Effect
of gamma-aminobutyric acid on resistance against stripe rust (caused by Puccinia
striiformis f. sp. tritici) in wheat cultivars
P.
Singh1, V.K. Zhawar1*, P.P.S. Pannu2
1Department of
Biochemistry, College of Basic Sciences and Humanities, Punjab Agricultural
University, Ludhiana-141 004, India
2Department of
Plant Pathology, College of Agriculture, Punjab Agricultural University,
Ludhiana-141 004, India
*Corresponding
Author Email :
vikram97jit@pau.edu
*ORCiD:
https://orcid.org/0000-0001-6104-8786
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Abstract
Aim:
The present study was undertaken to screen wheat cultivars for resistance
against stripe rust and the improvement of resistance by exogenous
gamma-aminobutyric acid (GABA) under field conditions and studying two
contrasting cultivars for antioxidant related defense activities at 1, 2 and
4 d of GABA, Puccinia striiformis f. sp. tritici (Pst) and
GABA+Pst treatments given to one-month-old seedlings.
Methodology: Wheat cultivars (PBW723, PBW725, PBW677, PBW550,
PBW343, PBW621, HD2967) were grown and exposed to Puccinia striiformis
f. sp. tritici (Pst) and GABA+Pst in fields and studied for yield
parameters. Subsequently, two cultivars found varying in resistance (PBW725
and HD2967) were analyzed for antioxidant enzymes in leaves and roots at 1,
2, and 4 day of GABA, Pst, and GABA+Pst and water as control given to 30 days
old seedlings in the greenhouse.
Results:
Field analysis found that the most resistant cultivar PBW725 reduced
vegetative growth but not yield compared to other resistant cultivars (PBW723
and PBW677) under Pst and improved both growth and yield under GABA+Pst.
GABA+Pst improved yield parameters in other cultivars also. In defense analysis,
superoxide dismutase (SOD), ascorbate peroxidase (APX) and
glutathione-S-transferase (GST) increased in the leaves of PBW725 while only
APX increased in HD2967 at 1 d of Pst. In roots also, SOD and GST increased
2-fold in PBW725 while only GST increased 1.3-fold in HD2967 at 1 d of Pst.
There was persistence of catalase (CAT), monodehydroascorbate reductase
(MDHAR), and dehydroascorbate reductase (DHAR) during Pst in the leaves of
PBW 725 while CAT decreased at 4 d in HD2967. In roots also, CAT and MDHAR
increased at 4 days of Pstin PBW725 while DHAR decreased in HD2967. Under
GABA, cultivar differences were not significant. GABA+Pst improved deficient
antioxidant enzymes in HD2967.
Interpretation: Energy
conservation and timely regulation of antioxidant enzymes during infection
was utilized by PBW725 against stripe rust. GABA deficiency can be a reason
for poor regulation of antioxidants in HD2967 under Pst. GABA application
improved resistance against stripe rust in wheat.
Key words: Antioxidant, Ascorbate, Gamma-aminobutyric acid,
Glutathione, Stripe rust, Triticum aestivum
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