AN EXPRESSION ANALYSIS OF AUXIN-RELATED GENES DURING INFLORESCENCE AND EARLY STAGES OF BERRY DEVELOPMENT IN GRAPEVINE

Auxin plays an important role in plant growth development, but the influence of auxin during inflorescence and early stages of berry development in grapevine has barely been investigated. The expression patterns of six VvYUC genes (related to auxin synthesis), VvTIR1-like (auxin receptor), VvPIN3-like (auxin efflux regulator), VvIAA9 and VvIAA19 (belongs to early auxin-responsive Aux/IAA gene family) were analysed in different organs. The results showed that the expression level of six VvYUC genes were lower than other auxin-related genes. Six VvYUC genes were expressed differentially in specific tissues. An exception was VvYUC10-like, transcripts of which were not found in any organ. By contrast, VvTIR1-like, VvPIN3-like, VvIAA9 and VvIAA19 were expressed in all organs (young leaf, mature leaf, tendril and stem) except VvIAA19 was not expressed in tendrils. This suggests that auxin-related genes were required for development of different organs. Transcripts of VvYUC genes were mainly detected before anthesis, only VvYUC6-like was expressed 6 days after anthesis. In addition, VvYUC10-like transcripts were not found before or after anthesis. Six VvYUC genes may be needed for grapevine inflorescence development, with the exception of VvYUC10-like, but do not affect fruit set. The expression of VvTIR1-like, VvPIN3-like, VvIAA9 and VvIAA19 were abundantly detected before and after anthesis, especially in the early stage of berry development. Our results show that these genes were related to the development of the inflorescence and to fruit set in the grapevine.