Cloning, expression, and functional analysis of the CaRIN gene, encoding a MADS-box transcription factor from pepper

Abstract

Abstract [Objective] The study aims to explore the expression and function of the RIN gene, encoding a MADS-box, and analyze its impact on the metabolism of carotenoids in pepper. [Methods] Based on the fruit development transcriptome of pepper, the full-length CDS of the MADS-box transcription factor Ca- RIN gene related to chili ripening was cloned. The bioinformatics, expression pattern, subcellular localization, and transcriptional activation activity were examined, and the effects of VIGS-induced CaRIN gene silencing on carotenoid metabolism were investigated. [Results] (1) The CDS of CaRIN gene was 732 bp in length. CaRIN gene encoded a protein containing 243 amino acids with a molecular mass of 27.95 kD and an isoelectric point (pI) of 7.06. CaRIN protein had a typical MEF2_ like MADS domain, belonging to the MICK type transcription factor. (2) CaRIN gene was mainly expressed in flowers and fruits with tissue specificity. CaRIN was located in the nucleus and had transcriptional activation activity. (3) The promoter of CaRIN gene had several hormone response elements such as ABRE, and exogenous ABA and ethephon accelerated the fruit to turn red and induced the high expression of CaRIN and related genes. (4) After VIGS-induced gene silencing of CaRIN , the expression level of PSY1, CCS, PDS, CRTZ, LCYB, and NCED1, genes involved in carotenoid metabolic pathway, was decreased by 0.27-0.59 times, and the total carotenoid content in fruits (0.379 mg/g) was decreased compared with the control (0.650 mg/g). [Conclusion] CaRIN may be an important regulatory factor of carotenoid metabolism in capsicum fruits.

Keywords

• pepper
• mads-box transcription factor
• carin
• vigs
• carotenoid