Journal of Agronomy and Field Innovations

Heat stress is a significant barrier to maize (Zea mays L.) production. Climate change worsens the challenge of ensuring food security. It is important to understand how heat tolerance operates at a molecular level for climate-smart crop development. RNA-Seq based transcriptomic analysis was used in the study to find heat stress-responsive genes in maize. Two contrasting lines—heat-tolerant inbred line (HT-88) and heat-susceptible (HS-42) cultivar—were exposed to heat stress (40 C for 8 hours daily) and normal conditions for 7 days. Transcriptome sequencing yielded ~180 million paired-end reads. Differential expression analysis using the sequencing data revealed that 4287 genes in the heat-tolerant lines were differentially expressed compared with the sensitive lines. GO enrichment revealed various heat stress-related processes, including heat stress response, protein folding, antioxidant activities, and cell signaling. KEGG pathway investigated the functional genes of altered heat shock proteins, genes related to antioxidant, and signaling mechanisms involving calcium and MAPK signaling pathways. Quantitative RT-PCR has confirmed that (12) differentially expressed candidate genes such as Hsf1, Hsp70, and APX2 have been identified. The physiological study revealed the fact that there is a direct relation between higher chlorophyll retention and lower electrolyte leakage rates in heat- tolerant genotypes along with the increased expression of relative transcription factors; gene products which are responsible for heat stress response. The finding of important genes with heat response ability and their regulatory systems could be of value in marker-assisted breeding as well as genetic engineering processes that will enhance maize heat resistance. Furthermore, this transcriptomic platform provides the opportunity to investigate the mechanisms of crop resistance to abiotic stress as well as to develop climate-dependent agricultural systems.