Role of Phosphate-Solubilizing Microbes in the Management of Plant Diseases - Phosphate Solubilizing Microorganisms - page 229

Fig. 10.2 Possible mode of disease management using P-solubilizing microorganism
inhibiting the growth of Macrophomina phaseolina and Rhizoctonia spp. (Gui ˜ az ´
et al. 2013 ).
10.3.1 Mechanism of Biocontrol by P-Solubilizing Bacteria
Some of the common modes of disease suppression adopted by the PGPR include
(1) competition for an ecological niche or a substrate, (2) the production of
inhibitory allelochemicals, and (3) induction of systemic resistance (ISR) in host
plants to a broad spectrum of pathogens (Haas et al. 2000 , 2002 ; Lugtenberg
et al. 2001 ; Ryu et al. 2004a ). A possible mode of disease management using
P-solubilizing microorganism is presented in Fig. 10.2 .
10.3.1.1 Rhizosphere Competence and Colonization
The variable response of PS microbes as a biocontrol agent in plant protection
strategies against phytopathogens under filed trials has largely contributed to the
failure of developing microbial biocontrol agents at commercial levels. The com-
monly differing performance of such microbes has been ascribed mainly to the poor
rhizosphere competence (Van Wees et al. 1997 ; Schroth and Hancock 1981 ;de
Weert and Bloemberg 2006 ) among other factors (McLean et al. 2005 ; Ghirardi
et al. 2012 ). Rhizosphere competence of any microbial cell is a prerequisite for the
expression of their beneficial effects on plant growth and health. The rhizosphere