The hardy wild grass that could save our bread

Date:
March 25, 2022
Source:
John Innes Centre
Summary:
An obscure species of wild grass contains 'blockbuster' disease
resistance that can be cross bred into wheat to give immunity
against one of the deadliest crop pathogens.



FULL STORY ==========================================================================
An obscure species of wild grass contains "blockbuster" disease resistance
that can be cross bred into wheat to give immunity against one of the
deadliest crop pathogens.


==========================================================================
A collaborative international team of researchers identified the stem rust resistance gene from the wild goat grass species Aegilops sharonensis.

The research team led by the John Innes Centre, The Sainsbury Laboratory,
and the University of Minnesota used bioinformatic advances to develop
the first accurate genome map of Aegilops sharonensis.

The genetic potential of this hardy relative of wheat found in Israel
and southern Lebanon has been largely unexplored.

Using the genetic map and a search tool technique called Mutant Hunter
the team scanned the genome for mutations looking for ones which were
different in plants that were immune to stem rust, a disease which has
troubled farmers for millennia.

This search identified a candidate gene, which the researchers thought
was responsible for protecting plants. Using molecular tweezers, they
isolated the gene of interest and transferred it into a susceptible plant, where it conferred strong protection against all tested strains of the
wheat stem rust fungus,Puccinia graminisf. sp. tritici.



==========================================================================
Dr Brande Wulff, a wheat researcher at King Abdullah University of Science
and Technology (KAUST), formerly a group leader at the John Innes Centre
and one of the authors of the study said: "We now have this blockbuster
gene that confers amazing immunity. If I were stem rust, I would be
shaking in my spore." "It has been an arduous research journey lasting
many years, but we have now found this gene that confers broad-spectrum resistance. We have yet to come across an isolate of the pathogen which
can overcome the gene," added John Innes Centre researcher Dr Guotai Yu,
first author of the study.

In this study which appears in Nature Communications, experiments
showed that the Sr62 gene encodes a molecule called a tandem protein
kinase. Ongoing studies are looking at how this gene functions so
researchers can biologically engineer the mechanism to be more efficient.

The research team plans to employ the new gene as part of a stack of genes
- - bred into commonly used wheat varieties -- using genetic modification technology. They predict more resistance genes will be identified in and
cloned from populations of Aegilops sharonensisand other wild grasses
using their methods of gene discovery and deployment.

Aegilops sharonensis is known to possess many traits of agricultural
importance such as resistance to major diseases including rusts. However,
its long generation time, tough seed coat, and difficulties of crossing
it with wheat cultivars have made it less tractable than other species
of wild grasses being mined for useful genetic traits.

This makes the findings in this study even more valuable, explains
Professor Brian Steffenson from the University of Minnesota and
co-author of the study: "Given the great difficulties in crossing
Aegilops sharonensis to wheat, we were fairly certain that the rust
resistance genes discovered in the wild species would be novel." Aegilops sharonensis has a very narrow habitat range along the coastal plain
of the Mediterranean Sea. Professor Steffenson adds: "It is therefore
timely and important that efforts were made to collect and characterize accessions of this species before they are lost to urbanization.

It is our hope that the resistance gene cloned in this research will, when combined other genes, confer long-lasting resistance in wheat varieties, thereby reducing the threat of the stem rust disease" The study highlights recent developments in Latin America where GM (Genetically Modified)
wheat engineered for drought tolerance has been approved - - potentially
paving the way for GM traits to be bred into wheat more widely in the
face of the climate crisis.

The search for resistance against stem rust has become more urgent as
epidemics of the disease are becoming more frequent and climate change threatens to further increase its spread.

"Pathogens like stem rust, already reduce the yield of wheat by 21
per cent.

Not only is the grain itself lost or damaged by the pathogen, but also
the energy that goes into production -- an equivalent of 420 billion
kilowatts - - enough to power 300 million homes in the developing world is wasted. If we can intervene with genetics, by recruiting the resistance
found in this wild- wispy looking grass then that would be an amazing contribution to agriculture and climate change," said Dr Wulff.


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


========================================================================== Journal Reference:
1. Guotai Yu, Oadi Matny, Nicolas Champouret, Burkhard Steuernagel,
Matthew
J. Moscou, Inmaculada Herna'ndez-Pinzo'n, Phon Green, Sadiye
Hayta, Mark Smedley, Wendy Harwood, Ngonidzashe Kangara, Yajuan
Yue, Catherine Gardener, Mark J. Banfield, Pablo D. Olivera,
Cole Welchin, Jamie Simmons, Eitan Millet, Anna Minz-Dub,
Moshe Ronen, Raz Avni, Amir Sharon, Mehran Patpour, Annemarie
F. Justesen, Murukarthick Jayakodi, Axel Himmelbach, Nils Stein,
Shuangye Wu, Jesse Poland, Jennifer Ens, Curtis Pozniak, Miroslava
Karafia'tova', Istva'n Molna'r, Jaroslav Doležel, Eric R. Ward,
T. Lynne Reuber, Jonathan D. G. Jones, Martin Mascher, Brian
J. Steffenson, Brande B. H. Wulff. Aegilops sharonensis genome-
assisted identification of stem rust resistance gene Sr62. Nature
Communications, 2022; 13 (1) DOI: 10.1038/s41467-022-29132-8 ==========================================================================

Link to news story: https://www.sciencedaily.com/releases/2022/03/220325093935.htm

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