TaZnF, a C3HC4 type RING zinc finger protein from Triticum aestivum is involved in dehydration and salinity stress

C3HC4-type RING finger proteins represent one of the largest transcription factors in the plant kingdom. They are known to play crucial roles in various plant processes like regulation of growth and development, signalling network and abiotic stress etc. The paper attempts to explore and dissect the function of TaZnF in response to abiotic stress like drought and salinity. The gene expression studies revealed the possible role of TaZnF in drought and salt stress response. The expression pattern was found to be similar in root tissue under both drought and salt stress. It was found to increase with the increase in the duration of stress with maximum fold > 3 under drought and > 15 fold in response to salt stress at 8 h. Arabidopsis transgenics overexpressing TaZnF were raised to analyse how the changes in gene expression levels affect plant's response under stress conditions. TaZnF overexpression conferred increased tolerance to both drought and salt stress as measured by several assays examining their growth and development. The transgenics showed better growth in response to dehydration stress given by both mannitol and Polyethylene glycol (PEG). Further, the transgenics were found to survive when subjected to drought stress for 14 days in contrast to wild type. They also showed high yield under severe drought conditions for one month in comparison to the wild type plants. Similarly the transgenics were found to perform well under salt stress conditions in terms of increased fresh weight, better growth, higher chlorophyll accumulation, higher membrane stability and increased proline content. The expression level of both drought and salt stress related marker genes was found to be higher in transgenics in comparison to wild type plants. Thus these observations clearly indicate that TaZnF functions as a positive regulator of stress response, and can be used as a candidate gene to improve and enhance drought and salt stress tolerance of various crop plants.