By Max De La Cruz Morrobel

Faculty Mentor: Dr. April Wynn

Abstract

Brassinosteroids (BRs) are a class of plant growth hormones that induce cellular growth and division whose fine-tuning can have valuable implications for developing higher-yielding transgenic crops. They travel through plasmodesmata (PD), a cytoplasmic sleeve between the cell walls of plants cells. PDs have a regulatory mechanism called callose deposition which constricts the channel and thereby the flow of molecules by the deposition of the polysaccharide callose via Glucan Synthase Like 8 (GSL8) whose levels are upregulated by the BR induced transcription factor BRI-EMS-SUPPRESSOR1 (BES1). Plasmodesmata-located Protein 5 (PDLP5) upregulates GSL8 activity, but by an unknown mechanism. To explore the role of PDLP5 in BR regulation, we grew wild type Col-0 and LoF pdlp5 Arabidopsis thaliana seedlings on ½ MS agar plates for ten days and treated them with 0nM, 10nM, or 100nM brassinolide for 24 hours. We performed a qRT-PCR on mRNA extracted from the seedlings to find the relative gene expression levels of callose synthesizing gene GLUCAN-SYNTHASE-LIKE 8 (GSL8). We analyzed the data with a two-tailed two-sample T-test (p = 0.05) and found that there is no significant difference between treatment groups. This suggests that there is no genetic basis in the regulation of PDLP5. Future work can look at protein interactions with PDLP5 and expression of other genes like BES1.