Maize 4-coumarate coenzyme A ligase Zm4CL-like9 gene positively regulates drought stress response in Arabidopsis thaliana

Maize is a major food crop in China, and drought is one of the major abiotic stresses that threaten the growth and development of the crop, seriously affecting the crop yield. 4-coumaric acid coenzyme A ligase (4CL) is a key enzyme in the phenylpropane metabolic pathway, which can regulate the lignin content of the plant and play an important role in the plant's resistance to drought stress, plays an important role in plant resistance to drought stress. In the present study, we screened the differentially expressed up-regulated gene Zm4CL-like9 under drought stress by pre-transcriptome sequencing data (PRJNA793522) in the laboratory, and analyzed the significant up-regulation of Zm4CL-like9 gene in roots under drought stress by qRT-PCR(Real-Time Quantitative Reverse Transcription PCR). The results of prokaryotic expression experiments showed that the protein encoded by the Zm4CL-like9 gene was able to be expressed in prokaryotic cells and could effectively improve the drought tolerance of E. coli. Phenotypic analysis of transgenic Arabidopsis plants under drought stress revealed that seed germination rate, root length, and plant survival after drought rehydration were significantly higher in transgenic Zm4CL-like9 Arabidopsis compared with wild-type Arabidopsis; physiological and biochemical indexes revealed that peroxidase activity, proline (Pro) content, and chlorophyll content were significantly higher in transgenic Arabidopsis compared with wild-type Arabidopsis. Under drought stress, the expression of drought-related genes was significantly up-regulated in transgenic Arabidopsis compared with wild-type Arabidopsis. Taken together, the Zm4CL-like9 gene enhances plant resistance to drought stress by reducing reactive oxygen species accumulation in plants.