Comparative transcriptomic analysis reveals novel roles of transcription factors and hormones during the flowering induction and floral bud differentiation in sweet cherry trees (Prunus avium L. cv. Bing)

LLANES, ANALÍA; CORREA, FRANCISCO; LUNA, VIRGINIA; VILLAR, LUIS; ROJAS, PAMELA; SAGREDO, BORIS; ALMADA, RUBÉN; LIENQUEO, IXIA; PEREZ, JORGE; MASCIARELLI, OSCAR

PLOS ONE

PUBLIC LIBRARY SCIENCE

Año: 2020 vol. 15 p. 1 - 28

1932-6203

In sweet cherry trees, flowering is commercially important because the flowers, after fertilization, will generate the fruits. In P. avium, the flowering induction and flower organogensisare the first developmental steps towards flower formation and they occur within specializedorgans known as floral buds during the summer, nine months before blooming. During thisperiod the number of floral buds per tree and the bud fruitfulness (number of flowers perbud) are stablished affecting the potential yield of orchards and the plant architecture. Thefloral bud development is sensitive to any type of stress and the hotter and drier summerswill interfere with this process and are calling for new adapted cultivars. A better understanding of the underlying molecular and hormonal mechanisms would be of help, but unlike themodel plant Arabidopsis, very little is known about floral induction in sweet cherry. Toexplore the molecular mechanism of floral bud differentiation, high-throughput RNAsequencing was used to detect differences in the gene expression of P. avium floral buds atfive differentiation stages. We found 2,982 differentially expressed genes during floral buddevelopment. We identified genes associated with floral initiation or floral organ identity thatappear to be useful biomarkers of floral development and several transcription factor families (ERF, MYB, bHLH, MADS-box and NAC gene family) with novel potential roles duringfloral transition in this species. We analyzed in deep the MADS-box gene family and weshed light about their key role during floral bud and organs development in P. avium. Furthermore, the hormonal-related signatures in the gene regulatory networks and the dynamicchanges of absicic acid, zeatin and indolacetic acid contents in buds suggest an importantrole for these hormones during floral bud differentiation in sweet cherry. These data providea rich source of novel informacion for functional and evolutionary studies about floral buddevelopment in sweet cherry and new tools for biotechnology and breeding.