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 Results of this magnitude couldn’t come at a more crucial time.
The most recent UN report, The State of Food Security and
Nutrition in the World 2022, found that in 2021 nearly 10% of
the world population was hungry, a situation that has been
steadily worsening over the last few years and eclipsing all
other threats to global health in scale. According to UNICEF, by
2030, more than 660 million people are expected to face food
scarcity and malnutrition. Two of the major causes of this are
inefficient food supply chains (access to food) and harsher
growing conditions for crops due to climate change. Improving
access to food and improving the sustainability of food crops in
impoverished areas are the key goals of this study and the RIPE
project.
Realizing Increased Photosynthetic Efficiency, or RIPE, is an
international research project that aims to increase global food
production by improving photosynthetic efficiency in food crops
for smallholder farmers in Sub-Saharan Africa with support from
the Bill & Melinda Gates Foundation, Foundation for Food &
Agriculture Research, and U.K. Foreign, Commonwealth &
Development Office.
“The number of people affected by food insufficiency continues
to grow, and projections clearly show that there needs to be a
change at the food supply level to change the trajectory,” said
Amanda De Souza, RIPE project research scientist, and lead
author. “Our research shows an effective way to contribute to
food security for the people who need it most while avoiding
more land being put into production. Improving photosynthesis is
a major opportunity to gain the needed jump in yield potential.”
Photosynthesis, the natural process all plants use to convert
sunlight into energy and yield, is a surprisingly inefficient
100+ step process that RIPE researchers have been working to
improve for more than a decade. In this first-of-its-kind work,
recently published in Science, the group improved the VPZ
construct within the soybean plant to improve photosynthesis and
then conducted field trials to see if yield would be improved as
a result.
The VPZ construct contains three genes that code for proteins of
the xanthophyll cycle, which is a pigment cycle that helps in
the photoprotection of the plants. Once in full sunlight, this
cycle is activated in the leaves to protect them from damage,
allowing leaves to dissipate the excess energy. However, when
the leaves are shaded (by other leaves, clouds, or the sun
moving in the sky) this photoprotection needs to switch off so
the leaves can continue the photosynthesis process with a
reserve of sunlight. It takes several minutes for the plant to
switch off the protective mechanism, costing plants valuable
time that could have been used for photosynthesis.
The overexpression of the three genes from the VPZ construct
accelerates the process, so every time a leaf transitions from
light to shade the photoprotection switches off faster. Leaves
gain extra minutes of photosynthesis which, when added up
throughout the entire growing season, increases the total
photosynthetic rate. This research has shown that despite
achieving a more than 20% increase in yield, seed quality was
not impacted.
“Despite higher yield, seed protein content was unchanged. This
suggests some of the extra energy gained from improved
photosynthesis was likely diverted to the nitrogen-fixing
bacteria in the plant’s nodules,” said RIPE Director Stephen
Long, Ikenberry Endowed University Chair of Crop Sciences and
Plant Biology at Illinois’ Carl R. Woese Institute for Genomic
Biology.
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The researchers first tested their idea in tobacco
plants because of the ease of transforming the crop’s genetics and
the amount of seeds that can be produced from a single plant. These
factors allow researchers to go from genetic transformation to a
field trial within months. Once the concept was proven in tobacco,
they moved into the more complicated task of putting the genetics
into a food crop, soybeans.
“Having now shown very substantial yield increases in both tobacco
and soybean, two very different crops, suggests this has universal
applicability,” said Long. “Our study shows that realizing yield
improvements is strongly affected by the environment. It is critical
to determine the repeatability of this result across environments
and further improvements to ensure the environmental stability of
the gain.”
Additional field tests of these transgenic soybean plants are being
conducted this year, with results expected in early 2023.
“The major impact of this work is to open the roads for showing that
we can bioengineer photosynthesis and improve yields to increase
food production in major crops,” said De Souza. “It is the beginning
of the confirmation that the ideas ingrained by the RIPE project are
a successful means to improve yield in major food crops.”
The RIPE project and its sponsors are committed to ensuring Global
Access and making the project’s technologies available to the
farmers who need them the most.
“This has been a road of more than a quarter century for me
personally,” said Long. “Starting first with a theoretical analysis
of theoretical efficiency of crop photosynthesis, simulation of the
complete process by high-performance computation, followed by
application of optimization routines that indicated several
bottlenecks in the process in our crops. Funding support over the
past ten years has now allowed us to engineer alleviation of some of
these indicated bottlenecks and test the products at field scale.
After years of trial and tribulation, it is wonderfully rewarding to
see such a spectacular result for the team.”
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RIPE is led by the University of Illinois in
partnership with The Australian National University, Chinese Academy
of Sciences, Commonwealth Scientific and Industrial Research
Organisation, Lancaster University, Louisiana State University,
University of California, Berkeley, University of Cambridge,
University of Essex, and U.S. Department of Agriculture,
Agricultural Research Service.
Long is a professor in the Department of Crop Sciences, part of the
College of Agricultural, Consumer and Environmental Sciences at the
University of Illinois.
[Source: Stephen Long]
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