During COVID, scientists turn to computers to understand C4
photosynthesis

Date:
October 16, 2020
Source:
Carl R. Woese Institute for Genomic Biology, University of Illinois
at Urbana-Champaign
Summary:
When COVID closed down their lab, a team of researchers turned to
computational approaches to understand what makes some plants better
adapted to transform light and carbon dioxide into yield through
photosynthesis. Most plants use C3 photosynthesis, which is more
common but not as efficient as C4. The researchers uncovered clues
as to how C4 crops are able to express key enzymes in specialized
cells that increase photosynthetic efficiency.



FULL STORY ==========================================================================
When COVID closed down their lab in March, a team from the University of
Essex turned to computational approaches to understand what makes some
plants better adapted to transform light and carbon dioxide into yield
through photosynthesis. They published their findings in the journal
Frontiers of Plant Science.


========================================================================== There are two kinds of photosynthesis: C3 and C4. Most food crops
depend on C3 photosynthesis where carbon is fixed into sugar inside
cells called 'mesophyll' where oxygen is abundant. However, oxygen can
hamper photosynthesis. C4 crops evolved specialized bundle sheath cells
to concentrate carbon dioxide, which makes C4 photosynthesis as much as
60 percent more efficient.

In this study, scientists wanted to find out how C4 crops are able to
express several important enzymes inside bundle sheath cells instead of
the mesophyll.

"The ultimate goal is to be able to understand these mechanisms so that we
can improve C3 photosynthesis in food crops like cowpea and cassava that smallholder farmers in sub-Saharan Africa depend on for their families'
food and income," said Chidi Afamefule, a postdoctoral researcher working
on Realizing Increased Photosynthetic Efficiency (RIPE) at Essex.

Led by the University of Illinois at the Carl R. Woese Institute
for Genomic Biology, RIPE aims to boost food production by improving photosynthesis with support from the Bill & Melinda Gates Foundation, Foundation for Food and Agriculture Research, and U.K. Foreign,
Commonwealth & Development Office. 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.

The team compared the DNA of four C3 grass crops (including barley
and rice) and four C4 grass crops (including corn and sorghum). Their
goal was to identify regions of DNA that might control the expression
of four enzymes involved in photosynthesis. This study is likely the
first comparison of the expression of these enzymes (SBPase, FBPase,
PRK, and GAPDH) in C3 and C4 crops.

"It would have been great to find a 'master regulator' that operates
in all these enzymes, but we didn't find it, and we suspect it doesn't
exist," said Afamefule, who led the study from his apartment during
the pandemic.

Instead, they discovered C4 crops have several "activators" within their
DNA that trigger expression in the bundle sheath and "repressors" that
restrict expression in the mesophyll. They hope that they can use this
genetic code to help less-efficient C3 crops photosynthesize better in
the future.

"There are already efforts underway to help C3 crops operate more like
C4 crops," said principal investigator Christine Raines, a professor
in the School of Life Sciences at Essex where she also serves as the Pro-Vice-Chancellor for Research. "Studies like this help us identify
small pieces within an incredibly complex machine that we have to
understand before we can fine-tune and reengineer it." The next step is
to validate these findings in the lab. The team returned to their lab
benches on July 6, 2020, adhering to all recommended safety guidelines
from the School of Life Sciences at Essex.

Realizing Increased Photosynthetic Efficiency (RIPE) aims to improve photosynthesis and equip farmers worldwide with higher-yielding crops to
ensure everyone has enough food to lead a healthy, productive life. RIPE
is sponsored by the Bill & Melinda Gates Foundation, the U.S. Foundation
for Food and Agriculture Research, and the U.K. Foreign, Commonwealth & Development Office.

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.


========================================================================== Story Source: Materials provided by Carl_R._Woese_Institute_for_Genomic_Biology,_University of_Illinois_at_Urbana-Champaign. Original written by Claire
Benjamin. Note: Content may be edited for style and length.


========================================================================== Journal Reference:
1. Chidi Afamefule, Christine A. Raines. Insights Into the Regulation
of the
Expression Pattern of Calvin-Benson-Bassham Cycle Enzymes in C3
and C4 Grasses. Frontiers in Plant Science, 2020; 11 DOI: 10.3389/
fpls.2020.570436 ==========================================================================

Link to news story: https://www.sciencedaily.com/releases/2020/10/201016090157.htm

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