Dual benefits of CmNOR/Cmnor heterozygous plants: prolonging shelf life and preserving fruit quality in oriental melon

Abstract

Oriental melon, a climacteric fruit prized for its superior quality, faces limited shelf life. Although knockout NON-RIPENING (CmNOR) prolongs storage duration at the expense of quality loss, the potential of its direct agricultural application to reconcile this conflict remains uninvestigated. Through crossing homozygotes Cmnor and wild-type (WT) plants, we created CmNOR/Cmnor heterozygotes. These heterozygotes exhibited a 6-day ripening delay accompanied by reduced sucrose and β-carotene levels, yet ultimately attained WT quality parameters. Exogenous ethylene treatment accelerated fruit softening but failed to restore key quality parameters in both heterozygotes and homozygotes to WT levels. Transcriptomic and quantitative polymerase chain reaction (qPCR) analysis revealed that homozygotes displayed >10-fold expression differences versus WT in quality-associated genes (e.g. involved in carotenoid biosynthesis and sucrose metabolism). These expression disparities diminished to approximately 2-fold in heterozygotes. Furthermore, heterozygotes extended shelf life by 3-5 days during storage at 20°C while maintaining fruit quality. Storage-phase differential genes clustered in water regulation and cell wall modification pathways, with heterozygous-WT expression disparities gradually decreasing over time. The CmNOR dosage effect dynamically modulates interconnected quality and preservation networks, proposing an editing-based solution to overcome the storability-quality dichotomy in climacteric fruits.

Acknowledgements

This work was financially supported by the National Natural Science Foundation of China (32330093 and 32372717), the Collaborative Innovation Center of BAAFS (KJCX20240408 and KJCX20240337), the Scientist Training Program of BAAFS (YXQN202403 and JKZX202401), the Construction of Cucurbits Collaboration and Innovation Center (XTCX202301), an Innovation and Development Program of Beijing Vegetable Research Center (KYCX202401), the Beijing Rural Revitalization Agricultural Science and Technology Project (NY2401130024), and the Ministry of Agriculture and Rural Affairs of China (CARS-25).

Authors contributions

Y.X., Q.W., and J.-F.W. designed the research; J.-F.W., Y.L., Y.-T.Y., S.-W.T., M.-Y.L., Y.R., C.Z., and S.-J.L. performed most of the experiments; J.-F.W., Y.L., Y.-T.Y., and J.Z. analyzed the RNA-seq data; J.Z., G.-Y.G., H.-Y.Z., Q.W., and Y.X. revised the manuscript.

Data availability

The raw and processed RNA-seq data reported in this paper has been uploaded to Gene Expression Omnibus (accession number: GSE296878).

Conflicts of interest statement

The authors declare that they have no conflict of interest.

Supplementary material

Supplementary material is available at Horticulture Research online.

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