Agriculture Reference
In-Depth Information
Chapter 10
Role of Phosphate-Solubilizing Microbes
in the Management of Plant Diseases
Almas Zaidi, Ees Ahmad, and Md. Saghir Khan
Abstract
Soilborne phytopathogens are one of the major problems in sustainable
crop production world over. To alleviate the damaging impact of pathogens on crop
yields, huge quantities of toxic chemicals especially pesticides are used in modern
agronomic practices, which, however, are extremely destructive to the environ-
ment. The non-desirability of applying huge quantities of pesticides to soil due in
part to residue problems, emergence of resistance among soil phytopathogens, and
lack of pathogen-resistant crop varieties has forced researchers to find solutions to
the increasing pesticides problems. To this end, biological control measures
consisting of microbial preparations are considered a promising option to the use
of expensive and environment disruptive pesticides. Microorganisms including
plant growth-promoting rhizobacteria (PGPR) in general have been found to syn-
thesize a wide array of metabolites with significant fungicidal and bactericidal
capabilities. The use of phosphate-solubilizing (PS) microorganisms among
PGPR has produced both direct and indirect effects on growth and development
of plants. The PS microbes endowed with biocontrol activity manage the pathogens
by one or simultaneous mechanisms of antibiosis, lysis, competition, and myco-
parasitism and prevent the yield losses. Even though the literature on the physio-
logical role of PS microorganisms in crop enhancement via P supply is adequately
available, the information on the ability of such organisms in the control of
phytopathogens is scarce. Here, different mechanisms utilized by PS organisms
for plant disease suppression are discussed. It is envisioned that the PS bacteria in
the near future are expected to reduce, if not completely eliminate, the use of
pesticides in insect-pests management strategies.
Keywords
PSM • Phytopathogens • Disease management • Antibiosis • Lytic
enzymes