7.7.9 Bacterial Diseases
B. subtiliswas isolated from healthy chestnut trees showed strong antagonistic
activity againstCryphonectria parasiticacause of chestnut blight (Wilhelm et al.
1998 ). Five strains ofPseudomonasinhibited the growth ofX. axonopodispv.
malvacearumand also increased cotton seed germination and seedling growth
(12.8%; 22.4%) by 12.8%) (Mondal 1999 ). The endophytic bacteriumB. amy-
loliquefaciens,B. subtilisandB. pumilusproduces several antibiotics (surfactin,
iturin, bacillomucine; azalomycin F, surfactin, arthrobactin; surfactin, amphomycin,
arthrobactin and valinomycin) which are highly inhibitory to the growth of
X. campestrispv.campestrisbecause of black rot of crucifers (Wulff et al. 2002 ).
The cotton seeds treated with the endophytic bacterium (Endo PR8) reducing
cotyledonary infection with black arm of cotton is caused byX. campestrispv.
malvacearum(Bhowmik et al. 2002 ). Before planting grapevine shoots should be
dipped with endophytic bacterium that produced highest fresh weight of the shoots
and roots, and quick growth with more lignin deposits (Barka et al. 2002 ).
Similarly, cotton seeds treated with bacterial endophyte (EPCO 102) showed
increased plant vigour under in vivo (Rajendran et al. 2006 ). Endophytic bacterium
(PfG32) was isolated from root region of onion plants and tested against bacterial
wilt in tomatoes as seedling dip resulted in reduced incidence of wilt disease
because it produces secondary metabolites (Mulya et al. 2006 ). Foliar spraying and
seed soaking with bacterial antagonistDelftia tsuruhatensis(strain HR4) was iso-
lated from root region of rice plants showed reduced the bacterial blight infection in
range of 7–32% (Han et al. 2005 ).
Under greenhouse conditions, endophyticB. subtilisstrain Lu144 remarkably
protected mulberry plants againstRalstonia solanacearumcausing bacterial wilt
disease (Ji et al. 2008 ). Bacterial endophytes such as Pantoea agglomerans,
Pseudomonas sp. andCurtobacterium luteumreduced the growth of Erwinia
carotovora(Figueiredo et al. 2009 ). Ninety three isolates of rhizobacteria were
tested againstXanthomonas axonopodispv. malvacearum.Of these,B. subtilisB49
recorded highest inhibitor on the growth of pathogen in vitro and highly effective in
controlling bacterial blight of cotton under greenhouse and field conditions
(Salaheddin et al. 2010 ). Bacterial endophytes (B. amyloliquefaciensBg-C31)
isolated fromBruguiera gymnorhizashowed to be effective in controlling bacterial
wilt of chilli under pot andfield condition (Hu et al. 2010 ).
Consortium of endophytic bacterial exhibited higher disease reduction of bac-
terial blight by two seed-dipping treatments of 24 and 48 h incubation time. The
combined application of bacterial endophytes showed better disease reduction of
bacterial leaf blight in rice (Susilowati et al. 2012 ). Endophytic bacterium,B.
subtiliswas applied as seedling dip, soil and foliar application resulted in reduced
the bacterial blight infection in rice under laboratory andfield condition and it was
found to increase the plant growth and yield (Nagendran et al. 2013 ).
150 A. Muthukumar et al.