Agriculture Reference
In-Depth Information
Plant Bioindicator for Nutritional Status
Bioindication and Biomonitoring
The development of quick and inexpensive methods to determine changes in
nutrient bioavailability is required in order to monitor soil nutrient dynamics for
better fertiliser management for a variety of crops in different environmental
conditions. Developing bioassays based on the use of specific plant sentinels or
bioindicators, may represent a reliable and efficient strategy to obtain quick,
accurate and low-cost information about nutrient availability changes in a given
crop system. Thus, the use of these modern biotechnologies could allow the
non-destructive analysis of plants under field conditions. Development of these
kinds of tools represents a new and challenging area of research.
Plants respond to nutrient supply or shortage through a complex of physiolog-
ical, morphological, and developmental responses, which are under the control of
several gene pathways. Microarray technology is a convenient tool for rapid
analysis of plant gene expression patterns under a variety of environmental and
nutritional conditions. Genome-wide microarray analyses showed extensive
changes in the expression of several genes involved in primary and secondary
metabolism, nutrient transport, protein synthesis, regulation of gene expression
and cellular growth processes (Maruyama-Nakashita et al.
2003
; Wang
et al.
2003
; Bi et al.
2007
; Li et al.
2010
; Kant et al.
2010
; Ma et al.
2012
). Such
studies not only improved our general understanding on plant responses to nutrient
availability but also provided a reliable data from which to develop new molecular
strategies for real-time monitoring of plant nutritional status.
Recently, Yang et al. (
2011
) used multiple whole genome microarray experi-
ments to identify gene expression biomarkers capable of assessing plant responses
under limiting and sufficient nitrogen conditions. Using logistic regression statisti-
cal approaches, they identified a common set of genes in maize whose expression
profiles quantitatively assessed the extent of plant stress under different nitrogen
conditions. Interestingly, such a biomarker gene set is independent of maize
genotype, tissue type, developmental stage, and environment (including plants
grown under controlled conditions and in the field), and thus has the potential to
be used as an agronomic tool for real-time monitoring and to optimise nitrogen
fertiliser usage.
The Gene Fusion Concept Enables to Define a New Class
of Transgenic Bioindicators
The existence of gene pools, which specifically respond to the nutritional status of
the plant, has introduced a new class of bioindicators, based on the concept of gene
fusion (Fig.
10.3
). A generic nutrient-responsive gene is formally considered as
