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Molecular Microbiology Research (Online) 2013, Vol.3 No.3 20-29
ISSN 1927-5595
http://mmr.sophiapublisher.com
23
Lemon grass oil reached maximum level at 5
th
day
after treatment when compared to control. The
enzyme activity subsequently declined. Among them,
Pf1 recorded maximum glucanase activity
.
The
maximum β-1, 3 glucanase activity was observed in
plants treated with Pf1 (29.220 µg of glucose min
-1
g
-1
of fresh tissue) followed by
Bacillus
EPCO16 (25.790
µg of glucose min
-1
g
-1
of fresh tissue), Copper
sulphate (24.220 µg of glucose min
-1
g
-1
of fresh tissue)
and Lemon grass oil (24.070 µg of glucose min
-1
g
-1
of
fresh tissue) on 5
th
day and thereafter declined. The
plants treated with pathogen alone recorded (20.410
µg of glucose min
-1
g
-1
of fresh tissue) only slight
increase in β-1, 3 glucanase activity. The healthy plant
recorded lesser β-1, 3 glucanase activity (15.780 µg of
glucose min
-1
g
-1
of fresh tissue) (Figure 1D).
1.2.5. Changes in the Super Oxide Dismutase (SOD)
activity in physic nut plants treated with plant oil,
bio control agents and micronutrient
The Super oxide Dismutase activity gradually
increased in physic nut leaves and following
treatments with
P. fluorescens
,
Bacillus
EPCO16,
Copper sulphate and Lemon grass oil, reached
maximum level at 5
th
day after treatment when
compared to control. The enzyme activity
subsequently declined.
Among them, Pf1 recorded
maximum SOD activity
(11.640 unit min
-1
g
-1
of fresh
tissue) followed by
Bacillus
EPCO16 (10.120 unit
min
-1
g
-1
of fresh tissue), Copper sulphate (9.360 unit
min
-1
g
-1
of fresh tissue) and Lemon grass oil (7.110
unit min
-1
g
-1
of fresh tissue) on 5
th
days and thereafter
declined. The plants treated with pathogen alone
recorded (6.210 unit min
-1
g
-1
of fresh tissue) only
slight increase in Super oxide dismutase (SOD)
activity. The healthy plant recorded lesser super oxide
dismutase (SOD) activity (4.440 unit min
-1
g
-1
of fresh
tissue) (Figure 1E).
1.2.6. Changes in the phenolic content in physic nut
plants treated with plant oil, bio control agents and
micronutrient
The phenolic activity gradually increased in physic
nut leaves following treatments with
P. fluorescens
,
Bacillus
EPCO16, Copper sulphate and Lemon grass
oil reached maximum level at 5
th
day after treatment
when compared to control. The enzyme activity
subsequently declined.
Among them, Pf1 recorded
maximum phenolic activity (15.390 µg of catechol g
-1
of
fresh tissue) followed by
Bacillus
EPCO16 (14.320 µg
of catechol g
-1
of fresh tissue), Copper sulphate
(13.880 µg of catechol g
-1
of fresh tissue) and Lemon
grass oil (12.470 µg of catechol g
-1
of fresh tissue) on
5
th
day and after declined. The plants treated with
pathogen alone recorded (11.510 µg of catechol g
-1
of
fresh tissue) only slight increase in phenolic content.
The healthy plant recorded lesser phenolic content
(9.450 µg of catechol g
-1
of fresh tissue) (Figure 1F).
1.2.7. Detection of different isozymes by gel
electrophoresis
1.2.7.1. Isoform pattern of peroxidase (PO)
Native gel electrophoretic separation of enzyme
extracts from plant oil, bio control agents and
micronutrient treated plants were tested for the
induction of isoform. The results showed that plants
treated with Pf1 and
Bacillus
EPCO16 showed three
isoform
viz
., PO1, PO2 and PO3. The other treatments
viz.,
Copper sulphate and Lemon grass oil showed two
isoforms
viz.,
PO1 and PO2. The result indicates that
the expression of PO3 peroxidase in physic nut plants
may be due to the treatment with Pf1 and
Bacillus
EPCO16 which expressed additional peroxidase
activity. The other treatments including control revealed
only one isoform with less intensity (Figure 2A).
1.2.7.2. Isoform pattern of poly phenol oxidase (PPO)
The results showed that plants treated with Pf1 and
Bacillus
EPCO16 showed three isoform
viz
., PPO1,
PPO2 and PPO3. The other treatments
viz.,
Copper
sulphate and Lemon grass oil showed two isoforms
viz.,
PPO1 and PPO2. The result indicated that the
expression of PPO3 poly phenol oxidase in physic nut
plants may be due to the treatment with Pf1 and
Bacillus
EPCO16 which expressed additional poly
phenol oxidase activity. The other treatments
including control revealed only one isoform with less
intensity (Figure 2B).
2. Discussion
2.1. Induction of defense mechanism in plants
2.1.1. Phenylalanine ammonia lyase (PAL)
Early induction of PAL is very important as the
biosynthesis of lignin originate from L-phenylalanine.