Plants respond to bacterial infection with a powerful chemical arsenal and signaling molecules to rid themselves of the microbes. The appearance of bacterial growth in or on plant tissues means that bacterial plant disease may be present, because saprophytes may be present. Plant pathogens are forming a huge problem on the economic and life stability. A plant pathogen is a broad term that refers to any of the organisms, such as fungi, bacteria, protists, nematodes, and viruses that cause plant diseases. Small RNAs of 18–23 nt from plant eukaryotic fungi, like Magnaporthe oryzae and Sclerotinia sclerotiorum, have already been confirmed [28, 29]. The study of plant pathogens belongs to the branch of biology known as plant pathology. On the other hand, some fungi need to be incubated under certain temperature, aeration, or light conditions to produce spores [10]. Cell 124 (4), 803–814. Pathogens include fungi, bacteria, nematodes, and viruses, all biological organisms that can cause disease symptoms and significantly reduce the productivity, quality, and even cause the death of plants. As mentioned above, phytopathogens differ among each other with respect to the location of infection; some of them grow on roots, stems, leaves, fruits or vegetables, and phloem or xylem. Other phytopathogens such as viruses, viroids, mollicutes, fastidious bacteria, and protozoa can intracellularly invade the plant tissues [28]. Molecular techniques, on the basis of nucleic acids (DNA or RNA), filled this gap. Each species of plants appears to be attacked by about 100 kinds of pathogens. The nematodes are one of most common phytopathogens which have definite symptoms. In some fungi as powdery mildew, adhesion is carried out by the release of cutinase enzyme from the spore, which makes the plant and spore areas of attachment more hydrophilic and cements the spore to the plant surface [22]. This chapter is distributed under the terms of the Creative Commons Attribution 3.0 License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Pompeo Weighs Plan to Place Cuba on U.S. Using an in silico bioinformatics approach to obtain full or partial cDNA sequences of genes and comparing them against known viral sequences in the NCBI (National Center for Biotechnology Information) Expressed Sequence Tag database, 119 novel virus-like sequences related to members of the families Partitiviridae, Totiviridae, Chrysoviridae, and Endornaviridae, were discovered. Avirulent of plant pathogens might be under three cases (1) Avirulent cannot colonize the plant, (2) Avirulent elicit the hypersensitivity reaction (HR), (3) Virulent harbor the Avr gene (Surico, 2013). The introduction of serological (or immunological) techniques in the 1960s was a breakthrough. Phytopathogens differ among each other with respect to the plant type, the location of infection, and the age of the organ or tissue (location of infection). Help us write another book on this subject and reach those readers. Successful infection results in the appearance of symptoms, such as discoloration, necrosis, dwarfism, and so on of the host. Finally, new plant NB-LRR alleles are selected that can recognize a new effector, restoring ETI. These parasites cause serious plant diseases, For nonpathogenic strains, are more existing in species of plant pathogens such as plant fungal pathogen such as Fusarium (Alabouvette and Olivain, 2002; Al-Ani, 2017b), Rhizoctonia (Simonetta et al., 2007), Colletotrichum (Askew et al., 2009; Ishikawa et al., 2012), and Phytophthora nicotianae (Able et al., 2000). By Metin Turan, Nurgül Kıtır, Ülker Alkaya, Adem Günes, Şefik Tüfenkçi, Ertan Yıldırım and Emrah Nikerel, By Danfeng Song, Salam Ibrahim and Saeed Hayek. This invasion is carried out by releasing spores within the vessels [29]. Plant Pathogens, Plant Growth, Everlon Cid Rigobelo, IntechOpen, DOI: 10.5772/65325. In this chapter, we are concerned with plant pathogens or phytopathogenic microbes such as bacteria, viruses, fungi, mollicutes, and so on. The history of pathogens and vectors, unique symptoms of diseases and economic importance of important viral diseases have been dealt with in the introductory chapter of this book. 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URL: https://www.sciencedirect.com/science/article/pii/B9780128184691000043, URL: https://www.sciencedirect.com/science/article/pii/B978012373944500167X, URL: https://www.sciencedirect.com/science/article/pii/B9780128148495000277, URL: https://www.sciencedirect.com/science/article/pii/B9780123739445003448, URL: https://www.sciencedirect.com/science/article/pii/B9780444525123001650, URL: https://www.sciencedirect.com/science/article/pii/B9780128096338212491, URL: https://www.sciencedirect.com/science/article/pii/B9780128171127000080, URL: https://www.sciencedirect.com/science/article/pii/B9780124104907000086, URL: https://www.sciencedirect.com/science/article/pii/S1877117316300278, URL: https://www.sciencedirect.com/science/article/pii/B9780444529756500125, Applied Plant Biotechnology for Improving Resistance to Biotic Stress, 2020, The effect of incompatible plant pathogens on the host plant, Laith Khalil Tawfeeq Al-Ani, Edson Luiz Furtado, in, Molecular Aspects of Plant Beneficial Microbes in Agriculture, Alabouvette and Olivain, 2002; Al-Ani, 2017b, Askew et al., 2009; Ishikawa et al., 2012, Karasawa et al., 1999; Shi et al., 2002; Kang et al., 2005, Al-Ani, 2006; Al-Ani and Salleh, 2010; Mohammed et al., 2011, 2012, 2013, 2014; Al-Ani and Al-Ani, 2011; Al-Ani et al., 2012; Al-Ani et al., 2013; Al-Ani 2017a,b,c; Al-Ani and Albaayit, 2018a,b; Al-Ani et al., 2018; Al-Ani, 2018a,b; Al-Ani, 2019a, b,c,d,e,f, Encyclopedia of Microbiology (Third Edition), Molecular Techniques for Diagnosis of Bacterial Plant Pathogens, Plant Pathogens and Disease: General Introduction, Encyclopedia of Agriculture and Food Systems, Small RNA in tolerating various biotic stresses, Transgenic Animal Technology (Third Edition), Progress in Molecular Biology and Translational Science, PATHOGEN DETECTION AND MANAGEMENT STRATEGIES IN SOILLESS PLANT GROWING SYSTEMS, Physiological and Molecular Plant Pathology, infectious entities, colony-forming units, pathogens quickly showing symptoms, culturable bacteria and fungi, light microscope, transmission electron microscope, nematodes and obligate pathogens, viruses. Only culturable organisms can be detected in this way, making this methodology unsuitable for nematodes, viruses and obligate (fungal) pathogens. This enabled a new class of sequence-specific genome editing tools, similar in strategy and overall structure to ZFNs, but with a novel DNA-binding protein format. Waleed M. Abdulkhair and Mousa A. Alghuthaymi (November 16th 2016). Available from: Basic procedures in the diagnosis of plant diseases, General Department of Basic Medical Sciences, Microbiology Department, National Organization for Drug Control and Research (NODCAR), Giza, Egypt, Biology Department, Science and Humanities College, Shaqra University, Al-Quway’iyah, Saudi Arabia. As well known, the symptoms start to appear after the incubation period of the pathogen has been finished. Plants cover the most area of the earth’s living environment as trees, grasses, flowers, and so on. The largest group of plant pathogens is the necrotrophic fungi and bacteria. The infectious disease means the ability of phytopathogen to transfer from the infected plant to another healthy one and causes the same disease and the same symptoms. Abstract. So the sort of ideal scenario is just to have a plant that isn't vulnerable to these nematodes. Development of these techniques is still ongoing. Penetration and infection are not usually correlated together, because some penetrated plants are resistant to phytopathogens [26]. Brief introduction to this section that descibes Open Access especially from an IntechOpen perspective, Want to get in touch? When appropriate physical and chemical signals, such as surface hardness, hydrophobicity, surface topography, and plant signals, are present, germ tube extension and differentiation take place [23]. Leach, ... N.A. Multidrug efflux pumps are key factors in bacterial resistance toward antibiotics by reducing the level of antimicrobial compounds in the bacterial cell. Plant pathogens, with a couple of minor exceptions, are microorganisms that belong to the same taxonomic groups, that is, bacteria, viruses, fungi, protozoa, and nematodes, which include the pathogens that cause disease in humans and animals. There are two types of inoculum: primary and secondary inoculum, which in turn cause primary and secondary infection. While unsuccessful (latent) infection does not lead to any observations for the symptoms. Each species of plants appears to be attacked by about 100 kinds of pathogens. Contact our London head office or media team here. In the case of parasitism-pathogenicity relationship, the plant is diseased with the appearance of different symptoms such as increased respiration, disintegration or collapse of cells, wilting, abscission, abnormal cell division and enlargement, and degeneration of specific components such as chlorophyll [15]. These factors can be assumed through determining the conditions both of inside or outside of plant that possibly responsible for reducing the ability of plant pathogens. Isolation on selective media can be used for identification and detection of culturable pathogens. Callose deposition is a nonspecific response of higher plants to injury and to other various types of infections. The plant pathogens comprise viruses, bacteria, fungi, nematode, and parasitic plant. Therefore, these pathogens can easily grow and spread within the plant tissues until a certain limit or death occurs. Plant pathogens are not discussed further in this article. Plant pathogens cause severe loss in terms of economics and production in agriculture sector. Image drawn by Samuel Vazquez III adapted from Jones, J.D., Dangl, J.L., 2006. "The field of nonhost resistance sets out to identify novel ways to engineer resistance to these plant pathogens, guided by approaches that already exist in nature," explained Matthew Moscou, a scientist at The Sainsbury Laboratory in Norwich, United Kingdom. Though there are several reports that center around the detection and diagnosis of fungal and viral pathogens, little information is accessible on the subject of bacterial plant pathogen diagnosis. This signal is a biochemical reaction, which acts as a receptor to a pathogen contact. Eva- I see. Several avirulent strains and natural product are used controlling of plant pathogens, as well as, the pests and (Al-Ani, 2006; Al-Ani and Salleh, 2010; Mohammed et al., 2011, 2012, 2013, 2014; Al-Ani and Al-Ani, 2011; Al-Ani et al., 2012; Al-Ani et al., 2013; Al-Ani 2017a,b,c; Al-Ani and Albaayit, 2018a,b; Al-Ani et al., 2018; Al-Ani, 2018a,b; Al-Ani, 2019a, b,c,d,e,f). At present, ELISA tests (enzyme-linked immunosorbent assay) are generally used in the agricultural sector and by commercial companies to detect the presence of bacteria and viruses in products such as potatoes, ornamentals and flower bulbs. These microorganisms are very small where they must be examined by an electron microscope. Plant pathogens also contribute to sRNA population to promote pathogenesis. This means it was impossible to get infectious and noninfectious plant diseases at the same time. A simple ‘zigzag model’ (Figure 2) was proposed to illustrate our current understanding of plant–pathogen interactions in an evolutionary context (Jones and Dangl, 2006). The abiotic agents (environmental factors) play an important and vital role in the disease development and severity or disease resistance. In some cases, the inoculum is produced on the plant surface as in fungi, bacteria, parasitic higher plants, and nematodes, which either produce their inoculum on the surface of infected plants or their inoculum reaches the plant surface when the infected tissue breaks down. Recent reports have strongly advocated the flow of sRNAs not only from plant to pathogen but also from pathogen to plant [29a]. Many soil inhabiting fungi are capable of living saprotrophically, carrying out the part of their life cycle in the soil. For population dynamics studies, quantitative PCR (Q-PCR) is used more and more. The majority of microbial pathogens, includingbacteriaandfungi,andapproximately80%of1480knownplantvirusesaretransmitted by insect vectors. Pathogens can also infect agricultural animals, but for this module, we will focus on plant pathogens. Interestingly, the biotic agents lead to infectious diseases, which develop under suitable environmental conditions. Plant pathogens form intimate relationships with plants to gain access to host resources needed to survive, grow, and reproduce. ! (Pettitt et al., 2002). By Waleed M. Abdulkhair and Mousa A. Alghuthaymi, Submitted: March 16th 2016Reviewed: August 23rd 2016Published: November 16th 2016. However, the obtaining of a successful infection is need to several factors. Licensee IntechOpen. Mollicutes have polymorphism and lack cell wall–like mycoplasma. The first step of plant disease treatment is observation of definite and clear symptoms on the plants. Generally, there are two plant disease causes: the pathogens and/or environmental factors. The three sides of this triangle are the plant, microorganisms, and the environmental factors. Plant pathogens that cause plant diseases reduce a grower's ability to produce crops and can infect almost all … Hence, this book chapter especially focuses on the evolution from traditional microbiological tools to modern molecular methods for identifying bacterial plant pathogens. These factors include (A) surface receptors. The variation in virulence on the part of the pathogen and susceptibility or resistance on the part of the plant are the result of a coevolutionary arms race (Anderson et al., 2010). The prevalence of different virulent strains of plant pathogens is leading to happen the mixing infection among these strains on the host or non-host may be leading to appear a new strain located between avirulence to high virulence. Copyright © 2020 Elsevier B.V. or its licensors or contributors. First, they are of pathogen origin, and second, their precursor molecules lack one or two criteria stringently set for a true miRNA [29]. 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