Cadmium Induced Gene Expression For Heavy Metal Transport In Barley

Heavy metal refers to metal whose proportions are more than 5 and density greater than 4.5 g/cm3, such as copper, lead, zinc, iron, cobalt, nickel, manganese, cadmium, mercury, tungsten, molybdenum, gold, silver and so on. Some heavy metals are needed for life activities such as manganese, copper and zinc. However, the majority of heavy metals like mercury, lead, cadmium are not necessary for life. Heavy metals taken up by roots and accumulated in the plant, are toxic to the plant, human and animals. Numerous studies have described symptoms and responses of plants when exposure to toxic metals. Cadmium (Cd) is a no-essential heavy metal that can be harmful at low concentrations in plant tissues. The aim of this study is to explore the regulation of genes involved in the transport of Cd into the grain. The hydroponic experiment was carried out to study the effect of cadmium (Cd) exposure on gene expression and mineral nutrient contents in barley grain of Golden promise. We mainly focused on the changes of heavy metal transport related gene expression in barley including MT, CDF and ZIP. The plant tissues were collected post pollination 20 days. The related genes expression level in leaf, grain and root were analyzed by means of Realtime PCR.The barley grain cryostat section was made before laser capture isolation to get different tissues in embryo, endosperm, aleurone layer and transport region in grain. Real-time PCR was employed to detect the target gene expression level.MT, ZIP, CDF genes were selected for analysis to different cadmium concentrations induced. In aleurone layers, MT gene expression were up regulated but MT1a and MT2b2. ZIP4 and ZIP7 expressions were inhabited. CDF MTPc1 expression level was not changed seriously. On the contrary, CDF MTPc4 expression was inhabited. In transfer regions, all kinds of MT 2 type genes had no change but MT1a and MT4 expressions were down regulated. In embryos, MT gene family, ZIP and CDF MTPc1 expression levels were enhanced. In endosperms, it was not find any changes for MT gene family. ZIP and CDF gene expressions were inhabited.We assum that responding genes may be important for Cd transport to grain in barley.