Expression and genomic structure of the dormancy-associated MADS box genes MADS13 in Japanese pears (Pyrus pyrifolia Nakai) that differ in their chilling requirement for endodormancy release

Abstract

We isolated three dormancy-associated MADS-box (DAM) genes (MADS13-1, MADS13-2 and MADS13-3) and showed regulated expression concomitant with endodormancy establishment and release in the leaf buds of Japanese pear 'Kosui'. Comparative analysis between 'Kosui' and Taiwanese pear TP-85-119 ('Hengshanli'), a less dormant pear cultivar, showed reduction of MADS13-1 expression level in 'Hengshanli' earlier than in 'Kosui' towards endodormancy release, suggesting the possible relationship between chilling requirement and MADS13-1 expression. Application of hydrogen cyanamide accelerated endodormancy release with a reduction in MADS13 expression, whereas heat treatment in autumn inhibited endodormancy establishment without induction of MADS13 expression, indicating a close relationship between the MADS13 expression pattern and endodormancy phase transitions. Moreover, both the cis-acting regulatory elements and the methylation status in the 5' upstream region of the MADS13-1 gene were not largely different between 'Kosui' and 'Hengshanli'. Genomic structures of MADS13-1 from 'Kosui' and 'Hengshanli' revealed a 3218 bp insertion in the first intron of 'Hengshanli' that might be ascribed to the lower expression of MADS13-1tw; however, this insertion was also found in pear genotypes with a high chilling requirement. These results indicated that the low expression of MADS13-1 in 'Hengshanli' towards endodormancy release could not be explained by the identified cis-acting regulatory elements, the methylation status of the putative promoter or by intron insertion.

Effects of Fluridone Treatment on Seed Germination and Dormancy-associated Gene Expression in an Ornamental Peach (<i>Prunus persica</i> (L.) Batsch)

“…In the Japanese pear, PpMADS13-1 and -2 in the leaf bud were shown to be upregulated during endodormancy establishment and downregulated during endodormancy release (Nishitani et al, 2012;Saito et al, 2013). In a previous study, LeMADS were also significantly repressed during chilling treatment of peach embryos (Worarad et al, 2016).…”

Dormancy Behaviors and Underlying Regulatory Mechanisms: From Perspective of Pathways to Epigenetic Regulation

“…However, the role of DNA methylation in the regulation of DAMs remains limited. In pear, three DAM paralogs display a similar up-and downregulation pattern during dormancy establishment and release (Saito et al 2013), resembling peach DAMs regulation (Li et al 2009), but no evident change of DNA methylation in buds was detected during dormancy onset, maintenance and release (Saito et al 2013).…”

“…Differential regulation of DAMs by chilling temperatures during dormancy release has been reported in Japanese apricot ( Prunus mume) (Sasaki et al 2011), Japanese pears ( Pyrus pyrifolia Nakai) (Saito et al 2013), potato (Campbell et al 2008), raspberry ( Rubus idaeus) (Mazzitelli et al 2007) and kiwifruit ( Actinidia spp) (Wu et al 2014). Ectopic expression of apricot DAM6 in poplar ( Populus tremula × Populus tremuloides) promotes dormancy onset in the transgenic lines (Sasaki et al 2011), indicating that apricot and poplar likely share the similar regulatory factor or mechanism.…”

Recent Advances in Genetics and Molecular Control of Bud Dormancy in Pipfruits

“…Additionally, it was recently shown that the silencing of PpDAM6 is preceded by changes in the methylation status of H3K27 residues of histones bound to its chromatin (Leida et al 2012), as well as occurs in the silencing of FLC and other genes that regulate vernalization in A. thaliana (Angel et al 2011). Although putative DAM orthologues were identified in pear (Ubi et al 2010;Saito et al 2013), apple (Falavigna et al 2014), raspberry (Mazzitelli et al 2007), kiwifruit (Wu et al 2012), leafy spurge ) and apricot , a complete functional characterization of DAM genes remains to be reported.…”