Objective N-glycosylation is a major co-translational and post-translational modification of proteins in eukaryotic cells, and plays an important role in endoplasmic reticulum associated protein degradation and adversity stress. α-Mannosidase (MNS) is involved in the removal of α-1,2 mannose from N-glycosylated glycoproteins. We analyzed the effect of OsMNS5 on growth and development in rice, providing a theoretical basis for further research on the physiological function of OsMNS5 as well as its role in endoplasmic reticulum associated degradation in rice.

Method OsMNS family members were identified using the rice genome database, and the protein physicochemical properties, phylogeny, conserved motifs, and cis-acting elements of their gene family members were systematically analyzed by bioinformatics methods. Gene editing of OsMNS5 was performed using CRISPR/Cas9 technology, and the effect of OsMNS5 knockout on rice growth was analyzed.

Result There are four members in the rice OsMNS gene family, distributed on four chromosomes, with similar protein conserved domains. The amino acid sequence length encoded by the OsMNS gene family is 572-684 aa, with a relative molecular weight range of 65.09-75.30 kD. The isoelectric point exhibits weak acidic to neutral characteristics, and the hydrophilicity coefficient is negative; The analysis of cis acting elements revealed that the promoter regions of OsMNS gene family members contain a large number of response elements related to plant hormones, adversity stress and light; OsMNS5 was homologous to Arabidopsis MNS5 through systematic evolutionary analysis in rice. OsMNS5 was knocked out using gene editing techniques to obtain two different types of homozygous mutants. Knocking out OsMNS5 reduced rice seed setting rate by 22.8% to 31.7%.

Conclusion Bioinformatics identified four MNS genes in rice, MNS proteins have conserved structural domains with homologous proteins in other species, OsMNS5 is homologous to AtMNS5 and may play an important role in endoplasmic reticulum associated degradation, and OsMNS5 knockout reduced the seed setting rate in rice. These results provide a theoretical basis for analyzing the biological functions of OsMNS5 in rice growth and development.