Comparative genomics of plant pathogenic Botrytis species with distinct host specificity
Valero-Jiménez, Claudio A. ; Veloso, Javier ; Staats, Martijn ; Kan, Jan A.L. van - \ 2019
BMC Genomics 20 (2019)1. - ISSN 1471-2164
Effector - Grey mould - Necrotroph - Secondary metabolite - Secretome
Background: Fungi of the genus Botrytis (presently containing ~ 35 species) are able to infect more than 1400 different plant species and cause losses in a wide range of crops of economic importance. The best studied species is B. cinerea, which has a broad host range and is one of the best studied necrotrophic plant pathogenic fungi. Most other Botrytis spp. have a narrow host range and have been studied in less detail. To characterize genomic variation among different representatives of Botrytis spp., we sequenced and annotated the draft genomes of nine Botrytis species: B. calthae, B. convoluta, B. elliptica, B. galanthina, B. hyacinthi, B. narcissicola, B. paeoniae, B. porri and B. tulipae. Results: Bioinformatics and comparative genomics tools were applied to determine a core of 7668 shared protein families in all Botrytis species, which grouped them in two distinct phylogenetic clades. The secretome of all nine Botrytis spp. was similar in number (ranging from 716 to 784 predicted proteins). A detailed analysis of the molecular functions of the secretome revealed that shared activities were highly similar. Orthologs to effectors functionally studied in B. cinerea were also present in the other Botrytis species. A complex pattern of presence/absence of secondary metabolite biosynthetic key enzymes was observed. Conclusions: Comparative genomics of Botrytis show that overall, species share the main signatures and protein families in the secreted proteins, and of known effectors. Our study provides leads to study host range determinants in the genus Botrytis and provides a stepping stone to elucidate the roles of effector candidates in the infection process of these species.
Tools of the crook : Infection strategies of fungal plant pathogens
Rodriguez-Moreno, Luis ; Ebert, Malaika K. ; Bolton, Melvin D. ; Thomma, Bart P.H.J. - \ 2018
The Plant Journal 93 (2018)4. - ISSN 0960-7412 - p. 664 - 674.
Effector - Fungus - Host immunity - Plant pathogen - Virulence
Fungi represent an ecologically diverse group of microorganisms that includes plant pathogenic species able to cause considerable yield loses in crop production systems worldwide. In order to establish compatible interactions with their hosts, pathogenic fungi rely on the secretion of molecules of diverse nature during host colonization to modulate host physiology, manipulate other environmental factors or provide self-defence. These molecules, collectively known as effectors, are typically small secreted cysteine-rich proteins, but may also comprise secondary metabolites and sRNAs. Here, we discuss the most common strategies that fungal plant pathogens employ to subvert their host plants in order to successfully complete their life cycle and secure the release of abundant viable progeny.
The complete genome sequence of the phytopathogenic fungus Sclerotinia sclerotiorum reveals insights into the genome architecture of broad host range pathogens
Derbyshire, Mark ; Denton-Giles, Matthew ; Hegedus, Dwayne ; Seifbarghi, Shirin ; Rollins, Jeffrey ; Kan, Jan van; Seidl, Michael F. ; Faino, Luigi ; Mbengue, Malick ; Navaud, Olivier - \ 2017
Genome Biology and Evolution 9 (2017)3. - ISSN 1759-6653 - p. 593 - 618.
Effector - Pacbio - Repeat-induced point mutation - Sclerotinia sclerotiorum - Two-speed
Sclerotinia sclerotiorum is a phytopathogenic fungus with over 400 hosts including numerous economically important cultivated species. This contrasts many economically destructive pathogens that only exhibit a single or very few hosts. Many plant pathogens exhibit a "two-speed" genome. So described because their genomes contain alternating gene rich, repeat sparse and gene poor, repeat-rich regions. In fungi, the repeat-rich regions may be subjected to a process termed repeat-induced point mutation (RIP). Both repeat activity and RIP are thought to play a significant role in evolution of secreted virulence proteins, termed effectors. We present a complete genome sequence of S. sclerotiorum generated using Single Molecule Real-Time Sequencing technology with highly accurate annotations produced using an extensive RNA sequencing data set. We identified 70 effector candidates and have highlighted their in planta expression profiles. Furthermore, we characterized the genome architecture of S. sclerotiorum in comparison to plant pathogens that exhibit "two-speed" genomes. We show that there is a significant association between positions of secreted proteins and regions with a high RIP index in S. sclerotiorum but we did not detect a correlation between secreted protein proportion and GC content. Neither did we detect a negative correlation between CDS content and secreted protein proportion across the S. sclerotiorum genome. We conclude that S. sclerotiorum exhibits subtle signatures of enhanced mutation of secreted proteins in specific genomic compartments as a result of transposition and RIP activity. However, these signatures are not observable at the whole-genome scale.
Colletotrichum higginsianum extracellular LysM proteins play dual roles in appressorial function and suppression of chitin-triggered plant immunity
Takahara, Hiroyuki ; Hacquard, Stéphane ; Kombrink, Anja ; Hughes, H.B. ; Halder, Vivek ; Robin, Guillaume P. ; Hiruma, Kei ; Neumann, Ulla ; Shinya, Tomonori ; Kombrink, Erich ; Shibuya, Naoto ; Thomma, Bart P.H.J. ; O'Connell, Richard J. - \ 2016
New Phytologist 211 (2016)4. - ISSN 0028-646X - p. 1323 - 1337.
Arabidopsis - Appressoria - Biotrophy - Chitin - Colletotrichum - Effector - LysM - Virulence
The genome of the hemibiotrophic anthracnose fungus, Colletotrichum higginsianum, encodes a large repertoire of candidate-secreted effectors containing LysM domains, but the role of such proteins in the pathogenicity of any Colletotrichum species is unknown. Here, we characterized the function of two effectors, ChELP1 and ChELP2, which are transcriptionally activated during the initial intracellular biotrophic phase of infection. Using immunocytochemistry, we found that ChELP2 is concentrated on the surface of bulbous biotrophic hyphae at the interface with living host cells but is absent from filamentous necrotrophic hyphae. We show that recombinant ChELP1 and ChELP2 bind chitin and chitin oligomers in vitro with high affinity and specificity and that both proteins suppress the chitin-triggered activation of two immune-related plant mitogen-activated protein kinases in the host Arabidopsis. Using RNAi-mediated gene silencing, we found that ChELP1 and ChELP2 are essential for fungal virulence and appressorium-mediated penetration of both Arabidopsis epidermal cells and cellophane membranes in vitro. The findings suggest a dual role for these LysM proteins as effectors for suppressing chitin-triggered immunity and as proteins required for appressorium function.
Convergent evolution of filamentous microbes towards evasion of glycan-triggered immunity
Rovenich, Hanna ; Zuccaro, Alga ; Thomma, Bart P.H.J. - \ 2016
New Phytologist 212 (2016)4. - ISSN 0028-646X - p. 896 - 901.
Chitin - Effector - Glycan recognition - Microbial cell wall - β-glucan
I. II. III. IV. V. VI. References Summary: All filamentous microbes produce and release a wide range of glycans, which are essential determinants of microbe-microbe and microbe-host interactions. Major cell wall constituents, such as chitin and β-glucans, are elicitors of host immune responses. The widespread capacity for glycan perception in plants has driven the evolution of various strategies that help filamentous microbes to evade detection. Common strategies include structural and chemical modifications of cell wall components as well as the secretion of effector proteins that suppress chitin- and β-glucan-triggered immune responses. Thus, the necessity to avoid glycan-triggered immunity represents a driving force in the convergent evolution of filamentous microbes towards its suppression.