Narciclasine alters chloroplast membrane structure and inhibits 5‐aminolevulinic acid and chlorophyll binding protein accumulation in wheat (Triticum aestivum) leaves

Abstract

Narciclasine (NCS), an Amaryllidaceae alkaloid from Narcissus tazetta bulbs, is a potent plant growth inhibitor. It shows a broad range of inhibitory effects on seed germination and seedling growth in wheat (Triticum aestivum). In this study, the chlorophyll content of light‐grown wheat seedlings was markedly reduced in the presence of NCS. In etiolated wheat leaf sections, the greening process initiated upon illumination was inhibited by NCS. The block of chlorophyll accumulation in the presence of NCS was most probably due to the block of the formation of 5‐aminolevulinic acid, an essential chlorophyll precursor. Western blot analysis showed that the formation of light harvesting chlorophyll a/b binding protein (LHCII) was also inhibited by NCS. Electron microscopy studies provided direct observation that the formation of chloroplast and internal membrane systems were blocked when etioplasts were illuminated in the presence of NCS. Thus, our study showed that NCS inhibited chlorophyll and chloroplast protein accumulation, concomitantly chloroplast formation.