Abstract:

On the basis of gene sequence analysis of the strawberry alkaline/neutral invertase gene family（Fa.A/N-Inv），strawberry cultivars‘Shen Yang’and‘Benihoppe’were employed as materials. The expression patterns of Fa.A/N-Inv genes under different conditions were analyzed by qRT-PCR. The dynamic enzyme activity of A/N-Inv and the sugar accumulation during fruit development stages were determined by spectrophotography and high-performance liquid chromatography（HPLC），respectively. Eight members of alkaline/neutral invertases were identified in the strawberry genome. The expression patterns of 4 Fa.A/N-Inv genes are tissue-，developmental stage-，and genotype-specific. The expression of  4 Fa.A/N-Invs was differentially induced by cytokinin（BA），gibberellic acid（GA）and auxin（IAA）. Sucrose and glucose，as substrate and product of A/N-Inv，hold positive and negative feedback regulation on expression of the 4 genes，respectively. Besides，as a signal molecule，sucrose could induce the expression of Fa.A/N-Inv genes. The enzyme activity of A/N-Inv in‘Shen Yang’was higher than that in‘Benihoppe’fruits of all stages except for the green fruit. The content of sucrose in ripe ‘Benihoppe’fruit（50.7 mg · g^-1 FW）was double of that in‘Shen Yang’fruit（23.2 mg · g^-1 FW）.

Key words: strawberry, alkaline/neutral invertase, sugar signal, enzyme activity