234
K. Lasudee et al.
(Lasudee et al. 2018). The treatment time given for each chemical is varied depending
on the concentration for example, Glomus mosseae spores were decontaminated with
chloramine-T for 30 min (Mohandas et al. 2013). Alternatively, F. mosseae CMURYA08 spores were surface sterilized by 2% sodium hypochlorite for 1 min followed
by 70% (v/v) ethanol (Lasudee et al. 2018) or by 4% (w/v) chloramine T trihydrate for
10 min (Chaiya et al. 2019). The spore cell wall could be broken by simple grinding
with a sterile micro pestle. However, the suspending solution varied depending on
author preferences. These solutions are steriled distilled water, phosphate buffer
saline (PBS), and 0.75% sodium chloride. Several selective media have been used
for isolation of endophytic actinobacteria from mycorrhizal spore namely ken knight
agar (Poovarasan et al. 2015), Waksman’s agar (Battini et al. 2016), starch casein agar,
humic acid vitamin agar (Lasudee et al. 2018), actinomycetes isolation agar (Chaiya
et al. 2019), etc. Furthermore, a general cultivation medium such as tryptic soy agar
(TSA) was also used for isolation (Long et al. 2017). Special media such as solidified
chitin water agar was reported for isolation of chitinase producing actinobacteria from
calcareous soil (Ames et al. 1989).
Moreover, the enrichment procedure proved successful for the isolation of endophytic actinobacteria from F. mosseae spores. Lasudee et al. (2018) soaked the spores
in soil extract broth and shaken at 120 rpm at room temperature for 1 h to enrich
endophytic actinobacteria. This procedure was considered to be essential because
the isolation of actinobacteria without an enrichment step led to the possibility of
not getting actinobacterial growth on selective media.
10.3 Plant Growth-Promoting (PGP) Activities
of Endophytic Actinobacteria
Mycorrhiza is the association of a fungus and root plants (Mohandas et al. 2013)
that play an important role in the agriculture ecosystem. The colonization of mycorrhizal fungi in root helps to promote plant growth via nutrient mobilization, biocontrol activity, etc. Interestingly, there are reports considering actinobacteria that can
promote plant growth by different mechanisms both directly and indirectly.
10.3.1 Endophytic Actinobacteria Associated with Nutrient
Uptake in Plants
Endophytic actinobacteria promote plant growth directly by facilitating the nutrient
acquisition of plants via many mechanisms including siderophore production and
solubilization of phosphate, phytate, or zinc as summarized in Table 10.2.
Phosphorus (P) is an essential macronutrient for the growth and development
of plants (Behera et al. 2014). However, most phosphorus in the soil is available
K. Lasudee et al.
(Lasudee et al. 2018). The treatment time given for each chemical is varied depending
on the concentration for example, Glomus mosseae spores were decontaminated with
chloramine-T for 30 min (Mohandas et al. 2013). Alternatively, F. mosseae CMURYA08 spores were surface sterilized by 2% sodium hypochlorite for 1 min followed
by 70% (v/v) ethanol (Lasudee et al. 2018) or by 4% (w/v) chloramine T trihydrate for
10 min (Chaiya et al. 2019). The spore cell wall could be broken by simple grinding
with a sterile micro pestle. However, the suspending solution varied depending on
author preferences. These solutions are steriled distilled water, phosphate buffer
saline (PBS), and 0.75% sodium chloride. Several selective media have been used
for isolation of endophytic actinobacteria from mycorrhizal spore namely ken knight
agar (Poovarasan et al. 2015), Waksman’s agar (Battini et al. 2016), starch casein agar,
humic acid vitamin agar (Lasudee et al. 2018), actinomycetes isolation agar (Chaiya
et al. 2019), etc. Furthermore, a general cultivation medium such as tryptic soy agar
(TSA) was also used for isolation (Long et al. 2017). Special media such as solidified
chitin water agar was reported for isolation of chitinase producing actinobacteria from
calcareous soil (Ames et al. 1989).
Moreover, the enrichment procedure proved successful for the isolation of endophytic actinobacteria from F. mosseae spores. Lasudee et al. (2018) soaked the spores
in soil extract broth and shaken at 120 rpm at room temperature for 1 h to enrich
endophytic actinobacteria. This procedure was considered to be essential because
the isolation of actinobacteria without an enrichment step led to the possibility of
not getting actinobacterial growth on selective media.
10.3 Plant Growth-Promoting (PGP) Activities
of Endophytic Actinobacteria
Mycorrhiza is the association of a fungus and root plants (Mohandas et al. 2013)
that play an important role in the agriculture ecosystem. The colonization of mycorrhizal fungi in root helps to promote plant growth via nutrient mobilization, biocontrol activity, etc. Interestingly, there are reports considering actinobacteria that can
promote plant growth by different mechanisms both directly and indirectly.
10.3.1 Endophytic Actinobacteria Associated with Nutrient
Uptake in Plants
Endophytic actinobacteria promote plant growth directly by facilitating the nutrient
acquisition of plants via many mechanisms including siderophore production and
solubilization of phosphate, phytate, or zinc as summarized in Table 10.2.
Phosphorus (P) is an essential macronutrient for the growth and development
of plants (Behera et al. 2014). However, most phosphorus in the soil is available