Comparison of Transcriptional Response of C(3) and C(4) Plants to Drought Stress Using Meta-Analysis and Systems Biology Approach

Drought stress affects a range of plant processes. It is still not well-known how C(3) and C(4) plants respond to drought. Here, we used a combination of meta-analysis and network analysis to compare the transcriptional responses of Oryza sativa (rice), a C(3) plant, and Zea mays (maize), a C(4) plant, to drought stress. The findings showed that drought stress changes the expression of genes and affects different mechanisms in the C(3) and C(4) plants. We identified several genes that were differentially expressed genes (DEGs) under stress conditions in both species, most of which are associated with photosynthesis, molecule metabolic process, and response to stress. Additionally, we observed that many DEGs physically located within the quantitative trait locus regions are associated with C isotope signature (d(13)C), photosynthetic gas exchange, and root characteristics traits. Through the gene co-expression and differential co-expression network methods, we identified sets of genes with similar and different behaviors among C(3) and C(4) plants during drought stress. This result indicates that mitogen-activated protein kinases (MAPK) signaling pathway plays an important part in the differences between the C(3) and C(4) species. The present study provides a better understanding of the mechanisms underlying the response of C(3) and C(4) plants to drought stress, which may useful for engineering drought tolerance in plants.