Genome-Wide Identification and Tissue-Specific Expression Profiling of Goji CER Gene Family

Background: Goji berry, known as a “superfood”, is widely distributed in northwest China and possesses significant medicinal and health value. The CER gene family serves as a key regulator of cuticular wax synthesis, which plays important roles in enhancing plant drought resistance and disease tolerance. However, genome-wide identification of the goji CER gene family and its expression analysis across different varieties and organs have not been reported. Methods: Based on SEM observations and wax load measurements, this study identified CER gene family members using whole genome data of the goji berry. Representative genes were selected and their expression patterns in different varieties and organs were validated by qRT‒PCR. Results: The stem wax load was significantly higher than that in other organs, while the leaf wax load of ‘Ningqi I’ goji was significantly higher than that in other varieties, consistent with SEM observations. A total of 113 CER gene family members were identified in goji berry, which were unevenly distributed on 12 chromosomes. The goji CER proteins mainly localized in the cell membrane, cytoplasm, chloroplast, and nucleus and clustered into five subfamilies. Ten conserved motifs were identified in CER proteins, with Motif5 and Motif7 being the most widely distributed. The LbaCER10-1 gene contained the highest number of exons (39). Cis-acting elements related to light-responsiveness, MeJA-responsiveness, and ABA-responsiveness showed high frequencies. Goji berry shared more homologous CER genes with tomato, potato, and tobacco than with Arabidopsis, with chr3 and chr9 being most conserved while chr7 showed greater variation. Conclusions: Integrating SEM, wax load, and qRT‒PCR results, LbaCER1-1 was identified as a candidate gene responsible for the higher wax load on goji stems, while LbaCER2-5 and LbaCER3-12 were candidate genes for greater wax load on ‘Ningqi I’ leaves.