SUMO-conjugating enzyme (Sce) and FK506-binding protein (FKBP) encoding rice (Oryza sativa L.) genes: genome-wide analysis, expression studies and evidence for their involvement in abiotic stress response

Abstract

We report an in-depth characterization of two major stress proteins namely SUMO-conjugating enzyme (Sce) and peptidyl prolyl cis-trans isomerase (PPIase) in rice (Oryza sativa L.). Sce mediates addition of SUMO group to various cell proteins, through process referred to as SUMOylation. Rice nuclear genome has two putative genes encoding the Sce protein (OsSce1 and OsSce2). PCR-amplified full-length OsSce1 cDNA functionally complemented the growth defect in yeast cells lacking the equivalent Ubc9 protein (ScDeltaubc9). RT-PCR analysis showed that transcript levels of OsSce1 and OsSce2 in rice seedlings were regulated by temperature stress. OsSce1 protein was localized to the nucleus in onion epidermal cells as evidenced by the transient GFP expression analysis following micro-projectile gun-based shooting of an OsSce1-GFP fusion construct. PPIase proteins assist molecular chaperones in reactions associated with protein folding and protein transport across membrane. There are 23 putative genes encoding for FK506-binding proteins (FKBPs; specific class of PPIase) in rice genome. OsFKBP20 cDNA was isolated as a stress-inducible EST clone. Largest ORF of 561 bases in OsFKBP20 showed characteristic FK506-binding domain at N-terminus and a coiled-coil motif at C-terminus. RNA expression analysis indicated that OsFKBP20 transcript is heat-inducible. OsFKBP20 over-expression in yeast endowed capacity of high temperature tolerance to yeast cells. Yeast two-hybrid analysis showed that OsSce1 protein physically interacts with the OsFKBP20 protein. It is thus proposed that OsSce1 and OsFKBP20 proteins in concert mediate the stress response of rice plants.

OsHsfA2c and OsHsfB4b are involved in the transcriptional regulation of cytoplasmic OsClpB (Hsp100) gene in rice (Oryza sativa L.)

“…PCR using primers specific for the first 550 bp of Gus gene was performed to confirm the integration of transfer DNA (T-DNA) in the transgenic plants. Transient assays in onion cells were performed as described earlier (Nigam et al 2008). 2kbPro OsClpB-cyt ::Gus construct was used in this experiment.…”

SUMOylation by a Stress-Specific Small Ubiquitin-Like Modifier E2 Conjugase Is Essential for Survival ofChlamydomonas reinhardtiiunder Stress Conditions

“…A technical exception to this rule is provided by several land plants that have undergone various rounds of polyploidization or entire genome fusions during interspecies hybridizations (Renny-Byfield and Wendel, 2014) and, thus, contain multiple SUMO E2 conjugase genes (Novatchkova et al, 2012). Two other technical exceptions are zebrafish (Dana rerio; Nowak and Hammerschmidt, 2006) and rice (Oryza sativa; Nigam et al, 2008), which contain two nearly identical SUMO E2 conjugase genes that are apparent products of recent gene duplications.…”

Characterization of orchardgrass p23, a flowering plant Hsp90 cohort protein

“…Major molecular chaperones such as Hsp101 (Queitsch et al 2000), Hsp70 (Lee and Schöffl 1996), and small Hsp (Kim et al 1997) have been reported to confer thermotolerance, but co-chaperones have not been well characterized. Although transcription levels of Hsp90 co-chaperones Hop and FKBP are induced by heat stress (Zhang et al 2003;Aviezer-Hagai et al 2007), only FKBP has a chaperone property (Bose et al 1996), and FKBP20 overexpression in yeast showed thermotolerance (Nigam et al 2008). Therefore, co-chaperones that exhibit chaperone activity may confer thermotolerance to cells.…”