*3.4. DEGs of Transcription Factors (TFs) under Drought Stress*

There are 228 (10.62%) DEGs that were assigned to bHLH TF. The basic helix-loop-helix proteins are one of the largest transcription factor families and are widely distributed in eukaryotes [50]. Many important drought-tolerant genes have been discovered in the bHLH family. Over-expression of OsbHLH148 in the transgenic rice make the plant more drought-tolerant by regulating the jasmonate signal transduction pathway [51]. Up-regulation of bHLH122 can significantly increase ABA levels in cells and it is a positive regulator of drought, NaCl and osmotic signaling [52]. AtbHLH112 is a nuclear-localized protein induced by salt, drought and ABA, and it can increase proline levels and improve ROS scavenging ability to enhance stress tolerance [53]. At the same time, there are also a number of other TFs that play an important role in plants' resistance to abiotic stresses, such as MYB (9.65%), ERF (8.20%) and NAC (7.13%). In this study, most of the genes that enhance plants' stress resistance were achieved by overexpression, so we will pay more attention to the up-regulated genes and dig out the role of specific genes in the processes of stress resistance by transgenic and gene-silencing technology.
