Transcriptional Plasticity and Cell Wall Characterization in High-Methanol-Producing Transgenic Tobacco Plants

Volatile organic compounds emanating from plant surfaces serve as a sustainable natural solution to combat biotic stresses in plants. Leaf methanol is the simplest and second major volatile organic compound after isoprene emitted through the leaf surface. Methanol has been neglected as a by-product of other secondary metabolites for a long time, but recent studies have suggested its importance in development and stress responses. In our previous findings, we had revealed that transgenic plants over-expressing PME, enhanced methanol production providing resistance against a broad spectrum of insects. In the current study, we extended our previous work to provide new insights by performing differential transcriptomics of high-methanol-producing insect-resistant transgenic lines. We found that 2262 genes were differentially expressed in the transgenics plants, including transcription factors, cell wall modulating, phytohormones signaling and development-related genes. Our results demonstrated that the expression levels of transcription factors associated with development and biotic stress were altered in the transgenic lines. In addition, phytohormones ABA and gibberellin signalling genes were upregulated, whereas ethylene and auxin signalling genes were downregulated. Moreover, biochemical characteristics of cell walls in both transgenic tobacco plants were comparable to the control plants.