Transcriptome analysis of asymmetric root growth of O. sativa induced by ambient temperature through ethylene pathway

Plant roots can sense external stimuli and make morphological changes. Under certain conditions, roots will grow asymmetrically to adapt to environmental changes. Ambient temperature (AT) and plant hormones have important effects on the growth of plant roots. Although it has been known that ethylene (ETH) was a key node regulating asymmetric root growth (ARG), the effect of AT on ARG was still unknown. Meanwhile, the relationship between AT, ETH, and ARG was also unclear. Here, we used O. sativa seedlings as material, and found that higher AT could induce ARG of O. sativa, which depended on ETH pathway. The results showed that AT-induced ARG depended on ETH synthesis and signal transduction, and the related genes were OsACOs and OsERFs. In the downstream of ETH, on one hand, there were significant differences in the expression of some genes related to auxin polar transport, signal transduction and synthesis, such as OsABCB15, OsNPFs, OsYUCCA5; On the other hand, the expression of genes regulated root elongation changed significantly, such as OsEXPA6, OsXTR8, OsCYCD3 and so on. In addition, there were significant differences in the expression of receptor like kinase (RLK) gene OsRMC, which inhibited ARG of O. sativa. The above DEGs were up-regulated in 35 degrees treatment and down regulated in inhibitor treatment. In conclusion, this study found for the first time that high AT can induce ARG through ETH pathway, and provided a basis for revealing the molecular mechanism of ARG induced by AT through ETH pathway.