Agriculture Reference
In-Depth Information
deficiency, with over 30% of the world's population affected. To solve
both problems, two of the main objectives of plant Fe researchers are to
obtain genotypes more efficient in Fe uptake (more tolerant to calcareous
soils) and to get edible seeds with higher Fe content for human nutrition.
For these goals, it is necessary to know better the mechanisms implicated
in Fe uptake and their regulation. To acquire Fe from soils, plants have
developed different strategies. Today, two main strategies are considered:
the Strategy I, present in non graminaceous plants (dicots, non grasses
monocots,…) and the Strategy II, present in graminaceous plants. When
plants suffer from Fe deficiency they switch on several morphological
and physiological changes in their roots, known as Fe deficiency stress
responses (hereafter named Fe responses), aimed to facilitate Fe
acquisition and mobilization. These responses are switched off once
plants acquire enough Fe, to avoid Fe intoxication and energy lost. Since
pea is a dicot plant species, this review is devoted to describe the
characteristics of Fe acquisition and Fe responses in Strategy I plants,
pointing out the role of some pea mutants (
brz
and
dgl
) in the studies
about this Strategy.
Keywords
: bronze mutant, chlorosis, dgl mutant, ethylene, iron, regulation,
iron responses
I
NTRODUCTION
Iron (Fe) participates in many essential plant functions, such as
photosynthesis, respiration and nitrogen metabolism [1-2]. In most cases, Fe is
involved in the transport of electrons and participates as co-factor of numerous
enzymes [2]. In relation to legume crops, such as pea, Fe plays a very
important role in the nodulation process since it is required for some of the
proteins implicated: leghemoglobin, nitrogenase, cytochromes,… [3]. Fe is
abundant in most soils but its availability is low, especially in calcareous soils
(more than 30% of arable soils), where its solubility is very low and is
frequent the incidence of Fe chlorosis [4]. In these soils, one of the more
important factors causing Fe chlorosis is bicarbonate while hypoxia, due to
flooding or other causes, can aggravate its negative effects [5]. According to
the World Health Organization, the most common nutritional disorder in
humans is Fe deficiency, with over 30% of the world's population affected [6].
Among the plant species frequently affected by Fe chlorosis are several
legume crops, such as bean, soybean, peanut, pea and others [7]. The usual
way to correct Fe deficiency is the application to soil of Fe chelates, which are
