Phytic acid is considered as one of the major antinutritional compounds in cereal and legume seeds. The development of lpa (low phytic acid) grains, resulting in increased mineral cation availability, is considered a major goal in the improvement of the nutritional quality of seed crops, especially those largely consumed in developing countries. From a mutagenized population of common bean we isolated a homozygous lpa mutant line (lpa-280-10) showing, compared to wild type, a 90% reduction of phytic acid, a 25% reduction of raffinosaccharides and a much higher amount of free or weakly bound iron cations in the seed. Genetic analysis showed that the lpa character is due to a recessive mutation that segregates in a monogenic, Mendelian fashion. Germination tests performed using varying ageing or stress conditions, clearly showed that the bean line lpa-280-10 has a better germination response than the wild type. These data, together with those obtained from 2 years of agronomic trials showing that the mutant seed yield is close to that of its parents and other evidence, indicate that the new lpa-280-10 mutation might be the first devoid of visible macroscopic negative effects in plants, pods and seeds.

Key words: inositol 1,4,5-tris-phosphate kinase, low phytic acid, myo-inositol-1,2,3,4,5,6-hexakisphosphate (InsP 6 ), myo-inositol-phosphate monophosphatase (IMP), myo-inositol-3-phosphate synthase (MIPS), multidrug resistance protein (MRP) type ATP-binding cassette (ABC) transporter, Phaseolus vulgaris (common bean). Summary• We previously identified the lpa1 (low phytic acid) 280-10 line that carries a mutation conferring a 90% reduction in phytic acid (InsP 6 ) content. In contrast to other lpa mutants, lpa1(280-10) does not display negative pleiotropic effects. In the present paper, we have identified the mutated gene and analysed its impact on the phytic acid pathway.• Here, we mapped the lpa1(280-10) mutation by bulk analysis on a segregating F 2 population, an then, by comparison with the soybean genome, we identified and sequenced a candidate gene. The InsP 6 pathway was analysed by gene expression and quantification of metabolites.• The mutated Pvmrp1(280-10) cosegregates with the lpa1(280-10) mutation, and the expression level of several genes of the InsP 6 pathway are reduced in the lpa1(280-10) mutant as well as the inositol and raffinosaccharide content. PvMrp2, a very similar paralogue of PvMrp1 was also mapped and sequenced.• The lpa1 mutation in beans is likely the result of a defective Mrp1 gene (orthologous to the lpa genes AtMRP5 and ZmMRP4), while its Mrp2 paralog is not able to complement the mutant phenotype in the seed. This mutation appears to down-regulate the InsP 6 pathway at the transcriptional level, as well as altering inositol-related metabolism and affecting ABA sensitivity.Abbreviations: ABC, ATP-binding cassette; MRP, multidrug resistance-associated protein; InsP 6, myo-inositol-1,2,3,4,5,6-hexakisphosphate; IMP, myo-inositolphosphate monophosphatase; MIPS, myo-inositol-3-phosphate synthase; MIK, myo-inositol kinase; IPK2, inositol 1,4,5-tris-phosphate kinase; ITPK, inositol 1,3,4-triphosphate 5 ⁄ 6-kinase; IPK1, inositol 1,3,4,5,6 pentakisphosphate 2-kinase.

A maize mutant defective in the synthesis of phytic acid during seed maturation was used as a tool to study the consequences of the lack of this important reserve substance on seed survival. Data on germinability, free iron level, free radical relative abundance, protein carbonylation level, damage to DNA, degree of lipid peroxidation, alpha- and gamma-tocopherol amount and antioxidant capacity were recorded on seeds of maize B73 and of an isogenic low phytic acid mutant (lpa1-241), either unaged or incubated for 7 d in accelerated ageing conditions (46 degrees C and 100% relative humidity). The lpa1-241 mutant, compared to wild type (wt), showed a lower germination capacity, which decreased further after accelerated ageing. Whole lpa1-241 mutant kernels contained about 50% more free or weakly bound iron than wt ones and showed a higher content of free radicals, mainly concentrated in embryos; in addition, upon accelerated ageing, lpa1-241 seed proteins were more carbonylated and DNA was more damaged, whereas lipids did not appear to be more peroxidated, but the gamma-tocopherol content was decreased by about 50%. These findings can be interpreted in terms of previously reported but never proven antioxidant activity of phytic acid through iron complexation. Therefore, a novel role in plant seed physiology can be assigned to phytic acid, that is, protection against oxidative stress during the seed's life span. As in maize kernels the greater part of phytic acid (and thus of metal ions) is concentrated in the embryo, its antioxidant action may be of particular relevance in this crop.

Sharpley et al., 1994). These lpa mutants produced seeds in which the chemistry of seed P, but not the total Phytic acid is a nearly ubiquitous component of plant seeds, supplyamount of P, was greatly altered (Raboy and Gerbasi, ing both phosphate (P) and cations during germination. However, during digestion, the phytic acid form of P is not bioavailable for

Ageing is a complex process that in muscle is usually associated with a decrease in mass, strength, and velocity of contraction. One of the most striking effects of ageing on muscle is known as sarcopenia. This inevitable biological process is characterized by a general decline in the physiological and biochemical functions of the major systems. At the cellular level, aging is caused by a progressive decline in mitochondrial function that results in the accumulation of reactive oxygen species (ROS) generated by the addition of a single electron to the oxygen molecule. The aging process is characterized by an imbalance between an increase in the production of reactive oxygen species in the organism and the antioxidant defences as a whole. The goal of this review is to examine the results of existing studies on oxidative stress in aging human skeletal muscles, taking into account different physiological factors (sex, fibre composition, muscle type, and function).