A HD-ZIP II HOMEBOX transcription factor, PpHB.G7, mediates ethylene biosynthesis during fruit ripening in peach
Gu, C.; Guo, Z-Hua.; Cheng, H-Yan.; Zhou, Y-Hang.; Qi, K-Jie.; Wang, G-Ming.; Zhang, S-Ling.
Plant Science An International Journal of Experimental Plant Biology 278: 12-19
ISSN/ISBN: 1873-2259 PMID: 30471725 DOI: 10.1016/j.plantsci.2018.10.008
Homeobox transcription factors belong to a superfamily that has been widely studied in plant growth and development, but little is known regarding their role in fruit development and ripening. Using a genome-wide expression analysis of homeobox (HB) genes and quantitative real-time PCR, a HD-ZIP it member, PpHB.G7, which presented higher levels of expression in ripening fruits than in developing fruits in all of the tested cultivars, was isolated from peach. Transient transformations showed that PpHB.G7 affects ethylene production and the expression of ethylene biosynthesis genes (PpACS1 and PpACO1). Both dual-luciferase and yeast one hybrid assays confirmed that PpHB.G7 interacts with the promoters of PpACS1 and PpACO1. Thus, PpHB.G7 mediates ethylene biosynthesis by stimulating PpACS1 and PpACO1 activities. Furthermore, we also found that the other eight HB genes were differentially expressed in the developing fruits, with seven of these genes belonging to the HD-ZIP family. These results suggest that the FIB genes in the HD-ZIP family play important roles in fruit development and ripening.