Fig. 1

Drought treatment, transcriptome analysis, and ABA-related gene expression profiling across 224 maize accessions. a Illustration of the drought treatment and typical appearance of seedlings subjected to WW (well-watered), WS1 (moderate drought), and WS2 (severe drought) water regimes. b The representative curve of relative leaf water content (RLWC) during the drought treatment and at the points at which WW, WS1, and WS2 plants were sampled. Error bars and s.d. (standard deviation) were from the above three biological replicates. c Principal component analysis (PCA) of the 627 transcriptomes. d–f Clustering analysis of the regulation pattern of ABA-related genes among 224 maize accessions. The color bar indicates the normalized gene expression. The gene expression patterns were sorted into three clusters by k-means clustering algorithm. Cluster 1: drought-inducible genes (d). Cluster 2: drought-repressed genes (e). Cluster 3: response variable genes (f). The transcriptomic hierarchies of all the accessions were constructed based on the gene expression levels of 56 ABA-related genes. They were presented on the top of cluster 1. The origin of maize accessions is indicated by the bars across the top of each panel: orange for TST (tropical/subtropical); blue for stiff stock and non-stiff stock (SS and NSS); gray for mixed origins