RNA-Seq analysis to investigate alternate bearing mechanism in Pistacia vera L.
Pistachio (Pistacia vera L.) production suffers a high level of alternate bearing. The mechanism underlying this negative phenomenon is different from other species, such as apple and olive. Pistachio produces a high number of inflorescence buds every year that in heavy cropping trees (ON) mostly fall during the kernel development phase, which occurs in July-August. Primary metabolites (i.e., carbohydrates) play a key role in the signaling related to inflorescence bud abscission. In this work, RNA-Seq was used as a tool to investigate transcriptome of inflorescence buds and fruits, sampled from branches with low (OFF) and high (ON) crop load. Reference based RNA-Seq analysis using Arabidopsis thaliana genome was performed to discover differentially regulated genes in ON vs. OFF branches. In fruits developed on ON branches, photosynthesis, terpenoid and alpha-amylase-related genes were induced while tetrapyrrole was repressed; in inflorescence buds, photosynthesis was repressed while two genes involved in terpenoids pathways were still induced in comparison to the buds bore on OFF branches. A comparison with citrus transcriptomic data was performed. The data collected in the present study will be further utilized by the completion of pistachio genome and transcriptome de novo assembly.
Martinelli, F., Marchese, A., Balan, B., Giovino, A., Caruso, T., Fretto, S. and Marra, F.P. (2018). RNA-Seq analysis to investigate alternate bearing mechanism in Pistacia vera L.. Acta Hortic. 1229, 71-78
alternate bearing, crop load, inflorescence bud abscission, RNA-Seq, transcriptome