Engineering seeds to resist drought
Date:
July 8, 2021
Source:
Massachusetts Institute of Technology
Summary:
Researchers have devised a way to protect seeds from the stress of
water shortage during their crucial germination phase, and even
provide the plants with extra nutrition. Simple and inexpensive,
the process could be deployed in arid regions to facilitate
agriculture on drought-stressed land.
FULL STORY ==========================================================================
As the world continues to warm, many arid regions that already have
marginal conditions for agriculture will be increasingly under stress, potentially leading to severe food shortages. Now, researchers at MIT
have come up with a promising process for protecting seeds from the
stress of water shortage during their crucial germination phase, and
even providing the plants with extra nutrition at the same time.
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The process, undergoing continued tests in collaboration with researchers
in Morocco, is simple and inexpensive, and could be widely deployed
in arid regions, the researchers say. The findings are reported this
week in the journal Nature Food, in a paper by MIT professor of civil
and environmental engineering Benedetto Marelli, MIT doctoral student
Augustine Zvinavashe '16, and eight others at MIT and at the King Mohammed
VI Polytechnic University in Morocco.
The two-layer coating the team developed is a direct outgrowth of years
of research by Marelli and his collaborators in developing seed coatings
to confer various benefits. A previous version enabled seeds to resist
high salinity in the soil, but the new version is aimed at tackling
water shortages.
"We wanted to make a coating that is specific to tackling drought,"
Marelli explains. "Because there is clear evidence that climate change
is going to impact the basin of the Mediterranean area," he says, "we
need to develop new technologies that can help to mitigate these changes
in the climate patterns that are going to make less water available to agriculture." The new coating, taking inspiration from natural coatings
that occur on some seeds such as chia and basil, is engineered to protect
the seeds from drying out. It provides a gel-like coating that tenaciously holds onto any moisture that comes along, and envelops the seed with it.
A second, inner layer of the coating contains preserved microorganisms
called rhizobacteria, and some nutrients to help them grow. When exposed
to soil and water, the microbes will fix nitrogen into the soil, providing
the growing seedling with nutritious fertilizer to help it along.
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"Our idea was to provide multiple functions to the seed coating,"
Marelli says, "not only targeting this water jacket, but also targeting
the rhizobacteria.
This is the real added value to our seed coating, because these are self- replicating microorganisms that can fix nitrogen for the plants, so they
can decrease the amount of nitrogen-based fertilizers that are provided,
and enrich the soil." Early tests using soil from Moroccan test farms
have shown encouraging results, the researchers say, and now field tests
of the seeds are underway.
Ultimately, if the coatings prove their value through further tests,
the coatings are simple enough that they could be applied at a local
level, even in remote locations in the developing world. "It can be
done locally," Zvinavashe says. "That's one of the things we were
thinking about while we were designing this. The first layer you could
dip coat, and then the second layer, you can spray it on. These are
very simple processes that farmers could do on their own." In general,
though, Zvinavashe says it would be more economical to do the coatings centrally, in facilities that can more easily preserve and stabilize
the nitrogen-fixing bacteria.
The materials needed for the coatings are readily available and often
used in the food industry already, Marelli says. The materials are also
fully biodegradable, and some of the compounds themselves can actually be derived from food waste, enabling the eventual possibility of closed-loop systems that continuously recycle their own waste.
Although the process would add a small amount to the cost of the seeds themselves, Marelli says, it may also produce savings by reducing the
need for water and fertilizer. The net balance of costs and benefits
remains to be determined through further research.
Although initial tests using common beans have shown promising results
by a variety of measures, including root mass, stem height, chlorophyll content, and other metrics, the team has not yet cultivated a full crop
from seeds with the new coating all the way through to harvest, which
will be the ultimate test of its value. Assuming that it does improve
harvest yields under arid conditions, the next step will be to extend the research to a variety of other important crop seeds, the researchers say.
"The system is so simple that it can be applied to any seed," Marelli
says.
"And we can design the seed coating to respond to different climate
patterns." It might even be possible to tailor coatings to the predicted rainfall of a particular growing season, he says.
========================================================================== Story Source: Materials provided by
Massachusetts_Institute_of_Technology. Original written by David
L. Chandler. Note: Content may be edited for style and length.
========================================================================== Journal Reference:
1. Augustine T. Zvinavashe, Julie Laurent, Manal Mhada, Hui Sun,
Henri Manu
Effa Fouda, Doyoon Kim, Salma Mouhib, Lamfeddal Kouisni, Benedetto
Marelli. Programmable design of seed coating function induces
water- stress tolerance in semi-arid regions. Nature Food, 2021;
DOI: 10.1038/ s43016-021-00315-8 ==========================================================================
Link to news story:
https://www.sciencedaily.com/releases/2021/07/210708111500.htm
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