Electronic Thesis and Dissertation Repository

Degree

Master of Science

Program

Biology

Supervisor

Dr. Sangeeta Dhaubhadel

Abstract

I identified members of the Cyclophilin (CYP) gene family in soybean (Glycine max) and characterized the GmCYP1, one of the members of soybean CYP. CYPs belong to the immunophilin superfamily with peptidyl-prolyl cis-trans isomerase (PPIase) activity. PPIase catalyzes the interconversion of the cis- and trans-rotamers of the peptidyl-prolyl amide bond of peptides. After extensive data mining, I identified 62 different CYP genes in soybean (GmCYP1 to GmCYP62), of which 8 are multi-domain proteins and 54 are single domain proteins. At least 25% of the GmCYP genes are expressed in soybean. GmCYP1 localizes to the nucleus and the cytoplasm and it interacts with an R1 MYB transcription factor, GmMYB176, in the nucleus. Furthermore, GmCYP1 forms a dimer in planta. A loss-of-function mutation of the Arabidopsis ortholog of GmCYP1 (ROC1, ROC3 and ROC5) showed sensitivity towards salt stress during the seed germination, but did not respond differently than wild type when salt stress was applied to mature plants. This suggests a germination specific role of ROC1, ROC3 and ROC5 in salt stress in Arabidopsis. Moreover, roc3 and roc5 showed early flowering phenotypes under long day condition but not under short day, suggesting a role in photoperiod specific transition from vegetative to reproductive stage in Arabidopsis. Overall, these results propose that GmCYP1 functions in response to salt stress and flowering in soybean.