Plants must continuously balance the trade-offs between growth and defense, a constraint that is exacerbated by biotic and abiotic stresses, particularly when they occur together. Ethylene (ET) serves as a central, integrative regulatory node controlling this by linking developmental programs to stress-responsive signaling networks. Advances at the molecular and systems levels have revealed that ET mediates the redistribution of metabolic resources via coordinated regulation of its synthesis, perception, and downstream signaling. The ETR (Ethylene Receptor)-CTR1 (Constitutive Triple Response 1)-EIN2 (Ethylene Insensitive 2)-EIN3(Ethylene Insensitive 3) signaling module lies at the core of this network, integrating multiple hormonal pathways. Through dynamic crosstalk with jasmonic acid (JA), salicylic acid (SA), abscisic acid (ABA), auxin (AUX), and gibberellins (GA), ET enables the fine-tuned coordination of growth inhibition, immune activation, and stress acclimation in response to environmental fluctuations. Processes such as induced systemic resistance, programmed cell death, and architectural plasticity further reinforce this regulatory framework, with ethylene-responsive transcription factors, including ERFs (ethylene responsive factor gene family) and WRKYs, acting as critical convergence points. Emerging insights into ACC (1-aminocyclopropane-1-carboxylic acid)-dependent signaling, chromatin remodeling, and tissue-specific regulation expand the functional scope of ET beyond traditional hormone paradigms. At the same time, the ability of pathogens to manipulate ET signaling underscores its dual role in both promoting immunity and facilitating susceptibility. By integrating molecular, physiological, and ecological perspectives, this review highlights ET as a central coordinator of plant stress resilience and growth optimization, providing a unifying framework for understanding how plants adapt to complex and dynamic environments.

Plant diseases significantly impact global food security, causing yield losses and reduced crop quality. Traditional detection methods are labor-intensive, slow, and hindering timely interventions. This chapter explores how AI, deep learning, and IoT technologies can revolutionize plant disease detection in sustainable agriculture. A review of recent research and experiments shows that convolutional neural networks (CNN), transfer learning models like ResNet and EfficientNet, and multispectral imaging can all be used to classify crops like rice, maize, and wheat with 90% to 98% accuracy. The integration of IoT sensors and cloud-based platforms enables real-time monitoring, early diagnosis, and optimized pesticide use, fostering sustainable practices. AI-driven disease detection helps make better predictions about crop yields, has less of an effect on the environment, and makes it easier to make decisions based on data. The chapter emphasizes the need for understandable AI systems and accessible tools for farmers to ensure equitable benefits and digital transformation in agriculture.

Tomato (Solanum lycopersicum) is a globally important horticultural crop, with Asia contributing 60.45% of total production, followed by the Americas at 13.36%. Tomato productivity is increasingly constrained by southern blight, a destructive disease responsible for yield losses ranging from 30 to 90% and annual economic damage of $10–20 million. The causal pathogen, Sclerotium rolfsii, infects the stem base and induces reddish-brown cankers through secretion of oxalic acid (OA) and cell wall-degrading enzymes, which girdle tissues, impair water transport, and result in rapid plant wilting and death. Its persistence in soil via sclerotia, broad host range, and adaptability make the disease difficult to manage. Recent advances in genomics, transcriptomics, proteomics and other multi-omics approaches have substantially improved understanding of pathogen virulence factors, host defense responses and disease epidemiology. These studies have revealed key roles of OA, carbohydrate-active enzymes, effector proteins, and sclerotial melanization in pathogenesis, while highlighting the activation of salicylic acid (SA)-, jasmonic acid (JA)-, and ethylene (ET)-mediated defense pathways in tomato. Although cultural, biological, and chemical measures are available, these measures often provide inconsistent protection when used alone. Promising strategies include the use of biocontrol agents, hypovirulence-inducing mycoviruses, and chemical fungicides such as carboxamides and quinone outside inhibitors (QoIs), though fungicide resistance remains a risk factor. Integrated Disease Management (IDM) approaches, such as combining biocontrol agents with fungicides, demonstrate enhanced efficacy. This review also evaluates progress in resistance breeding, grafting, RNA interference (HIGS and SIGS), CRISPR-based genome editing, and exploitation of wild genotypes for durable resistance. Furthermore, emerging precision agriculture tools, including hyperspectral imaging, machine learning-assisted disease detection and climate-resilient management strategies, were discussed as new components of sustainable disease management.

Wheat blast, caused by Magnaporthe oryzae pathotype Triticum (MoT), poses a major threat to wheat (Triticum aestivum) cultivation, particularly in South America and Bangladesh. The rapid evolution and spread of the pathogen necessitate the development of durable and broad-spectrum resistance in wheat cultivars. This review summarizes current insights into the multi-layered defense mechanisms of wheat, encompassing resistance (R) genes, pattern-triggered immunity (PTI), and effector-triggered immunity (ETI) against MoT. The R-genes provide race-specific resistance through ETI, while both ETI and PTI are required to form integral layers of the plant immune system that synergistically reinforce host defense network. Recent advances in genomics, transcriptomics, and molecular breeding have facilitated the discovery and deployment of key R-genes and signaling components involved in PTI and ETI pathways. Integrating these immune strategies through gene pyramiding, marker-assisted selection (MAS), and genome editing offers a promising route towards enhanced and durable resistance in hosts. Harnessing and optimizing these multilayered immune systems will be pivotal to securing wheat productivity amid the growing threat of wheat blast.

Emerging fungal plant pathogens are significant biotic stresses to crops that threaten global food security, biodiversity, and agricultural sustainability. Historically, these pathogens cause devastating crop losses and continue to evolve rapidly due to climate change, international trade, and intensified farming practices. Recent advancements in diagnostic technologies, including remote sensing, sensor-based detection, and molecular techniques, are transforming disease monitoring and detection. These tools, when combined with data mining and big data analysis, facilitate real-time surveillance and early intervention strategies. There is a need for extension and digital advisory services to empower farmers with actionable insights for effective disease management. This manuscript presents an inclusive review of the socioeconomic and historical impacts of fungal plant diseases, the mechanisms driving the emergence of these pathogens, and the pressing need for global surveillance and reporting systems. By analyzing recent advancements and the challenges in the surveillance and diagnosis of fungal pathogens, this review advocates for an integrated, multidisciplinary approach to address the growing threats posed by these emerging fungal diseases. Fostering innovation, enhancing accessibility, and promoting collaboration at both national and international levels are crucial for the agricultural community to protect crops from these emerging biotic stresses, ensuring food security and supporting sustainable farming practices.

Asian soybean rust (ASR), caused by the fungus Phakopsora pachyrhizi, is a devastating threat to global soybean production, with potential yield losses of over 80 %. The pathogen's ability to complete multiple infection cycles and its high genetic variability present significant challenges for management, as reliance on fungicides is both costly and increasingly undermined by the development of resistance issues. Genetic resistance, conferred by major resistance genes (Rpp1-Rpp7), offers a sustainable alternative, but the durability of this single-gene-mediated resistance is often lost by evolving pathogen populations. Gene pyramiding, the strategic stacking of multiple Rpp genes within a single cultivar through crossbreeding or DNA recombinant technology, has emerged as a sustainable solution to achieve enhanced resistance against diverse ASR isolates. Pyramiding or stacking of Rpp genes has been proven to increase the resistance level and enlarge the resistance spectrum against a complex ASR population. These multigene pyramided lines demonstrate greater durability of resistance than single Rpp lines, offering a prospective avenue for developing elite soybean cultivars against ASR. Many of these lines could be deployed to characterize pathotype differentiation of P. pachyrhizi with higher precision than differential varieties. However, several challenges, including incomplete transfer of key genetic elements, dominance effects among resistance genes, genotype x environment interactions, linkage drag, and the extended time required for breeding, complicate the implementation of gene pyramiding. Recent advancements in genomic tools, such as marker-assisted selection (MAS), genomic selection (GS), and next-generation genome editing, such as CRISPR/ CAS, show potential to revolutionize the gene pyramiding process, improving precision and efficiency. This review synthesizes current progress in gene pyramiding strategies, highlights innovative tools for overcoming existing challenges, and explores future research directions to mitigate ASR's impact and promote sustainable soybean production worldwide.

Cross-kingdom infections, where pathogens from one kingdom infect organisms of another, were historically regarded as rare anomalies with minimal concern. However, emerging evidence reveals their increasing prevalence and potential to disrupt the delicate balance between plant, animal, and human health systems. Traditionally recognized as plant-specific, a subset of phytopathogens, including certain fungi, bacteria, viruses, and nematodes, have demonstrated the capacity to infect non-plant hosts, particularly immunocompromised individuals. These pathogens exploit conserved molecular mechanisms, such as immune evasion strategies, stress responses, and effector proteins, to breach host-specific barriers and establish infections. Specifically, fungal pathogens like Fusarium spp. and Colletotrichum spp. employ toxin-mediated cytotoxicity and cell-wall-degrading enzymes, while bacterial pathogens, such as Pseudomonas syringae, utilize type III secretion systems to manipulate host immune responses. Viral and nematode phytopathogens also exhibit molecular mimicry and host-derived RNA silencing suppressors to facilitate infections beyond plant hosts. This review features emerging cases of phytopathogen-driven animal and human infections and dissects the key molecular and ecological determinants that facilitate such cross-kingdom transmission. It also highlights critical drivers, including pathogen plasticity, horizontal gene transfer, and the convergence of environmental and anthropogenic stressors that breach traditional host boundaries. Furthermore, this review focuses on the underlying molecular mechanisms that enable host adaptation and the evolutionary pressures shaping these transitions. To address the complex threats posed by cross-kingdom phytopathogens, a comprehensive One Health approach that bridges plant, animal, and human health strategies is advocated. Integrating molecular surveillance, pathogen genomics, AI-powered predictive modeling, and global biosecurity initiatives is essential to detect, monitor, and mitigate cross-kingdom infections. This interdisciplinary approach not only enhances our preparedness for emerging zoonoses and phytopathogen spillovers but also strengthens ecological resilience and public health security in an era of increasing biological convergence.

Soil-borne plant pathogens pose a serious threat to global food security by causing extensive yield losses and compromising crop quality. Conventional chemical-based control methods often prove inadequate, environmentally harmful, and disruptive to beneficial soil microbiota, highlighting the urgent need for sustainable alternatives. Plant growth-promoting fungi (PGPF) have emerged as effective biocontrol agents capable of suppressing diverse soil-borne pathogens while simultaneously enhancing plant growth and resilience. This review synthesizes current knowledge on the tripartite interactions among plants, pathogens, and PGPF within the rhizosphere, with emphasis on their roles in disease suppression, rhizosphere competence, and plant health promotion. The findings highlight that PGPF such as Trichoderma, Penicillium, Aspergillus, non-pathogenic Fusarium, hypovirulent binucleate Rhizoctonia and sterile fungi can significantly reduce diseases caused by fungi, oomycetes, bacteria, nematodes, and protists through mechanisms including antibiosis, hyperparasitism, competition, and induction of systemic resistance. Evidence also indicates that consortium approaches and bioformulations enhance field efficacy compared to single-strain applications. Despite this progress, challenges such as variability in field performance, limited shelf life of inoculants, and gaps in understanding ecological interactions constrain large-scale use. Overall, the review underscores that PGPF-based strategies represent a promising and sustainable alternative to chemical pesticides, with strong potential for integration into holistic crop disease management under changing climatic conditions.

In the context of climate change, the need to ensure food security and safety has taken center stage. Chemical fertilizers and pesticides are traditionally used to achieve higher plant productivity and improved plant protection from biotic stresses. However, the widespread use of fertilizers and pesticides has led to significant risks to human health and the environment, which are further compounded by the emissions of greenhouse gases during fertilizer and pesticide production and application, contributing to global warming and climate change. The naturally occurring sulfated linear polysaccharides obtained from edible red seaweeds (Rhodophyta), carrageenans, could offer climate-friendly substitutes for these inputs due to their bi-functional activities. Carrageenans and their derivatives, known as oligo-carrageenans, facilitate plant growth through a multitude of metabolic courses, including chlorophyll metabolism, carbon fixation, photosynthesis, protein synthesis, secondary metabolite generation, and detoxification of reactive oxygen species. In parallel, these compounds suppress pathogens by their direct antimicrobial activities and/or improve plant resilience against pathogens by modulating biochemical changes via salicylate (SA) and/or jasmonate (JA) and ethylene (ET) signaling pathways, resulting in increased production of secondary metabolites, defense-related proteins, and antioxidants. The present review summarizes the usage of carrageenans for increasing plant development and defense responses to pathogenic challenges under climate change. In addition, the current state of knowledge regarding molecular mechanisms and metabolic alterations in plants during carrageenan-stimulated plant growth and plant disease defense responses has been discussed. This evaluation will highlight the potential use of these new biostimulants in increasing agricultural productivity under climate change.

Climate change is increasingly conceded as a significant menace to global agricultural productivity, with plant diseases emerging as a critical challenge in this context. Plant diseases can result in an annual reduction of approximately US220 billion in agricultural productivity, impacting global economies and socio-economic stability. To address these challenges, it is crucial to explore the intricate relationship between climatic variables and the occurrence, intensity, and geographic distribution of plant diseases, highlighting how shifts in temperature, CO2 levels, and precipitation patterns exacerbate pathogen virulence and alter disease dynamics. This review examines the historical and projected impacts of climate change on vulnerable crops and regions, emphasizing the heightened risk to food security. The molecular basis of climate-modulated plant defense mechanisms and pathogen virulence is dissected, offering insights into the underlying biological processes that govern these interactions. In response to this escalating threat, we discuss climate-informed plant disease management strategies, including early warning systems, adaptive surveillance, and the development of resilient crops through biotechnological advancements such as genetic engineering, gene silencing, and genome editing. Additionally, we explore the role of resource-saving technologies and precision agriculture in mitigating the adverse repercussions of climate change on plant health. The review concludes with an exploration of critical research needs and future perspectives, underscoring the urgent need for interdisciplinary approaches to safeguard sustainable agricultural productivity in a rapidly changing climate.

White mold, caused by the fungal pathogen Sclerotinia sclerotiorum (Lib.) de Bary, is a significant biotic stress impacting horticultural and field crops worldwide. This disease causes plants to wilt and ultimately die, resulting in considerable yield losses. This monocyclic disease progresses through a single infection cycle involving basal infections from myceliogenically germinated sclerotia or aerial infections initiated by ascospores from carpogenically germinated sclerotia. The pathogen has a homothallic mating system with a weak population structure. Relatively cool temperatures and extended wetness are typical conditions for spreading the disease. Each stage of infection triggers a cascade of molecular and physiological events that underpin defense responses against S. sclerotiorum. Molecular markers can help rapid diagnosis of this disease in plants. Effective management strategies encompass altering the crop microclimate, applying fungicides, reducing inoculum sources, and developing resistant plant varieties. Integrated approaches combining those strategies often yield the best results. This review discusses the latest insights into the biology, epidemiology, infection mechanisms, and early detection of white mold. This review also aims to provide comprehensive guidelines for sustainable management of this destructive disease while reducing the use of excessive pesticides in crop fields.

Soybean (Glycine max L.) is an important crop in Asia, accounting for 17% of global soybean cultivation. However, this crop faces formidable challenges from the devastating foliar disease, Asian Soybean Rust (ASR), caused by Phakopsora pachyrhizi, a biotrophic fungus with a broad host range, causing substantial yield losses (10–100%) in Asia. This comprehensive review consolidates knowledge on ASR, encompassing its impact, historical perspectives, genetic diversity, epidemic drivers, early detection, risk assessment, and sustainable management strategies of ASR in the region. ASR has expanded globally from Asia, reaching Africa and Americas, driven by wind-dispersed urediniospores. Genetic diversity studies reveal the complexity of P. pachyrhizi, with distinct populations exhibiting varying virulence patterns. Factors affecting ASR epidemics in Asia include host susceptibility, landscape connectivity, climate, and environmental conditions. Understanding the interplay of these factors is essential for early intervention and control of ASR in soybean fields. Effectively managing ASR can exploit the utilization of diverse intervention strategies, encompassing disease forecasting, automated early detection, disease resistance, fungicide application, and biological control. A pivotal aspect of successful, sustainable disease management lies in reducing the ASR pathogen virulence and preventing it from developing fungicide resistance, while the highpoint of effectiveness in disease control is attained through a synergistic approach, integrating various strategies. In summary, this comprehensive review provides insights into multifaceted approaches that contribute to the development of sustainable and economically impactful soybean production in the face of the persistent threat of ASR in Asia.

Sclerotinia sclerotiorum (Lib.) de Bary is a broad host-range fungus that infects an inclusive array of plant species and afflicts significant yield losses globally. Despite being a notorious pathogen, it has an uncomplicated life cycle consisting of either basal infection from myceliogenically germinated sclerotia or aerial infection from ascospores of carpogenically germinated sclerotia. This fungus is unique among necrotrophic pathogens in that it inevitably colonizes aging tissues to initiate an infection, where a saprophytic stage follows the pathogenic phase. The release of cell wall-degrading enzymes, oxalic acid, and effector proteins are considered critical virulence factors necessary for the effective pathogenesis of S. sclerotiorum. Nevertheless, the molecular basis of S. sclerotiorum pathogenesis is still imprecise and remains a topic of continuing research. Previous comprehensive sequencing of the S. sclerotiorum genome has revealed new insights into its genome organization and provided a deeper comprehension of the sophisticated processes involved in its growth, development, and virulence. This review focuses on the genetic and genomic aspects of fungal biology and molecular pathogenicity to summarize current knowledge of the processes utilized by S. sclerotiorum to parasitize its hosts. Understanding the molecular mechanisms regulating the infection process of S. sclerotiorum will contribute to devising strategies for preventing infections caused by this destructive pathogen.

Southern blight of tomato caused by Sclerotium rolfsii can cause severe plant mortality and yield losses. The use of rhizobacteria for the biological control of Southern blight disease is a potent alternative to chemical fungicides. Although rhizobacteria are prolific candidates, comprehensive reports regarding their use in tomato disease management are limited. The present study screened six rhizobacterial strains for antagonism against S. rolfsii in dual culture and culture filtrate assays. The selected promising strains were tested further for plant-growth-promoting and biocontrol potentials under in vitro, greenhouse, and field conditions. Of the six strains screened, Stenotrophomonas maltophilia PPB3 and Bacillus subtilis PPB9 showed the superior performance displaying the highest antagonism against S. rolfsii in dual culture (PPB3 88% and PPB9 71% inhibition), and culture filtrate assays (PPB3 53–100% and PPB9 54–100% inhibition at various concentrations). Oxalic acid produced by S. rolfsii was significantly inhibited by both rhizobacteria and supported their growth as a carbon source. The strains produced hydrogen cyanide, chitinases, siderophores, biofilm, and indole acetic acid. They showed the potential to solubilize phosphate and fix nitrogen. Seed treatment with S. maltophilia PPB3 and B. subtilis PPB9 improved seed germination and tomato seedling vigour. Significant increases in plant growth, chlorophyll contents, and N, P, and K concentrations were attained in bacterized plants compared to non-treated controls. The application of antagonists on container-grown seedlings in a greenhouse environment and field-grown tomato plants reduced symptoms of damping-off and Southern blight. The sclerotial counts decreased significantly in these soils. Bacteria-inoculated plants had a higher yield than those in the non-treated control. Bacteria colonized the entire roots, and their populations increased significantly in the protected plants. The results show the potential capabilities of S. maltophilia PPB3 and B. subtilis PPB9 for growth promotion, nutrient acquisition, and biocontrol of southern blight disease in tomatoes.

Plant growth-promoting fungi (PGPF) constitute diverse genera of nonpathogenic fungi that provide a variety of benefits to their host plants. PGPF show an effective role in sustainable agriculture. Meeting increasing demand for crop production without damage to the environment is the biggest challenge nowadays. The use of PGPF has been recognized as an environmentally friendly way of increasing crop production. These fungi have proven to increase crop yields by improving germination, seedling vigor, plant growth, root morphogenesis, photosynthesis, and flowering through either a direct or indirect mechanism. The mechanisms of PGPF involve solubilizing and mineralizing nutrients for easy uptake by plants, regulating hormonal balance, producing volatile organic compounds and microbial enzyme, suppressing plant pathogens and ameliorating abiotic stresses. Successful colonization is an intrinsic factor for most PGPF to exert their beneficial effects on plants. A certain level of specificity exists in the interactions between plant species and PGPF for root colonization and growth promoting effects. There is a gap between the number of reported efficacious PGPF and the number of PGPF as biofertilizer. Efforts should be strengthened to improve the efficacy and commercialization of PGPF. Hence, this chapter summarizes valuable information regarding the application and mechanisms of PGPF in sustainable agriculture.

The plant growth-promoting fungi (PGPF) have long been known to improve plant growth and suppress plant diseases. The PGPF Penicillium viridicatum GP15-1 elicited plant growth and induced systemic resistance (ISR) in Arabidopsis thaliana against Pseudomonas syringae pv. tomato DC3000 (Pst), leading to a restriction of pathogen growth and disease development. Examination of local and systemic genes indicated that GP15-1 did not modulate the expression of any of the tested defence-related marker genes involved in salicylic acid (SA), jasmonic acid (JA) and ethylene signalling pathways. Subsequent challenge of GP15-1-colonized plants with Pst bacterium primed Arabidopsis plants for enhanced activation of the JA-inducible Atvsp (vegetative storage protein) gene at a later stage of infection. To assess the contribution of different signalling pathways in GP15-1-elicited plant growth and ISR, Arabidopsis genotypes implicated in SA signalling expressing the nahG transgene (NahG) or carrying disruption in NPR1 (npr1), JA signalling (jar1) and ethylene signalling (ein2) were tested. The GP15-1-induced plant growth and ISR were fully compromised in an ein2 mutation. Root colonization assay revealed that the inability of the ein2 mutant to express GP15-1-induced plant growth and ISR was not associated with reduced root colonization by GP15-1. In conclusion, our results demonstrate the ethylene signalling pathway is involved in plant growth promotion and ISR elicitation by the PGPF P.viridicatum GP15-1 in Arabidopsis. These results provide evidence that ethylene signalling has a substantial role in plant growth and disease resistance.