Exploring soil biology to understand high yields due to SRI method of cultivation

1
Evaluation of antagonistic and plant growth
promoting properties of actinomycetes isolated
from herbal vermicompost
K. Deepthi, P. Humayun, V. Srinivas, J. Simi,
M. Sreevidya, G. Alekhya and S. Gopalakrishnan
Evaluation of the Herbal vermicompost
actinomycetes isolates against Fungal pathogens
of Chickpea and Sorghum
Isolates Zone of inhibition in mm Zone of inhibition in mm Zone of inhibition in mm Zone of inhibition in mm Zone of inhibition in mm Zone of inhibition in mm Zone of inhibition in mm
Isolates FOC MP B.cinerea RB-6 RB-24 RB-115 S.rolfsii
CAI-13 7.2 12.2 14.0 10.0 6.7 0.0
CAI-54 6.1 2.8 0.0 1.0 1.0 0.0 -
CAI-84 5.8 0.0 2.0 0.0 0.0 0.0 -
CAI-85 12.0 7.1 11.7 3.7 6.0 0.0 -
CAI-87 15.4 11.7 13.7 5.3 6.0 0.0 -
CAI-93 6.0 9.8 11.3 7.3 9.7 7.0 -
CAI-97 7.6 13.5 12.7 4.0 8.0 0.0 -
CAI-104 6.2 0.0 10.5 2.3 1.0 0.0 -
CAI-132 10.8 7.0 13.3 3.0 2.3 0.0 -
CAI-134 5.0 0.0 6.7 0.0 1.7 0.0 -
CAI-140 8.8 14.7 18.5 4.0 8.0 0.0 -
CAI-155 10.0 14.3 15.7 10.3 12.0 0.0 -
KAI-35 13.9 21.1 13.0 12.7 14.0 13.3
KAI-161 14.3 20.1 14.3 13.7 15.3 14.0
INTRODUCTION Pesticides are used extensively in
agriculture to control insect pests and plant
pathogens however their use has led to
environmental pollution and health hazards. Hence
there is an urgent need to look for an
alternative, which are less toxic, environment
friendly, economical and which can effectively
control insect pests and diseases. One of the
most promising area of interest is biological
control. Actinomycetes play a greater role in
biological control as they produce many
extracellular metabolites like toxins and
antibiotics which not only control plant diseases
but also help in growth and vitality of the
plant.

• MATERIALS AND METHODS
• The herbal vermicompost samples have been spread
  plated on starch casein agar and the most
  prominent isolates have been selected and
  evaluated for their biocontrol and PGP traits.
• The initial screening has been done by performing
  dual culture assay (against plant pathogens of
  chickpea and sorghum viz. Sclerotium rolfsii,
  Rhizoctonia bataticola (three strains viz. RB-6,
  -24 and -115) Fusarium oxysporum f.sp. ciceri,
  Botrytis cinerea, and Macrophomina phaseolina
  causes collar rot, dry root rot, Fusarium wilt,
  Botrytis grey mould diseases in chick pea and
  charcoal rot in sorghum, respectively).
• The isolates have also been evaluated for their
  biocontrol and PGP traits such as lipases,
  protease, cellulase, siderophore, HCN, Chitinase
  and Indole acetic acid production. as well as
  wilt sick field conditions.
• The promising isolates against Rb-6, 24 115 have
  been further evaluated by Blotter paper assay
  method.
• The isolates which showed greater antagonistic
  activity have been further evaluated for their
  secondary metabolite production.

• RESULTS
• A total of 15 have been studied for their
  activity, out of which 10 actinomycetes (CAI-13,
  -85, -87, -93, -97,-140,-155 and KAI-35, -161,
  -180) were found to have broad spectrum activity
  against all fungal pathogens.
• Almost all the isolates have been found to
  utilize cellulose, lipids, proteins, chitin and
  produced siderophore, indole acetic acid and
  hydrogen cyanide.
• The following cultures, CAI-13, -85, -87,-155,
  KAI-35,-161 180 prevented infection of chickpea
  roots by Rb series.

SRI
CONT
Evaluation of most promising isolates against
fungal pathogens






KAI-35 Vs FOC
CAI-87 Vs MP



Charcoal rot in Sorghum
Sclerotium infection in chickpea
KAI-161 Vs Botrytis
CAI-97 Vs RB6
Publications Gopalakrishnan, et al., (2011).
Managing soil-borne plant pathogenic fungi using
actinomycetes isolated from herbal vermicompost.
Submitted in World J of Microbiology and
Biotechnology on 19th Mar 2011 Gopalakrishnan,
et al., (2011). Evaluation of Actinomycetes
isolated from herbal vermicompost for biological
control of Fusarium wilt of chickpea. Crop
Protection DOI j.cropro.2011.03.006 Gopalakrishna
n, et al., (2010). Evaluation of bacteria
isolated from rice rhizosphere for biological
control of sorghum caused by M. phaseolina. World
J of Microbiology and Biotechnology
Gopalakrishnan, et al., (2010). Efficacy of
Jatropha, Annona and Parthenium biowash on
Sclerotium rolfsii, FOC and M. phaseolina
pathogens of chickpea and sorghum. African J of
Biotechnology 9 (47) 8048-8057.
CAI-87,-54
Kai-35,-161
An uprooted chickpea plant with Fusarium infection
Isolates positive for lipase production
Corresponding author Dr S Gopalakrishnan, Email
s.gopalakrishnan_at_cgiar.org