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Article|20 Jan 2022|OPEN
Galactinol synthase 1 improves cucumber performance under cold stress by enhancing assimilate translocation
Haibo Dai1 , Zihui Zhu1 , Zhenguang Wang1 , Zhiping Zhang1 , Weiwen Kong1 and Minmin Miao,1,2,3 ,
1College of Horticulture and Plant Protection, Yangzhou University, Yangzhou 225009, China
2Joint International Research Laboratory of Agriculture and Agri-Product Safety of Ministry of Education of China, Yangzhou University, Yangzhou 225009, China
3Key Laboratory of Plant Functional Genomics of the Ministry of Education/Jiangsu Key Laboratory of Crop Genomics and Molecular Breeding, Yangzhou University, Yangzhou 225009, China
*Corresponding author. E-mail: mmmiao@yzu.edu.cn

Horticulture Research 9,
Article number: uhab063 (2022)
doi: https://doi.org/10.1093/hr/uhab063
Views: 176

Received: 19 May 2021
Revised: 20 Nov 2021
Published online: 20 Jan 2022

Abstract

Cucumber (Cucumis sativus L.) predominantly translocates raffinose family oligosaccharides (RFOs) in the phloem and accumulates RFOs in leaves. Galactinol synthase (GolS) catalyzes the critical step of RFO biosynthesis, and determining the functional diversity of multiple GolS isoforms in cucumber is of scientific significance. In this study, we found that all four isoforms of CsGolS in the cucumber genome were upregulated by different abiotic stresses. β-Glucuronidase staining and tissue separation experiments suggested that CsGolS1 is expressed in vascular tissues, whereas the other three CsGolSs are located in mesophyll cells. Further investigation indicates that CsGolS1 plays double roles in both assimilate loading and stress response in minor veins, which could increase the RFO concentration in the phloem sap and then improve assimilate transport under adverse conditions. Cold-induced minor vein-specific overexpression of CsGolS1 enhanced the assimilate translocation efficiency and accelerated the growth rates of sink leaves, fruits, and whole plants under cold stress. Finally, our results demonstrate a previously unknown response to adverse environments and provide a potential biotechnological strategy to improve the stress resistance of cucumber.