N-methyladenosine-mediated feedback regulation of abscisic acid perception via phase-separated ECT8 condensates in Arabidopsis.

N-methyladenosine (mA) is the most abundant internal modification in eukaryotic mRNAs, yet how plants recognize this chemical modification to swiftly adjust developmental plasticity under environmental stresses remains unclear. Here we show that mA mRNA modification and its reader protein EVOLUTIONARILY CONSERVED C-TERMINAL REGION 8 (ECT8) act together as a key checkpoint for negative feedback regulation of abscisic acid (ABA) signalling by sequestering the mA-modified ABA receptor gene PYRABACTIN RESISTANCE 1-LIKE 7 (PYL7) via phase-separated ECT8 condensates in stress granules in response to ABA. This partially depletes PYL7 mRNA from its translation in the cytoplasm, thus reducing PYL7 protein levels and compromising ABA perception.

GLABROUS INFLORESCENCE STEMS3 binds to and activates RHD2 and RHD4 genes to promote root hair elongation in Arabidopsis.

Root hairs are crucial in the uptake of essential nutrients and water in plants. This study showed that a zinc finger protein, GIS3 is involved in root hair growth in Arabidopsis. The loss-of-function gis3 and GIS3 RNAi transgenic line exhibited a significant reduction in root hairs compared to the wild type.

Shaping the landscape of N6-methyladenosine RNA methylation in Arabidopsis.

N 6-methyladenosine (m6A) modification on messenger RNAs (mRNAs) is deposited by evolutionarily conserved methyltransferases (writers). How individual m6A writers sculpt the overall landscape of the m6A methylome and the resulting biological impact in multicellular organisms remains unknown. Here, we systematically surveyed the quantitative m6A methylomes at single-nucleotide resolution and their corresponding transcriptomes in Arabidopsis (Arabidopsis thaliana) bearing respective impaired m6A writers.

FIONA1-Mediated m A Modification Regulates the Floral Transition in Arabidopsis.

N -methyladenosine (m A) mRNA modification represents the most widespread form of internal modifications in eukaryotic mRNAs. In the model plant Arabidopsis thaliana, those known methyltransferases mainly deposit m A at their target transcripts near the stop codon or in the 3' untranslated region. Here, it is reported that FIONA1 (FIO1), a human METTL16 ortholog, acts as a hitherto unknown m A methyltransferase that determines m A modifications at over 2000 Arabidopsis transcripts predominantly in the coding region.

N-methyladenosine modification underlies messenger RNA metabolism and plant development.

RNA modifications constitute an essential layer of gene regulation in living organisms. As the most prevalent internal modification on eukaryotic mRNAs, N-methyladenosine (mA) exists in many plant species and requires the evolutionarily conserved methyltransferases, demethylases, and mA binding proteins for writing, erasing, and reading mA, respectively. In plants, mA affects many aspects of mRNA metabolism, including alternative polyadenylation, secondary structure, translation, and decay, which underlies various plant developmental processes and stress responses.

TOP1α, UPF1, and TTG2 regulate seed size in a parental dosage-dependent manner.

Cues of maternal and paternal origins interact to control seed development, and the underlying molecular mechanisms are still far from clear. Here, we show that TOPOISOMERASE Iα (TOP1α), UP-FRAMESHIFT SUPPRESSOR 1 (UPF1), and TRANSPARENT TESTA GLABRA2 (TTG2) gametophytically, biparentally regulate seed size in Arabidopsis. TOP1α and UPF1 are mainly expressed in antipodal cells, and loss of their function leads to ectopic TTG2 expression in these female gametophytic cells.

Genome and Transcriptome Provide Insights into the Origin and Evolution of Streptophyta.

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.

Zinc finger protein 5 (ZFP5) associates with ethylene signaling to regulate the phosphate and potassium deficiency-induced root hair development in Arabidopsis.

Zinc finger protein transcription factor ZFP5 positively regulates root hair elongation in response to Pi and potassium deficiency by mainly activating the expression of EIN2 in Arabidopsis. Phosphate (Pi) and potassium (K) are major plant nutrients required for plant growth and development, and plants respond to low-nutrient conditions via metabolic and morphology changes. The C2H2 transcription factor ZFP5 is a key regulator of trichome and root hair development in Arabidopsis.

Messenger RNA Modifications in Plants.

Over 160 distinct RNA modifications are known and collectively termed the epitranscriptome. Some of these modifications have been discovered in mRNA, uncovering a new layer of gene regulation. Transcriptome-wide mapping of epitranscriptomic codes and the discovery of their writers, erasers, and readers that dynamically install, remove, and interpret RNA modifications, respectively, are fundamental to understanding the epitranscriptome.

In vitro propagation of Australian native ornamental plant, Scaevola.

In this chapter, we describe a robust method for the micropropagation of Australian fan flower, Scaevola, a native plant increasingly being used in the ornamental horticulture industry. Shoot segments from different species of Scaevola can be successfully multiplied following this protocol. Multiple shoots can be obtained in hormone-free Murashige and Skoog medium.

Chemically induced virus resistance in Arabidopsis thaliana is independent of pathogenesis-related protein expression and the NPR1 gene.

Salicylic acid (SA) treatment triggers inhibition of replication or movement of several positive-sense RNA plant viruses in tobacco. This resistance can also be stimulated by nonlethal concentrations of cyanide and antimycin A (AA) without triggering induction of pathogenesis-related PR-1 protein genes. In two ecotypes of Arabidopsis thaliana (Columbia and Nössen), SA-induced resistance to a tobamovirus, Turnip vein clearing virus (TVCV), was also induced by nonlethal concentrations of cyanide and AA without concomitant induction of PR-1 gene expression.