Transcriptome-wide survey and expression analysis of stress-responsive NAC genes in Chrysanthemum lavandulifolium

The plant-specific NAC (NAM, ATAF, and CUC) transcription factor family plays a vital role in various plant growth and developmental processes as well as in stress resistance. Using RNA sequencing, we found that the CINAC genes (CINAC1-44) were the most strongly up-regulated transcription factor family in Chrysanthemum layandulifolium leaves under salt treatment. We carried out reverse transcriptase polymerase chain reaction to monitor CINAC genes response against multiple stresses and hormonal treatments including salt, drought, cold, heat, abscisic acid and salicylic acid treatments. The results showed that 35 CINAC genes were differentially expressed in different organ, and 32 CINAC genes could respond to at least 2 kinds of treatments. Quantitative real time polymerase chain reaction showed that 10 CINAC genes belonging to 7 different subfamilies could respond to at least 5 kinds of treatments. Over 50-fold variation in transcriptional levels of CINAC17 and CINAC21 genes was observed under 6 different types of treatments. In the present study, high-level expression of CINAC genes under abiotic stresses and hormonal treatments suggests that the NAC transcription factors play important roles in abiotic stress tolerance and adaptation. (C) 2012 Elsevier Ireland Ltd. All rights reserved.