Determination of the expression of some nac transcription factors from citrus during drought stress

Plants face conditions that restrict their growth and development throughout their lives. These conditions that adversely affect or limit growth and development of plants are defined as stress. Drought is a serious problem limiting the agricultural production in many parts of the world. With the advancement of techniques used in molecular biology, molecular mechanisms of drought response in plants has been explored and genes playing a key role in drought adaptation and tolerance have been identified. Among these genes, transcription factors (TFs) constitute an important group consisting of large gene families and they have an important role in regulation of expressions gene involved in various cellular processes. NAC TFs are one of these TF family playing a key role in the regulation of drought response in plants. In this study, first citrus orthologs of five important NAC genes playing a role in drought stress in the other plants (ANAC002/ATAF1, ANAC072/RD26, ANAC042/JUB1, ANAC053/NTL4 ve ANAC062/NTL6) were selected. Then the expressions of these NAC genes were analyzed in response to 14-day of drought stress in sour orange (Citrus aurantium), Carrizo (Citrus sinensis X Poncirus trifoliata), Rangpur lime (Citrus x limonia) and orange (Citrus sinensis) plants using real-time RT-PCR. Gene expression analyses revealed that the expression of the ANAC002/ATAF1 and ANAC072/RD26 genes were significantly increased in response to drought stress in drought resistant Rangpur lime rootstock. However, no significant change was observed in the expression of genes in response to drought stress in sour orange, Carrizo rootstocks and orange plants. As a result, it was concluded that the ANAC002/ATAF1 and ANAC072/RD26 TF genes may play important role in drought resistance of Rangpur lime rootstocks and could be used for improving drought tolerance in other Citrus species.