Characterization of Citrus maxima CYP86A22-like gene involved in stem and fruit development

Abstract In the present study, a novel CYP86A22-like (CYP86A22L) was identified from Citrus maxima fruits. CmCYP86a22L contained most conserved motifs of plant CYP450 family, and its transcript levels was high in different fruit tissues but dramatically decreased during fruit development. To elucidate the specific role of the variable substrate recognition site (SRS) SRS6 region in CmCYP86A22L, C-terminal fragment containing SRS6 region was transiently expressed in tobacco leaves, and exogenous CmCYP86A22L mRNAs were significantly upregulated as expected. Furthermore, the stem diameters of CmCYP86A22L transient expression lines were wider than mock in 3~12 days after infiltration, accompanied by increases cell layers of xylem, phloem and cortex, and cortex cell volume. Additionally, the CmCYP86A22L transient expression stems lacked visible cuticle on epidermal cells. These results collectively suggested that CmCYP86A22L was involved in fruit development, and the SRS6 region of CmCYP86a22L could regulate stem growth.