Dormancy-Associated MADS-Box (DAM) Genes Influence Chilling Requirement of Sweet Cherries and Co-Regulate Flower Development with SOC1 Gene.

Jiyuan Wang,Hui Li,Shiping Wang,Wenping Xu,Yueting Qu,Zhen Gao,Caixi Zhang,Songtao Jiu,Lei Wang,Chao Ma

doi:10.3390/ijms21030921

Abstract

Floral bud dormancy release of fruit tree species is greatly influenced by climate change. The lack of chilling accumulation often results in the occurrence of abnormal flower and low yields of sweet cherries (Prunus avium L.) in warm regions. To investigate the regulation of dormancy in sweet cherries, six DAM genes with homology to peach DAM, designated PavDAM1-6, have been identified and characterized. Phylogenetic analysis indicate that these genes are similar to DAMs in peach, apple and pear. The expression patterns of the PavDAMs in the low-chill cultivar ‘Royal Lee’ were different from that in the high-chill cultivar ‘Hongdeng’. ‘Royal Lee’ exhibits lower transcriptional level of PavDAM1 compared to ‘Hongdeng’, especially at the stage of chilling accumulation, and transcriptional levels of PavDAM4/5 were high in both cultivars during the endodormancy. Ectopic expression of PavDAM1 and PavDAM5 in Arabidopsis resulted in plants with abnormal flower and seed development, especially the PavDAM5. Higher transcriptional levels of SOC1 were observed in transgenic PavDAM1/5 lines, and ectopic expression of PavSOC1 had the similar floral phenotype. Further, protein interaction analysis demonstrated that PavDAM1/5 could interact with PavSOC1 in vivo and in vitro, which will help clarify the molecular mechanism of the flower development in sweet cherry or other fruit trees.

Highlights

Floral bud dormancy is an important biological process allowing sweet cherries (Prunus avium L.) to survive in winter
We cloned the PavDAM1-6 from sweet cherries, and six DORMANCY-ASSOCIATED MADS-BOX (DAM) genes with homology to peach DAM, have been identified and characterized from low-chill cultivar ‘Royal Lee’ and high-chill cultivar ‘Hongdeng’
‘Royal Lee’ exhibits lower transcriptional level of PavDAM1 compared with ‘Hongdeng’, especially at the stage of chilling accumulation, and transcriptional levels of PavDAM4/5 were high in both cultivars during the endodormancy

Summary

Introduction

Floral bud dormancy is an important biological process allowing sweet cherries (Prunus avium L.) to survive in winter. The dormancy has three main phases: paradormancy, endodormancy and ecodormancy [1]. Endodormancy plays a pivotal role for the chilling accumulation in the dormant phases. Endodormancy is released and enters into the ecodormancy [2]. Our previous report showed that the high-chill sweet cherry cv. Hongdeng, have a high percentage of abnormal female floral organs in warm regions because of a lack of chilling accumulation during the endodormancy, but not in cool regions [6]. We found that expression of MADS-Box genes were associated with the formation of polycarpy and fruit doubling under high temperature in sweet cherries [7]

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Results

Discussion

Conclusion