Expression of aquaporin PIP2;1 as an indicator of Zea mays L. cultivar tolerance to reduced soil moisture

Abstract

Purpose. To investigate expression of aquaporin PIP2;1 in maize cultivars ‘Pereiaslavskyi’ and ‘Dostatok’, (moderately drought-resistant) and ‘Yachta’ and ‘Flahman’ (drought-resistant), which grew for 10 days in low humidity substrate (30%). To evaluate possible influence of lipids and fatty acids on the functional activity of PIP2;1 under above humidity conditions. Methods. Biochemical: study of lipids and fatty acids in cytoplasmic membrane fraction from the roots (liquid chromatography); molecular: detection of the relative expression of aquaporin PIP2;1 in the roots (polymerase chain reaction, PCR); morphometric measurements and statistical methods for result processing. Results. Studies showed that in moderately drought-tolerant maize cultivars ‘Pereiaslavskyi’ and ‘Yachta’, PIP2;1 expression decreased, while in drought-tolerant ‘Dostatok’ and ‘Flahman’, on the contrary, it increased. In ‘Dostatok’ and ‘Flahman’ smaller root water deficit compared with ‘Pereiaslavskyi’ and ‘Yachta’ in conditions of low humidity of the substrate was recorded. In addition, the quantity of sterols and phospholipids increased in the plasma membrane of all hybrids. Conclusions. Reduced expression of PIP2;1 observed in ‘Pereiaslavskyi’ and ‘Yachta’, is a characteristic feature of not drought tolerant plants and indicates reaction to a decrease in substrate moisture and counteraction to dehydration, since a smaller amount of aquaporins ensures water retention in the cells. Contrary, at a substrate moisture content of 30%, PIP2;1 expression in drought-resistant hybrids ‘Dostatok’ and ‘Flahman’ increased which was accompanied by lesser root water deficiency (comparing to that of ‘Pereiaslavskyi’ and ‘Yachta’). It is quite probable that the enhanced expression of the PIP2;1 isoform in cultivars ‘Dostatok’ and ‘Flahman’ is a specific indicator of hybrids drought resistance. The obtained data are important for improving the selection of drought resistant maize hybrids.