Agriculture Reference
In-Depth Information
fertilizers, and therefore, the production cost was minimized. The exploitation of
P-solubilizing bacteria as biofertilizer thus has enormous potential for making use
of ever-increasing fixed P in soil and natural reserves of phosphate rocks.
7.5 Some Examples of Biotechnological Tools to Identify
Potential PSB
More than 99 % of soil microorganisms including P solubilizers have not been
cultured successfully. Thus, culture-independent methods are needed for evaluating
the functional diversity and ecology of PSB involved in P cycling in soils. Molec-
ular approaches for such culture-independent methods have been developed. The
molecular techniques based on nucleic acid composition like LMW RNA profiling
and PCR-based techniques are excellent tools for this purpose, as they are precise,
reproducible, and not dependent on culture media composition or growth phase of
microorganisms (Peix et al.
2007
). An understanding of coupled biological process
at the molecular level is fundamental for assessing the composition and function of
microbes which in turn affect the health of soil that eventually could lead to
increased soil fertility and consequently the crop production. In this regard, several
molecular and cellular techniques are available which in conjunction with biolog-
ical and chemical indicators help to better understand the functionality of microbes
and, hence, the soil health (Gautam and Jha
2011
). Some of the techniques used in
identifying microbes with varied biological potentials are discussed briefly.
7.5.1 DNA Measurement
Quantification of DNA following its extraction and enrichment (in insoluble
P-containing media) from any environmental sample may provide a simple and
practicable method for estimating the amount of microbial biomass (Girvan
et al.
2004
). However, further work on correlating DNA measurements with a
particular soil type is required. The total DNA isolation is done, and then it is
followed by the amplification of 16S rDNA or the intergenic region (i.e., the region
between16S rDNA and 23S rDNA) with the universal primers. The amplicon is
then proceeded for sequencing to identify the most abundant type of bacterium
present in the sample and to reveal the bacterial diversity.
