The effects of copper and ascorbic acid treatments on sunflower's (Helianthus annuus L.) metallothionein and NAC transcription factor gene expressions under stress of chromium

Abiotic and biotic stresses affect all living organisms. Heavy metals, have been contaminated to environment both natural and anthropogenic origins, have negative effects on plant metabolism. Plants respond to environmental pollutants like heavy metals by stimulating the stress response proteins' gene expressions. This study aimed to determine the effects of a micro nutrient element, copper (Cu) (0,25 μM CuSO45H2O) and a non-enzymatic antioxidant, ascorbic acid (AsA) (200 mg/L) on the Metallothionein (MT) and NAC transcription factor genes expressions of chromium stressed in Helianthus annuus L.. For this purpose, the expression levels of MT (HanMT2-1 and HanMT4) and NAC transcription factor genes (TF ID: Han682, Han2027 and Han2724) were analyzed by qRT-PCR technique. The results show that expression levels of MT and NAC transcription factor genes under Cr stress changed based on organ and up-regulated in the roots. Additionally, there are protective roles of Cu and AsA against Cr stress and also, MT and NAC transcription factor genes may take charge in stress tolerance by activating signal pathway.