Letters in 2021

A study finds that N-terminal RT–Cas9 nickase fusion, versus the commonly applied C-terminal fusion, and multiple-nucleotide substitutions in prime editing guide RNAs can synergistically and greatly enhance the efficiency of prime editor 3 in rice and maize.

Single-cell profiling of callus from hypocotyl explants shows the heterogeneity of this tissue and identifies gene networks needed for plant regeneration, in particular the essential roles of WOX5 and WOX7 in this biological process.

This study reports a donor DNA-free approach for gene knock-up based on CRISPR. It induced designed promoter swap or replacement for target genes by triggering genomic inversion or duplication so as to elevate gene expression and generate new traits.

Plants have developed defences against herbivores, but with multiple threats at different times, those defences may be compromised. This experiment finds that plants adapt over time to anticipate prevalent herbivores and common patterns of attack.

The coat protein complex II (COPII) is a type of specialized vesicle coat protein that mediates vesicle trafficking from the endoplasmic reticulum (ER) to the Golgi apparatus. A population of giant COPII vesicles is identified and shown to be produced in response to the plant hormone abscisic acid (ABA) and abiotic stresses in Arabidopsis.

This study of 4,000-year-old Egyptian yarn examines the cellular nature of the flax fibres to investigate their durability and integrity, as well as their differences from modern flax.

Analyses of four International Maize and Wheat Improvement Center global spring wheat trial datasets showed that genotype–environment interactions have changed over recent decades and crossover interactions have increased, largely owing to climatic factors, making breeders’ decision-making harder.

Phytochrome B was found to directly trigger light-dependent chromatin remodelling by physically interacting with a component of PRC2, thereby regulating the expression of target genes, including growth-promoting genes.

New emerged variants of stem rust threaten wheat production globally. Here, mutational genomics is used to characterize a new resistance gene named Sr27 both in wheat and in triticale, and the corresponding secreted effector in the pathogen, AvrSr27.

A probe to visualize membrane potential in real time is used to connect rapid auxin-induced membrane depolarization with root growth inhibition, which are both controlled by the AFB1 auxin receptor.

Vicine and convicine are the main anti-nutritional factors restricting the consumption of faba bean. Transcript profiling combined with metabolite profiling was applied to identify a key enzyme responsible for the biosynthesis of vicine and convicine in faba bean.

This study showed efficient base editing of mitochondria and chloroplast genomes in both lettuce and rapeseed by DddA-derived cytosine base editors (DdCBEs), and DNA-free editing in chloroplasts by delivering DdCBE mRNA to protoplasts, which avoids off-target effects.

This study used bacterial cytidine deaminase fused to the DNA binding domains of transcription activator-like effector nucleases to enable targeted base editing in the Arabidopsis thaliana plastid genome, generating T₁ plants with inheritable homoplasmic mutations.

Plant diversity for agriculture has been found to increase biomass, but what about resource allocation? This study of two- to four-crop species mixtures finds increased productivity compared with monocultures but reduced harvest indices, since all of the crops studied have been optimized for monocultures.

CBF transcription factors are central to cold stress responses. The authors show that only monomeric reduced forms can induce target genes. The redox status of CBFs is controlled by thioredoxin, isotype-h2, Trx-h2.

This study generated a transcriptional atlas of developing Arabidopsis seeds with single-nucleus RNA-sequencing, reporting transcriptionally uncharacterized nuclei types in the chalazal endosperm and spatially and temporally heterogenous imprinting in the seeds.

The IQ67 DOMAIN (IQD) family are plant-specific calmodulin-binding proteins. Several members are associated with the microtubule cytoskeleton, and now IQD6, IQD7 and IQD8 are characterized as functioning in the set-up of the cell division plane in the root meristem of Arabidopsis.

PI(4,5)P₂ is importantly involved in a broad array of cellular processes, including polar auxin transport, vesicle trafficking and anisotropic cell growth. An inducible system is developed in Arabidopsis to conduct tunable depletion of PI(4,5)P₂ and reveal new roles of this membrane lipid.

Coffea stenophylla is a recently rediscovered, narrow-leaved wild coffee from Upper West Africa. Rigorous sensory evaluation (tasting) rates its flavour profile as analogous to high-quality Arabica coffee, but it can grow at much higher temperatures.

The light-dependent protochlorophyllide oxidoreductase (LPOR) is involved in chlorophyll synthesis and insertion into the thylakoid membrane. Here, a high-resolution structure of membrane-bound LPOR advances the mechanistic understanding of chlorophyll synthesis and thylakoid biogenesis.