Methyl-CpG binding domain protein acts to regulate the repair of cyclobutane pyrimidine dimers on rice DNA

Regulation of Oryza sativa molybdate transporter1;3 degradation via RING finger E3 ligase OsAIR3

High concentrations of As in contaminated environments pose a serious threat to plant, human, and animal health. In this study, we characterized an As-responsive Really Interesting New Gene (RING) E3 ubiquitin ligase gene under arsenate (AsV) stress, named as Oryza sativa As-Induced RING E3 ligase 3 (OsAIR3). AsV treatment highly induced the expression of OsAIR3. OsAIR3-EYFP was localized to the nucleus in rice protoplasts and exhibited E3 ligase activity. Yeast two-hybrid screening and bimolecular fluorescence complementation and pull-down assays revealed the interaction of OsAIR3 with an O. sativa molybdate transporter (OsMOT1;3) in the plasma membrane and cytoplasm. In addition, an in vitro cell-free degradation assay was performed to demonstrate the degradation of OsMOT1;3 by OsAIR3 via the 26S proteasome system. Heterogeneous overexpression of OsAIR3 in Arabidopsis yielded AsV-tolerant phenotypes, as indicated by the comparison of cotyledon expansion, root elongation, shoot fresh weight, and As accumulation between the OsAIR3-overexpressing and control plants. Collectively, these findings suggest that OsAIR3 positively regulates plant response to AsV stress.

MYB57 transcriptionally regulates MAPK11 to interact with PAL2;3 and modulate rice allelopathy

Rice allelopathy is a natural method of weed control that is regarded as an eco-friendly practice in agroecology. The allelopathic potential of rice is regulated by various genes, including those that encode transcription factors. Our study characterized a MYB transcription factor, OsMYB57, to explore its role in the regulation of rice allelopathy. Increasing the expression of OsMYB57 in rice using the transcription activator VP64 resulted in increased inhibitory ratios against barnyardgrass. The gene expression levels of OsPAL, OsC4H, OsOMT, and OsCAD from the phenylpropanoid pathway were also up-regulated, and the content of l-phenylalanine increased. Chromatin immunoprecipitation incorporated with HiSeq demonstrated that OsMYB57 transcriptionally regulated a mitogen-activated protein kinase (OsMAPK11); in addition, OsMAPK11 interacted with OsPAL2;3. The expression of OsPAL2;3was higher in the allelopathic rice PI312777 than in the non-allelopathic rice Lemont, and OsPAL2;3 was negatively regulated by Whirly transcription factors. Moreover, microbes with weed-suppression potential, including Penicillium spp. and Bacillus spp., were assembled in the rhizosphere of the rice accession Kitaake with increased expression of OsMYB57, and were responsible for phenolic acid induction. Our findings suggest that OsMYB57 positively regulates rice allelopathy, providing an option for the improvement of rice allelopathic traits through genetic modification.

Investigating the efficacy of UVSE protein at repairing CPD and 6-4 pp DNA damages in human cells

UV exposure could induce carcinogenic mutation in human cells, including CPD (Cyclobutane pyrimidine dimer), and 6-4 pp (6-4 photoproduct) DNA damages. Spiting the active BER (Base Excision Repair) system of human cells, it lacks initiator glycosylase, rendering these damages to be only repaired through NER (Nucleotide Excision Repair) system. Some microorganisms such as Deinococcus radiodurans bacteria have a BER system for repairing these damages with an enzyme coded by the uvsE gene. This study evaluated the efficacy of the recombinant UVSE protein for repairing the CPD and 6-4 pp DNA damages in human cells. At the current study, the optimized sequence of the uvsE gene was synthesized and expressed in Hek293T cell line. The identity of protein was ascertained through ELISA assay and the stability of expression was measured via qPCR. The human Hek293T cells with the recombinant protein and without it were exposed to the UV light, and the repair of DNA damages was analyzed in both conditions using CPD and 6-4PP ELISA Combo Kit. The results indicated that uvsE gene was successfully colonized and expressed and expression showed to be stable. Hek293T cells with recombinant uvsE gene showed efficacy at repairing 80% of CPD and 85% of 6-4 photoproducts during one hour, and more than 95% of damages over 4 h' repair time. Considering the outcome of this study, it could be concluded that the uvsE recombinant product is highly effective at repairing both CPD and 6-4 pp damages and could be considered as a preventive agent for UV-induced skin cancers.

Oryza sativa heat-induced RING finger protein 1 (OsHIRP1) positively regulates plant response to heat stress

OsHIRP1 is an E3 ligase that acts as a positive regulator in the plant response to heat stress, thus providing important information relating to adaptation and regulation under heat stress in plant. Extreme temperature adversely affects plant growth, development, and productivity. Here, we report the molecular functions of Oryza sativa heat-induced RING finger protein 1 (OsHIRP1), which might play an important role in the response to heat. Transcription of the OsHIRP1 was upregulated in response to heat and drought treatment. We found that the OsHIRP1-EYFP fusion protein was localized to the nucleus after heat treatment (45 °C). Two interacting partners, OsARK4 and OsHRK1, were identified via yeast-two-hybrid screening, which were mainly targeted to the nucleus (OsARK4) and cytosol (OsHRK1), and their interactions with OsHIRP1 were confirmed by biomolecular fluorescence complementation (BiFC). An in vitro ubiquitination assay showed that OsHIRP1 E3 ligase directly ubiquitinates its interacting proteins, OsAKR4 and OsHRK1, as substrates. Using an in vitro cell-free degradation assay, we observed a clear reduction in the levels of the two proteins under high temperature (45 °C), but not under low temperature conditions (4 °C and 30 °C). Seeds of OsHIRP1-overexpressing plants exhibited high germination rates compared with the control under heat stress. The OsHIRP1-overexpressing plants presented high survival rates of approximately 62-68%, whereas control plants displayed a low recovery rate of 34% under condition of acquired thermo-tolerance. Some heat stress-inducible genes (HsfA3, HSP17.3, HSP18.2 and HSP20) were up-regulated in OsHIRP1-overexpressing Arabidopsis than control plants under heat stress conditions. Collectively, these results suggest that OsHIRP1, an E3 ligase, positively regulates plant response to heat stress.

Lsi1 modulates the antioxidant capacity of rice and protects against ultraviolet-B radiation

Silicon (Si) enhances the resistance of rice to biotic and abiotic stress. In rice, the accumulation of Si is controlled by the low silicon rice 1 (Lsi1) gene; overexpression of Lsi1 (Lsi1-OX) increases Si uptake and accumulation, while the reverse is observed in Lsi1-RNA interference (Lsi1-RNAi) transgenic rice. When the two transgenic rice lines and wild-type (WT) rice were exposed to ultraviolet (UV)-B radiation, the Lsi1-OX or Lsi1-RNAi rice showed differential microRNA (miRNA) expression, compared to WT rice. These miRNAs were predicted to target genes involved in light signal transduction and cell detoxification. The greatest capacities of ascorbate peroxidase, superoxide dismutase, peroxidase, and phenylalanine ammonia lyase (PAL) and highest contents of phenolics, flavonoids, and proline were found in Lsi1-OX rice, followed by WT rice and Lsi1-RNAi transgenic rice. A further comparison of the transcript levels of individual PAL genes revealed that the expression of PAL2-2 (Os02g0626400) was positively regulated by Lsi1. Our results demonstrate that Lsi1 overexpression or interference causes changes in both miRNA expression and antioxidant capacity in rice, and therefore modulates rice tolerance to UV-B radiation. Furthermore, we demonstrated that PAL2-2 was positively regulated by Lsi1 during this process.

Extrapolation of significant genes and transcriptional regulatory networks involved in Zea mays in response in UV-B stress

A wide range of plant species growth influenced when they exposed to solar UV-B radiation. Leaves of the plant are highly affected by UV-B radiation lead to the reduction in the growth of the plant. Current work demonstrates the comparative transcriptional changes and visible symptoms occurred in the maize leaf growth zone (GZ). Primary objective of this study was to identify differentially expressed genes (DEGs) responsible for leaf growth and their association in the transcriptional regulatory network under UV-B stress. Whole transcriptomic data was analysed and the quality check was tested for each sample and further genome-wide mapping and DEGs were performed. Gene Ontology (GO) based functional annotation, associated transcriptional networks and molecular pathways were annotated. Reduction in cell production due to UV-B stress causes a decrease in leaf's length and size was observed. Further, the specific role of the DEGs, in UV-B signalling pathways and other molecular functions responsible for leaf cell death was discovered. Results also infer that the major changes occurred in the cell cycle, transcriptional regulation, post-transcriptional modification, phytohormones, flavonoids biosynthesis, and chromatin remodeling. UV-B signalling pathways and the transcriptional regulatory networks infer the different molecular steps along with downstream transcriptional and post-transcriptional control of metabolic enzymes used in long-term memory adoption and attainment resistance to UV-B stress identified. Effects of UV-B radiation on leaf growth was noted in this study. UV-B stress response genes and associated transcriptional regulatory networks were identified, can be used in developing the marker assist UB-B stress tolerant genotypes of the maize.

Overexpression of Lsi1 in cold-sensitive rice mediates transcriptional regulatory networks and enhances resistance to chilling stress

Frequent cold spells in late spring can damage early rice seedlings. However, overexpression of the silicon-uptake gene Lsi1 (Lsi1-OX) in cold-sensitive rice (Oryza sativa L., accession: Dular) notably enhances its chilling resistance. In this study, we found that continual chilling led to chlorophyll and RNA degradation in wild-type Dular leaves, whereas leaves from a Lsi1-OX line exhibited no obvious changes. A comparison of the global mRNA expression between the two rice lines showed that genes encoding photosynthesis-antenna proteins were downregulated and those encoding the proteasome were upregulated in the wild-type organism. Moreover, the differential responses of the two rice lines to chilling stress were found to correlate with the transcription factor OsWRKY53, which was predicted target of the respective microRNA (miRNA) novel-m0586-5p. In addition, miRNAs that targeted genes involved in the process of reactive oxygen species (ROS) metabolism were differentially expressed in the two rice lines after chilling stress, when comparative analysis of the outcomes of RNA sequencing on the two rice lines. Our results suggest that when overexpressed Lsi1 in cold-sensitive rice, it possibility regulates the transcription factor OsWRKY53 in addition to the genes involved in the ROS metabolism, thus mediating resistance to chilling stress.