Distinctive gene expression patterns define endodormancy to ecodormancy transition in apricot and peach

Authors: YU, JIALI - University Of Tennessee; CONRAD, ANNA - University Of Kentucky; DECROOCQ, VERONIQUE - University Of Bordeaux; ZHEBENTYAYEVA, TETYANA - Pennsylvania State University; WILLIAMS, DAN - University Of Tennessee; Bennett, Dennis; ROCH, GUILLAUME - Institut National De La Recherche Agronomique (INRA); AUDERGON, JEAN-MARC - Institut National De La Recherche Agronomique (INRA); Dardick, Christopher - Chris; Liu, Zongrang; ABBOTT, ALBERT - University Of Kentucky; STATON, MEG - University Of Tennessee

Submitted to: Frontiers in Plant Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 2/6/2020
Publication Date: 2/28/2020
Citation: Yu, J., Conrad, A., Decroocq, V., Zhebentyayeva, T., Williams, D., Bennett Jr, D.R., Roch, G., Audergon, J., Dardick, C.D., Liu, Z., Abbott, A., Staton, M. 2020. Distinctive gene expression patterns define endodormancy to ecodormancy transition in apricot and peach. Frontiers in Plant Science. 11:180. https://doi.org/10.3389/fpls.2020.00180.
DOI: https://doi.org/10.3389/fpls.2020.00180

Interpretive Summary: Dormancy and chilling requirement are important traits to regulate plant flowering time and adaption to various climates, which are important for fruit production. Here, we analyzed and compared genome-wide gene expression profiles among different apricot and peach cultivars with distinct dormancy behaviors and chilling requirements. Our analyses identified a large number of genes that respond to chilling temperatures during dormancy, and many of these genes also control pollen development, cell wall biosynthesis, and a series of genetic and epigenetic regulatory programming. Our work provides important information for identifying the key genes controlling chilling requirement and dormancy traits as well as flowering time, which will be of practical significance for breeding of new fruit tree cultivars in the future.

Technical Abstract: Dormancy is an important mechanism for winter hardiness in fruit trees; however, the genetic control of dormancy phase transitions is still unclear. Here, we utilized the transcriptome profiles of apricot (Prunus armeniaca) cultivars with different bloom dates (BD) to explore the genetic regulation of bud dormancy. Floral buds from four apricot genotypes were collected at a series of time points spanning from beginning of chill accumulation in fall to bud break in spring. From RNA sequencing, we identified 1,367 differentially expressed genes between the endodormancy and ecodormancy stages. Co-expression and functional analyses revealed that genes expressed during endodormancy were involved in chromatin remodeling and reproduction, and the genes induced at ecodormancy were mainly related to pollen development and cell wall biosynthesis. The same experimental design was conducted in four peach (Prunus persica) genotypes with known chill requirements (CR), yielding 1,603 genes significantly upregulated and 499 genes downregulated at the ecodormancy stage. 608 differential expression genes were shared in both peach and apricot, including three DORMANCY ASSOCIATED MADS-box (DAM) genes (DAM4, DAM5 and DAM6). Of the 608 genes, 99 are located within peach CR quantitative trait loci (QTL), suggesting these genes as candidates for dormancy regulation. A co-expression network integrating peach and apricot genes indicated pollen development and oxidation reduction genes were induced at ecodormancy in both species. Gene expression analyses between two Prunus species highlighted the conserved transcriptional control of physiological activities in endodormancy and ecodormancy, and reveal genes that may be involved in the transition between the two stages.