Annual review of phytopathology最新文献

Phytopathogenic and food spoilage microorganisms are major contributors to postharvest crop losses. Some species of fungi are able to produce mycotoxins, posing health risks to both humans and animals. Control methods based on synthetic fungicides raised environmental and health concerns and led to the development of fungicide-resistant pathogens. As a result, biological control has gained momentum as an eco-friendly alternative. Microbial biocontrol agents (BCAs) are increasingly being commercialized, with recent research exploring volatile-mediated interactions between BCAs, pathogens, and the treated commodities. Volatile organic compounds (VOCs) play a crucial role in biocontrol. This review focuses on fungal volatiles, their chemical diversity, their effects, and the application of VOC-emitting fungi or synthetic VOCs as biofumigants. Future research directions include enhancing VOC-producing agents through targeted mutagenesis and synthetic biology, understanding interspecies interactions, and applications of artificial intelligence in analytical chemistry, which shall lead to increased efficiency and precision in postharvest biocontrol.

Migratory plant-parasitic nematodes (PPNs) pose significant threats to global agriculture and forestry. Recent advances in next-generation sequencing on migratory endoparasitic nematodes have revealed substantial genomic diversity, enhancing our understanding of their evolutionary adaptations and molecular mechanisms of pathogenicity. Their genomic plasticity also reflects functional adaptations for an endoparasitic lifestyle (i.e., detoxification and antioxidant defenses, anhydrobiosis or cryptobiosis, and environmental stress tolerance). Key findings highlight an expanding array of parasitism proteins, suggesting a more complex network of effectors than was previously recognized. This review provides an updated overview of relevant aspects of the biology and parasitic strategies of migratory endoparasitic nematodes, with a focus on species within clades 10 and 12. These molecular insights underscore the importance of ongoing research into lesser-studied species, which will ultimately contribute to the development of targeted strategies for nematode control and crop protection.

Recessive mutations in the mildew locus O (MLO) gene were first identified as key factors conferring broad-spectrum resistance to powdery mildew in barley. This discovery inspired extensive research on MLOs and novel breeding strategies for powdery mildew resistance by targeting MLO genes in various crops. Over the past two decades, studies have revealed broader roles for MLOs beyond powdery mildew susceptibility, including regulating interactions with diverse pathogens and symbionts, root thigmomorphogenesis, and reproductive development. Recent findings identify MLOs as calcium channels, offering a unifying molecular framework for understanding their diverse biological functions. However, significant challenges remain in comprehensively understanding the cellular and molecular mechanisms underlying MLO functions. In this review, we examine the MLO-related literature to delineate the multifaceted roles of MLOs in plant immunity and development. By integrating published phylogenetic, genetic, biochemical, and molecular studies with original in silico analyses, we propose mechanistic models to contextualize the diverse functions of MLOs with a focus on plant immunity and susceptibility.

The chestnut blight pathogen Cryphonectria parasitica is well-known for the devastation it caused to North American forests. It is less well recognized that numerous other fungi in the Cryphonectriaceae are emerging as threats to native and planted forests in the tropics and Southern Hemisphere. Unlike C. parasitica, these fungi, such as Chrysoporthe cubensis, initially gained attention due to a canker disease in plantations of non-native Eucalyptus. More than four decades of research have revealed a wide diversity of Cryphonectriaceae species that infect many other tree genera in the Myrtales. These fungi often exist as endophytes but become problematic when trees are planted outside their native range. Growing numbers of species are also undergoing host shifts from native to susceptible trees such as Eucalyptus, posing serious risks to both natural and planted forests. These fungi provide an example of the biodiversity of tree-infecting fungi that is understudied, despite their significant potential to harm forest ecosystems.

Bacterial blight (BB), caused by Xanthomonas oryzae pathovar oryzae (Xoo), is a major rice disease in Asia and Africa. Xoo possesses virulence factors for pathogenicity and race differentiation that complicate resistance breeding of rice. The availability of 48 BB resistance (R) genes (Xa/xa) portends the selection of R genes for broad and durable resistance. To establish durable resistance, understanding the pathogen virulence spectrum and host resistance mechanisms is required. This review examines the global distribution and diversity of Xoo populations, highlights the different resistance mechanisms of 15 Xa/xa genes, and identifies the three effective resistance genes for 24 countries. The review proposes strategies for durable, broad-spectrum resistance to BB.

Seeds are the cornerstone of food security for a growing global population. An ample supply of healthy, high-quality seeds of improved crop varieties is crucial to human nutrition and health. To meet this need, the global seed industry has become increasingly complex, characterized by multinational operations speeding the development of new varieties and efficiently providing adequate seed supplies. With accelerating international seed movement, the potential risks associated with seedborne pathogens are receiving increasing scrutiny, and phytosanitary regulations are frequently changing. At the same time, technological advances are driving the development of progressively more sensitive seed health testing methods, which are often required by national plant protection organizations to allow seed lots to be imported. Emerging seedborne plant pathogens, such as viral diseases of tomato, maize, and cucurbits, and changing import requirements have caused major disruptions in seed industry operations in recent years. A variety of innovative public-private sector collaborations has emerged in response to the challenges of international seed movement.

Understanding how organisms regulate protein translation in response to stress is vital for both fundamental biology and biotechnological innovation. However, our knowledge of this area remains limited due to the inherent complexity of the translational regulatory process. Recent advances in multiomics and single-molecule technologies now allow for an integrated analysis of the multilayered regulation of translation in plants in response to biotic and abiotic stresses. In this review, we provide essential background information for newcomers to the field and synthesize recent discoveries in stress-induced translation into the following key areas: mRNA features (cap, Kozak sequence, uAUGs and uORFs, secondary structures, modifications, alternative splicing, small RNAs), ribosomal biogenesis and heterogeneity, tRNA and codon usage, master translation regulatory factors, spatial dynamics of translation, tools for studying translation regulation, and translational engineering for crop resilience. In assembling this review, we also uncovered significant knowledge gaps that represent exciting opportunities for future research.

The success of plant-parasitic nematodes (PPNs) depends on the integration of sensory cues and neuromuscular motor outputs, leading to behaviors such as hatching, host-finding, locomotion, feeding, and reproduction. Although the nervous system is often a target for control, much of our knowledge of PPN nervous system structure and function has been inferred from the free-living nematode Caenorhabditis elegans. However, the past two decades have seen substantial advances in our understanding of PPN nervous systems. These suggest that although many features of PPN neurobiology are conserved across nematodes, the behavioral repertoire of PPNs also requires distinct neuronal, structural, and functional properties that have diverged from their free-living ancestors. This review focuses on host-finding and feeding behaviors and their underlying neuronal basis; however, the diversity of PPNs implies there is much to be discovered in the rich repertoire of PPN behaviors.

Plant susceptibility (S) genes exploited by pathogenic bacteria play critical roles in disease development, collectively contributing to symptoms, pathogen proliferation, and spread. S genes may support pathogen establishment within the host, suppress host immunity, regulate host physiology or development, or function in other ways. S genes can be passive, e.g., involved in pathogen attraction or required for pathogen effector localization or activity, or active, contributing directly to symptoms or pathogen proliferation. Knowledge of S genes is important for understanding disease and other aspects of plant biology. It is also useful for disease management, as nonfunctional alleles can slow or prevent disease and, because they are often quantitative, can exert less selection on pathogens than dominant resistance genes, allowing greater durability. In this review, we discuss bacterial exploitation of S genes, S-gene functional diversity, approaches for identifying S genes, translation of S-gene knowledge for disease control, and future perspectives on this exciting area of plant pathology.

Intense competition for resources among microorganisms imposes strong selective pressure for traits that provide a competitive advantage, including traits that harm others. The type VI secretion system (T6SS) is a versatile contractile injection apparatus encoded by many Gram-negative bacteria. This system is best known for its lethal use in deploying effectors toxic to neighboring bacteria. However, T6SSs can also be used to secrete effectors into the environment to influence nutrient acquisition. Additionally, for some bacteria, T6SSs deploy effectors toxic to eukaryotic hosts and are involved in virulence, which, however, has not been demonstrated for plant-associated bacteria. Here, we review the diverse functions and evolutionary basis of T6SSs. We discuss the potential ecological impacts of T6SSs in plant-associated communities. Understanding outcomes is important for finding the best approaches for using bacteria in sustainable management of plant agricultural systems.