393 research outputs found
Transgenic approaches for plant disease control:Status and prospects 2021
No full textPlant diseases represent a major constraint on agricultural production. Finding sustainable novel means for their control is an important challenge. The ever-increasing knowledge and understanding of plant-microbe interactions has led to several ingenious transgenic approaches to combat disease. The first transgenic disease-resistant plants expressed single or a few stacked genes encoding antimicrobial proteins. Whereas the first attempts were disappointing in the field, several examples from recent field studies are promising and some of these use ingenious designer approaches. Less progress has been made with antimicrobial metabolites where the challenges lie in obtaining biosynthetic genes and in coordinating their expression. The increased understanding of the processes regulating plant defence (plant immunity) and modes of action of pathogen effector proteins have also led to novel strategies for designing resistant plants. The most promising of these is host-induced gene silencing that targets specific pathogens, either the effectors or, preferably, essential housekeeping genes. With these approaches, and several maverick examples of "genes pulled out of a hat," the technical effort in designing resistant plants is finally paying off. The prospects are good, biologically speaking, but can industry deliver? There is still an issue of public acceptance of genetic engineering of crop plants, especially in Europe; so whilst considerable strategic and practical progress has been made over the last decade, vanishingly few products have been adopted by agriculture. Some of these have been in use for over two decades. As yet, all are against viral diseases and not against diseases caused by microorganisms.</p
Biotechnology for plant disease control.
No full textThis chapter focuses on the development and application of new strategies for combating disease, which are based on the newest knowledge coming from comparative genomics and by molecular genetic manipulation of key components involved in plant defences, pathogenicity and signaling.</p
The status and prospects for biotechnological approaches for attaining sustainable disease resistance
No full textBacterial plant pathogens.
No full textThis chapter provides information on the taxonomy, symptoms, modes of dispersal, infection stages, survival and infection mechanisms and pathogenicity determinants of plant pathogenic bacteria. The lifestyles of some model plant pathogenic bacteria are discussed and some important bacterial diseases of various forest trees, horticultural and field crops are also presented
Biological control of plant diseases.
No full textBiological control can be defined into several categories of which two have special relevance for biological control of plant diseases, i.e. inoculation and conservation biological control. This chapter defines biological control, and provides some tips on how to select a good biological control agent, whose success depends on the target pathogen, the crop, the cropping system, the resident microbiota and the environment. It also describes the mechanisms involved in biological control, such as competition, antibiosis, hyperparasitism (i.e. mycoparasitism, when it relates to fungal-fungal interactions), induced plant disease resistance and microbial plant-growth promotion. The importance of understanding the plant host/disease cycle for optimal biological control is also emphasized
The disease cycle and lifestyles.
No full textAfter the first contact between host and pathogen, a series of specific events follow which leads to the development of a disease and, ultimately, an epidemic. This series of events is called a disease cycle. Often, a disease cycle is essentially the same as the pathogen's life cycle, but the key difference is that a disease cycle primarily describes the disease as it develops as a result of the interaction between the host plant and the pathogen. In the first section of the chapter, a series of terms describing what is essentially a continuum of lifestyles were explained; through commensal via mutualistic and pathogenic to saprophytic. There are two extremes of pathogenic lifestyle-biotrophic and necrotrophic. Pathogens that are purely biotrophic are usually obligate parasites, whereas necrotrophic pathogens can also survive as saprophytes
What is a plant disease?
No full textThis chapter provides an introduction to the various factors, i.e. the host plants, the pathogens (fungi and fungal-like organisms, bacteria, viruses and nematodes) and the environment, and their interactions that may or may not result in a plant disease
Do HVNAC-like transcription factors regulate host defence against the powdery mildew (Blumeria graminis f.sp. hordei) in barley (Hordeum vulgare)?
No full textExploring the synergistic potential of Trichoderma gamsii T6085 and Clonostachys rosea IK726 for biological control of Fusarium head blight in wheat
No full textWe explore the combined use of two beneficial fungal isolates, Trichoderma gamsii T6085 (Tg) and Clonostachys rosea IK726 (Cr), to enhance Fusarium head blight (FHB) management by biological control. We found no evidence for mycoparasitism or inhibition via diffusible metabolites, but Tg volatiles inhibited Cr growth slightly. Although Cr reduced Tg spore germination and mycelial growth in liquid culture, this effect seemed absent in planta. The BCAs differently modulated defence-related (DR) genes when colonizing roots or spikes. At seven days post-inoculation (dpi), root-applied Cr, alone and co-inoculated, induced a minor upregulation of PR1. In leaves, a systemic signalling response by root inoculation was detected. In spikes, Pal1, PR1, and Lox1 were upregulated by Cr alone and co-inoculated at 96 hours post-inoculation (hpi). However, Lox1 activation was enhanced by co-inoculation. On spikes inoculated with Fg, the BCAs revealed different patterns of DR gene modulation indicating involvement of different biocontrol mechanisms. In detail, Pgip2 was primarily upregulated at 24 hpi in co-inoculated spikes whereas at 72 hpi activation of DR genes was observed only with Tg. Notably, the disease incidence was reduced by 93 % by co-inoculation. In addition, the inoculum potential of F. graminearum on straw was reduced by all BCAs treatments, with ≥ 96 % reduction of perithecia after six months incubation. Our results show the potential of combining Tg and Cr as a more effective and stable FHB management strategy, than by treatments with the individual strains
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