Comparative transcriptome analysis reveals the function of SlPRE2 in multiple phytohormones biosynthesis, signal transduction and stomatal development in tomato

Abstract As a member of the basic/helix-loop-helix family transcription factors, the atypical bHLH Paclobutrazol Resistances (PREs) regulate plant morphology, cell size, pigment metabolism and abiotic stress in response to different phytohormones. However, little is known about the network regulation mechanisms of PREs regulated plant growth and development. In this study, the function and mechanism of SlPRE2 in tomato plant growth and development were investigated. The Quantitative RT-PCR results showed that the expression of SlPRE2 was regulated by multiple phytohormones and abiotic stresses. And it showed a light-repressed expression in photoperiod. The RNA-seq results revealed that the SlPRE2 regulated many genes involved in photosynthesis, chlorophyll metabolism, phytohormone metabolism and signaling, and carbohydrate metabolism, suggesting the role of SlPRE2 in gibberellin, brassinosteroid, auxin, cytokinin, abscisic acid and salicylic acid regulated plant development process. Moreover, the SlPRE2 overexpression plants showed widely opened stomata in young leaves, and four genes involved in stomatal development showed changed expression. Overall, the results demonstrate the regulation mechanism of SlPRE2 regulated phytohormone and stress response and the function of SlPRE2 in stomatal development in tomato. These findings provide useful clues for understanding the molecular mechanisms of SlPRE2 regulated plant growth and development in tomato.