Foxtail Millet Stress Associated Protein Gene SiSAP4 Enhances Drought Stress Tolerance in Transgenic Arabidopsis

Abiotic stresses like drought affect plant growth and crop yield with climate change worsening. Stress associated proteins (SAPs), as the zinc finger proteins with A20/AN1 domain, play an important role in regulating abiotic stress response. As a typical summer dryland grain crop in the north of China, foxtail millet has the characteristics of drought resistance, making it a valuable resource for anti-stress gene exploitation and utilization. In this study, SiSAP4 gene was cloned from foxtail millet variety Yugu 1. Analysis showed that SiSAP4 gene was expressed in roots, stems and leaves at seedling stage, and the highest expression level was detected in leaves. Expression patterns under different stress conditions showed that expression level of SiSAP4 gene was significantly up-regulated under drought stress, suggesting it may be involved in drought stress response. Subcellular localization indicated that SiSAP4 was present in the nucleus and cytoplasm. It was revealed that SiSAP4 had no function in transcriptional activation in the yeast system. Overexpression of SiSAP4 in transgenic Arabidopsis resulted in enhanced tolerance to drought stress, which was simultaneously demonstrated by increased expression of a broad range of stress response genes. Based on those results, SiSAP4 has the potential to be used in transgenic breeding to improve drought stress tolerance in other crops. © 2021 Friends Science Publishers