Articles in 2019

A study sequenced and analysed two genomes of basal streptophyte algae that adapt to freshwater and subaerial/terrestrial environments, respectively, providing insights into plant terrestrialization, an important evolutionary transition in the history of life.

Photosystem I is trimeric in most cyanobacteria but monomeric in plants and algae; however, tetrameric photosystem I is found in many heterocyst-forming cyanobacteria and their close relatives, possibly as an adaptation to high light levels.

Eukaryotic translation initiation factor 4E-interacting proteins able to regulate translation have not yet been reported in plants. A study now characterizes an eIF4E-interacting protein, CERES, as a non-canonical translation initiation factor that modulates translation in plants.

The authors use natural variation in maize to identify a locus involved in shoot sodium exclusion and associated with salinity tolerance. The encoded protein is the sodium transporter ZmHAK4, and the gene is conserved in other crops.

This study revealed prevalent cytidylation and uridylation at the 3′ ends of pre-miRNAs in Arabidopsis. Moreover, the nucleotidyl transferase proteins contributing to the pre-miRNA tailing and the diverse functions of the tailing were uncovered.

Tannins in grains prevent sparrow consumption but cause bitterness for people with sensitive taste. A study uncovered genes controlling tannin presence in sorghum and revealed a coevolution among humans, sorghums and birds linked by tannins in African agroecosystems.

Mast seeding is a reproductive trait of some perennial plants that display synchronous, highly variable annual production of fruit. The drivers of mast seeding are not well understood. Here, the authors report a global-scale investigation of masting behaviour and reveal a link with nutrient economy.

High-resolution cryo-EM structures of Chlamydomonas light-harvesting complex II (LHCII)–photosystem II (PSII) supercomplexes show loosely and moderately associated LHCIIs forming multiple pathways for energy transfer to PSII reaction centres.

By examining chromatin accessibility and modification as well as sequence conservation in 13 plant species, this study characterizes thousands of putative cis-regulatory elements and reveals their prevalence, dynamic evolution and chromatin signatures.

The 26S proteasome subunit RPT2a is reported to promote post-transcriptional gene silencing by repressing the RNA quality control machinery, and thereby interconnecting the two pathways that regulate cellular RNA homeostasis in plants.

Long-range cis-regulatory elements play important roles in regulating agronomic traits, but they are largely uncharacterized in crops. This study provides genetic, epigenomic and functional molecular evidence to support their widespread existence in the maize genome.

BicA is a bicarbonate transporter involved in cyanobacterial photosynthesis. The structure of BicA from Synechocystis suggests a mechanism for all SLC26/4-family transporters and can aid bioengineering of BicA to boost CO₂ assimilation.

Sterols are essential structural components of cell membranes and have functions in many different physiological processes. For example, brassinosteroids are a class of sterol phytohormones that are important in regulating plant growth and development. This study describes the identification of a protein factor that regulates sterol homeostasis in Arabidopsis.

Subfunctionalization allows gene paralogues to perform distinct ancestral functions. Now, Glover et al. report the functional divergence of proteins of the TRANSPARENT TESTA GLABRA 1 (TTG1) WD40-repeat family in Arabidopsis, showing that small changes in highly conserved proteins can result in major changes to their functions.

Taxonomic monographs have been considered too vast and daunting as a source for studying biodiversity, but this novel study of morning glories combines herbarium specimens with DNA barcodes and high-throughput sequencing to describe new species and discover hidden traits.

Non-photochemical quenching (NPQ) protects plants from photodamage. A mutant lacking LHCII, the main antenna complex of plants, shows that NPQ mainly occurs in LHCII, but there is an additional quenching site within the Photosystem II core.

Chitin oligomers from fungal cell walls induce plant immunity. Genetic evidence shows that chitin deacetylation by a secreted fungal enzyme hides the presence of the pathogen from the immune recognition system and is essential for host colonization.

The 2.37 Å structure of a tetrameric photosystem I complex from the cyanobacterium Anabaena shows a dimer of dimers organization. This oligomerization is physiologically linked to cyclic electron flow and thylakoid membrane organization.

There are three families of orange carotenoid protein (OCP), a cyanobacterial blue-light sensor. OCPX most closely resembles their common ancestor. OCP2 has fast deactivation and weak antenna interaction but does not dimerize, unlike OCPX and OCP1.

Gibberelins comprise a large number of species, with some being bioactive forms and the others being inactive. The different gibberelin species are interconvertible, and a new subfamily of cytochrome P450 enzymes has now been identified to be responsible for gibberelin deactivation in Brassicaceae.