traits for the crop plants. Apart from following government-enforced guidelines, one
of the major constraints in field application is soil type and it directly influences the
survival and growth of the microbial communities (Fig. 22.9). To introduce a
genetically engineered orgainsm, we need to give special attention to the fact that
government legislation varies from country-to-country. Soil parameters such as
compaction, oxygen content, pH and temperature are also crucial in this respect
because they can affect the functioning of the microbes. In contrast to wild type
indigenous strains, the genetically modified organisms are often less adaptive perhaps as a consequence of burdensome metabolic demands due to the expression and
perhaps overexpression of foreign DNA (Glick 2020). In addition, PGPR strains
often do not have equal abilities to compete with soil-borne phytopathogens and
other antagonistic soil microbial communities, the PGPR strains sometimes do not
have the capacities to tolerate a wide range of soil contaminants, and habituation to
growing in nutrient-rich media under laboratory conditions may have resulted in
functional loss of active genes that previously made the microbes suitable in
contaminated rhizopshere environments (Glick 2020; Fig. 22.9).
22.8 Conclusion
Heavy metal(loid)-affected agricultural crops have benefitted for many years from
the application of indigenous HM-resistant PGPR. Although there are a lot of
constraints associated with the application of these microorganisms, their great
diversity and natural abundance in contaminated soil offers a ray of hope as we
explore their potential role in agriculture. Recent advancements in bioremediation
strategies have given us cause for optimism. But, before field application, these
PGPR should be verified for their degree of metal resistance, their level of plant
growth-promoting traits, and obviously their ability to reduce HM-content in plant
parts under controlled conditions. Henceforth, these PGPR are naturally dwelling
microflora that should be isolated, enriched and applied for sustainable agriculture in
HM-contaminated fields.
22 Beneficial Role of Plant Growth-Promoting Rhizobacteria in Bioremediation of. . .
483
of the major constraints in field application is soil type and it directly influences the
survival and growth of the microbial communities (Fig. 22.9). To introduce a
genetically engineered orgainsm, we need to give special attention to the fact that
government legislation varies from country-to-country. Soil parameters such as
compaction, oxygen content, pH and temperature are also crucial in this respect
because they can affect the functioning of the microbes. In contrast to wild type
indigenous strains, the genetically modified organisms are often less adaptive perhaps as a consequence of burdensome metabolic demands due to the expression and
perhaps overexpression of foreign DNA (Glick 2020). In addition, PGPR strains
often do not have equal abilities to compete with soil-borne phytopathogens and
other antagonistic soil microbial communities, the PGPR strains sometimes do not
have the capacities to tolerate a wide range of soil contaminants, and habituation to
growing in nutrient-rich media under laboratory conditions may have resulted in
functional loss of active genes that previously made the microbes suitable in
contaminated rhizopshere environments (Glick 2020; Fig. 22.9).
22.8 Conclusion
Heavy metal(loid)-affected agricultural crops have benefitted for many years from
the application of indigenous HM-resistant PGPR. Although there are a lot of
constraints associated with the application of these microorganisms, their great
diversity and natural abundance in contaminated soil offers a ray of hope as we
explore their potential role in agriculture. Recent advancements in bioremediation
strategies have given us cause for optimism. But, before field application, these
PGPR should be verified for their degree of metal resistance, their level of plant
growth-promoting traits, and obviously their ability to reduce HM-content in plant
parts under controlled conditions. Henceforth, these PGPR are naturally dwelling
microflora that should be isolated, enriched and applied for sustainable agriculture in
HM-contaminated fields.
22 Beneficial Role of Plant Growth-Promoting Rhizobacteria in Bioremediation of. . .
483