RESUMEN
Drought and high salinity affect plant growth, development, yield, and quality. MYB transcription factors (TFs) in plants play an indispensable regulatory role in resisting adverse stress. In this study, screening and functional validation of the TF FtMYB30, which can respond extensively to abiotic stress and abscisic acid (ABA), was achieved in Tartary buckwheat. FtMYB30, one of the SG22 (sub-group 22) family of R2R3-MYB TFs, localized in the nucleus and had transcriptional activation activity. Under drought and salt stress, FtMYB30 overexpression reduced the oxidative damage in transgenic plants by increasing the activity of proline content and antioxidant enzymes and significantly upregulate the expression of RD29A, RD29B, and Cu/ZnSOD, thereby enhancing drought/salt tolerance in transgenic Arabidopsis. Additionally, overexpression of FtMYB30 can reduce the sensitivity of transgenic plants to ABA. Moreover, AtRCAR1/2/3 and AtMPK6 directly interact with the FtMYB30 TF, possibly through the crosstalk between MAPKs (mitogen-activated protein kinases) and the ABA signaling pathway. Taken together, these results suggest that FtMYB30, as a positive regulator, mediates plant tolerance to salt and drought through an ABA-dependent signaling pathway.
Asunto(s)
Arabidopsis , Fagopyrum , Ácido Abscísico/farmacología , Ácido Abscísico/metabolismo , Sequías , Tolerancia a la Sal/genética , Arabidopsis/metabolismo , Factores de Transcripción/genética , Factores de Transcripción/metabolismo , Fagopyrum/genética , Fagopyrum/metabolismo , Antioxidantes/metabolismo , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Plantas Modificadas Genéticamente/metabolismo , Estrés Fisiológico/genética , Proteínas Quinasas Activadas por Mitógenos/metabolismo , Prolina/metabolismo , Regulación de la Expresión Génica de las PlantasRESUMEN
OBJECTIVE: To identify factors associated with YMDD mutation in patients with chronic hepatitis B before and after lamivudine treatment in Zunyi region. METHODS: 53 patients with chronic hepatitis B were enrolled in this study, HBV DNA,HBV markers, ALT, AST, TBil, albumin in the serum were examined at 0, 3, 6, 12, 18 and 24 months after lamivudine treatment. HBV genotype and YMDD mutation were determined by sequencing before lamivudine treatment. YMDD mutation was checked again if serum HBV DNA rebound to more than 1 x 10(4) copies/ml after the initial decrease. RESULTS: HBV genotype in Zunyi region is constitute of B, C and B+C genotype. YMDD mutation occurred in 18 cases after lamivudine treatment, the rate of YMDD mutation was 15.1%, and 34.0% after 1 year and 2 years treatment. There are four types of mutation: rtL180M/M204V, rtL180M/M204I, rtM204I, rtL180M. rtM204V mutation in C gene was always accompanied by rtL180M mutation (100%). The rate of rtL180M/M204V mutation in genotype C group was significantly higher than that in genotype B group (77.8% to 25.0%), the same was true for the rtL180M/ M204I mutation (22.2% to 12.5%). There was no point mutation in genotype C group. The point mutation of rtM204I and rtL180M appeared only in genotype B group. Gender, nation, family history of hepatitis B and HBeAg were not associated with YMDD mutation (P more than 0.05), while the mutation rate was associated with the disease course and severity of disease. YMDD mutation did not occur in patients with low HBV DNA level (less than 10(5) copies/ml). CONCLUSION: YMDD mutation after lamivudine therapy is associated with HBV genotype and P gene mutation type, and prolonged treatment increases the the mutation rate. In order to reduce the incidence of YMDD mutation, patients with shorter disease course, lower HBV DNA level, more serious liver damage should be treated with lamivudine.