This document discusses the role of γ-amino butyric acid (GABA) in abiotic stress tolerance in plants. It first introduces GABA, its biosynthesis, and physiological roles. It then explores GABA's role in improving tolerance to various abiotic stresses like heat, drought, chilling, and salinity by enhancing photosynthesis, antioxidant activity, and osmolyte accumulation. The document also discusses methods for quantifying GABA levels and case studies demonstrating GABA's protective effects under different stress conditions in crops like maize, rice and fruits. Finally, it covers the potential commercial applications and health benefits of GABA.

2. Role of γ-amino butyric acid (GABA) in
abiotic stress tolerance

3. INTRODUCTION TO AMINOACIDS AND GABA
BIOSYNTHESIS OF GABA, ITS PHYSIOLOGICAL,
MORPHOLOGICAL AND ABIOTIC RESPONSES
TO PLANTS
ROLE OF GABA IN ABIOTIC STRESS
TOLERANCE
CORRELATION BETWEEN GABA v/s
DIFFERENT ABIOTIC STRESSES
QUANTIFICATION OF GABA
CASE STUDIES
HEALTHY BENEFITS AND COMMERCIAL
APPLICATIONS GABA
3

4. TOPIC DIVIDED
INTO
γ-AMINO
BUTYRIC ACID
ABIOTIC
STRESS
1. What are aminoacids?
2. Classification of
aminoacids?
3. Functions of
aminoacids in relation
with plants?
4. About GABA?
1.What is stress and
strain?
2. Types of abiotic
stresses?
3. GABA comparison with
different abiotic
stresses?
Role γ-amino butyric acid (GABA) in abiotic
stress tolerance

5.  A compound that contains an amino group, a carboxyl
group and a side-chain that is specific to each amino acid
 An amino acid in which the amino group is on the carbon
adjacent to the carboxyl group
 There are 20 common α–amino acids used by the
ribosomes to make proteins. These 20 have L chirality at
the α–carbon.
AMINO ACIDS

6. PROTEIN AMINO
ACIDS
NON PROTEIN
AMINO ACIDS
ALL THE 20
AMINOACIDS
such as
Glutamine
Alanine
Glycine
Lysine
Methionine
ALPHA
NON
PROTEIN
NON ALPHA
NON
PROTEIN
1. Ornithine
2. Homocysteine
3. S-Adenosyl
methionine
4. DOPA (3, 4
Dihydroxy
phenylalanine)
1. Beta alanine
2. Aminolevulinic
acid
3. Taurine
4. γ-amino butyric
acid(GABA)
CLASSIFICATION OF AMINO ACIDS

7. BENEFICIARY OF AMINO ACIDS
Plant can biosynthesize all the amino acids they need with
other nutrient, but it consume energy with very complex
procedure.
Applying amino acids can help plant to focus on growing
and yielding.
Amino acids effect on
PLANT
Protein Biosynthesis
Resistance to abiotic
stress
Photosynthesis
Stomata Activity
Chelation
Phytoharmones
Pollination and fruit
formation
Amino acids effect on
SOIL
 Increase microbial
activity

9. 9

10. γ-amino butyric acid (GABA) is a well recognized
ubiquitous non-protein amino acid , short, four
carbon non protein amino acid that is non protein
in nature and it is found in most prokaryotic and
eukaryotic organisms .
It is an important component of the free amino acid
pool of living organisms.
It can be found in all types of organisms including
bacteria, fungi, plants and animals .
γ-AMINO BUTYRIC ACID (GABA)

11. History of γ-AMINO BUTYRIC ACID
(GABA)
 Before 1883 known as a metabolite of plants and
microorganisms.
In 1949 identified in plants tissue and incorporated in proteins.
In 1950, further GABA was discovered to be an integral part of
the mammalian central nervous system.
In 1953 first indications of an inhibitory activity.
Florey proposed that GABA acts as an inhibitory
neurotransmitter in the brain and subsequently, it was
suggested that GABA is almost 1000 times higher than other
neurotransmitters in the vertebrate brain and also has a role in

12. Chemical structure of γ-AMINO BUTYRIC
ACID (GABA)
Chemical formula:
C4HgNO2
Boiling point:

13. Shelp et al.,
1999
BIOSYNTHESIS OF γ-AMINO BUTYRIC
ACID (GABA)

14. ROLE OF γ-AMINO BUTYRIC
ACID(GABA)

15. Shelp et al.,
Role of γ-aminobutyric acid
(GABA) in plants

16. Shelp et al.,
Regulation of γ-aminobutyric acid (GABA) levels by biotic
and abiotic stresses

17. Role of γ-aminobutyric acid (GABA) in
abiotic stress tolerance

18. MORPHOLOGICAL responses of plants to
EXOGENOUS GABA
 It improves the root and shoot fresh weight of the
seedlings
 Net photosynthesis rate, SPAD, anti-oxidant
enzymes, nitrogen metabolism enzymes are
enhanced.
 Number of female flowers per plant will be
increased.
 Positive effect on coiling of the tendrils.

19. Physiological responses of plants to
EXOGENOUS GABA
 Carbon and nitrogen metabolism
 Responses to biotic stress factors
 Improvement of shelf life and storage quality
 Responses to abiotic stress factors

20. There are different methods such as:
1. High performance liquid chromatography
(HPLC)
2. Amino acid automatic analyzer
3. Biosensors
 Amino acid automatic analyzer is the most
commonly used method for quantification
Nikmaram et al., 2017
Quantification of γ-aminobutyric
acid (GABA)

21. The most common method of GABA determination,
carried out with an amino acid automatic analyzer, was
described by Xu et al.
The basic principle of operation is the continuous flow
chromatography procedure in which the sample is loaded into
a column of cation-exchange resin.
Procedure:
 In this method, free amino acid extracts (in protein
hydrolysates or in native samples) were obtained after
filtration through a 0.45 μm nylon syringe filter, and were
analyzed by injection into amino acid automatic analyzer
during a 50 min run.
 Amino acids were post-column derivatized with ninhydrin
reagent and detected by absorbance at 570 nm.
Nikmaram et al., 2017

22. Transporters of γ-aminobutyric
acid (GABA)
 GABA can be transported across the plasma membrane and
organelle membranes.
 GABA transporters were first identified in animals and then
identified in plants in 1999.
2 types of transporters:
1. Low affinity GABA transporters:
 Aminoacid permease 2
 Aminoacid permase 3
 Proline transporters 2
 Proline transporters 3
2. High affinity GABA transporters:
Shelp et al.,

23. Protective role of GABA under heat
stress
ILLEFFECTS OF EXTREME
HEAT ON PLANTS LEADS TO:
Retarded growth
Lower yield
Alteration in physiological and
developmental processes
Altering the expression level
of certain genes
Affects the photosynthetic
process
PROTECTIVE ROLE OF GABA
UNDER HEAT STRESS:
Improves plant dry mass and
growth
It maintains membrane
integrity and decreased cell
damage
Level of organic acids, sugars
and amino acids will be
enhanced
Net photosynthetic rate and
antioxidant enzymes will be
increased
It enhances the growth and
quality of the crop

24. Wu Li et al.,
2018
Photosynthetic physiology of maize
seedling

25. Wu Li et al.,
Super-oxide dismutase activity in leaves and root of
maize seedling

26. Protective role of GABA under
drought stress
ILLEFFECTS OF DROUGHT
STRESS ON PLANTS
LEADS TO:
 Affects plant growth
and development in both
early and developmental
phases.
 Membrane damage
 Chlorophyll reduction
 Reduced antioxidant
enzyme
PROTECTIVE ROLE OF
GABA UNDER
DROUGHTSTRESS:
Decreases the lipid
peroxidation and membrane
damage
Antioxidant enzyme
activity increased

27. Vijayakumari et al.,
Proline and total sugars content in Piper nigrum
varieties exposed to various treatments

28. Vijayakumari et al.,
SOD and GPX activity in Piper nigrum varieties exposed
to various treatments

29. HPTLC detection and quantification of GABA in
leaves of Piper nigrum varieties exposed to
various treatments
A – Control
B – GABA
C – PEG
D – GABA
2 varieties:
V1: Panniyur 1
V2: Panniyur 5

30. Protective role of GABA under
chilling stress
ILLEFFECTS OF
CHILLING STRESS
ON PLANTS LEADS
TO:
Reduced plant
growth and even death
Water soaking of
tissues
Abnormal curling
Failure to ripen
normally
Vascular browing
PROTECTIVE ROLE OF
GABA UNDER
CHILLINGSTRESS:
Quality of the crop will
be increased
Energy level enhances
Antioxidant enzyme
activity will be increased

31. Chilling injury index of peach fruit after storage at 1°C
for 3 to 5 weeks.
Yang et al.,
2016

32. Effect of 5mM GABA treatment on activities of
SOD, CAT, GPX and GST of peach fruit after
storage at 1°C for 3 or 5 weeks.
Yang et al., 2016

33. Effect of 5 mM GABA treatment on contents of ATP,
ADP and AMP and energy charge of peach fruit
after storage at 1° C for 3 or 5 weeks.
Yang et al., 2016

34. Protective role of GABA under salt
stress
ILLEFFECTS OF
SALT STRESS ON
PLANTS LEADS TO:
Seed germination
will be decreased
Growth metabolism
will be reduced
Reduction in carbon
dioxide assimilation
Reduced biomass
Photosynthesis is
inhibited
PROTECTIVE ROLE OF
GABA UNDER SALT
STRESS:
Improves plant dry
mass and growth
It maintains membrane
integrity and decreased
cell damage
Level of organic acids,
sugars and amino acids
will be enhanced

35. Li et al., 2016
Effect of GABA on the germination rate of
wheat seeds under different NaCl
concentrations

36. Effect of GABA on the germination rate of
wheat seeds under different NaCl
concentrations
Li et al., 2016

37. Effect of GABA on photosynthesis, stomatal
conductance and water use efficiency of wheat under
different NaCl concentrations
Li et al., 2016

38. Effect of GABA on photosynthetic pigments of
wheat under different NaCl concentrations
Li et al.,

39. Protective role of GABA under
HEAVY METAL stress
ILLEFFECTS OF
HEAVY METAL
STRESS ON PLANTS
LEADS TO:
Leaf chlorosis
Reduced biomass
Generates ROS
species
Reduced root growth
Chlorosis of tissues
PROTECTIVE ROLE OF
GABA UNDER HEAVY
METAL STRESS:
Net photosynthetic rate
and antioxidant enzymes
will be increased
It enhances the growth
and quality of the crop

40. Effect of GABA on total fatty acid content in
root and shoot of rice seedlings with arsenite
and GABA treatments.
Kumar et al., 2019

41. Effect of GABA on stress responsive aminoacids levels
in root and shoot of rice seedlings with arsenite and
GABA treatments.
Kumar et al., 2019
Kumar et al.,

42. COMMERICAL APPLICATIONS OF GABA
SL
NO
AUTHOR CROP YEAR REMARKS
1 Lin, et al., Maize 2016
Net photosynthesis rate,
SPAD, anti-oxidant enzymes,
nitrogen metabolism
enzymes are enhanced.
2
Gong and
Gao
White
gourds
2016
Growth and quality of the
crop
3
Ziogas, et
al.,
citrus 2017
Higher germination rate and
seedling development
4
Malekzadeh,
et al.,
Tomato 2014
Inhibition of tomato seedling
development due to chilling
injury have been reduced
and enhancement of the
activity of antioxidant

43. SL
NO
AUTHOR CROP YEAR REMARKS
5
Kumari,, et
al.,
Pigeon pea 2020
Increases leaf turgor,
increased osmolytes and
reduced
oxidative damage by
stimulation of antioxidants
6 Zhou, et al.,
Creeping
Bent grass
2016
Increases in accumulations
of aminoacids, organic acids,
total sugars and also the
enhancement of
photosynthesis.
7 Navin, et al., Rice 2019
Higher level of saturated,
unsaturated and total fatty
acid content and stress
responsive aminoacids

44. HEALTHY BENEFITS
OF GABA
 Reduction of hypertension
 Inhibition of chronic diseases associated with alcohol
 Prevention of cancer cell proliferation
 Modulation of blood cholesterol levels
 Legumes are a good potential source for GABA
production due to their high amounts of proteins

45. SL NO REFERED JOURNALS NAAS
RATINGS
1 Plos one 8.74
2 Plant cell reports 9.83
3 Plant physiology reports 5.50
4 Biologia plantarum 7.60
5 Food chemistry 12.31
6 Plant cell and environment 12.36
7 Scientific reports 10
8 Critical reviews in plant sciences 12.23
9 Ecotoxicology and environmental safety 10.87
10 Trends in plant science 20
REFERNCE
S