PpHB22, a member of HD-Zip proteins, activates PpDAM1 to regulate bud dormancy transition in ‘Suli’ pear (Pyrus pyrifolia White Pear Group)

• Published in: Plant physiology and biochemistry Vol. 127; pp. 355 - 365
• Main Authors: Yang, Qinsong, Niu, Qingfeng, Li, Jianzhao, Zheng, Xiaoyan, Ma, Yunjing, Bai, Songling, Teng, Yuanwen
• Format: Journal Article
• Language: English
• Published: France Elsevier Masson SAS 01.06.2018
• Subjects: ABA; Bud dormancy; HD-Zip family; Pear (Pyrus pyrifolia); PpDAM1; PpHB22; ABA; PpDAM1; PpHB22; Pear (Pyrus pyrifolia); HD-Zip family; Bud dormancy
• ISSN: 0981-9428; 1873-2690
• DOI: 10.1016/j.plaphy.2018.04.002

Homeodomain-leucine zipper (HD-Zip) proteins, which form one of the largest and most diverse families, regulate many biological processes in plants, including differentiation, flowering, vascular development, and stress signaling. Abscisic acid (ABA) has been proved to be one of the key regulators of bud dormancy and to influence several HD-Zip genes expression. However, the role of HD-Zip genes in regulating bud dormancy remains unclear. We identified 47 pear (P. pyrifolia White Pear Group) HD-Zip genes, which were classified into four subfamilies (HD-Zip I–IV). We further revealed that gene expression levels of some HD-Zip members were closely related to ABA concentrations in flower buds during dormancy transition. Exogenous ABA treatment confirmed that PpHB22 and several other HD-Zip genes responded to ABA. Yeast one-hybrid and dual luciferase assay results combining subcellular localization showed that PpHB22 was present in nucleus and directly induced PpDAM1 (dormancy associated MADS-box 1) expression. Thus, PpHB22 is a negative regulator of plant growth associated with the ABA response pathway and functions upstream of PpDAM1. These findings enrich our understanding of the function of HD-Zip genes related to the bud dormancy transition. [Display omitted] •PpHB22 is identified and characterized from 47 HD-Zip genes in pear genome.•The expression of PpHB22 is correlated with ABA content and dormancy status.•PpHB22 is located in nucleus and directly activates the transcription of PpDAM1.