Genome-wide transcriptome analysis of two maize inbred lines under drought stress during the seedling stage

To understand the transcriptome changes during drought tolerance in maize, the drought-tolerant line Han21 and drought-sensitive line Ye478, which show substantial differences in drought tolerance at the seedling stage, were selected for this study. Using the GeneChip Maize Genome Arrays, we applied genome-wide gene expression analysis to the two genotypes under gradual drought stress and re-watering. We identified 2172 common regulated transcripts in both lines under drought stress, with 1084 common up-regulated transcripts and 1088 common down-regulated transcripts. Among the 2172 transcripts, 58 potential protein kinases and 117 potential transcription factors were identified. The potential components of the ABA signaling pathway were identified from the common regulated transcripts. We also identified 940 differentially regulated transcripts between the two lines. Among the 940 transcripts, the differential expression levels of 29 transporters and 15 cell wall-related transcripts may contribute to the different tolerances of the two lines. Additionally, we found that the drought-responsive genes in the tolerant Han21 line recovered more quickly when the seedlings were re-watered, and 311 transcripts in the tolerant Han21 line were exclusively up-regulated at the re-watering stage compared to the control and stress conditions. Our study provides a global characterization of two maize inbred lines during drought stress and re-watering and will be valuable for further study of the molecular mechanisms of drought tolerance in maize.

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Zheng J, Fu J, Gou M, Huai J, Liu Y, Jian M, Huang Q, Guo X, Dong Z, Wang H, Wang G