Effects of Abscisic Acid and Sucrose on the Differential Expression of Anthocyanin Biosynthesis Genes in Strawberry

Abscisic acid (ABA) and sucrose could promote anthocyanins accumulation.However, the molecular mechanism of ABA, sucrose and interaction of ABA/sucrose in the accumulation of anthocyanins in strawberry fruit is unclear.We applied 95 M ABA, 100 mM sucrose and 95 M ABA + 100 mM sucrose to spray the strawberry fruit at de-greening stage.Subsequently, the treated fruits were collected at 0 and 8 days for RNA sequencing (RNAseq).The result showed that the expression patterns of differentially expressed genes (DEGs) in response to sucrose were similar to that of ABA + sucrose treatment, and ABA was similar to that of control (water), showing that synergistic interaction may occur between ABA and sucrose in promoting anthocyanin accumulation in strawberry fruit.Meanwhile, ABA, sucrose and ABA + sucrose treatments changed transcript level of MYB-bHLH-WD repeat (MBW) complex, WRKY and structural genes which are the crucial genes regulating biosynthesis of anthocyanins.The identification and expression analysis of MBW complex, WRKY, structural gene, glutathione S-transferase (GST), auxin response factor (ARF) and auxin responsive protein (Aux/IAA) related to anthocyanin synthesis suggested that up-regulation of WRKY31 (Cluster-12337.98154),WRKY71 (Cluster-12337.81062)and 6 GSTs (Cluster-12337.70402,Cluster-12337.74163,Cluster-12337.67740,Cluster-12337.80939,Cluster-12337.64226 and Cluster-12337.63035), and down-regulation of MYB1R1 (Cluster-12337.57122),bHLH48 (Cluster-12337.58812),bHLH51 (Cluster-12337.38826),bHLH93 (Cluster-12337.103164),WRKY2 (Cluster-12337.112247),WRKY53 (Cluster-12337.102451),WRKY24 (Cluster-12337.25453),ARF5 (Cluster-12337.73750),Aux/IAA4 (Cluster-12337.76254)and Aux/IAA16 (Cluster-12337.73689)contribute to accumulation of anthocyanins in ABA + sucrose or individual treatments.The structural genes of anthocyanin biosynthesis, including DFR (Cluster-12337.70165),UFGT (Cluster-12337.64199and Cluster-12337.80836) and ANS (Cluster-12337.69226and cluster