60
A. Dahiya et al.
regulon (Sashidhar and Podile 2009). The overexpression of phosphate uptake ABC
transporter permease protein (PhoT) and the phosphate uptake ABC transporter ATP
binding protein (phoC) in S. meliloti was found to enhance phosphate solubilization
and yield in Medicago (Carmen and Roberto 2010).
3.9 Conclusion
Plant beneficial endophytic microbes have great potential to act as biofertilizers and
biopesticides for growth enhancement and protection from plant disease, respectively. Many bacterial endophytes can solubilize phosphorus, potassium, metals, and
other toxic substances by producing various organic acids and enzymes. Moreover,
the complex interactions in the rhizosphere and endophytic PSB with, other microorganisms, plant, and the environment-influenced solubilization of bound phosphates,
Pi uptake, and plant growth promotion. Under field conditions, plant genotypes have
been found as an important determinant in the development of a positive plantendophyte association. Majority of them containing endophytes tend to survive the
harshness of the environment and challenge biotic and abiotic stresses. Altough,
inconsistency in the performance of these inoculant strains is a major constraint to
the widespread use of microbial inoculants in commercial agriculture (Rodriguez
et al. 2006). It is, therefore, identification of the rare and promising bacterial endophytes with general plant beneficial characteristics would require a combination of
culture-dependent and culture-independent techniques. With a further understanding
of the functioning of bacterial endophytes, in the future scientists may be able to
engineer bacterial endophytes to facilitate their potential to improve plant growth
and development (Miller et al. 2010). The knowledge generated on biodiversity and
genetic manipulation of P solubilizing endophytic bacteria thus require to design
strategies for their efficient potential for sustainable and organic agriculture. This
includes ecological consideration of single/group of microbial communities, their
interactions in the rhizosphere or within roots (endophytes), their ability to mobilize
P from different soil fractions, and farm management practices that influence these
processes. More problems are yet to be resolved so as to utilize them in product
development of biotechnological significance. The manipulation of bacterial traits
with improved efficiency of P solubilization in endophytic bacteria and their inoculation as phosphatic biofertilizers may boost plant growth leading to improved soil
health and crop productivity.
References
Achat DL, Morel C, Bakker MR, Augusto L, Pellerin S, Gallet-Budynek A, Gonzalez M (2010)
Assessing turnover of microbial biomass phosphorus: combination of an isotopic dilution method
with a mass balance model. Soil Biol Biochem 42:2231–2240
A. Dahiya et al.
regulon (Sashidhar and Podile 2009). The overexpression of phosphate uptake ABC
transporter permease protein (PhoT) and the phosphate uptake ABC transporter ATP
binding protein (phoC) in S. meliloti was found to enhance phosphate solubilization
and yield in Medicago (Carmen and Roberto 2010).
3.9 Conclusion
Plant beneficial endophytic microbes have great potential to act as biofertilizers and
biopesticides for growth enhancement and protection from plant disease, respectively. Many bacterial endophytes can solubilize phosphorus, potassium, metals, and
other toxic substances by producing various organic acids and enzymes. Moreover,
the complex interactions in the rhizosphere and endophytic PSB with, other microorganisms, plant, and the environment-influenced solubilization of bound phosphates,
Pi uptake, and plant growth promotion. Under field conditions, plant genotypes have
been found as an important determinant in the development of a positive plantendophyte association. Majority of them containing endophytes tend to survive the
harshness of the environment and challenge biotic and abiotic stresses. Altough,
inconsistency in the performance of these inoculant strains is a major constraint to
the widespread use of microbial inoculants in commercial agriculture (Rodriguez
et al. 2006). It is, therefore, identification of the rare and promising bacterial endophytes with general plant beneficial characteristics would require a combination of
culture-dependent and culture-independent techniques. With a further understanding
of the functioning of bacterial endophytes, in the future scientists may be able to
engineer bacterial endophytes to facilitate their potential to improve plant growth
and development (Miller et al. 2010). The knowledge generated on biodiversity and
genetic manipulation of P solubilizing endophytic bacteria thus require to design
strategies for their efficient potential for sustainable and organic agriculture. This
includes ecological consideration of single/group of microbial communities, their
interactions in the rhizosphere or within roots (endophytes), their ability to mobilize
P from different soil fractions, and farm management practices that influence these
processes. More problems are yet to be resolved so as to utilize them in product
development of biotechnological significance. The manipulation of bacterial traits
with improved efficiency of P solubilization in endophytic bacteria and their inoculation as phosphatic biofertilizers may boost plant growth leading to improved soil
health and crop productivity.
References
Achat DL, Morel C, Bakker MR, Augusto L, Pellerin S, Gallet-Budynek A, Gonzalez M (2010)
Assessing turnover of microbial biomass phosphorus: combination of an isotopic dilution method
with a mass balance model. Soil Biol Biochem 42:2231–2240