Expression analysis of NAC type transcription factors on wheat seedlings under abiotic stress conditions


Tezin Türü: Doktora

Tezin Yürütüldüğü Kurum: Orta Doğu Teknik Üniversitesi, Fen Edebiyat Fakültesi, Biyolojik Bilimler Bölümü, Türkiye

Tezin Onay Tarihi: 2011

Öğrenci: MEHMET CENGİZ BALOĞLU

Danışman: HÜSEYİN AVNİ ÖKTEM

Özet:

Wheat is the most important grain crop grown in our country providing greatest part of the daily nutritional requirement. Abiotic factors including salinity, drought, cold and heat stresses affect quality and yield of wheat varieties used for the production of both bread and pasta flour. NAC proteins form one of the widest families of plant specific transcription factors. Members of this family are related with development, defense and abiotic stress responses. TaNAC69-1 and TtNAM-B2 genes were isolated from T.aestivum and T.turgidum, respectively. Then they were cloned into different monocot and dicot expression vectors to be used for further wheat and tobacco genetic transformation studies. To understand effects of salinity, drought, cold and heat stresses on expression profiles of TaNAC69-1 and TtNAM-B2 genes, quantitative real time PCR was performed. The time series expression profiles of TaNAC69-1 show that it was significantly up-regulated following by salt, drought, cold and heat stress treatments. Except for heat stress, expression of TtNAMB-2 gene also significantly induced under drought, salt and cold stress conditions. Microarray analysis also performed to indicate effects of cold and heat stress treatments on global gene expression profiles of wheat. Differentially regulated genes show that temperature changes directly affected a large and complex transcriptional network associated with defense, metabolism and development. Genes involved in cold stress-responsive and different cold acclimation proteins were extremely up-regulated upon exposure to cold stress. Both expression levels of small and large sub-unit heat shock proteins significantly increased following heat stress period. In addition to these protective agents, transcription factors also played a central role to deal with severe effects of low and high temperature conditions.