About this Research Topic
Plant pathogenic fungi can be classified as biotrophic, necrotrophic or hemibiotrophic, depending on their host interaction for their nutrition. Necrotrophic fungi kill host plant cells and use the contents to support their own growth. Necrotrophic fungi may also induce apoptosis in host cells instead of breaking plant cell walls, or induce their own apoptosis. Hemibiotrophic fungi use sequential strategies of biotrophic and necrotrophic infection to invade and colonize plants. Therefore, it is possible that some pathogenic fungi described so far may also have a short biotrophic phase. Certain necrotrophs may also live as saprophytes during their life cycle, while others may live only as obligate necrotrophs. Initially, necrotrophs were considered to invade their hosts by enzymatic or/and toxigenic secretions, but now it is currently accepted that they also use other mechanisms during pathogenesis, such as the production of reactive oxygen species (ROS), elicitors that activate host immune responses (DAMPs, chitin), or virulence effectors that suppress host immune responses (polygalacturonases, SCFE1, small RNAs, PAMPs).
Necrotrophs have been classified according to the extent of their host specificity. Among the most specific necrotrophs are those that produce toxins that are known to be toxic only to a limited number of plants (Cochliobolus spp., Parastagonospora nodorum, Pyrenophora spp., Macrophomina phaseolina, Phytopthora capsici, Moniliophthora roreri and Alternaria spp.). Nectrotrophic species with a wide host range include Botrytis cinerea, Alternaria brassicicola, Plectosphaerella cucumerina, Monilinia spp., Sclerotinia sclerotiorum and Fusarium spp. Many studies have been conducted on plant resistance to fungal necrotrophic pathogens. However, there is much less known about these pathogens and their ability to infect, despite their substantial role in crop losses. Insights from ‘omics’ studies on nectrotrophic pathogens have led to the identification of candidate virulence factors, and necrotrophic strategies can be predicted. Comparative analysis of the genomes of different groups of pathogens should improve our ability to decipher the genetic basis of infection by these necrotrophic pathogens. Understanding the pathogenesis mechanisms of necrotrophic fungi, and comparisons between taxa and their ability to adapt to different lifestyles, can advance not only in the knowledge of plant disease progression, but also in their control. Research focusing on the comparison of virulence effectors of fungal necrotrophs with their targets on host cells will also help to understand their pathogenic mechanisms on plants.
We invite submissions of Original Research, Review, Perspectives and Methods manuscripts that provide insights into biology of both the pathogen and host plant around:
• Fungal necrotrophs on plant cells: ability to adapt to different life cycles, the genetic basis of plant infection, differential expression of necrotrophic marker genes accompanied by functional validation
• Pathogenesis mechanisms of necrotrophic fungi: enzymatic and toxigenic secretion and their biosynthetic pathways, necrotrophic strategies.
• Known mechanisms: ROS, elicitors that activate host immune responses (DAMPs, chitin), virulence effectors that suppress host immune responses (polygalacturonases, SCFE1, small RNAs, PAMPs).
Descriptive studies, including those using 'omics approaches, will not be considered for review unless they address further functional insights into a relevant biological process.
Paloma Melgarejo is an author on one patent issued in Spain and one patent issued internationally, and has co-obtained plant variety rights for the following strawberry varieties: Aguedilla, Amiga, Carisma, Fontanilla, Fuentepina, Marina, Medina, and Santaclara. Maria Del Mar Jimenez-Gasco is an author on two patents issued in Spain, relating to the identification of Fusarium oxysporum.
Keywords: toxins, lytic enzymes, apoptosis, elicitors, virulence effectors, necrotrophs
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