Transcriptome profile analysis of overexpression of SlRBZ results in etiolation and dwarfism by impairing chlorophyll, carotenoid, and gibberellin biosynthesis in tomato

Purpose: Many studies have demonstrated that ZFPs have important functions in many biological processes, including plant growth and development, stress response, and phytohormone response. RanBP2-type zinc finger transcription factors have been characterized in animals and humans. However, their functions remain largely unknown in plants. Therefore, the functions of RanBP ZFPs in plants need further study to shed new insights into the importance of these transcription factors in developmental processes. Methods: The transcriptomes of between overexpression of SlRBZ transgenic and wild-type tomato by RNA-seq analysis were evaluated using the Illumina HiSeq™ 2000 sequencing platform. Raw sequences were filtered and the resulting sets of clean reads were used for the following analysis by Tophat and DEGseq software. qRT–PCR validation was performed using SYBR Green assays. Results: In this study, we identified a RanBP2-type zinc finger protein gene (SlRBZ) in tomato. SlRBZ was constitutively expressed in roots, stems, leaves, flowers and fruits. Overexpression of SlRBZ resulted in etiolated and dwarf phenotypes in tomato. Determination of physiological index showed that chlorophyll, carotenoid, and GAs contents were evidently decreased in transgenic plants. Furthermore, the qRT-PCR and RNA-Seq analyses demonstrated that the transcription of the genes involved in these biosynthesis pathways obviously decreased in SlRBZ-OE plants. In addition, ultrastructural observation by transmission electron microscopy indicated that plastids could not develop into mature chloroplasts with normal chloroplast membrane and thylakoid membrane system in SlRBZ-OE plants. Conclusions: The results suggest that overexpression of SlRBZ may impair the biosynthesis of chlorophyll, carotenoid, and gibberellin through blocking chloroplast development, resulting in etiolation and dwarfism in tomato. Overall design: The transcriptomes of between overexpression of SlRBZ transgenic and wild-type tomato by RNA-seq analysis were evaluated, in duplicate, using the Illumina sequencing platform.