Plant Immunity Against Viruses

Plant viruses impose a serious threat on agriculture, which motivates extensive breeding efforts for viral resistant crops and inspires lasting interests on basic research to understand the mechanisms underlying plant immunity against viruses. Viruses are obligate intracellular parasites. Their genomes are usually small and only encode a few products that are essential to hijack host machinery for their nucleotide and protein biosynthesis, and that are necessary to suppress host immunity. Plants evolved multilayers of defense mechanisms to defeat viral infection. In this research topic, we gathered 13 papers covering recent advances in different aspects of plant immunity against viruses, including reviews on RNA silencing and R gene based immunity and their application, translational initiation factor mediated recessive resistance, genome editing based viral immunity, role of chloroplast in plant-virus interaction, and research articles providing new mechanistic insights on plant-virus interactions. We hope that this Research Topic helps readers to have a better understanding of the progresses that have been made recently in plant immunity against viruses. A deeper understanding of plant antiviral immunity will facilitate the development of innovative approaches for crop protections and improvements.

Concern about the environmental consequences of the widespread use of pesticides has increased, and evidence of pesticide-resistant virus vectors have continued to emerge. This volume presents a timely survey of the mechanisms of plant resistance and examines current developments in breeding for resistance, with particular emphasis on advances in genetic engineering which allow for the incorporation of viral genetic material into plants. Discusses the mechanisms of innate resistance in strains of tobacco, tomato, and cowpea; various aspects of induced resistance, including the characterization and roles of the pathogenesis-related proteins; antiviral substances and their comparison with interferon; and cross-protection between plant virus strains. Also presents several papers which evaluate the status of genetic engineering as it relates to breeding resistant plants. Among these are discussions of the potential use of plant viruses as gene vectors, gene coding for viral coat protein, satellite RNA, and antisense RNA, and practical issues such as the durability of resistant crop plants in the field.

Symptomatology: changes in the appearance of plants. Symptomatology: changes within infected plants. Symptomatology: effects on host-plant metabolism. Methods of transmission. Transmission by animals while feeding. Methods of assay. The composition of virus particles. The morphology of viruses. Types of inactivation. Virus multiplication. Movement within host plants. Genetic variability. Classification. The control of virus diseaes.

Plant viruses cause many of the most important diseases threatening crops worldwide. Over the last quarter of a century, an increasing number of plant viruses have emerged in various parts of the world, especially in the tropics and subtropics. As is generally observed for plant viruses, most of the emerging viruses are transmitted horizontally by biological vectors, mainly insects. Reverse genetics using infectious clones--available for many plant viruses--has been used for identification of viral determinants involved in virus-host and virus-vector interactions. Although many studies have identified a number of factors involved in disease development and transmission, the precise mechanisms are unknown for most of the virus-plant-vector combinations. In most cases, the diverse outcomes resulting from virus-virus interactions are poorly understood. Although significant advances have been made towards understand the mechanisms involved in plant resistance to viruses, we are far from being able to apply this knowledge to protect cultivated plants from the all viral threats.The aim of this Special Issue was to provide a platform for researchers interested in plant virology to share their recent results. To achieve this, we invited the plant virology community to submit research articles, short communications and reviews related to the various aspects of plant virology: ecology, virus-plant host interactions, virus-vector interactions, virus-virus interactions, and control strategies. This issue contains some of the best current research in plant virology.

Plant proteases are involved in most aspects of plant physiology and development, playing key roles in the generation of signaling molecules and as regulators of essential cellular processes such as cell division and metabolism. They take part in important pathways like protein turnover by the degradation of misfolded proteins and the ubiquitin-proteasome pathway, and they are responsible for post-translational modifications of proteins by proteolysis at highly specific sites. Proteases are also implicated in a great variety of environmentally controlled processes, including mobilization of storage proteins during seed germination, development of seedlings, senescence, programmed cell death and defense mechanisms against pests and pathogens. However, in spite of their importance, little is known about the functions and mode of actions of specific plant proteases. This Research Topic collects contributions covering diverse aspects of plant proteases research.

Molecular Plant Immunity provides an integrated look at both well-established and emerging concepts in plant disease resistance providing the most current information on this important vitally important topic within plant biology. Understanding the molecular basis of the plant immune system has implications on the development of new varieties of sustainable crops, understanding the challenges plant life will face in changing environments, as well as providing a window into immune function that could have translational appeal to human medicine. Molecular Plant Immunity opens with chapters reviewing how the first line of plant immune response is activated followed by chapters looking at the molecular mechanisms that allow fungi, bacteria, and oomycetes to circumvent those defenses. Plant resistance proteins, which provide the second line of plant immune defense, are then covered followed by chapters on the role of hormones in immunity and the mechanisms that modulate specific interaction between plants and viruses. The final chapters look at model plant-pathogen systems to review interaction between plants and fungal, bacterial, and viral pathogens. Written by a leading team of international experts, Molecular Plant Immunity will provide a needed resource to diverse research community investigated plant immunity.

This book provides a comprehensive look at the field of plant virus evolution. It is the first book ever published on the topic. Individual chapters, written by experts in the field, cover plant virus ecology, emerging viruses, plant viruses that integrate into the host genome, population biology, evolutionary mechanisms and appropriate methods for analysis. It covers RNA viruses, DNA viruses, pararetroviruses and viroids, and presents a number of thought-provoking ideas.

Plant pathology deals mainly with biotic phenomena that interfere with the normal metabolism of plants. Plants have developed mechanisms to deal with pathogenic attacks, while at the same time, pathogens are actively devising ways of overcoming the plant defense systems. Plant pathologists have been advancing their studies from morphological and physiological to now molecular studies at the gene level. There are various approaches for different microorganisms and plants. This makes the study of plant pathology diverse. This book, Advances in Plant Pathology, attempts to investigate advances in viral, fungal, bacterial, and other diagnostic molecular approaches in various plants.

An Introduction to Plant Immunity is a comprehensive guide to plant immunology and stress response. The book covers the topic in 21 detailed chapters, starting from an introduction to the subject to the latest knowledge about plant disease resistance. The topics covered in the book include plant pathogens, plant diseases, plant immunity, passive defense mechanisms, acquired resistance, molecular genetics of plant immunology, protein function and genetic engineering. Each chapter provides a reader-friendly introduction along with clear sections detailing each topic. Additionally, detailed references for further reading are also provided. The combination of basic and advanced information on plant immunity make this book an essential textbook for students in botany and plant biology courses. Researchers interested in plant genomics and the effects of environmental and microbial interactions on plants will also benefit from this informative reference.