Grahame Jackson posted a new submission ‘A single laccase acts as a key component of environmental sensing in a broad host range fungal pathogen’

Saturday, 23 March 2024 08:16:28

PestNet

Submission

A single laccase acts as a key component of environmental sensing in a broad host range fungal pathogen

Nature

• Nathaniel M. Westrick, 
• Eddie G. Dominguez, 
• Madeline Bondy, 
• Christina M. Hull, 
• Damon L. Smith & 
• Mehdi Kabbage 

Communications Biology volume 7, Article number: 348 (2024) 

Abstract

Secreted laccases are important enzymes on a broad ecological scale for their role in mediating plant-microbe interactions, but within ascomycete fungi these enzymes have been primarily associated with melanin biosynthesis. In this study, a putatively secreted laccase, Sslac2, was characterized from the broad-host-range plant pathogen Sclerotinia sclerotiorum, which is largely unpigmented and is not dependent on melanogenesis for plant infection. Gene knockouts of Sslac2 demonstrate wide ranging developmental phenotypes and are functionally non-pathogenic. These mutants also displayed indiscriminate growth behaviors and enhanced biomass formation, seemingly as a result of their inability to respond to canonical environmental growth cues, a phenomenon further confirmed through chemical stress, physiological, and transcriptomic analyses. Transmission and scanning electron microscopy demonstrate apparent differences in extracellular matrix structure between WT and mutant strains that likely explain the inability of the mutants to respond to their environment. Targeting Sslac2 using host-induced gene silencing significantly improved resistance to S. sclerotiorum, suggesting that fungal laccases could be a valuable target of disease control. Collectively, we identified a laccase critical to the development and virulence of the broad-host-range pathogen S. sclerotiorum and propose a potentially novel role for fungal laccases in modulating environmental sensing.

Read on: https://www.nature.com/articles/s42003-024-06034-7

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Saturday, 23 March 2024 08:16:28

Grahame
Jackson posted a new submission ‘A single laccase acts as a key component of
environmental sensing in a broad host range fungal pathogen’

Submission

A single laccase acts as a key component of environmental sensing in a
broad host range fungal pathogen

Nature

• Nathaniel M. Westrick, 
• Eddie G. Dominguez, 
• Madeline Bondy, 
• Christina M. Hull, 
• Damon L. Smith & 
• Mehdi Kabbage 

Communications
Biology volume 7,
Article number: 348 (2024) 

Abstract

Secreted laccases are important enzymes on a broad ecological scale for
their role in mediating plant-microbe interactions, but within ascomycete fungi
these enzymes have been primarily associated with melanin biosynthesis. In this
study, a putatively secreted laccase, Sslac2, was characterized
from the broad-host-range plant pathogen Sclerotinia sclerotiorum,
which is largely unpigmented and is not dependent on melanogenesis for plant
infection. Gene knockouts of Sslac2 demonstrate wide ranging
developmental phenotypes and are functionally non-pathogenic. These mutants
also displayed indiscriminate growth behaviors and enhanced biomass formation,
seemingly as a result of their inability to respond to canonical environmental
growth cues, a phenomenon further confirmed through chemical stress,
physiological, and transcriptomic analyses. Transmission and scanning electron
microscopy demonstrate apparent differences in extracellular matrix structure
between WT and mutant strains that likely explain the inability of the mutants
to respond to their environment. Targeting Sslac2 using
host-induced gene silencing significantly improved resistance to S.
sclerotiorum, suggesting that fungal laccases could be a valuable target of
disease control. Collectively, we identified a laccase critical to the
development and virulence of the broad-host-range pathogen S.
sclerotiorum and propose a potentially novel role for fungal laccases
in modulating environmental sensing.

Read on: https://www.nature.com/articles/s42003-024-06034-7

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Double-stranded RNA prevents and cures infection by rust fungi

Friday, 08 December 2023 07:17:55

Grahame Jackson posted a new submission ‘Double-stranded RNA prevents and cures infection by rust fungi’

Submission

Double-stranded RNA prevents and cures infection by rust fungi

Nature

• Rebecca M. Degnan, 
• Louise S. Shuey, 
• Julian Radford-Smith, 
• Donald M. Gardiner, 
• Bernard J. Carroll, 
• Neena Mitter, 
• Alistair R. McTaggart & 
• Anne Sawyer 

Communications Biology volume 6, Article number: 1234 (2023) 

ABSTRACT
Fungal pathogens that impact perennial plants or natural ecosystems require management strategies beyond fungicides and breeding for resistance. Rust fungi, some of the most economically and environmentally important plant pathogens, have shown amenability to double-stranded RNA (dsRNA) mediated control. To date, dsRNA treatments have been applied prior to infection or together with the inoculum. Here we show that a dsRNA spray can effectively prevent and cure infection by Austropuccinia psidii (cause of myrtle rust) at different stages of the disease cycle. Significant reductions in disease coverage were observed in plants treated with dsRNA targeting essential fungal genes 48 h pre-infection through to 14 days post-infection. For curative treatments, improvements in plant health and photosynthetic capacity were seen 2–6 weeks post-infection. Two-photon microscopy suggests inhibitory activity of dsRNA on intercellular hyphae or haustoria. Our results show that dsRNA acts both preventively and curatively against myrtle rust disease, with treated plants recovering from severe infection. These findings have immediate potential in the management of the more than 10-year epidemic of myrtle rust in Australia.

Read on: https://www.nature.com/articles/s42003-023-05618-z

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Plants that survived dinosaur extinction pulled nitrogen from air

Sunday, 03 December 2023 14:55:40

Grahame Jackson posted a new submission ‘Plants that survived dinosaur extinction pulled nitrogen from air’

Submission

Plants that survived dinosaur extinction pulled nitrogen from air

ScienceDaily

Nitrogen fixing bacteria may have helped some cycads survive to the present day

Source:

Duke University

Summary:

Ancient cycad lineages that survived the extinction of the dinosaurs may have done so by relying on symbiotic bacteria in their roots to fix atmospheric nitrogen. The finding came from an effort to understand ancient atmospheres, but became an insight into plant evolution instead.

Once a favored food of grazing dinosaurs, an ancient lineage of plants called cycads helped sustain these and other prehistoric animals during the Mesozoic Era, starting 252 million years ago, by being plentiful in the forest understory. Today, just a few species of the palm-like plants survive in tropical and subtropical habitats.

Like their lumbering grazers, most cycads have gone extinct.

Read on: https://www.sciencedaily.com/releases/2023/11/231116135005.htm

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