OsPP65 Negatively Regulates Osmotic and Salt Stress Responses Through Regulating Phytohormone and Raffinose Family Oligosaccharide Metabolic Pathways in Rice
Qing Liu, Jierong Ding, Wenjie Huang, Hang Yu, Shaowen Wu, Wenyan Li, Xingxue Mao, Wenfeng Chen,Junlian Xing, Chen Li1* and Shijuan Yan*
Rice
Abstract
Although type 2C protein
phosphatases (PP2Cs) have been demonstrated to play important roles in
regulating plant development and various stress responses, their
specific roles in rice abiotic stress tolerance are still largely
unknown. In this study, the functions of OsPP65 in rice osmotic and salt
stress tolerance were investigated. Here, we report that OsPP65 is
responsive to multiple stresses and is remarkably induced by osmotic and
salt stress treatments. OsPP65 was highly expressed in rice seedlings
and leaves and localized in the nucleus and cytoplasm. OsPP65 knockout
rice plants showed enhanced tolerance to osmotic and salt stresses.
Significantly higher induction of genes involved in jasmonic acid (JA)
and abscisic acid (ABA) biosynthesis or signaling, as well as higher
contents of endogenous JA and ABA, were observed in the OsPP65 knockout
plants compared with the wild-type plants after osmotic stress
treatment. Further analysis indicated that JA and ABA function
independently in osmotic stress tolerance conferred by loss of OsPP65.
Moreover, metabolomics analysis revealed higher endogenous levels of
galactose and galactinol but a lower content of raffinose in the OsPP65
knockout plants than in the wild-type plants after osmotic stress
treatment. These results together suggest that OsPP65 negatively
regulates osmotic and salt stress tolerance through regulation of the JA
and ABA signaling pathways and modulation of the raffinose family
oligosaccharide metabolism pathway in rice. OsPP65 is a promising target
for improvement of rice stress tolerance using gene editing.
Keywords: PP2C, Osmotic stress tolerance, ABA, JA, Raffinose family oligosaccharide, Rice
