Global transcriptome and weighted gene co-expression network analyses of growth-stage-specific and hybrid-cultivar-specific drought stress responses in maize

Abstract

Background Drought is the major abiotic stress threatening maize ( Zea mays L.) production globally. Therefore, deciphering the molecular basis of maize drought tolerance remains pertinent. Results Here, through a comprehensive comparative leaf transcriptome analysis of drought-tolerant hybrid ND476 plants subjected to water-sufficient (control) and water-deficit (drought) treatment conditions at four (V12, VT, R1, and R4) crop growth stages, we report key cultivar-specific and growth-stage-specific molecular mechanisms regulating drought stress responses in maize. Based on the transcriptome analysis, a total of 3451 differentially expressed genes (DEGs) were identified from the four experimental comparisons, with 2403, 650, 397 and 313 DEGS observed at the V12, VT, R1, and R4 stages, respectively. The expression changes in these genes effected corresponding metabolic pathway responses related to drought tolerance in maize. Subsequently, 3451 DEGs were divided into 12 modules by weighted gene co-expression network analysis (WGCNA), comprising 277 hub genes covering drought-responsive genes involved in water-deficit stress and developmental signaling crosstalk. Interestingly, the co-expressed genes that clustered into similar modules exhibited diverse expression tendencies and got annotated to different GO terms at different stages. MapMan analysis revealed that DEGs related to stress signal transduction, detoxification, transcription factor regulation, hormone signaling and secondary metabolites biosynthesis were universal across the four growth stages. However, the DEGs associated with photosynthesis and amino acid metabolism; protein degradation; transport; and RNA transcriptional regulation were uniquely enriched at the V12, VT, R2, and R4 stages, respectively. Conclusions Our results affirmed that maize drought stress adaptation is a whole-plant response as well as a stage-specific response process. We hope that our findings will aid in clarifying the fundamental cultivar-specific and growth-stage-specific molecular mechanisms regulating drought stress responses in maize. In addition, the genes and metabolic pathways identified here can be valuable genetic resources or selection targets for developing new drought resistant maize cultivars.

Genetics of Germination and Seedling Traits under Drought Stress in a MAGIC Population of Maize

“…Zm00001d002126 was associated with CL/RL and down-regulated in a drought-tolerant inbred line [ 80 ] Zm00001d002199 receptor-like serine/threonine-protein kinase was identified as a hub-gene. Receptor kinases, another vital type of membrane protein, was found to be differentially expressed in response to drought stress in maize [ 82 ]. Zm00001d037273 was associated with the CL/RL ratio and implicated in heat stress response ( HSR ).…”