Comparative metabolomics of developmental alterations caused by mineral deficiency during in vitro culture of Gentiana triflora

Abstract

Gentians (Gentiana triflora, G. scabra, and hybrids of the two) are mainly cultivated as ornamental flowers in Japan. Because gentians are allogamous plants, their diversity and heterozygosity have become a major problem. Recently, explants were clonally cultured to maintain genetic purity, but culture conditions have not been studied systematically, thus the essential nutrients required for gentian culture are unknown. We therefore investigated the effects of potassium (K) and phosphorus (P) deficiency in culture media. Explants grew under K or P deficiency conditions, but P deficiency caused the formation of new structures which are similar to overwintering buds. To elucidate the mechanism behind the gentian response to mineral deficiency, we performed targeted metabolome analyses using capillary electrophoresis-mass spectrometry. Multivariate analysis using metabolite profiles showed that characteristic metabolite patterns arise in response to K or P deficiency. Under P deficiency there is a severe decrease in energy metabolites, which may in turn trigger overwintering bud formation in vitro. These findings may contribute to understanding the horticultural conditions required by gentians to trigger bud formation, and may provide a new strategy for maintaining genetic purity for long periods.