Search

OsGADD45a1, a member of the growth arrest and DNA damage-inducible 45 (GADD45) family in rice, has a newly identified homologue, OsGADD45a2, which differs from OsGADD45a1 in only three amino acids. The role and function of the OsGADD45a2 in DNA demethylation are not well-understood and were investigated in this study. Osgadd45a2mutants exhibited reduced height, shorter panicle length, fewer grains per panicle, and a lower seed setting rate compared with wild-type plants. Moreover, the results showed that OsGADD45a2negatively regulates rice blast fungus resistance and exhibited high expression in various tissues. Using the 3000 Rice Genomes Project database, we identified four major haplotypes (each with over 100 cultivars) based on single-nucleotide polymorphisms in the coding sequence of OsGADD45a2. Among these, Hap4 was associated with a significantly greater plant height than Hap1–3, possibly due to a functional alteration of OsGADD45a2linked to the SNP at position 2614993. In OsGADD45a2overexpression lines, significant decreases in CG and CHG methylation levels were observed in protein-coding genes, leading to their upregulation. Overall, our findings indicate that OsGADD45a2acts as a methylation regulator, mediating the expression of genes essential for plant growth and development and blast resistance.

ABSTRACTEAR motif-containing proteins are able to repress gene expression, therefore play important roles in regulating plants growth and development, plant response to environmental stimuli, as well as plant hormone signal transduction. ABA is a plant hormone that regulates abiotic stress tolerance in plants via signal transduction. ABA signaling via the PYR1/PYLs/RCARs receptors, the PP2Cs phosphatases, and SnRK2s protein kinases activates the ABF/AREB/ABI5-type bZIP transcription factors, resulting in the activation/repression of ABA response genes. However, functions of many ABA response genes remained largely unknown. We report here the identification of the ABA-responsive gene SlEAD1(Solanum lycopersicum EAR motif-containing ABA down-regulated 1) as a novel EAR motif-containing transcription repressor gene in tomato. We found that the expression of SlEAD1was down-regulated by ABA treatment, and SlEAD1 repressed reporter gene expression in transfected protoplasts. By using CRISPR gene editing, we generated transgene-free slead1mutants and found that the mutants produced short roots. By using seed germination and root elongation assays, we examined ABA response of the slead1mutants and found that ABA sensitivity in the mutants was increased. By using qRT-PCR, we further show that the expression of some of the ABA biosynthesis and signaling component genes were increased in the slead1mutants. Taken together, our results suggest that SlEAD1is an ABA response gene, that SlEAD1 is a novel EAR motif-containing transcription repressor, and that SlEAD1 negatively regulates ABA responses in tomato possibly by repressing the expression of some ABA biosynthesis and signaling genes.

In this work, taking NiSe2as a prototype to be used as cocatalyst in photocatalytic hydrogen evolution, we demonstrate that the crystal phase of NiSe2plays a vital role in determining the catalytic stability, rather than activity. Theoretical and experimental results indicate that the phase structure shows negligible influence to the charge transport and hydrogen adsorption capacity. When integrating with carbon nitride (CN) photocatalyst forming hybrids (m-NiSe2/CN and p-NiSe2/CN), the hybrids show comparable photocatalytic hydrogen evolution rates (3.26 µmol/h and 3.75 µmol/h). Unlike the comparable catalytic activity, we found that phase-engineered NiSe2exhibits distinct stability, i.e., m-NiSe2can evolve H2steadily, but p-NiSe2shows a significant decrease in catalytic process (∼57.1% decrease in 25 h). The factor leading to different catalytic stability can be ascribed to the different surface conversion behavior during photocatalytic process, i.e., chemical structure of m-NiSe2can be well preserved in catalytic process, but partial p-NiSe2tends to be converted to NiOOH.