EFFECT OF ELICITORS IN INDUCTION OF RESISTANCE AGAINST BACTERIAL BLIGHT AND PHENYLPROPANOID PATHWAY IN POMEGRANATE
Loading...
Date
2018-10
Authors
Journal Title
Journal ISSN
Volume Title
Publisher
University of Horticultural Sciences, Bagalkot
Abstract
Bacterial blight caused by Xanthomonas axonopodis pv. punicae (Xap) is a
destructive and wide spread foliar disease in pomegranate, resulting yield losses up to
60-80%. The present study conducted to evaluate the effect of elicitors in induction of
resistance against bacterial blight and phenylpropanoid pathway in pomegranate. The
results obtained during the course of study revealed that among the different inducers
tested in vitro, complete inhibition zone was observed in Bacillus subtilis (100 %) at
3x109 CFU/ml, followed by Pseudomonas putida (75.83 %) at 3x109 CFU/ml of
concentration, while inhibition was not observed in abiotic elicitors such as
arachidonic acid, BABA, chitosan, eicosapentaenoic acid, GABA and proline.
Under green house condition, prophylactic application of BABA 600 ppm
(2.68%) recorded least PDI, which was on par with Pseudomonas putida at 3x109
CFU/ml (3.35%) and GABA 600 ppm (3.66%). As curative application, chitosan
0.2% (4.17%) recorded least PDI, but was on par with proline 600 ppm (4.82%) and
followed by P. putida at 3x109 CFU/ml (5.38%). The response of phenylpropanoid
pathway genes to inducers treatment was studied. Highest expression of PAL gene
was observed in GABA 600 ppm treatment showing 65.08 folds at 6 hpi. Chitosan 0.2
% treatment induced highest expression of C4H, 4CL and COMT genes showing
14.86, 17.88 and 33.34 folds upregulation at 144, 0 and 144 hpi respectively. Highest
expression of CAD gene was observed in Pseudomonas putida at 3x109 CFU/ml
treatment showing 17.10 folds upregulation at 0 hpi. The temporal time gap study
revealed that a minimum of 2 days required for maximum resistance development in
BABA 600 ppm treatment with least PDI of 0.94 per cent whereas a minimum of 5
days gap required for GABA 600 ppm (1.42%) and Pseudomonas putida at 3x109
CFU/ml (1.10%).
Under field conditions, Pseudomonas putida 3x109 CFU/ml (4.81%) recorded
least PDI on leaves but was on par with BABA 600 ppm (4.98 %) and GABA 600
ppm (5.58%). In case of fruit blight, Pseudomonas putida (3x109 CFU/ml) exhibited
highest protection by recording PDI of 2.76 but was on par with BABA 600 ppm
(2.81%) and chitosan 0.2% (2.99%) followed by GABA 600 ppm (3.91%). Further
BABA 600 ppm recorded total yield of 12.04 t/ha which was on par with
Pseudomonas putida at 3x109 CFU/ml (11.73 t/ha) and GABA 600 ppm (11.36 t/ha).