4
D. K. Maheshwari and S. Dheeman
harness the beneficial influence of the past and future of mineral nutrient management
and sustainable agriculture by endophytes. Nutrient management is an approach of
sustaining mineral nutrients in plants and soil systems. Originally, this approach is a
derivation of integrated nutrient management (INM) holding focus on nitrogen (N),
phosphorus (P), and potassium (K) nutrients by blending agrochemicals with effective microorganisms (EM). In the insights of mineral nutrient management (MiNuM),
endophytes have been used to increase the spectrum of soil fertility and mineralization or immobilization of various trace elements like N, P, K, Zn, Fe, Cu, Mg, and
S.
The soil microorganisms can improve plant responses against biotic and abiotic
stresses and aid them in health management are called ‘beneficial bacteria’. Altogether the plant-microbe-soil creates a tripartite relationship in soil ecology, which
is often studied under plant-microbe interaction. Plant-microbe interaction (PMI)
is a complex relationship that exists above-ground and below-ground. The belowground PMI is more complex than the above, because of consisting complex interface
with soil. The soil affects these relationships via its physico-chemical properties in
addition to abiotic and biotic factors.
Few PGPR develops an intimate relationship with plants and becomes colonized
inside tissues without any visible symptoms that are usually termed as endophytes.
Endophytes are also found in the seeds of few plants, thus, these are termed as ‘seed
endophytes’. Basically, in the below-ground PMI, they are known for their versatility and helping plant via several mechanisms such as nitrogen fixation, phosphate
solubilization, potassium (K) and zinc (Zn) solubilization, siderophores production,
phytohormone production, volatile production of hydrogen cyanic (HCN) acid, 1aminocyclopropane, 1-carboxylic acid (ACC) deaminase production, biocontrol of
fungal phytopathogens, induced systemic resistance (ISR) and systemic acquired
resistance (SAR). Endophytes are important to consider in the usage of nutrient
mineralization due to their significant traits (Maheshwari and Dheeman 2019).
The heterogeneous community of endophytes includes root-nodulating Rhizobia
to facultative endophytes such as Bacillus, Pseudomonas, Azotobacter, etc. The abundant existence of Bacillus in soil may be attributed due to spore formation, resistance
to high temperature, and cold shock resistance (Pandey et al. 2018). Endophytes can
solubilize phosphorus (P) and potassium (K) along with the ability to mineralize
Zinc (Zn) and oxidize sulfur (S). On the other hand, few endophytes involve in Nfixation (mineralization of N to fix in the form of Ammonia). This way, endophytes
have emerged as a versatile candidate. They endure in harsh environments with their
feasible strategies and deals with the limitation of agricultural production caused
by soil factors. The exact mechanism by which endophytes improve plant health
remains largely speculative; however, possible explanation includes mineral nutrient
management (include acquisition of nutrients as direct involvement in plant growth
promotion largely reviewed in this book by eminent scholars). Endophyte to serve
as biofertilizer or Phyto-stimulator helps in maintaining the soil. These include the
acquisition of nutrients as a direct involvement in plant growth promotion; however,
other mechanisms support indirectly toward plant growth and sustainable agriculture.
D. K. Maheshwari and S. Dheeman
harness the beneficial influence of the past and future of mineral nutrient management
and sustainable agriculture by endophytes. Nutrient management is an approach of
sustaining mineral nutrients in plants and soil systems. Originally, this approach is a
derivation of integrated nutrient management (INM) holding focus on nitrogen (N),
phosphorus (P), and potassium (K) nutrients by blending agrochemicals with effective microorganisms (EM). In the insights of mineral nutrient management (MiNuM),
endophytes have been used to increase the spectrum of soil fertility and mineralization or immobilization of various trace elements like N, P, K, Zn, Fe, Cu, Mg, and
S.
The soil microorganisms can improve plant responses against biotic and abiotic
stresses and aid them in health management are called ‘beneficial bacteria’. Altogether the plant-microbe-soil creates a tripartite relationship in soil ecology, which
is often studied under plant-microbe interaction. Plant-microbe interaction (PMI)
is a complex relationship that exists above-ground and below-ground. The belowground PMI is more complex than the above, because of consisting complex interface
with soil. The soil affects these relationships via its physico-chemical properties in
addition to abiotic and biotic factors.
Few PGPR develops an intimate relationship with plants and becomes colonized
inside tissues without any visible symptoms that are usually termed as endophytes.
Endophytes are also found in the seeds of few plants, thus, these are termed as ‘seed
endophytes’. Basically, in the below-ground PMI, they are known for their versatility and helping plant via several mechanisms such as nitrogen fixation, phosphate
solubilization, potassium (K) and zinc (Zn) solubilization, siderophores production,
phytohormone production, volatile production of hydrogen cyanic (HCN) acid, 1aminocyclopropane, 1-carboxylic acid (ACC) deaminase production, biocontrol of
fungal phytopathogens, induced systemic resistance (ISR) and systemic acquired
resistance (SAR). Endophytes are important to consider in the usage of nutrient
mineralization due to their significant traits (Maheshwari and Dheeman 2019).
The heterogeneous community of endophytes includes root-nodulating Rhizobia
to facultative endophytes such as Bacillus, Pseudomonas, Azotobacter, etc. The abundant existence of Bacillus in soil may be attributed due to spore formation, resistance
to high temperature, and cold shock resistance (Pandey et al. 2018). Endophytes can
solubilize phosphorus (P) and potassium (K) along with the ability to mineralize
Zinc (Zn) and oxidize sulfur (S). On the other hand, few endophytes involve in Nfixation (mineralization of N to fix in the form of Ammonia). This way, endophytes
have emerged as a versatile candidate. They endure in harsh environments with their
feasible strategies and deals with the limitation of agricultural production caused
by soil factors. The exact mechanism by which endophytes improve plant health
remains largely speculative; however, possible explanation includes mineral nutrient
management (include acquisition of nutrients as direct involvement in plant growth
promotion largely reviewed in this book by eminent scholars). Endophyte to serve
as biofertilizer or Phyto-stimulator helps in maintaining the soil. These include the
acquisition of nutrients as a direct involvement in plant growth promotion; however,
other mechanisms support indirectly toward plant growth and sustainable agriculture.