N 6 -Methyladenine (6mA) DNA methylation has recently been implicated as a potential new epigenetic marker in eukaryotes, including the dicot model Arabidopsis thaliana. However, the conservation and divergence of 6mA distribution patterns and functions in plants remain elusive. Here we report high-quality 6mA methylomes at single-nucleotide resolution in rice based on substantially improved genome sequences of two rice cultivars, Nipponbare (Nip; Japonica) and 93-11 (Indica). Analysis of 6mA genomic distribution and its association with transcription suggest that 6mA distribution and function is rather conserved between rice and Arabidopsis. We found that 6mA levels are positively correlated with the expression of key stressrelated genes, which may be responsible for the difference in stress tolerance between Nip and 93-11. Moreover, we showed that mutations in DDM1 cause defects in plant growth and decreased 6mA level. Our results reveal that 6mA is a conserved DNA modification that is positively associated with gene expression and contributes to key agronomic traits in plants.

Advances in the detection and mapping of messenger RNA (mRNA) N 6 -methyladenosine (m 6 A) and 5-methylcytosine (m 5 C), and DNA N 6 -methyldeoxyadenosine (6mA) redefined our understanding of these modifications as additional tiers of epigenetic regulation. In plants, the most prevalent internal mRNA modifications, m 6 A and m 5 C, play crucial and dynamic roles in many processes, including embryo development, stem cell fate determination, trichome branching, leaf morphogenesis, floral transition, stress responses, fruit ripening, and root development. The newly identified and widespread epigenetic marker 6mA DNA methylation is associated with gene expression, plant development, and stress responses. Here, we review the latest research progress on mRNA and DNA epigenetic modifications, including the detection, dynamics, distribution, functions, regulatory proteins, and evolution, with a focus on m 6 A, m 5 C, and 6mA. We also provide some perspectives on future research of the newly identified and unknown epigenetic modifications of mRNA and DNA in plants.

Abiotic stresses, such as temperature extremes, drought, salinity, and heavy metals are major factors limiting crop productivity and sustainability worldwide. Abiotic stresses disturb plant growth and yield formation. Several chemical compounds, known as plant growth regulators (PGRs), modulate plant responses to biotic and abiotic stresses at the cellular, tissue, and organ levels. Thiourea (TU) is an important synthetic PGR containing nitrogen (36%) and sulfur (42%) that has gained wide attention for its role in plant stress tolerance. Tolerance against abiotic stresses is a complex phenomenon involving an array of mechanisms, and TU may modulate several of these. An understanding of TU-induced tolerance mechanisms may help improve crop yield under stress conditions. However, the potential mechanisms involved in TU-induced plant stress tolerance are still elusive. In this review, we discuss the essential role of TU-induced tolerance in improving performance of plants growing under abiotic stresses and potential mechanisms underlying TU-induced stress tolerance. We also highlight exploitation of new avenues critical in TU-induced stress tolerance.

Grain quality improvement is a key target for rice breeders, along with yield. It is a multigenic trait that is simultaneously influenced by many factors. Over the past few decades, breeding for semi-dwarf cultivars and hybrids has significantly contributed to the attainment of high yield demands but reduced grain quality, which thus needs the attention of researchers. The availability of rice genome sequences has facilitated gene discovery, targeted mutagenesis, and revealed functional aspects of rice grain quality attributes. Some success has been achieved through the application of molecular markers to understand the genetic mechanisms for better rice grain quality; however, researchers have opted for novel strategies. Genomic alteration employing genome editing technologies (GETs) like clustered regularly interspaced short palindromic repeats (CRISPR)/CRISPR-associated protein 9 (Cas9) for reverse genetics has opened new avenues of research in the life sciences, including for rice grain quality improvement. Currently, CRISPR/Cas9 technology is widely used by researchers for genome editing to achieve the desired biological objectives, because of its simple targeting. Over the past few years many genes that are related to various aspects of rice grain quality have been successfully edited via CRISPR/Cas9 technology. Interestingly, studies on functional genomics at larger scales have become possible because of the availability of GETs. In this review, we discuss the progress made in rice by employing the CRISPR/Cas9 editing system and its eminent applications. We also elaborate possible future avenues of research with this system, and our understanding regarding the biological mechanism of rice grain quality improvement.

The Streptophyta include unicellular and multicellular charophyte green algae and land plants. Colonization of the terrestrial habitat by land plants is a major evolutionary event that has transformed the planet. So far, lack of genome information on unicellular charophyte algae hinders the understanding of the origin and the evolution from unicellular to multicellular life in Streptophyta. This work reports the high‐quality reference genome and transcriptome of Mesostigma viride, a single‐celled charophyte alga with a position at the base of Streptophyta. There are abundant segmental duplications and transposable elements in M. viride, which contribute to a relatively large genome with high gene content compared to other algae and early diverging land plants. This work identifies the origin of genetic tools that multicellular Streptophyta have inherited and key genetic innovations required for the evolution of land plants from unicellular aquatic ancestors. The findings shed light on the age‐old questions of the evolution of multicellularity and the origin of land plants.

BackgroundDue to dengue virus disease, half of the world population is at severe health risk. Viral encoded NS2B-NS3 protease complex causes cleavage in the nonstructural region of the viral polyprotein. The cleavage is essentially required for fully functional viral protein. It has already been reported that if function of NS2B-NS3 complex is disrupted, viral replication is inhibited. Therefore, the NS2B-NS3 is a well-characterized target for designing antiviral drug.ResultsIn this study docking analysis was performed with active site of dengue NS2B-NS3 protein with selected plant flavonoids. More than 100 flavonoids were used for docking analysis. On the basis of docking results 10 flavonoids might be considered as the best inhibitors of NS2B-NS3 protein. The interaction studies showed resilient interactions between ligand and receptor atoms. Furthermore, QSAR and SAR studies were conducted on the basis of NS2B-NS3 protease complex docking results. The value of correlation coefficient (r) 0.95 shows that there was a good correlation between flavonoid structures and selected properties.ConclusionWe hereby suggest that plant flavonoids could be used as potent inhibitors of dengue NS2B-NS3 protein and can be used as antiviral agents against dengue virus. Out of more than hundred plant flavonoids, ten flavonoid structures are presented in this study. On the basis of best docking results, QSAR and SAR studies were performed. These flavonoids can directly work as anti-dengue drug or with little modifications in their structures.

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