Identification of the maize drought-resistant gene Zinc-finger Inflorescence Meristem 23 through high-resolution temporal transcriptome analysis
Tangnur Kaderbek, Liangliang Huang, Yang Yue, Zhaoying Wang, Jiahao Lian, Yuting Ma, Jianrui Li, Junhong Zhuang, Jianmin Chen, Jinsheng Lai, Weibin Song, Chao Bian, Qiujie Liu, Xiaomeng Shen
Abstract
Drought is a major abiotic stress that significantly limits maize productivity. However, previous transcriptomic studies with limited time-point sampling have hindered the construction of robust co-expression networks, making it challenging to identify reliable hub genes involved in drought tolerance. To overcome this limitation, we generated a high-temporal-resolution transcriptome dataset spanning 108 time points from maize seedlings subjected to two consecutive rounds of drought and re-watering treatments. A total of 8477 drought-responsive genes (DRGs) were identified by comparing drought-stressed and well-watered controls. Using weighted gene co-expression network analysis (WGCNA), we constructed 17 co-expression modules, of which 8 were strongly associated with drought stress responses and collectively contained 353 hub genes. Among them, we validated the drought resistance functions of ZmCPK35 , a known drought-responsive gene, and Zinc-finger Inflorescence Meristem 23 ( ZmZIM23 ), a newly identified drought-regulatory gene, within the M10 module. Functional analysis revealed that ZmZIM23 enhances drought tolerance by improving water-use efficiency, reducing transpiration rates, and promoting biomass accumulation. Furthermore, yeast one-hybrid (Y1H) and dual-luciferase (LUC) assays demonstrated that ZmWRKY40 , another M10 module member, transcriptionally regulates both ZmZIM23 and ZmCPK35 . By integrating high-resolution transcriptomic data with co-expression network analyses, this study unveils key drought-responsive regulatory networks in maize and identifies novel candidate genes for improving drought tolerance. These findings provide valuable insights into the genetic foundation of drought adaptation and offer potential targets for the development of drought-resistant maize cultivars. • High-resolution temporal transcriptome analysis of maize under drought, covering 108 time points and 469 high-quality RNA-seq profiles. • Identified 8,477 drought-responsive genes, including functional genes involved in drought resistance and regulatory genes modulating stress-responsive pathways. • Constructed a drought-responsive co-expression network with 353 drought-related hub genes distributed across eight modules. • Identification of ZmZIM23 as a key regulator of drought tolerance.