Abstract Botrytis cinerea is a fungal pathogen that causes necrotic disease on more than a thousand known hosts widely spread across the plant kingdom. How B. cinerea interacts with such extensive host diversity remains largely unknown. To address this question, we generated an infectivity matrix of 98 strains of B. cinerea on 90 genotypes representing eight host plants. This experimental infectivity matrix revealed that the disease outcome is largely explained by variations in either the host resistance or pathogen virulence. However, the specific interactions between host and pathogen account for 16% of the disease outcome. Furthermore, the disease outcomes cluster among genotypes of a species but are independent of the relatedness between hosts. When analyzing the host specificity and virulence of B. cinerea, generalist strains are predominant. In this fungal necrotroph, specialization may happen by a loss in virulence on most hosts rather than an increase of virulence on a specific host. To uncover the genetic architecture of Botrytis host specificity and virulence, a genome-wide association study (GWAS) was performed and revealed up to 1492 genes of interest. The genetic architecture of these traits is widespread across the B. cinerea genome. The complexity of the disease outcome might be explained by hundreds of functionally diverse genes putatively involved in adjusting the infection to diverse hosts.
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Genetic and molecular landscapes of the generalist phytopathogen Botrytis cinerea
Kingdom: Fungi, phylum: Ascomycota, subphylum: Pezizomycotina, class: Leotiomycetes, order: Helotiales, family: Sclerotiniaceae, genus:
This polyphagous necrotroph has extensive genetic diversity at all population levels shaped by climate, geography, and plant host variation.
Genetic architecture of virulence and host specificity is polygenic using multiple weapons to target hosts, including secretory proteins, complex signal transduction pathways, metabolites, and mobile small RNA.
Efforts to control
- NSF-PAR ID:
- 10477329
- Publisher / Repository:
- Wiley-Blackwell
- Date Published:
- Journal Name:
- Molecular Plant Pathology
- Volume:
- 25
- Issue:
- 1
- ISSN:
- 1464-6722
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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Summary SUMOylation as one of the protein post‐translational modifications plays crucial roles in multiple biological processes of eukaryotic organisms.
Botrytis cinerea is a devastating fungal pathogen and capable of infecting plant hosts at low temperature. However, the molecular mechanisms of low‐temperature adaptation are largely unknown in fungi.Combining with biochemical methods and biological analyses, we report that SUMOylation regulates pathogen survival at low temperature and oxidative DNA damage response during infection in
B. cinerea . The heat shock protein (Hsp70) BcSsb and E3 ubiquitin ligase BcRad18 were identified as substrates of SUMOylation; moreover, their SUMOylation both requires a single unique SUMO‐interacting motif (SIM).SUMOylated BcSsb regulates β‐tubulin accumulation, thereby affecting the stability of microtubules and consequently mycelial growth at low temperature. On the contrary, SUMOylated BcRad18 modulates mono‐ubiquitination of the sliding clamp protein proliferating cell nuclear antigen (PCNA), which is involved in response to oxidative DNA damage during infection.
Our study uncovers the molecular mechanisms of SUMOylation‐mediated low‐temperature survival and oxidative DNA damage tolerance during infection in a devastating fungal pathogen, which provides novel insights into low‐temperature adaptation and pathogenesis for postharvest pathogens as well as new targets for inhibitor invention in disease control.
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Li-Jun, Ma (Ed.)Abstract Fungi of the genus Botrytis infect >1,400 plant species and cause losses in many crops. Besides the broad host range pathogen Botrytis cinerea, most other species are restricted to a single host. Long-read technology was used to sequence genomes of eight Botrytis species, mostly pathogenic on Allium species, and the related onion white rot fungus, Sclerotium cepivorum. Most assemblies contained <100 contigs, with the Botrytis aclada genome assembled in 16 gapless chromosomes. The core genome and pan-genome of 16 Botrytis species were defined and the secretome, effector, and secondary metabolite repertoires analyzed. Among those genes, none is shared among all Allium pathogens and absent from non-Allium pathogens. The genome of each of the Allium pathogens contains 8–39 predicted effector genes that are unique for that single species, none stood out as potential determinant for host specificity. Chromosome configurations of common ancestors of the genus Botrytis and family Sclerotiniaceae were reconstructed. The genomes of B. cinerea and B. aclada were highly syntenic with only 19 rearrangements between them. Genomes of Allium pathogens were compared with ten other Botrytis species (nonpathogenic on Allium) and with 25 Leotiomycetes for their repertoire of secondary metabolite gene clusters. The pattern was complex, with several clusters displaying patchy distribution. Two clusters involved in the synthesis of phytotoxic metabolites are at distinct genomic locations in different Botrytis species. We provide evidence that the clusters for botcinic acid production in B. cinerea and Botrytis sinoallii were acquired by horizontal transfer from taxa within the same genus.more » « less
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Abstract Small RNAs (sRNAs) of the fungal pathogen
Botrytis cinerea can enter plant cells and hijack host Argonaute protein 1 (AGO1) to silence host immunity genes. However, the mechanism by which these fungal sRNAs are secreted and enter host cells remains unclear. Here, we demonstrate thatB. cinerea utilizes extracellular vesicles (EVs) to secrete Bc-sRNAs, which are then internalized by plant cells through clathrin-mediated endocytosis (CME). TheB. cinerea tetraspanin protein, Punchless 1 (BcPLS1), serves as an EV biomarker and plays an essential role in fungal pathogenicity. We observe numerousArabidopsis clathrin-coated vesicles (CCVs) aroundB. cinerea infection sites and the colocalization ofB. cinerea EV marker BcPLS1 andArabidopsis CLATHRIN LIGHT CHAIN 1 , one of the core components of CCV. Meanwhile, BcPLS1 and theB. cinerea- secreted sRNAs are detected in purified CCVs after infection.Arabidopsis knockout mutants and inducible dominant-negative mutants of key components of the CME pathway exhibit increased resistance toB. cinerea infection. Furthermore, Bc-sRNA loading intoArabidopsis AGO1 and host target gene suppression are attenuated in those CME mutants. Together, our results demonstrate that fungi secrete sRNAs via EVs, which then enter host plant cells mainly through CME. -
Summary Spray‐induced gene silencing (SIGS) is an innovative and eco‐friendly technology where topical application of pathogen gene‐targeting RNAs to plant material can enable disease control. SIGS applications remain limited because of the instability of RNA, which can be rapidly degraded when exposed to various environmental conditions. Inspired by the natural mechanism of cross‐kingdom RNAi through extracellular vesicle trafficking, we describe herein the use of artificial nanovesicles (AVs) for RNA encapsulation and control against the fungal pathogen, Botrytis cinerea . AVs were synthesized using three different cationic lipid formulations, DOTAP + PEG, DOTAP and DODMA, and examined for their ability to protect and deliver double stranded RNA (dsRNA). All three formulations enabled dsRNA delivery and uptake by B . cinerea . Further, encapsulating dsRNA in AVs provided strong protection from nuclease degradation and from removal by leaf washing. This improved stability led to prolonged RNAi‐mediated protection against B . cinerea both on pre‐ and post‐harvest plant material using AVs. Specifically, the AVs extended the protection duration conferred by dsRNA to 10 days on tomato and grape fruits and to 21 days on grape leaves. The results of this work demonstrate how AVs can be used as a new nanocarrier to overcome RNA instability in SIGS for crop protection.more » « less
