P.fluorescensstrain (PDY7) was highly effective in reducing the incidence of
bacterial blight of rice (58.83 and 51.88%) under glass house andfield condition.
This is mainly due to the production of antibiotics called 2,4-diacetylphloroglucinol
(DAPG) (Velusamy et al. 2013 ). Twenty six bacterial strains isolated from leaf, root
and stem region of mangrove plant (Rhizopora mucronata). Among these, highest
number bacterial isolates from leaf (38.5%) followed by root (34.5%) and stem
(26.9%). Of these,five bacterial strains namelySerratia, Bacillus, Pseudomonas,
MicrococcusandEnterobacterexhibited broad-spectrum of antagonistic activity
against fungal and bacterial pathogen (Jose and Christy 2013 ). Among the bacterial
strains tested, strain MB04 and MB08 were highly inhibitory to the growth ofX.
campestris pv. oryzaecausing rice bacterial blight (Yuliar 2014 ).
The endophytic bacteria isolated from tomato plants tested against bacterial wilt
pathogen. Of the isolates tested, only Ps1 and Ps8 can inhibitR. solanacearum
in vitro using seed coat method. In in vivo test, 30 days old tomato seedlings were
soaked with endophytic bacteria showed 8.07–9.19% disease suppression within
15 – 16 days incubation period (Purnawati et al. 2014 ). Cotton seeds treated with
endophytic bacteria strainsB. subtilisUFLA285 recorded the lowest bacteria blight
incidence of 26% (de Medeiros et al. 2015 ). Four endophytic bacteria isolated from
potato stem tissue and it was tested against the growth ofStreptomyces scabiesin
agar plate method. The results revealed that all the isolates were highly inhibitory to
the growth of test pathogen (Flatley et al. 2015 ).
7.8 Conclusion
Plant pathogenic fungi particularly Pythium, Phytophthora, Sclerospora,
Rhizoctonia, PeronosclerosporaandPlasmoparacause enormous crop losses. At
present, fungicides are the only source to control plant diseases but they have
several disadvantages that (i) many of them are toxic to human being and animals,
and (ii) that develop further resistance to the pathogen. Several important questions
remain unanswered concerning the practical use of endophyte‘supplements’in
agriculture. However, with the correct management, they hold potential for the
control of current and emerging pathogens, as well as biotic stresses, as we
encounter deviation in these through climate change. This is likely to be achieved
through a better understanding of signalling between the host plant and the
microbiome, and, ultimately, the manipulation of root exudation profiles to recruit a
more beneficial root microbiome, of which the endosphere is an integral part. The
quality of these BCAs can be further increased by using fundamental knowledge to
improve methods for their production and to increase their shelf life.
7 Role of Bacterial Endophytes in Plant Disease Control 151