RESUMO
BACKGROUND: Plant annexins are calcium- and lipid-binding proteins that have multiple functions, and a significant amount of research on plant annexins has been reported in recent years. However, the functions of annexins in diverse biological processes in rice are largely unclear. RESULTS: Herein, we report that OsANN4, a calcium-binding rice annexin protein, was induced by abscisic acid (ABA). Under ABA treatment, the plants in which OsANN4 was knocked down by RNA interference showed some visible phenotypic changes compared to the wild type, such as a lower rooting rate and shorter shoot and root lengths. Moreover, the superoxide dismutase (SOD) and catalase (CAT) activities of the RNAi lines were significantly lower and further resulted in higher accumulation of O2.- and H2O2 than those of the wild-type. A Non-invasive Micro-test Technology (NMT) assay showed that ABA-induced net Ca2+ influx was inhibited in OsANN4 knockdown plants. Interestingly, the phenotypic differences caused by ABA were eliminated in the presence of LaCl3 (Ca2+ channel inhibitor). Apart from this, we demonstrated that OsCDPK24 interacted with and phosphorylated OsANN4. When the phosphorylated serine residue of OsANN4 was substituted by alanine, the interaction between OsANN4 and OsCDPK24 was still observed, however, both the conformation of OsANN4 and its binding activity with Ca2+ might be changed. CONCLUSIONS: OsANN4 plays a crucial role in the ABA response, partially by modulating ROS production, mediating Ca2+ influx or interacting with OsCDPK24.
Assuntos
Ácido Abscísico/farmacologia , Anexinas/metabolismo , Cálcio/metabolismo , Oryza/genética , Reguladores de Crescimento de Plantas/farmacologia , Proteínas Quinases/metabolismo , Espécies Reativas de Oxigênio/metabolismo , Anexinas/genética , Catalase/genética , Catalase/metabolismo , Peróxido de Hidrogênio/metabolismo , Oryza/fisiologia , Fenótipo , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Proteínas Quinases/genética , Interferência de RNA , Plântula/genética , Plântula/fisiologia , Superóxido Dismutase/genética , Superóxido Dismutase/metabolismoRESUMO
The phytohormone auxin plays a critical role in plant growth and development, and its spatial distribution largely depends on the polar localization of the PIN-FORMED (PIN) auxin efflux carrier family members. In this study, we identify a putative auxin efflux carrier gene in rice, OsPIN3t, which acts in auxin polar transport but is also involved in the drought stress response in rice. We show that OsPIN3t-GFP fusion proteins are localized in plasma membranes, and this subcellular localization changes under 1-N-naphthylphthalamic acid (NPA) treatment. The tissue-specific expression patterns of OsPIN3t were also investigated using a ß-glucuronidase (GUS) reporter, which showed that OsPIN3t was mainly expressed in vascular tissue. The GUS activity in OsPIN3tpro::GUS plants increased by NAA treatment and decreased by NPA treatment. Moreover, knockdown of OsPIN3t caused crown root abnormalities in the seedling stage that could be phenocopied by treatment of wild-type plants with NPA, which indicated that OsPIN3t is involved in the control of polar auxin transport. Overexpression of OsPIN3t led to improved drought tolerance, and GUS activity significantly increased when OsPIN3tpro::GUS plants were subjected to 20% polyethylene glycol stress. Taken together, these results suggest that OsPIN3t is involved in auxin transport and the drought stress response, which suggests that a polar auxin transport pathway is involved in the regulation of the response to water stress in plants.
Assuntos
Proteínas de Transporte/metabolismo , Oryza/fisiologia , Proteínas de Plantas/metabolismo , Proteínas de Arabidopsis/genética , Transporte Biológico/efeitos dos fármacos , Proteínas de Transporte/genética , Membrana Celular/metabolismo , Secas , Regulação da Expressão Gênica de Plantas , Técnicas de Silenciamento de Genes , Proteínas de Fluorescência Verde/genética , Proteínas de Fluorescência Verde/metabolismo , Ácidos Indolacéticos/metabolismo , Dados de Sequência Molecular , Oryza/efeitos dos fármacos , Ftalimidas/farmacologia , Proteínas de Plantas/genética , Raízes de Plantas/genética , Plantas Geneticamente Modificadas , Proteínas Recombinantes de Fusão/genética , Proteínas Recombinantes de Fusão/metabolismo , Plântula/genéticaRESUMO
In vivo and in vitro treatments were carried out to investigate the effects of a 95% ethanol extract of Chroogomphus rutilus (CRE) on antioxidant, hypoglycemic, hypolipidemic, and antitumor properties. CRE showed potent radical scavenging activity against DPPH in vitro. It could increase antioxidant enzymatic activities (superoxide dismutase and glutathione peroxidase) and could reduce malondialdehyde content in vivo in mice in which aging was induced by D-galactose. CRE had hypoglycemic activity and could significantly inhibit α-glucosidase activity in vitro and decrease blood glucose concentration in vivo. CRE could decrease the serum total cholesterol, triglyceride, and low-density lipoprotein cholesterol levels and increase the high-density lipoprotein cholesterol level in diabetic mice. The MTT assay showed that CRE also had a certain inhibitory effect on the tumor cells. These results suggest that CRE may be beneficial for human health and could be useful for applications in medicine, the food industry, and agriculture.