Agriculture Reference
In-Depth Information
A recent study in maize was conducted to understand the combined effects of enhanced
atmospheric CO
2
and drought on the stress responses by monitoring foliar metabolites
(LC and GC-MS) and transcripts [307]. The concentrations of 28 out 33 leaf metabolites
were altered by drought. Soluble carbohydrates, aconitate, shikimate, serine, glycine, pro‐
line and eight other amino acids increased, and leaf starch, malate, fumarate, 2-oxogluta‐
rate and seven amino acids decreased with drought. Overall analysis of both
transcriptomic and metabolomic data supported that water stress inhibited C4 photosyn‐
thesis and induced photorespiration in this species.
In plants, isoprene is a dual purpose metabolite that can act as thermo-protective agent
proposed to prevent degradation of photosynthetic enzymes/membrane structures [310] and/
or as reactive molecule reducing abiotic oxidative stress [311]. Gene expression and metabolite
profiles of isoprene emitting wild type plants and RNAi-mediated non-isoprene emitting grey
poplars (
Populus x canescens
) were compared by using poplar Affymetrix microarrays and non-
targeted FT-ICR-MS (Fourier Transform Ion Cyclotron Resonance Mass Spectrometry) [312].
A transcriptional down-regulation of genes encoding enzymes of phenylpropanoid biosyn‐
thetic and regulatory pathways, as well as distinct metabolic down-regulation of condensed
tannins and anthocyanins, in non-isoprene emitting genotypes was seen, when high temper‐
ature and light intensities possibly caused a transient drought stress. The results suggested
that non-isoprene emitting poplars are more susceptible to environmental stress and provided
new evidences about the physiological and ecological roles of isoprene in the protection of
plants from environmental stresses.
6. Conclusions and final remarks
The Intergovernmental Panel on Climate Change 2012 (IPCC, 2012) indicated that tem‐
perature rising, drought, floods, desertification and deterioration of arable land and
weather extremes will severely affect agriculture, especially in drought-prone regions of
the developing world [313]. Regarding food security, this threatening scenario highlights
the need for a globally concerted research approach to address crop improvement to mit‐
igate crop failure under marginal environments. One of the major goals of plant im‐
provement is to develop crops fit to cope with environmental injuries but still capable to
achieve substantial yield under abiotic stress.
Data from traditional breeding, plant molecular breeding based in the development of
molecular markers, candidate gene identification or gene expression profiles and from the use
of transgenic approaches are becoming more and more frequent. Resulting plants are being
evaluated in controlled conditions (greenhouse and growth chambers) but also, importantly,
in the field to confirm the generation of improved cultivars. Despite the difficulty to establish
reliable methods to assess new breed or engineered plant phenotypes as result of those
approaches, some efforts are anticipated to fulfill the gap between plant molecular biology and
plant physiology.
Search WWH ::
Custom Search