Biological Sciences
Plant Fungus
Plant fungus refers to any type of fungus that specifically affects plants. These fungi can cause diseases in plants, leading to reduced crop yields and economic losses in agriculture. They can infect various parts of the plant, including the roots, stems, leaves, and fruits, and are a significant concern for plant health and food production.
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4 Key excerpts on "Plant Fungus"
eBook - ePub- Sarah C. Watkinson, Lynne Boddy, Nicholas Money(Authors)
- 2015(Publication Date)
- Academic Press(Publisher)
Phytophthora infestans (oomycete) (pp. 277–279). This led to death by starvation, of 1.5 million people, and emigration of over a million, largely to North America. The necessity to understand fungal diseases of plants is evident!In this chapter we will first consider the variety of fungi that causes diseases of plants and then the differences in susceptibility of plants to pathogens, and how plants defend themselves. We will next examine the main events in the disease cycle of pathogens, from arrival, attachment, and entry into the plant, through the different ways that pathogens establish in and exploit the plants, finally to exit of the pathogen from the plant, and survival until it finds another suitable host. These general concepts will be illustrated with case studies of a range of types of disease, mainly of crop plants. Of course, plants in natural environments also suffer from fungal diseases, as do other autotrophs such as lichens and seaweeds, and these are mentioned in separate sections. Finally we look at newly emerging diseases and the potential threats they pose to the security of our food supply.Spectrum of Interactions of Fungi with Plants
Fungi that attack living plants are called pathogens, or phytopathogens – to distinguish them from fungi that cause disease in other organisms. This is a catchall term that includes fungi that destroy living cells and feed on their contents, as well as fungi that absorb nutrients from living cells without killing them, but as a consequence, considerably reduce plant fitness. Plant pathologists commonly use the terms necrotrophs and biotrophs to describe these two categories of phytopathogen, respectively. The situation is complicated further by the fact that some fungi can initiate plant infection as biotrophs and switch later to the wholesale destruction of tissues as necrotrophs, a relationship termed hemi-biotrophic
eBook - ePubFungi
Biology and Applications
- Kevin Kavanagh(Author)
- 2011(Publication Date)
- Wiley(Publisher)
This chapter is too concise to cover all fungal plant diseases of economic significance, and some important diseases (e.g. those that cause cankers and galls) did not even feature. From this very shallow insight into plant pathology, it is very obvious that fungal diseases of plants have, and will in the future, put tremendous stress on world food production. From the wilts to the gall diseases, these fungi have evolved, and are continually evolving, diverse mechanisms for infecting and colonizing the world plant population. Plant pathology researchers have made a tremendous contribution to the science of understanding these diseases. The ‘global economy’ and changing cultural and breeding practices (e.g. organic farming and genetic engineering) are now placing further challenges on plant pathologists to determine how these virulent pathogens are moving around the world (gene flow), if host or non-host disease resistance exists and how it can be introgressed into agronomically desirable crops and if new environmentally friendly and durable chemical and biological disease control methods can be developed. Both traditional and more novel molecular biology techniques are being adopted to answer these questions in order to safeguard the world plant population. But pressures on food and feed supply are ever increasing due to both a growing population and climate change. There is an urgent need to test models in order to get a clearer picture as to how climate change will impact upon agronomic practices, pathogen dynamics and population biology, and disease epidemiology.Acknowledgements Thanks to Seamus Kennedy for help with graphical illustrations and to Brian Fagan and Gerard Leonard for supplying diseased material. Revision QuestionsQ 12.1 Define the terms parasitism, symbiosis and saprophytism.Q 12.2 What is the disease triangle?Q 12.3 Describe a generalized disease cycle.Q 12.4 Describe how enzymes produced by fungi are critical to pathogenesis.Q 12.5 Define the two types of fungal toxin.Q 12.6 Define protectant, systemic and eradactive in relation to fungicides.Q 12.7 Give an example of the use of direct biological control for the control of fungal pathogens.Q 12.8 What plants are affected by Verticillium wilts?Q 12.9 List some of the global impacts of fungal diseases of plants.ReferencesAgrios, G.N. (ed.) (1998) Plant Pathology
eBook - ePub- Iqbal Ahmad, Fohad Mabood Husain(Authors)
- 2017(Publication Date)
- Wiley-Blackwell(Publisher)
Chapter 8 The Significance of Fungal Biofilms in Association with Plants and Soils Michael W. Harding1 , Lyriam L.R. Marques2 , Bryon Shore3 and G.C. Daniels11 Alberta Agriculture and Forestry, Crop Diversification Centre South, Brooks, Canada2 MicroBio SMARTS, Calgary, Canada3 Nautilus Environmental, Calgary, Canada8.1 Introduction
Phytopathogenic microorganisms cause worldwide economic losses in all industries involving plant production such as agriculture, horticulture, floriculture, turf-grass, nursery crops, and forestry operations. In addition, pathogens attack plant materials in post-harvest storages. Global economic losses due to plant diseases were estimated at 10 to 15 percent, resulting in a cost of $76.1 billion between 1988 and 1990 [1, 2]. Many microorganisms that interact with plants can survive or thrive within soils. Soils are living ecosystems composed of heterogeneous physical, chemical, and biological environments interacting in a complex manner. Soil microorganisms, mainly bacteria and fungi, are the predominant component of the soil biota and strongly influence primary production through involvement in several key ecosystem functions, including: (i) nutrient recycling through decomposition of dead organic matter, (ii) biogeochemical cycles, (iii) soil formation, structure and moisture regime, through their contribution to the development of aggregates and pore spaces which influence water infiltration and movement in the soil, (iv) degradation of soil contaminants, and (v) promotion of plant health through symbiotic interactions that improve nutrition, promote growth, and offer protection against plant pathogens.Microbiologists have documented that microbial populations in their natural environments form biofilms—complex communities attached to surfaces in a self-produced polymeric matrix [3–6]. The study of microbial biofilms has led to a shift in our understanding of how microorganisms grow, survive, adapt, and exploit hosts and resources. The bulk of biofilm research has been done on bacteria in aquatic or clinical settings, and a few examples on plants [7–9]. Fungal biofilms have also been studied, mainly in model yeast pathogens responsible for human and animal diseases [10–14]. Only recently have reports of filamentous fungal biofilms been gradually accumulating. The focus of this chapter is to review and integrate what is known about filamentous fungal biofilms with special attention to those formed on or within plant tissues or in soils.
eBook - ePubFungi
Biology and Applications
- Kevin Kavanagh(Author)
- 2017(Publication Date)
- Wiley-Blackwell(Publisher)
14 Fungal Pathogens of Plants Fiona Doohan and Binbin Zhou 14.1 Introduction A wide range of fungi cause diseases of plants (see Chapter 1 for a description of fungal taxonomy, morphology, and reproduction). To be classified as a fungal plant pathogen or phytopathogen (phyto = plant), a fungus should, if possible, satisfy Koch’s postulates or rules. Koch determined that an organism was the cause of an infectious disease if it can: (1) be isolated from a diseased host, (2) be cultured in the laboratory, (3) cause the same disease upon re‐introduction into another host plant, and (4) be re‐isolated from that host. However, some fungal pathogens cannot be cultured, or in some cases it is not easy to carry out Koch’s tests. Since the early nineteenth century, thousands of fungi have been recognized as parasites of plants. Parasitism occurs where one species lives off another, as distinct from symbiosis where different species live in harmony with each other and the relationship is mutually beneficial, or saprophytism where organisms grow on dead organic matter. Plant‐pathogenic fungi are classified as: Biotrophs : only grow and multiply when in contact with their host plants (and therefore cannot be cultured on nutrient media); for example, the fungi that cause rusts, powdery mildews, and downy mildews. Non‐obligate pathogens : grow and multiply on dead organic matter (and can therefore be cultured on nutrient media) as well as on living host tissue. These can be further distinguished as facultative saprophytes or facultative pathogens. Facultative saprophytes complete most of their lifecycle as parasites, but under certain conditions they grow on dead organic matter
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