New research reveals antifungal symbiotic peptide in legume
Findings pave the way for developing environmentally friendly fungicides


Date:
July 20, 2020
Source:
Donald Danforth Plant Science Center
Summary:
Scientists have identified a sub class of peptides in the nodules of
the legume, Medicago truncatula that proved effective in inhibiting
growth of the fungus causing gray mold.



FULL STORY ========================================================================== Fungal diseases cause substantial losses of agricultural harvests
each year.

The fungus Botrytis cinerea causing gray mold disease is a major problem
for farmers growing strawberries, grapes, raspberries, tomatoes and
lettuce. To mitigate the problem, they often resort to applying chemical fungicides which can lose their effectiveness over time. Danforth Center scientists, Dilip Shah, PhD, research associate member, Siva Velivelli,
PhD, postdoctoral associate, Kirk Czymmek, PhD, principal investigator
and director, Advanced Bioimaging Laboratory and their collaborators at
the Pacific Northwest National Laboratory have identified a sub class of peptides in the nodules of the legume, Medicago truncatula that proved effective in inhibiting growth of the fungus causing gray mold. The
results of their research, Antifungal symbiotic peptide NCR044 exhibits
unique structure and multifaceted mechanisms of action that confer plant protection, were recently published in the journal, Proceedings of the
National Academy of Sciences.


==========================================================================
"We are excited about the possibility of developing this class of
peptides as a spray-on fungicide that would provide farmers with an environmentally friendly alternative to chemical fungicides for pre-
and post-harvest management of fungal diseases," said Dilip Shah. "When
applied to crops, the peptides will eventually break down to amino acids
in the soil and be used by beneficial microbes as an energy source."
Medicago truncatula is a relative of alfalfa. Shah and his team produced recombinantly large quantities of the highly charged NCR044 peptide
that is expressed in the nodules of this legume. They then applied the
peptide in low concentrations to tobacco and tomato plants in the lab
and challenged the plants with the gray mold fungus. The plants showed significant protection from this fungal disease.

To understand the antimicrobial mechanism within the cell, they
collaborated with Czymmek, who is also a mycologist and has studied
fungal cell biology for many years. Using time-lapse confocal and super resolution microscopy, the team was able to observe dynamically how the
peptide binds to fungal spores and germlings, how it is internalized
and where it goes inside the fungal cell. One key finding here was
the confirmation that the peptide concentrated in the nucleolus, the
organelle where ribosomal assembly takes place.

"It was a pleasure to work with Dilip and his team. As a young
scientist, Siva, was able to move diligently across a very diverse set
of platforms and techniques, following-up on leads from the scientific
data. Ultimately, he was able to apply these corroborating techniques and uncover significant new information to create robust conclusions about
the research project," said Czymmek, "It was really great science."
The unique team of scientists with expertise in fungal and plant cell
biology combined with advanced imaging capabilities allowed them to make critical interpretations and confirm their hypotheses. Their collaborator
and co-author on the paper, Garry Buchko, PhD at the Pacific Northwest
National Laboratory solved the first three-dimensional structure of
a nodule-specific peptide revealing a largely disordered, and highly
dynamic, peptide structure containing a short anti-parallel ?-sheet,
tiny ?-helix, and when oxidized, two stabilizing disulfide bonds.

A portion of the project was funded by TechAccel. Shah and Czymmek
will continue their research and have applied to the National Science Foundation for a grant to further explore how antifungal nodule-specific peptides kill harmful fungal pathogens in vitro and in planta.


========================================================================== Story Source: Materials provided by
Donald_Danforth_Plant_Science_Center. Note: Content may be edited for
style and length.


========================================================================== Journal Reference:
1. Siva L. S. Velivelli, Kirk J. Czymmek, Hui Li, Jared B. Shaw,
Garry W.

Buchko, Dilip M. Shah. Antifungal symbiotic peptide NCR044 exhibits
unique structure and multifaceted mechanisms of action that confer
plant protection. Proceedings of the National Academy of Sciences,
2020; 117 (27): 16043 DOI: 10.1073/pnas.2003526117 ==========================================================================

Link to news story: https://www.sciencedaily.com/releases/2020/07/200720103320.htm

--- up 5 days, 1 hour, 54 minutes
* Origin: -=> Castle Rock BBS <=- Now Husky HPT Powered! (1337:3/111)