3 Microbial Endophytes: Sustainable Approach …
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of plants resulting in improved plant performance and plant protection against biotic
and abiotic stresses.
Besides, the host plant, environmental factors have been found to strongly influence the endophytic diversity of a particular plant. Moreover, host plant age, genotype, geographical location, and even the tissue being analyzed can determine the
type of endophytic bacteria it harbors (Hallmann and Berg 2006). Besides this, host
plant growth stages can also determine the endophytic diversity of a plant, where plant
stages enriched in nutrient availability tend to have increased bacterial diversity (Shi
et al. 2014). Climatic conditions have also been reported to influence the endophytic
colonizers of a plant species. Earlier, Penuelas et al. (2012) reported that changes in
a climate significantly altered the abundance and composition of endophytic bacteria
within the leaf tissues.
Different plant species growing in the same soil can have distinctly different
endophytic diversity, suggesting that the type of endophytic community of a plant is
strongly influenced by the nature of the plant host species (Ding et al. 2013; Ding and
Melcher 2016). Germida et al. (1998) reported that canola and wheat plants grown
in the same field had a very different spectrum of bacterial species as endophytes.
Even the different cultivars of a plant species grown in the same soil can also differ in
their endophytic diversity. Graner et al. (2003) reported that four different cultivars
of Brassica napus possessed different endophytic bacterial inhabitants. Song et al.
(1999) also reported significantly different endophytic bacterial diversity for peanut
cultivar grown in different fields. Moreover, Rashid et al. (2012) isolated different
types of endophytic bacteria by growing one cultivar of tomato in 15 different agricultural soils. Similarly, Graner et al. (2003) reported that wilt resistant cultivar of
Brassica napus contained a higher proportion of endophytic bacteria antagonistic to
the wilt-causing Verticillium longisporum than the susceptible cultivar. The restructured endophytic communities of asymptomatic and symptomatic Paullinia cupana
plants were observed when challenged by Colletotrichum spp. Bogas et al. (2015),
suggested that the presence of phytopathogens in plants is an important factor in
the restructuring of endophytic bacterial communities. Hence, the selection of endophytic bacterial communities is a dynamic process that is tightly controlled by the
host plant (Berg and Hallmann 2006; Trivedi et al. 2010).
3.5 Phosphorus Solubilization by Endophytic
Microorganisms
The mechanisms of plant growth promotion employed by endophytic microorganisms are similar to the mechanisms used by rhizospheric bacteria. Endophytic
microbes help in the acquisition of nutrients for plant growth and development. The
main difference being that endophytic microbes are no longer subject to the vagaries
of changing soil conditions, once they have been established within the tissues of
the host plant, These changing conditions include variations in temperature, soil pH,
43
of plants resulting in improved plant performance and plant protection against biotic
and abiotic stresses.
Besides, the host plant, environmental factors have been found to strongly influence the endophytic diversity of a particular plant. Moreover, host plant age, genotype, geographical location, and even the tissue being analyzed can determine the
type of endophytic bacteria it harbors (Hallmann and Berg 2006). Besides this, host
plant growth stages can also determine the endophytic diversity of a plant, where plant
stages enriched in nutrient availability tend to have increased bacterial diversity (Shi
et al. 2014). Climatic conditions have also been reported to influence the endophytic
colonizers of a plant species. Earlier, Penuelas et al. (2012) reported that changes in
a climate significantly altered the abundance and composition of endophytic bacteria
within the leaf tissues.
Different plant species growing in the same soil can have distinctly different
endophytic diversity, suggesting that the type of endophytic community of a plant is
strongly influenced by the nature of the plant host species (Ding et al. 2013; Ding and
Melcher 2016). Germida et al. (1998) reported that canola and wheat plants grown
in the same field had a very different spectrum of bacterial species as endophytes.
Even the different cultivars of a plant species grown in the same soil can also differ in
their endophytic diversity. Graner et al. (2003) reported that four different cultivars
of Brassica napus possessed different endophytic bacterial inhabitants. Song et al.
(1999) also reported significantly different endophytic bacterial diversity for peanut
cultivar grown in different fields. Moreover, Rashid et al. (2012) isolated different
types of endophytic bacteria by growing one cultivar of tomato in 15 different agricultural soils. Similarly, Graner et al. (2003) reported that wilt resistant cultivar of
Brassica napus contained a higher proportion of endophytic bacteria antagonistic to
the wilt-causing Verticillium longisporum than the susceptible cultivar. The restructured endophytic communities of asymptomatic and symptomatic Paullinia cupana
plants were observed when challenged by Colletotrichum spp. Bogas et al. (2015),
suggested that the presence of phytopathogens in plants is an important factor in
the restructuring of endophytic bacterial communities. Hence, the selection of endophytic bacterial communities is a dynamic process that is tightly controlled by the
host plant (Berg and Hallmann 2006; Trivedi et al. 2010).
3.5 Phosphorus Solubilization by Endophytic
Microorganisms
The mechanisms of plant growth promotion employed by endophytic microorganisms are similar to the mechanisms used by rhizospheric bacteria. Endophytic
microbes help in the acquisition of nutrients for plant growth and development. The
main difference being that endophytic microbes are no longer subject to the vagaries
of changing soil conditions, once they have been established within the tissues of
the host plant, These changing conditions include variations in temperature, soil pH,