Potluri Navya Rohini
Promising botanicals and piriformospora indica for the management of blackeye cowpea mosaic virus in yard long bean - Vellayani Department of plant pathology, college of agriculture 2023 - 121p.
MSc
The study entitled “Promising botanicals and Piriformospora indica for the
management of Blackeye cowpea mosaic virus in yard long bean” was conducted at
Department of Plant Pathology, College of Agriculture, Vellayani during 2021-2023,
with the objective of field evaluation of potential botanicals and the beneficial fungal
root endophyte P. indica for the management of Blackeye cowpea mosaic virus
(BlCMV) in yard long bean / vegetable cowpea; and to elucidate its biochemical and
molecular mechanisms.
BlCMV was maintained in systemic host, yard long bean (Vigna ungiculata var.
sesqipedalis (L.) Verdcourt) variety Vellayani Jyothika and local lesion host,
Chenopodium amaranticolor through mechanical transmission / sap inoculation. In yard
long bean, initial symptoms like mosaic patterns, leaf blistering, vein banding, vein
clearing and stunting were observed at seven days after inoculation (DAI) in newly
emerged trifoliate leaves; which was followed by mosaic, vein netting, floral
deformation, stunting and yield reduction. The artificially inoculated vegetable cowpea
plants had a vulnerability index (V. I.) of 79.3. In C. amaranticolor, an average of 26
local lesions of size 2 mm was recorded at five DAI.
BICMV, a member of potyviridae, was serologically detected using polyclonal
antibodies of potyviruses viz., Cowpea aphid-borne mosaic virus (CABMV) (DSMZ,
Germany) through Direct antigen coating - Enzyme linked immuno-sorbent assay
(DAC-ELISA) and Dot immuno-binding assay (DIBA) as the polyclonal antibody of
BICMV was not commercially available and was molecularly detected through Reverse
Transcription – Polymerase Chain Reaction (RT-PCR) with coat protein specific
primers of BlCMV.
Fungal root endophyte, P. indica culture was obtained from Department of Plant
Pathology was maintained by periodical sub-culturing in potato dextrose agar (PDA)
and potato dextrose broth (PDB) media. P. indica was mass-multiplied in coir pith-dried
farm yard manure (FYM) mixture (1:1) amended with two per cent gram flour and was
allowed to colonize the vegetable cowpea seedlings. P. indica-colonization resulted in
14.9 per cent more shoot biomass, 28.9 per cent more root biomass than the control
plants at 30 DAI; and also 71 per cent more number of pods per plant and 64 per cent
more yield per plant. The fungal colonization enhanced the other biometric characters
like shoot length, root length, number of leaves, leaf area and number of tertiary roots
at different intervals, compared to the non-colonized control plants at 30 DAI. The days
taken for flowering in P. indica-colonized plants were decreased by 14 days and the
yield per plot in P. indica-colonized was 10.5 kg against 4.6 kg in the control plots.
A pot culture experiment was laid out in CRD with 11 treatments and 5
replications to evaluate the efficiency of prophylactic as well as curative application of
1 per cent of P. niruri and B. diffusa; and P. indica, in managing BlCMV in vegetable
cowpea. Pre- and post- application of P. niruri and B. diffusa and P. indica-colonisation
significantly reduced the incidence and severity of BlCMV, upon pre- as well as postinoculation of the virus, compared to the control plants. Prophylatic application of the
above treatments resulted in better control of the disease and recovered the loss in
biomass and yield caused by the virus infection. The highest reduction of the disease
with enhanced biomass and yield was recorded in pre-colonization of P. indica.
Similarly, a field study laid out in RBD with 6 treatments and 4 replications (with and
without P. indica along with botanicals – 1 % P. niruri) to evaluate their efficiency
against natural incidence of BlCMV. The disease incidence and severity was less in P.
indica-colonised plants with minimal loss of biomass and yield due to the virus
infection.
In order to evaluate the influence of P. indica in modulating different
biochemical process of the plants against BlCMV infection, the activity of various
antioxidant defense enzymes viz. peroxidase, catalase and superoxide dismutase were
assayed. A significant increase in the activity of above enzymes was observed in the P.
indica-colonized plants compared to the control plants, upon post-inoculation of
BlCMV; thus the better performance of P. indica-colonized plants upon the virus
infection is correlated. BlCMV-infected plants showed increased accumulation of
reactive oxygen species like super oxides as evidenced by NBT staining and hydrogen
peroxide by DAB staining, which cause oxidative stress in the plants. P. indicacolonization was able to mitigate the increase in ROS concentration caused due to
BlCMV infection, thus reducing the symptoms. Moreover, chlorophyll content and
phenylalanine ammonia lyase activities were more in P. indica-colonised plants. The
differential gene expression of salicylic acid (NPR1 and PR1) and ethylene (ETR1 and
EIN1) signaling genes clearly demonstrates its involvement in P. indica-mediated
tolerance against BlCMV in vegetable cowpea.
Thus, the present study reveals that P. indica-colonisation and spraying of 1 per
cent P. niruri in vegetable cowpea at 5 and 25 DAT could significantly and
substantially reduce the incidence and severity of BlCMV infection without
compromising the biomass and yield of the crop; and is a reliable and chemical-free
method to control blackeye cowpea mosaic disease. Bio-protective action of P. indica
might be attributed to the increased activity of antioxidant enzymes, which in turn leads
to suppression in ROS accumulation in the colonized plants, upon being challenged by
the virus. The combined effect of AVPs and P. indica on management of BlCMV in
vegetable cowpea needs more studies in future
English and malayalam
piriformospora indica
mosaic virus
plant pathology
yard long bean
632.3 / POT/PR PG
Promising botanicals and piriformospora indica for the management of blackeye cowpea mosaic virus in yard long bean - Vellayani Department of plant pathology, college of agriculture 2023 - 121p.
MSc
The study entitled “Promising botanicals and Piriformospora indica for the
management of Blackeye cowpea mosaic virus in yard long bean” was conducted at
Department of Plant Pathology, College of Agriculture, Vellayani during 2021-2023,
with the objective of field evaluation of potential botanicals and the beneficial fungal
root endophyte P. indica for the management of Blackeye cowpea mosaic virus
(BlCMV) in yard long bean / vegetable cowpea; and to elucidate its biochemical and
molecular mechanisms.
BlCMV was maintained in systemic host, yard long bean (Vigna ungiculata var.
sesqipedalis (L.) Verdcourt) variety Vellayani Jyothika and local lesion host,
Chenopodium amaranticolor through mechanical transmission / sap inoculation. In yard
long bean, initial symptoms like mosaic patterns, leaf blistering, vein banding, vein
clearing and stunting were observed at seven days after inoculation (DAI) in newly
emerged trifoliate leaves; which was followed by mosaic, vein netting, floral
deformation, stunting and yield reduction. The artificially inoculated vegetable cowpea
plants had a vulnerability index (V. I.) of 79.3. In C. amaranticolor, an average of 26
local lesions of size 2 mm was recorded at five DAI.
BICMV, a member of potyviridae, was serologically detected using polyclonal
antibodies of potyviruses viz., Cowpea aphid-borne mosaic virus (CABMV) (DSMZ,
Germany) through Direct antigen coating - Enzyme linked immuno-sorbent assay
(DAC-ELISA) and Dot immuno-binding assay (DIBA) as the polyclonal antibody of
BICMV was not commercially available and was molecularly detected through Reverse
Transcription – Polymerase Chain Reaction (RT-PCR) with coat protein specific
primers of BlCMV.
Fungal root endophyte, P. indica culture was obtained from Department of Plant
Pathology was maintained by periodical sub-culturing in potato dextrose agar (PDA)
and potato dextrose broth (PDB) media. P. indica was mass-multiplied in coir pith-dried
farm yard manure (FYM) mixture (1:1) amended with two per cent gram flour and was
allowed to colonize the vegetable cowpea seedlings. P. indica-colonization resulted in
14.9 per cent more shoot biomass, 28.9 per cent more root biomass than the control
plants at 30 DAI; and also 71 per cent more number of pods per plant and 64 per cent
more yield per plant. The fungal colonization enhanced the other biometric characters
like shoot length, root length, number of leaves, leaf area and number of tertiary roots
at different intervals, compared to the non-colonized control plants at 30 DAI. The days
taken for flowering in P. indica-colonized plants were decreased by 14 days and the
yield per plot in P. indica-colonized was 10.5 kg against 4.6 kg in the control plots.
A pot culture experiment was laid out in CRD with 11 treatments and 5
replications to evaluate the efficiency of prophylactic as well as curative application of
1 per cent of P. niruri and B. diffusa; and P. indica, in managing BlCMV in vegetable
cowpea. Pre- and post- application of P. niruri and B. diffusa and P. indica-colonisation
significantly reduced the incidence and severity of BlCMV, upon pre- as well as postinoculation of the virus, compared to the control plants. Prophylatic application of the
above treatments resulted in better control of the disease and recovered the loss in
biomass and yield caused by the virus infection. The highest reduction of the disease
with enhanced biomass and yield was recorded in pre-colonization of P. indica.
Similarly, a field study laid out in RBD with 6 treatments and 4 replications (with and
without P. indica along with botanicals – 1 % P. niruri) to evaluate their efficiency
against natural incidence of BlCMV. The disease incidence and severity was less in P.
indica-colonised plants with minimal loss of biomass and yield due to the virus
infection.
In order to evaluate the influence of P. indica in modulating different
biochemical process of the plants against BlCMV infection, the activity of various
antioxidant defense enzymes viz. peroxidase, catalase and superoxide dismutase were
assayed. A significant increase in the activity of above enzymes was observed in the P.
indica-colonized plants compared to the control plants, upon post-inoculation of
BlCMV; thus the better performance of P. indica-colonized plants upon the virus
infection is correlated. BlCMV-infected plants showed increased accumulation of
reactive oxygen species like super oxides as evidenced by NBT staining and hydrogen
peroxide by DAB staining, which cause oxidative stress in the plants. P. indicacolonization was able to mitigate the increase in ROS concentration caused due to
BlCMV infection, thus reducing the symptoms. Moreover, chlorophyll content and
phenylalanine ammonia lyase activities were more in P. indica-colonised plants. The
differential gene expression of salicylic acid (NPR1 and PR1) and ethylene (ETR1 and
EIN1) signaling genes clearly demonstrates its involvement in P. indica-mediated
tolerance against BlCMV in vegetable cowpea.
Thus, the present study reveals that P. indica-colonisation and spraying of 1 per
cent P. niruri in vegetable cowpea at 5 and 25 DAT could significantly and
substantially reduce the incidence and severity of BlCMV infection without
compromising the biomass and yield of the crop; and is a reliable and chemical-free
method to control blackeye cowpea mosaic disease. Bio-protective action of P. indica
might be attributed to the increased activity of antioxidant enzymes, which in turn leads
to suppression in ROS accumulation in the colonized plants, upon being challenged by
the virus. The combined effect of AVPs and P. indica on management of BlCMV in
vegetable cowpea needs more studies in future
English and malayalam
piriformospora indica
mosaic virus
plant pathology
yard long bean
632.3 / POT/PR PG