Letters in 2016

The phenotypic expression of SP11 alleles ­— male determinants of self-incompatibility in Brassica rapa ­— is controlled by a five-phased linear hierarchy. A study has found that a polymorphic 24-nt small RNA controls the linear hierarchy of four of the SP11 alleles.

To explore how climate warming may affect rice yield, a study used field experiments and three modelling approaches to examine the sensitivity of rice yield to warming. The study predicts that severe rice yield losses are likely to occur without effective crop improvement.

Pottery remains from archaeological sites in the Libyan Sahara provide the earliest direct evidence for plant processing in pottery, dating to 8200–6400 cal BC. The remains show processing of grasses and aquatic plants gathered from the then green Sahara.

Interrogation of a worldwide database of leaf traits in forest canopies shows that a large proportion of ‘full-sun’ readings were made in the shade. The majority of leaves exist in the shade but research is too focused on conditions in the sun.

Despite improved farming practices, models suggest that droughts like those of the 1930s would still be devastating to the US today. High temperatures are more damaging than rainfall deficit, leading to losses ∼50% larger than the severe drought of 2012.

Two genes controlling the transcriptional network involved in stomatal development in Arabidopsis thaliana have a conserved function in the non-vascular moss Physcomitrella patens. Moss mutants without stomata show delayed capsule dehiscence.

Little is known of the effects of drought on nutrient cycling in forests. Long-term monitoring of nutrient fluxes shows that drought causes loss of potassium from boreal forests, which may contribute to reduced potassium availability in a warming world.

Proanthocyanidins are important phenolic compounds that affect the taste of plant-based food. A combination of genetics and biochemistry solves the role of leucoanthocyanidin reductase in the polymerization of (epi)catechin units in Medicago.

The mechanism for T-DNA integration, a critical step of Agrobacterium-mediated transgenesis, remains elusive. Now, a study shows that polymerase θ controls T-DNA integration and generates the error-prone sequences at the sites of integration.

By assembling the genome of Cardamine hirsuta and conducting comparative genomic and transcriptomic analyses, a study reveals the prevalent role of transcription factors and gene duplication in morphological evolution.

Plants can regenerate tissues after injury. The heterodimeric transcription factor complex ERF115–PAT1 is activated by the cell death of neighbouring cells, and is crucial for stem cell replenishment and the high regenerative potential of plants.

Many plants exhibit iridescence but no link has been demonstrated between this phenomenon and photosynthesis. This study shows the epidermal chloroplasts of Begonia to have photonic properties that increase both light capture and quantum yield.

C₄ photosynthesis has evolved independently in over 60 plant lineages. This study shows expression of key C₄ enzymes being controlled by light and the chloroplast in C₃ leaves, potentially facilitating repeated evolution of C₄ traits.

A population genomics study reveals a high similarity between a New World landrace of African rice and an Ivory Coast landrace. Together with diaries from captains of slave ships, the evidence presented traces the ancestry of the New World rice to its African origin.

Fungi are the most prevalent class of plant pathogens, causing many diseases in crops. The authors show that in order to fight against them, plants produce and export miRNAs to silence important fungal genes, reducing the pathogen's virulence.

By examining imprinted gene expression and methylomes in Arabidopsis lyrata and A. thaliana, a study found that while imprinted genes are largely conserved between the species, different epigenetic mechanisms were employed to maintain the imprinted gene expression.

Extended growing seasons due to climate warming might counter rises in CO₂ by increasing photosynthesis. However, in eastern North America, earlier springs over 30 years have reduced nitrogen availability to forest trees by increasing demand, limiting carbon sequestration.

New approaches to create site-specific gene replacements and insertions in plants have been developed based on intron-targeting CRISPR/Cas9. These approaches efficiently generate replacements and insertions at the OsEPSPS gene in rice, resulting in glyphosate-resistant plants.

Chlamydomonas reinhardtii possesses an atypical violaxanthin de-epoxidase, homologous to a bacterial enzyme rather than plant or algal enzymes with the same function. This illustrates an unexpected diversity of photoprotection mechanisms in the green lineage of photosynthetic organisms.

Two novel ROP-GAP proteins (PHGAP1/2) localize to cortical cell division site during cytokinesis in Arabidopsis. They interact with phragmoplast-orienting kinesins (POK), and are necessary for correct orientation of cell plates during division.