Abstract:

In this study,Cucumis sativus‘9930’was used as the material. The cucumber phenotype during different stages,the annotation of miR156/157-SPL,the structure and expression of genes were analyzed. The results showed cucumber exhibited an age-dependent developmental pattern,the leaf 1/2,leaf 3/4 and leaf 5 stages were classified as the juvenile stage,transition stage and adult stage,respectively. In cucumber genome,seven Csa-MIR156 loci,three Csa-MIR157 loci and 14 Csa-SPL were identified and distributed on chromosome 1,2,3,4 and 6,respectively. Exon number of Csa-SPL span is from 2 to 10,and their SBP domains are coded by exon 1 and 2. SBP domains contain two zinc finger domains （Zn_1 and Zn_2）and a nuclear localization signal. In addition,the large molecular weight of Csa-SPL8 and Csa-SPL11 contain several additional domains. Csa-SPL were clustered into 5 sub-family by phylogenetic tree analysis. Eleven Csa-SPL were predicted as target of Csa-miR156/157,and three of them （Csa-SPL5,10 and 14）hold the Csa-miR156/157 binding sites within the 3′UTR. Csa-SPL7,as a miR156 target,holds a specific mutation in 11th position. Interesting,this mutation is conserved among Cucurbitaceae plants. Gene detection results showed Csa-MIR156B and C functioned as the major loci,the expression of Csa-miR156 decreased and its Csa-SPL targets increased during age development. Specifically,Csa-SPL7 was highly expressed in cotyledon stage and its abundance showed no change during plant development. The expression pattern of Csa-SPL7 was consisted with the mutation within Csa-miR156 binding site,which suggested negative regulation by Csa-miR156 was relieved in Csa-SPL7. In summary,this study suggests miR156/157-SPL pathway plays a role in regulating cucumber vegetative traits（leaf shape,internode length and tendril formation）,moreover,the releasing of SPL7 may play an unknown role during early vegetative stage in Cucurbitaceae plants.

Key words: cucumber, Csa-miR156/157, Csa-SPL, gene expression