BnGLO4 gene cloning and bioinformatics analysis in Brassica napus L

High oleic acid rapeseed oil offers superior nutritional and health benefits, but its mass production is limited due to poor resistance and slightly lower yield. Photosynthesis serves as the foundation of biological survival and closely correlates with crop resistance to stresses, yield, and quality. To identify photosynthesis-related genes, transcriptome sequencing was conducted on high oleic acid rapeseed Gaoyousuan No. 1 and low oleic acid rapeseed Xiangyou 15 resulting in the identification of a total of 9396 differentially expressed genes (4669 up-regulated and 4727 down-regulated). From these genes nine candidate genes were screened using GO and KEGG analysis with BnGLO4 being selected for cloning purposes. The BnGLO4 gene fragment has a length of 1161 bp with an ORF sequence of 1092 bp encoding a theoretical isoelectric point of pI 7.60; it encodes an unstable lipid-soluble protein localized in peroxisomes without transmembrane structural domains or signal peptides. Its amino acid sequence homology was highest with that of BnaA01G0355200ZS, BnaA01G0355600ZS, BnaA05G0410400ZS, BnaC01G0441800ZS, and Brassica rapa (XP_0091171 45.1), Brassica napus (CDY39100.1), Brassica cretica (KAF3533604.1) and Brassica oleracea var. oleracea (XP_0136106 44.1) belonging to the same cruciferous family.

The BnGLO4 gene may be associated with responses to abiotic stresses such as salt, drought, and temperature extremes along with photosynthesis and growth in rapeseed plants. The expression levels of the GLO4 gene (BnaA01G0355200 ZS) were highest in filaments while being higher at each stage in seeds and siliques with the highest expression level at day 14 in seeds. Expression was significantly upregulated after 3 ​h of salt stress treatment, reaching a maximum at 12 ​h before slightly decreasing at 24 ​h. The findings of this study lay a foundation for further investigation on photosynthesis and stress response in high oleic rapeseed.