disease, 'Candidatus Liberibacter asiaticus' (CLas). Grounded in a design of experiments framework, we evaluated the peptides in a screening pipeline involving three distinct assays: a bacterial culture assay with Liberibacter crescens, a CLas-infected excised citrus leaf assay, and an assay to evaluate effects on bacterial acquisition by the nymphal stage of hemipteran vector Diaphorina citri. A subset of the 20-mer NCR peptide fragments inhibits both CLas growth in citrus leaves and CLas acquisition by D. citri. Two peptides induced higher levels of D. citri mortality. These findings reveal 20-mer NCR peptides as a new class of plant-derived biopesticide molecules to control citrus greening disease.

Effectiveness and genetic control of Trichoderma spp. as a biological control of wheat powdery mildew disease.

Wheat powdery mildew (WPM) is one of the most devasting diseases that affects wheat yield worldwide. Few efforts have been done to control such a serious disease. Looking for an effective way to control WPM is urgently needed. Biological control is an effective way in controlling plant diseases worldwide. In this study, the efficiency of three different Trichoderma spp. in controlling WPM at seedling growth stage was tested using 35 highly diverse wheat genotypes. Highly significant differences were found in WPM resistance among the four treatments confirming the efficiency of Trichoderma in controlling WPM. Out of the three species, Trichoderma asperellum T34 (T34) was the most effective species in controlling WPM as it reduced the symptoms with a percentage of 50.56%. A set of 196 wheat genotypes was used to identify the genetic control of the WPM induced resistance by T34. A total of 39, 27, and 18 gene models were identified to contain the significant markers under Pm, T34, and the improvement in powdery mildew resistance due to T34 (T34_improvement) conditions. Furthermore, no gene model was common between T34 and Pm suggesting the presence of completely different genetic systems controlling the resistance under T34 and Pm. The functional annotation and biological process pathways of the detected gene models confirm their association with the normal and induced resistance. This study, for the first time, confirm the efficiency of T34 in controlling WPM and provide a deep understanding of the genetic control of induced and normal resistance to WPM.

Dual transcriptomic & metabolomic analysis of elicited flax sheds light on the kinetics of immune defense activation against the biotrophic pathogen Oidium lini.

Flax (Linum usitatissimum) grown under controlled conditions displayed genotype-dependent resistance to powdery mildew (Oidium lini) following COS-OGA (comprising chitosan- and pectin-derived oligomers) elicitor application. The present study reveals a two-step immune response in plants preventively challenged with the elicitor: an initial, rapid response characterized by the transcription of defense genes whose protein products act in contact with or within the cell wall, where biotrophic pathogens initially thrive, followed by a prolonged activation of cell wall peroxidases and accumulation of secondary metabolites. Thus, dozens of genes encoding membrane receptors, pathogenesis-related proteins, and wall peroxidases were initially overexpressed. Repeated COS-OGA treatments had a transient effect on the transcriptome response while cumulatively remodeling the metabolome over time, with a minimum of two applications required for maximal metabolomic shifts. Secondary metabolites, in particular terpenoids and phenylpropanoids, emerged as major components of this secondary defense response alongside pathogenesis-related proteins and wall peroxidases. The sustained accumulation of secondary metabolites, even after cessation of elicitation, contrasted with the short-lived transcriptomic response. Wall peroxidase enzyme activity also exhibited cumulative effects, increasing strongly for weeks after a third elicitor treatment. This underscores the plasticity of the plant immune response in the face of a potential infection, and the need for repeated preventive applications to achieve the full protective potential of the elicitor.

Impacts of increasing soil salinity on genetic resistance (I-3 gene)-based management of Fusarium wilt (F. oxysporum f. sp. lycopercisi race 3) in California processing tomatoes.

California is the primary processing tomato (Solanum lycopersicum) producer in the United States. Fusarium oxysporum f. sp. lycopercisi race 3 (Fol3), the cause of Fusarium wilt, is a major yield loss driver. Fol3 has recently been observed causing disease in resistant cultivars (I-3 R-gene), often in association with high soil salinity. This study undertook to better understand the effect of salinity on resistance-based management of Fol3. Surveys established opportunity for salinity-Fol3-tomato interactions in 44% of commercial fields examined, with harmful soil salt levels up to 3.6 dS/m (P < 0.001), high sodium (P < 0.001), and high sodicity (SAR > 13, P < 0.001). In controlled field studies of Fol3 in NaCl:CaCl2-treated soil, Fol3-resistant cultivars either only developed wilt under salt or only developed wilt above the industry non-hybrid threshold (2%) under salt across two trial years. Absence of yield differences indicate low to no economic impact of disease enhancement (P > 0.05). NaCl, CaCl2 and Na2SO4 had no effect on Fol3 propagule production in liquid agar vs. water agar controls (P > 0.05) although CaCl2 increased propagule loads 7-fold vs. ionic controls (PEG) (P = 0.036). NaCl:CaCl2 (2:1) reduced propagule loads up to 65% vs. no-salt (P = 0.029) in soil with pathogen-infested tomato tissue. These results together establish the opportunity for salinity-Fol3-tomato interactions and potential for salt to influence efficacy of resistant cultivar-based management-this does not appear to be primarily due to salt-enhancement of pathogen populations, pointing to a yet unexplored direct influence of salt on host resistance.

From microbes to microbiomes: Applications for plant health and sustainable agriculture.

Plant-microbe interaction research has had a transformative trajectory, from individual microbial isolate studies to comprehensive analyses of plant microbiomes within the broader phytobiome framework. Acknowledging the indispensable role of plant microbiomes in shaping plant health, agriculture, and ecosystem resilience, we underscore the urgent need for sustainable crop production strategies in the face of contemporary challenges. We discuss how the synergies between advancements in 'omics technologies and artificial intelligence can help advance the profound potential of plant microbiomes. Furthermore, we propose a multifaceted approach encompassing translational considerations, transdisciplinary research initiatives, public-private partnerships, regulatory policy development, and pragmatic expectations for the practical application of plant microbiome knowledge across diverse agricultural landscapes. We advocate for strategic collaboration and intentional transdisciplinary efforts to unlock the benefits offered by plant microbiomes and address pressing global issues in food security. By emphasizing a nuanced understanding of plant microbiome complexities and fostering realistic expectations, we encourage the scientific community to navigate the transformative journey from discoveries in the laboratory to field applications. As companies specializing in agricultural microbes and microbiomes undergo shifts, we highlight the necessity of understanding how to approach sustainable agriculture with site-specific management solutions. While cautioning against over-promising, we underscore the excitement of exploring the many impacts of microbiome-plant interactions. We emphasize the importance of collaborative endeavors with societal partners to accelerate our collective capacity to harness the diverse and yet-to-be-discovered beneficial activities of plant microbiomes.

Modification of the Helper Component Proteinase of Papaya Ringspot Virus Vietnam Isolate to Generate Attenuated Mutants for Disease Management by Cross Protection.

Papaya (Carica papaya) production is seriously limited by papaya ringspot virus (PRSV) worldwide, including in Vietnam. Control of PRSV by cross protection is dependent on the availability of effective mild strains. Here, an infectious cDNA clone was constructed from PRSV isolate TG5 from South Vietnam. Site-directed mutagenesis with point mutations on the essential motifs of the helper component proteinase (HC-Pro) was performed, with or without deleting five amino acids (d5) from its N-terminal region. Mutants TG-d5, TG-d5I7, and TG-d5L206 containing d5, d5 + F7I, and d5 + F206L, respectively, induced mild mottling followed by symptomless recovery on papaya and infected Chenopodium quinoa without lesion formation. Each mutant accumulated in papaya at reduced levels with a zigzag pattern and was stable beyond six monthly passages. The cross-protection effectiveness of the three mutants in papaya against TG5 was investigated, each with 60 plants from three independent trials. The results showed that each mutant provided complete protection (100%) against TG5, 1 month after the challenge inoculation, as verified by the lack of severe symptoms and lack of local lesions in C. quinoa. Further tests revealed that TG-d5I7 also confers high levels of protection against other severe PRSV isolates from South Vietnam, including isolates DN (97%) and ST2 (50%). However, TG-d5I7 is ineffective or less effective (0 to 33%) against seven other severe PRSV strains from different geographic origins, including the isolate HN from North Vietnam. Our results indicate that the protection by the three mutants is highly strain-specific and suitable for the control of PRSV in South Vietnam.