Articles in 2015

Predictions suggest that a high proportion of plant species will be threatened with extinction in the near future. A global assessment of the threat status of cacti suggests that these iconic plants are amongst the most threatened taxonomic groups, with 31% of the 1,478 evaluated species at risk of extinction.

The frequency of severe droughts is increasing in many regions around the world as a result of climate change. An analysis of tree growth and mortality data from forests worldwide suggests that large trees fare worse under drought than small trees.

RSL4 is a transcription factor synthesized during a 4-hour pulse at the initiation of the root hair elongation phase, and then degraded by the proteasome. Low phosphate conditions increase the length of the pulse, resulting in longer root hair.

The geographic extent of stripe rust, a fungal disease that adversely affects wheat production, has increased in recent decades. Observations and model simulations suggest that over 5 million tonnes of wheat are lost to this pathogen each year, necessitating a sustained annual investment of at least US$32 million into rust resistance research.

There is a lack of knowledge on how defence gene priming is repressed under standard conditions. Now, mutant analyses show that the histone chaperone CAF-1 acts under normal conditions to prevent spurious activation of defence responses.

The signalling pathway underlying the self-incompatibility response in Brassicaceae remains elusive. Genetic and physiological experiments now show that Ca²⁺-influx, probably mediated by glutamate receptor-like channels, leads to self-pollen rejection.

Magnesium chelatase catalyses Mg insertion into the centre of protoporphyrin IX during chlorophyll synthesis. The crystal structure of magnesium chelatase from the cyanobacterium Synechocystis shows an active site deeply buried within protein lined with evolutionary conserved residues.

Agricultural rice production germinates seeds and establishes seedlings underwater. Now a trehalose-6-phosphate (T6P) phosphatase, OsTPP7, is shown to enhance anaerobic germination tolerance by increasing T6P turnover and thus starch mobilization.

Competition for light has profound effects on plant performance in virtually all terrestrial ecosystems. An experimental study in a temperate forest understorey suggests that low light levels limit warming-induced changes in the composition of the forest floor plant community.

In plants kinesin-14 motors have been proposed as dynamic cross-linkers between actin and microtubule cytoskeleton. This study shows that OsKCH1, a kinesin-14 from rice, is a non-processive, minus-end-directed motor that transports actin filaments along microtubules.

Coordination between vesicle trafficking and osmotic solute uptake is needed for plant growth. It is regulated by the interaction between voltage sensor domains of K⁺ channels and a SNARE protein, conferring a voltage dependence on secretory traffic.

The production of alga-derived lipids, a valuable source of biofuels, is restricted by the growth arrest of algae. Now a regulator of algal lipid accumulation is identified using an integrative chromatin signature and transcriptomic analysis.

Terrestrial ecosystem productivity is widely accepted to be nutrient limited. A series of standardized nutrient addition experiments, carried out on grasslands on five continents, suggests aboveground grassland productivity is commonly limited by multiple nutrients, including potassium and micronutrients.

Phytochromes are bistable molecular switches that control plant light responses. Phytochromes A and B have similar absorption properties but different effects. Modelling of phytochrome B function shows that dimerization underlies its specific activity.

The contribution of epigenetic factors to inbreeding depression and heterosis remains elusive. Now epigenetic Arabidopsis hybrids show that epigenetic diversity and regulation contribute to both.

The V-ATPase impaired in the det3 mutant acidifies trans-Golgi network/early endosome, and is needed for exocytosis of cargo vesicles, which are involved in recycling important membrane proteins such as the brassinoid receptor and cellulose synthase.

Plants lack the retrograde motor dynein. Although kinesin-14 from Physcomitrella patens is a minus-end-directed motor, it is not individually processive. But four or more molecules acting together can transport liposomes and may substitute for dynein in plants.

Plant somatic cells are totipotent, but once differentiated, must keep their own identity and function. Chromatin regulator PRC2 represses downstream transcription factors and prevents dedifferentiation and division of fully mature root hair cells.

Transgenic American cotton resistant to lepidopteran pests increases yields and revenues while reducing pesticide use compared to non-GM varieties. However, when grown without artificial irrigation the economic benefits over Asiatic cotton are less clear.

Gibberellin is a major hormone in plant growth. Mixing old-style grafting with modern molecular genetics in Arabidopsis shows that the GA₁₂ precursor is the chemical form of gibberellin undergoing long-distance transport across plant organs.