The OsWRKY63-OsWRKY76-OsDREB1B module regulates chilling tolerance in rice.

Rice (Oryza sativa) is sensitive to low temperatures, which affects the yield and quality of rice. Therefore, uncovering the molecular mechanisms behind chilling tolerance is a critical task for improving cold tolerance in rice cultivars. Here, we report that OsWRKY63, a WRKY transcription factor with an unknown function, negatively regulates chilling tolerance in rice. OsWRKY63-overexpressing rice lines are more sensitive to cold stress. Conversely, OsWRKY63-knockout mutants generated using a CRISPR/Cas9 genome editing approach exhibited increased chilling tolerance. OsWRKY63 was expressed in all rice tissues, and OsWRKY63 expression was induced under cold stress, dehydration stress, high salinity stress, and ABA treatment. OsWRKY63 localized in the nucleus plays a role as a transcription repressor and downregulates many cold stress-related genes and reactive oxygen species scavenging-related genes. Molecular, biochemical, and genetic assays showed that OsWRKY76 is a direct target gene of OsWRKY63 and that its expression is suppressed by OsWRKY63. OsWRKY76-knockout lines had dramatically decreased cold tolerance, and the cold-induced expression of five OsDREB1 genes was repressed. OsWRKY76 interacted with OsbHLH148, transactivating the expression of OsDREB1B to enhance chilling tolerance in rice. Thus, our study suggests that OsWRKY63 negatively regulates chilling tolerance through the OsWRKY63-OsWRKY76-OsDREB1B transcriptional regulatory cascade in rice.

OsWRKY28 positively regulates salinity tolerance by directly activating OsDREB1B expression in rice.

KEY MESSAGE: OsWRKY28 confers salinity tolerance by directly binding to OsDREB1B promoter and increasing its transcriptional activity, and negatively regulates abscisic acid mediated seedling establishment in rice. WRKY transcription factors have been reported to play a vital role in plants growth, development, abiotic and biotic stress responses. In this study, we explored the functions of a transcription factor OsWRKY28 in rice. The transcript level of OsWRKY28 was strikingly increased under drought, chilling, salt and abscisic acid treatments. The OsWRKY28 overexpression lines showed enhanced salinity stress tolerance, whereas the oswrky28 mutants displayed salt sensitivity compared to wild-type plants. Under salt stress treatment, the expression levels of OsbZIP05, OsHKT1;1 and OsDREB1B were significantly lower yet the level of OsHKT2;1 was significantly higher in oswrky28 mutants than those in wide type plants. Our data of yeast one-hybrid assay and dual-luciferase assay supported that OsWRKY28 could directly bind to the promoter of OsDREB1B to enhance salinity tolerance in rice. In addition, OsWRKY28 overexpression lines displayed hyposensitivity and the oswrky28 mutants showed hypersensitivity compared to wild-type plants under exogenous abscisic acid treatment. Based on the results of yeast two-hybrid assay and GAL4-dependent chimeric transactivation assay, OsWRKY28 physically interacts with OsMPK11 and its transcriptional activity could be regulated by OsMPK11. Together, OsWRKY28 confers salinity tolerance through directly targeting OsDREB1B promoter and further activating its transcription in rice.

Efficacy and Safety of Ertugliflozin Added to Metformin: A Pooled Population from Asia with Type 2 Diabetes and Overweight or Obesity.

INTRODUCTION: The efficacy and safety of ertugliflozin have not been well characterized in Asian populations with type 2 diabetes (T2D) and overweight or obesity as defined by the Chinese Diabetes Society [body mass index (BMI) ≥ 24 kg/m2]. METHODS: These post hoc analyses of pooled data from two randomized, double-blind, 26-week studies assessed the efficacy and safety of ertugliflozin (5 mg or 15 mg) compared with placebo in participants from Asia with T2D and baseline BMI ≥ 24 kg/m2, with inadequate glycemic control on metformin. Longitudinal analyses were used to calculate least squares (LS) mean [95% confidence interval (CI)] change from baseline in glycemic indices and body weight. The proportions of participants achieving efficacy targets and experiencing adverse events (AEs) were assessed. RESULTS: The 445 participants had a mean age of 55.5 years, T2D duration 6.6 years, glycated hemoglobin (HbA1c) 8.1%, and BMI 27.6 kg/m2. At week 26, placebo-adjusted LS mean (95% CI) changes from baseline for ertugliflozin 5 mg and 15 mg, respectively, were - 0.78% (- 0.95% to - 0.61%) and - 0.80% (- 0.98% to - 0.63%) for HbA1c, and - 1.74 kg (- 2.29 kg to - 1.19 kg) and - 2.04 kg (- 2.60 kg to - 1.48 kg) for body weight. A greater proportion of participants receiving ertugliflozin 5 mg and 15 mg versus placebo, respectively, achieved HbA1c < 7.0% (42.1% and 46.3% vs. 13.9%), body weight reduction ≥ 5% (35.5% and 38.3% vs. 11.1%), and systolic blood pressure < 130 mmHg (42.4% and 34.5% vs. 21.7%). The proportion of participants with AEs was 52.6% (ertugliflozin 5 mg), 52.3% (ertugliflozin 15 mg), and 55.6% (placebo). CONCLUSIONS: In participants from Asia with T2D inadequately controlled by metformin monotherapy, and BMI ≥24 kg/m2, ertugliflozin (5 mg or 15 mg) resulted in greater glycemic and body weight reductions compared with placebo and was generally well tolerated. TRIAL REGISTRATION: Clinicaltrials.gov identifiers NCT02033889, NCT02630706.

OsWRKY76 positively regulates drought stress via OsbHLH148-mediated jasmonate signaling in rice.

Drought stress is a major environmental threat that limits plant growth and crop productivity. Therefore, it is necessary to uncover the molecular mechanisms behind drought tolerance in crops. Here, OsWRKY76 positively regulated drought stress in rice. OsWRKY76 expression was induced by PEG treatment, dehydration stress, and exogenous MeJA rather than by no treatment. Notably, OsWRKY76 knockout weakened drought tolerance at the seedling stage and decreased MeJA sensitivity. OsJAZ12 was significantly induced by drought stress, and its expression was significantly higher in OsWRKY76-knockout mutants than in wild-type ZH11 under drought stress. Yeast two-hybrid and bimolecular fluorescence complementation assays showed that OsWRKY76 interacted with OsJAZ12. OsWRKY76 weakened the interaction between OsbHLH148 and OsJAZ12 in yeast cells. The OsJAZ12 protein repressed the transactivation activity of OsbHLH148, and this repression was partly restored by OsWRKY76 in rice protoplasts. Moreover, OsDREB1E expression was lower in OsWRKY76-knockout mutants than in wild-type ZH11 under drought stress, but it was upregulated under normal growth conditions. Yeast one-hybrid, electrophoretic mobility shift, and dual-luciferase assays showed that OsWRKY76 and OsbHLH148 bound directly to the OsDREB1E promoter and activated OsDREB1E expression in response to drought stress. These results suggest that OsWRKY76 confers drought tolerance through OsbHLH148-mediated jasmonate signaling in rice, offering a new clue to uncover the mechanisms behind drought tolerance.