Diverse maize inbreds share the leaf transcriptome but diverge in response to ozone

Climate change and increasing pollutants such as ozone lead to yield losses. Maize genotypes have divergent photosynthetic responses to ozone with B73 being relatively tolerant and NC338, and Hp301 sensitive. Genetic correlations among photosynthetic traits increase in Ozone indicating the presence of cryptic genetic variation. Sensitive lines NC338 and Hp301 show a breakdown in photosynthesis. We examined five genotypes B73, Mo17, C123, NC338 and Hp301 in carefully controlled ambient and elevated ozone conditions. As variation in Maize genomes is enormous the transcriptome of each condition was captured empirically, using long read libraries for each genotype and condition (n=10). Short reads for 12 independent samples (n=120) were used to quantify and test differential expression. In the leaf, the portfolio of expressed genes and transcripts is stable and derived from the syntenic genome. All expressed genes were present in the B73 genome and most were syntenic between the B73 and Mo17 reference genomes (94.5 percent). Transcriptional response to ozone exposure was divergent among genotypes. B73 had a very limited transcriptional response, while NC338 response was dramatic. The 81 genes that were differentially expressed in all 5 genotypes were enriched for photosynthesis related genes while there were no discernable patterns to the genotype specific transcriptional response.