Phenotype, physiology and transcriptome analysis of vivipary in cucumber

Vivipary is a common phenomenon in nature. However, vivipary in cucumber affects seed production and processing, and it is necessary to understand the mechanism. In this study, the phenotype, physiology and transcriptome of easy-viviparous cucumber inbred line ‘D1158’ were analyzed. The vivipary manifested on the 35th day after pollination, and the viviparous germination rate reached 50 % on the 55th day after pollination. The viviparous germplasm resources were mainly concentrated in South China and North China types rather than European greenhouse and pickle types. Besides, high temperature, withered plants, and postripeness promoted vivipary. Differentially expressed genes in transcriptome were enriched in hormone signal transduction, energy and nutrient metabolism, and cellular component biosynthesis pathways. BR, CTK, IAA, and JA signals were activated, while ABA and ETH signals were inhibited in vivipary. Starch degradation and biosynthesis of soluble sugars, amino acids, fatty acids, and phenylpropanoids were up-regulated, possibly facilitating cell proliferation in vivipary. A potential regulatory pattern in the formation of vivipary in cucumber was constructed, and candidate genes were predicted. The results may enhance the comprehension of vivipary in cucumber and provide a basis for future research.