Parallel degradome-seq and DMS-MaPseq substantially revise the miRNA biogenesis atlas in Arabidopsis.

MicroRNAs (miRNAs) are produced from highly structured primary transcripts (pri-miRNAs) and regulate numerous biological processes in eukaryotes. Due to the extreme heterogeneity of these structures, the initial processing sites of plant pri-miRNAs and the structural rules that determine their processing have been predicted for many miRNAs but remain elusive for others. Here we used semi-active DCL1 mutants and advanced degradome-sequencing strategies to accurately identify the initial processing sites for 147 of 326 previously annotated Arabidopsis miRNAs and to illustrate their associated pri-miRNA cleavage patterns.

Structured 3' UTRs destabilize mRNAs in plants.

Background: RNA secondary structure (RSS) can influence the regulation of transcription, RNA processing, and protein synthesis, among other processes. 3' untranslated regions (3' UTRs) of mRNA also hold the key for many aspects of gene regulation. However, there are often contradictory results regarding the roles of RSS in 3' UTRs in gene expression in different organisms and/or contexts.

Intrinsically disordered proteins SAID1/2 condensate on SERRATE for dual inhibition of miRNA biogenesis in Arabidopsis.

Intrinsically disordered proteins (IDPs) SAID1/2 are hypothetic dentin sialophosphoprotein-like proteins, but their true functions are unknown. Here, we identified SAID1/2 as negative regulators of SERRATE (SE), a core factor in miRNA biogenesis complex (microprocessor). Loss-of-function double mutants of caused pleiotropic developmental defects and thousands of differentially expressed genes that partially overlapped with those in also displayed increased assembly of microprocessor and elevated accumulation of microRNAs (miRNAs).

Glutathione-dependent denitrosation of GSNOR1 promotes oxidative signalling downstream of H O.

Photorespiratory hydrogen peroxide (H O ) plays key roles in pathogenesis responses by triggering the salicylic acid (SA) pathway in Arabidopsis. However, factors linking intracellular H O to activation of the SA pathway remain elusive. In this work, the catalase-deficient Arabidopsis mutant, cat2, was exploited to elucidate the impact of S-nitrosoglutathione reductase 1 (GSNOR1) on H O -dependent signalling pathways.

Functional analysis of the role of hydrogen sulfide in the regulation of dark-induced leaf senescence in Arabidopsis.

There is growing evidence that hydrogen sulfide (HS) is involved in many physiological processes in plants, but the role of HS in dark-induced leaf senescence remains unknown. In this work, we found that HS not only inhibited chlorophyll degradation but also caused the accumulation of photoreactive pheide a in detached leaves under extended darkness. Despite this, transcript levels of senescence-associated genes (SAGs) were less affected in HS-treated detached leaves compared with those in HS-untreated detached leaves.