Agriculture Reference
In-Depth Information
to enhance the antioxidant responses (Fe deficiency causes oxidative stress) at
the root level upon bicarbonate treatment than the sensitive ones.
Consequently, this ability could be used as a marker to select tolerant cultivars
[64].
To further improve the obtention of Fe chlorosis tolerant varieties, it is
necessary to know better which are the mechanisms involved in Fe acquisition
and how are regulated by plants. In this way, to decipher the
BRZ
and
DGL
genes could contribute to obtain pea cultivars with more efficient Fe responses
and better adapted to calcareous soils but without the problems of Fe
intoxication caused by the mutations of these genes.
I
RON
B
IOFORTIFICATION IN
P
EA
According to the World Health Organization, the most common
nutritional disorder in humans is Fe deficiency induced anemia, with over one-
third of the world's population affected [6]. To solve this problem, a promising
possibility is to obtain edible seeds with higher Fe content for human nutrition.
Until now, most efforts about Fe biofortification have been focused on rice
[65] but legume crops also offer interesting possibilities for, at least, two
reasons. First, they are an important source of nutrients for humans, especially
in parts of the developing world [66]. Second, seeds of legumes, such as pea,
normally have higher Fe concentrations than cereal grains and other edible
vegetables [6,67]. Moreover, there is a great variability in seed Fe among
different pea cultivars, ranging from 23 to 105 mgKg
-1
[67], which can be used
in breeding programs.
The amount of Fe in the seeds depends on uptake from the soil into the
roots, translocation into the shoots via the xylem, transfer into the leaves and
other structures and translocation into the seeds via the phloem [65-66,68].
Iron content decreased in the vegetative tissues of pea plants during the
reproductive phase indicating remobilization of Fe from leaves to seeds.
However, continued Fe uptake and transport during seed fill is as important as
remobilization [66].
To get seeds with higher Fe content (Fe biofortification) different
strategies can be used, besides the traditional breeding programs. A first
strategy is to increase uptake of Fe from the soils: i.e., by overexpressing ferric
reductase or iron transporter genes [65]. As example, Vasconcelos et al [69]
have overexpressed the
AtFRO2
gene in soybean. The transgenic lines
obtained accumulate higher Fe levels in leaves than the wt ones but similar
