This document discusses the development of C4 rice. C4 rice is a transgenic rice that shows an altered C4 photosynthetic pathway instead of the typical C3 pathway found in rice. The goal is to increase rice yields by 50% by 2050 to feed a growing global population. Researchers are using genetic engineering and biotechnology tools to modify the anatomy, biochemistry, and physiology of rice plants to exhibit C4 pathway traits. Current research involves fine-tuning the enzymes and timing of the C4 pathway in rice. International consortiums are working towards proving the concept and developing high-yield C4 rice.

1. DEVELOPMENT OF C4 RICE
THE CHALLENGE OF NEW GREEN REVOLUTION AND
ITS CURRENT PROGRESS AND FUTURE CHALLENGES
Submitted by-
Siddhant Bohidar
+3 Final Yr
BS 12 BOT 413

2.  INTRODUCTION
 WHAT IS C4 RICE ?
 C3 VS. C4 PLANTS
 ANATOMY OF C3 & C4 PLANTS
 COMARISION OF C3 & C4 PHOTOSYNTHETIC
PATHWAYS
 EVOLUTIONARY SIGNIFICANCE OF C4 PLANTS
 TECHNIQUES TOWARDS CONSTRUCTION OF C4 RICE
 FINE TUNING
 CURRENT RESEARCHES & PROGRESS
 CONCLUSION
CONTENTS

3. INTRODUCTION
90% of the world’s rice is grown and consumed in Asia,
with each hectare of rice-producing land providing food for
27 people.
By 2050, because of population growth and increasing
urbanisation, each remaining hectare will have to feed at
least 43 people.
This means that yields must be increased by at least 50%
over the next 40 years to prevent mass food scarcity.
Since predictive models suggest that yield increases of
this magnitude can only be achieved by improving
photosynthesis, and because evolution has increased
photosynthetic efficiency by 50% in the form of the C4
pathway, one solution is to generate C4 rice.

4. WHAT IS C4 RICE ?
 C4 RICE IS A TRANSGENIC RICE WHICH SHOWS AN
ALTERED C4 PATHWAY INSTEAD OF C3 PATHWAY.
 IT CAN BE ACHIEVED BY CHANGING IN ANATOMY,
BIOCHEMISTRY & PHYSIOLOGY OF C3 RICE PLANTS USING
GENETIC ENGINEERING AND BIOINFORMATICS TOOLS.

5. C3 VS. C4 PLANTS
C3 Plants C4 Plants
Stomata Open at Night
Closed during Day
Partially closed
during day and
partially closed at
night
Carbon dioxide
fixation
Carbon dioxide is
“fixed” into a three
carbon compound
that is stable
Carbon dioxide is
temporarily stored as
a 4 carbon stable
compound
Water Loss Has trouble with
water loss due to
transpiration.
Less water loss than
C3 plants.

6. Leaf – Level of Organization

7. Leaf – Level of Organization
Cuticle
Epidermis
Mesophyll
Vascular bundle
Bundle sheath
Stoma

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12. C3 plant
C4 plant

13. EVOLUTIONARY SIGNIFICANCE OF C4 PLANTS
Grasses have two major photosynthetic pathways: the C3 pathway that
is characteristic of most plants and a specialized C4 pathway. C4
grasses dominate tropical and subtropical grasslands and savannas,
and C3 grasses dominate the world's cooler temperate grassland
regions. This striking pattern has been attributed to C4 physiology,
with the implication that the evolution of the pathway enabled C4
grasses to persist in warmer climates than their C3 relatives (Edwards
and Smith, 2010). The evolution of a new biochemical pathway is
based on the formation of novel genes, or purposeful changes in
existing genes. Most of the high yielding crops in agriculture use the
C4 photosynthetic pathway. In spite of their manifold origins, they are
all categorized by elevated rates of photosynthesis and well-organized
use of water, nitrogen and other essential inputs. As a morphological
and biochemical novelty, the C4 photosynthetic pathway has an
adaptation to hot, arid environments or CO2 deficit. The C4 pathway
independently appeared at least 50 times during angiosperm evolution
(Vicentini et al., 2008).

14. TECHNIQUES TOWARDS CONSTRUCTION OF C4 RICE

15. SINCE THE PLANTS ARE LIGHT SENSITIVE AND TEMPERATURE
SENSITIVE, IT IS HIGHLY NECESSARY TO FINE TUNE THE PATHWAY.
THE ENZYMES MUST BE TUNED IN SUCH A WAY THAT THEY MUST
CARRY OUT ITS FUNCTIONS IN A SYNCRONISED WAY.
FOR EXAMPLE, TIMING OF ACTIONS OF ENZYMES MUST BE
MAINTAINED SO THAT THE PHYSIOLOGICALACTIVITY CAN TAKE
PLACE IN A SMOOTH MANNER.
SO MANY SCIENTISTS, TOGETHER WITH BIOCHEMICALAND
ANATOMICALALTERATION ARE TRYING TO ADJUST OR TUNE THE
ENZYMES FOR PATHWAY.
FINE TUNING : A MAJOR PROBLEM

16.  A group of scientists in IRRI, Phillipines have formed a c4 consortium for
developing C4 rice which is financially supported by Bill and Mellinda Gates
foundation.
 In India also a C4 consortium has been formed under the leadership of JNU,
New Delhi in collaboration with CRRI, Cuttack ; IARI, New Delhi & University
of Hyderabad, Hyderabad
CURRENT RESEARCHES & PROGRESS

17. CONCLUSION
 TO AVOID A HUMANITARIAN DISASTER, RICE PRODUCTION NEEDS TO KEEP
PACE WITH THE RATE OF POPULATION GROWTH.
 BECAUSE PLANTS THAT USE THE C4 PATHWAY CAN MAINTAIN FASTER RATES
OF PHOTOSYNTHESIS AND HIGHER YIELDS THAN THOSE THAT USE THE C3
PATHWAY, IT HAS BEEN PROPOSED THAT RICE SHOULD BE ENGINEERED TO USE
C4 PHOTOSYNTHESIS.
 THIS IS EXTREMELY AMBITIOUS, AND SO WE ARGUE THAT PROOF OF CONCEPT
IS NEEDED.
 FURTHERMORE, BECAUSE THERE IS INCREASING EVIDENCE THAT LEAF
MORPHOLOGY AND METABOLISM ARE CO-ORDINATED, WE ARGUE THAT
INITIAL STUDIES SHOULD BE DESIGNED TO INVESTIGATE THE MECHANISTIC
INTERFACE BETWEEN LEAF MORPHOLOGY AND METABOLISM IN C3 AND C4
LEAVES