Background:
Cysteine proteinase inhibitor (cystatin, CPI) is one of themost importantmolecules involved in plant
development and defense, especially in the regulation of stress responses. However, it is still unclearwhether the
Jatropha curcas
CPI (
JcCPI) gene functions in salinity response and tolerance. In this study, the sequence of the
JcCPI gene, its expression pattern, and the effects of overexpression in
Escherichia coli
and
Nicotiana benthamiana
were examined. The purpose of this study was to evaluate the regulatory role of
JcCPI in salinity
stress tolerance.
Results:
The CPI gene, designated
JcCPI, was cloned from
J. curcas; its sequence shared conserved domains with
other plant cystatins. Based on a transcription pattern analysis,
JcCPI was expressed in all tissues examined, but
its expression was highest in the petiole. Additionally, the expression of
JcCPI was induced by salinity stress. A
potential role of
JcCPI was detected in transgenic
E. coli, which exhibited strong CPI activity and high salinity
tolerance.
JcCPI was also transferred to tobacco plants. In comparison to wild-type plants, transgenic plants
expressing
JcCPI exhibited increased salinity resistance, better growth performance, lower malondialdehyde
(MDA) contents, higher anti-oxidase activity, and higher cell viability under salinity stress.
Conclusions:
Based on the results of this study, overexpression of
JcCPI in
E. coli and
N. benthamiana conferred
salinity stress tolerance by blocking cysteine proteinase activity. The
JcCPI gene cloned in this study will be
very useful for the development of stress-tolerant crops.
