Heterologous Expression of a Salinity and Developmentally Regulated Rice Cyclophilin Gene (OsCyp2) in E. coli and S. cerevisiae Confers Tolerance Towards Multiple Abiotic Stresses

Abstract

Cyclophilin 2 (OsCyp2) is a cytosolic member of immunophilin family from rice. We have isolated its full length cDNA (1,056 bp) with an open reading frame of 519 bp encoding a polypeptide of 172 amino acids and an estimated pI of 8.61. Peptidyl prolyl cis-trans isomerase activity of the protein was determined using N-succinyl-ala-ala-pro-phe-p-nitroanilidine as peptide substrate. It has a catalytic efficiency (K (cat)/K (m)) of 4.5 x 10(6)/(mol/l)/s, which is comparable to known cyclophilins from plants. Its activity is specifically inhibited by cyclosporin A, a macrolide drug inhibitor of cyclophilins. Transcript analysis showed it to be a developmentally and differentially regulated gene; showing changes in abundance at seedling, tillering and heading stage under non-stress and salinity stress conditions. Expression of OsCyp2 enhances the ability of Escherichia coli to survive under diverse abiotic stresses viz. salinity, high temperature, osmotic stress (mannitol) and oxidative stress (H(2)O(2)). OsCyp2 was able to complement the yeast mutant lacking native Cyp2 and also improved the growth of wild type yeast under above-mentioned stress conditions. Based on these results, we propose that OsCyp2 may serve as a 'suitable candidate' for raising transgenic plants for enhanced multiple abiotic stress tolerance.

Proteomic identification of OsCYP2, a rice cyclophilin that confers salt tolerance in rice (Oryza sativa L.) seedlings when overexpressed

“…In addition, cold stress inhibits OsCYP2 expression in Shanyou 10 and Liangyoupeijiu seedlings.These data suggest that OsCYP2 expression is not specific in salt stress, but is ubiquitous in the response of rice seedlings to other types of stresses, including drought, heat and cold. Importantly, the above conclusion is consistent with the previous findings that OsCYP2 can respond to various stresses including high salt, drought, heat, oxidative stress and hypoxia stress [9,24]. Therefore, we speculate that OsCYP2 may function as a key integrator in response to multiple stresses.…”

“…The addition of CsA is able to reduce total PPIase activity of both wild type and two transgenic lines. Although it has been demonstrated by heterologous expression that OsCYP2 possessed PPIase activity [9], our findings provide powerful evidence at in vivo level to validate it.…”

“…OsCYP2 had peptidyl-prolyl cis-trans isomerase (PPIase or rotamase) activity that was specifically inhibited by cyclosporine A [9]. Moreover, OsCYP2 lacks introns, and the 5' end of transcript contains an AT-rich region, suggesting that OsCYP2 was likely to be preferentially translated during stress conditions [10].…”

“…Actually, OsCYP2 could respond to multiple environmental stresses such as high salt, drought, heat and oxidative stress. For example, heterologous expression of OsCYP2 was able to enhance ability of E. coli to survive, to complement the yeast mutant lacking native OsCYP2 and to improve the growth of wild type yeast under the above mentioned abiotic stresses [9]. In addition, significantly differential changes in transcript abundance of OsCYP2 were found in shoots of salt sensitive (IR64) and tolerant (Pokkali) rice cultivars at different developmental stages under normal and salt stress conditions [9].…”

1H, 13C and 15N NMR assignments of cyclophilin LRT2 (OsCYP2) from rice

“…One of these protein products is the LRT2 protein. Expression of LRT2 has been induced by multiple abiotic stresses, and overexpression of it has been shown to enhance multiple stress tolerance in E. coli and S. cerevisiae , and salinity stress tolerance in rice, making it a target protein for study of stress resistance mechanisms in plants (Kumari et al 2009; Ruan et al 2011). Also, LRT2 has recently been associated to the C2HC-type Zinc finger protein (OsZFP, Os01g0252900) by yeast two hybrid cDNA library screening, a protein that has an important regulatory role in lateral root development (Cui et al 2017).…”