Differential response of three contrasting pea (Pisum arvense, P. sativum and P. fulvum) species to salt stress: Assessment of variation in antioxidative defence and miRNA expression

Abstract

Soil salinity is one of the major abiotic stresses leading to crops yield failure. For investigation of salinity response in pea, in vitro cultures of three pea species (Pisum arvense, P. sativum and P. fulvum) were induced. Regenerated shoots of these pea species were grown on a medium with moderate and high NaCl concentrations (75, 120, 150 and 200 mM NaCl) to compare the antioxidative capacity in response to salt stress. Growth reduction was observed in all species and it correlated with the increase of NaCl concentration. After four weeks of treatment, the crude tissue extracts were used for measuring the stress response parameters. Level of lipid peroxidation increased in all three species, but in P. fulvum the effect of NaCl was less pronounced. Total chlorophyll and phenolic content showed differences among the three species, while the DPPH-scavenging activity was the most evident in P. fulvum. The northern blot analysis of the miRNA398 expression showed a similar pattern between P. sativum and P. arvense but different to that of P. fulvum, as in P. fulvum miRNA 398 was only expressed at moderate NaCl concentration, with total inhibition at high concentrations. On the basis of these results it can be concluded that P. fulvum could represent a gene pool for improving P. sativum and P. arvense stress defence capacity.