AUTHOR=Zhang Zhengrong , Liu Xin , Li Rong , Yuan Li , Dai Yaqing , Wang Xiaoyun 

TITLE=Identification and Functional Analysis of a Protein Disulfide Isomerase (AtPDI1) in Arabidopsis thaliana

JOURNAL=Frontiers in Plant Science

VOLUME=9

YEAR=2018

URL=https://www.frontiersin.org/journals/plant-science/articles/10.3389/fpls.2018.00913

DOI=10.3389/fpls.2018.00913

ISSN=1664-462X

ABSTRACT=<p>Protein disulfide isomerase (PDI) catalyzes the conversion of thiol-disulfide and plays an important role in various physiological events in animals. A PDI (<italic>Oa</italic>PDI) from a tropical plant was detailed studied and it was found to be involved in response of biotic stress (<xref ref-type="bibr" rid="B13">Gruber et al., 2007</xref>). However, the activities of PDI related to physiological functions in plants are poorly understood. In the present study, a homolog of human PDI in <italic>Arabidopsis</italic> (<italic>At</italic>PDI1), encoded by the gene (<italic>At3g54960</italic>), was characterized. The recombinant <italic>At</italic>PDI1 protein had disulfide isomerase activity <italic>in vitro</italic> and two pairs of conservative cysteines in catalytic domains play a crucial role in the PDI activities. Expression of <italic>At</italic>PDI1 in <italic>Escherichia coli</italic> significantly enhanced stress tolerance of cells and the mutations of critical cysteines almost lose this function. In plants, <italic>AtPDI1</italic> was strongly induced by abiotic stresses and exogenous abscisic acid. An <italic>Arabidopsis</italic><italic>AtPDI1</italic> knockdown mutant (<italic>pdi1</italic>) and overexpression lines of transgenic plants obtained by this investigation were used to further examine the function of <italic>At</italic>PDI1. The mutant line was more sensitive to stresses than the wild-type, while overexpressing <italic>At</italic>PDI1 increased tolerance of seedlings to abiotic stresses, with a higher germination ratio and longer length of roots than the wild-type. Our results suggested <italic>At</italic>PDI1 played roles in anti-stresses in <italic>Arabidopsis</italic>, which relate to the activities of PDI.</p>