Mass spectrometry-based method to investigate the natural selectivity of sucrose as the sugar transport form for plants

• MS technique was employed to dissect the intrinsic structure feature of sucrose.
• Sucrose has the most labile glycosidic bond among sucrose isomers.
• Sucrose has the most stable integral structure among sucrose isomers.
• K+ is a better co-transporter for sucrose based on the MS results.
• The above results are the new explanation for the nature selection of sucrose.

Sucrose is the carbon skeletons and energy vector for plants, which is important for plants growth. Among thousands of disaccharides in Nature, why chose sucrose for plants? In this paper, we analyzed the intrinsic structural characteristics of four sucrose isomers with different glycosidic linkage by mass spectrometry (MS) technique. Our results show that sucrose has the most labile glycosidic bond compared with other three isomers, which is helpful for releasing glucose and fructose unit. Besides, sucrose has the most stable integral structure, which is hard to dehydrate and degrade into fragments through losing one or three even four-carbon units, just as its three isomers. In other words, sucrose is more easily holds an integral structure during the transport process, whenever it is necessary, and sucrose can be cleaved into glucose and fructose easily. Besides, we also investigate the internal relationship of sucrose with K+ by tandem mass spectrometry and viscosity measurement. The related results have shown that the K+ can stabilize sucrose to a greater extent than the Na+. Furthermore, under the same conditions, K+ ions reduce the viscosity of sucrose–water system much more than Na+. These results suggest that K+ is a better co-transporter for sucrose.Of course, the transport of sucrose in plants is a very complicated process, which is involved in many proteins. This paper directly accounts for the basic structure feature of sucrose, and the results discovered could provide the novel insight for the answer why Nature chose sucrose for plants.

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