Inhibition of Rice Serotonin N-Acetyltransferases by MG149 Decreased Melatonin Synthesis in Rice Seedlings

Abstract

We examined the effects of two histone acetyltransferase (HAT) inhibitors on the activity of rice serotonin N-acetyltransferases (SNAT). Two rice recombinant SNAT isoenzymes (SNAT1 and SNAT2) were incubated in the presence of either MG149 or MB3, HAT inhibitors. MG149 significantly inhibited the SNAT enzymes in a dose-dependent manner, especially SNAT1, while SNAT2 was moderately inhibited. By contrast, MB3 had no effect on SNAT1 or SNAT2. The application of 100 μM MG149 to rice seedlings decreased melatonin by 1.6-fold compared to the control, whereas MB3 treatment did not alter the melatonin level. MG149 significantly decreased both melatonin and N-acetylserotonin when rice seedlings were challenged with cadmium, a potent elicitor of melatonin synthesis in rice. Although MG149 inhibited melatonin synthesis in rice seedlings, no melatonin deficiency-induced lamina angle decrease was observed due to the insufficient suppression of SNAT2, which is responsible for the lamina angle decrease in rice.

Mapping and Screening of Candidate Gene Regulating the Biomass Yield of Sorghum (Sorghum bicolor L.)

“…One notable exception is OsCYP71A1 in rice. OsCYP71A1 is associated with melatonin synthesis, encoding a protein with analogous functionality in sorghum [50]. There is also evidence that OsCYP71A1 may be a promising target for enhancing rice production under adverse environmental conditions [51].…”

Genetic and evolutionary dissection of melatonin response signaling facilitates the regulation of plant growth and stress responses

“…SNAT is a key gene in melatonin biosynthesis that exhibits specific antiabiotic stress functions in rice, wheat, cotton, tomato, cucumber, tobacco, and Arabidopsis (Figure 2). For example, OsSNAT2 RNAi rice plants showed decreased tolerance to Cd, salt, cold and high temperature, 43–46 while gain‐of‐function OsSNAT1 mutants had strong melatonin‐related phenotypes such as resistance to Cd, alkaline, and copper toxicity 44,47–50 . The homologous gene‐ TaSNAT overexpressing in wheat was mainly functional to mitigate salt stress 51 .…”