PLANT CELL TISSUE AND ORGAN CULTURE, cilt.136, sa.3, ss.479-487, 2019 (SCI-Expanded)
Abiotic stresses, such as heavy metals, adversely affect the living groups including plants. It should be ensured that plants are resistant to environmental stresses in order to increase their growth and development. In this sense, it is an important step for agriculture identify stress-related genes whose tolerance against environmental stresses can be increased. NAC transcription factor (TF) genes provide plant growth and development as well as regulate abiotic stress responses. Therefore, this study was conducted to determine expression levels of NAC TF genes (TF ID: Han682, Han2027 and Han2724) against chromium (Cr; 1mM) stress in sunflower tolerant to heavy metals. The effects of copper (Cu; 0,25mM), which are micronutrient elements, and exogenous ascorbic acid (AsA; 200mg/L) treatments on the expression of these genes and some stress parameters such as chlorophyll amount, leaf relative water content, cell membrane damage are examined. According to the results obtained, Cr stress decreased chlorophyll content and leaf water content and increased cell membrane damage. Treatment of AsA and Cu in combination with Cr reduced toxicity by decreasing cell membrane damage by increasing chlorophyll content and leaf relative water content. The results obtained show that Cu and AsA can equally improve Cr stress. Expression profiles of NAC TF genes obtained by quantitative real-time PCR (q-PCR) were changed with plant tissues. NAC TF genes, which are upregulated with Cr stress in the root, have been determined to be a heavy metal response gene.