engleski

The transport ability of protective biomolecule quercetin through Arabidopsis thaliana is improved by the rare-earth element europium

Quercetin (Q) is a plant polyphenolic from the group of flavonoids with strong antioxidative, antiviral and antibacterial activities, yet its ability of long-distance movement through a plant is quite limited. Moreover, the mobility of exogenously applied Q through an Arabidopsis thaliana plant is minimal or not possible at all. Recently, it was discovered that biological properties of free flavonoids can be improved by their chelation with metals. In last years it was proven that a rare-earth metal europium (Eu(III)) is naturally present in some plants, though in small quantities and, more interesting, can affect their physiological processes. Accordingly, we tested whether Eu(III) could bind to flavonoid Q, and if so would and how affect the transport ability of Q through Arabidopsis. Our in vitro results showed that Eu(III) binds to Q, and at the ratio rQ/Eu(III) = 0.2 complex stoichiometry 1/1 (Q/Eu(III)) reaches its maximal concentration with ˃ 95% of the total concentration of UV/Vis absorbing species in the solution. This complex stoichiometry was therefore used in further in vivo examinations, and the results showed that the long-distance transport of Q through Arabidopsis root could be stimulated by complexation with Eu(III). During transport, the Q/Eu(III) complex got degraded and therefore enabled efficient, slow, release of protective metabolite at the distal site, offering enhanced Q delivery. The spectrophotometric data suggested, one of possible reasons of Q/Eu(III) degradation could be the interaction of the complex with double stranded RNAs present in Arabidopsis. Since Q itself has a very limited transportation ability, yet positively affects plant defence responses, its improved long-distance transportation could lead to a better protection of plant tissues. Accordingly, our results suggest that the rare-earth element Eu(III) can improve the biological relevance of protective biomolecule Q.

quercetin; europium; transport; Arabidopsis thaliana

nije evidentirano