Volume 2 Issue 9, September 2016

Rising atmospheric CO₂ is expected to boost crop yields during drought events because it promotes stomatal closure and saves water. However, field experiments with soybean in a simulated future CO₂ atmosphere suggest that crop canopy interactions with climate might prevent this mechanism from delivering its expected benefits.

The core of the photosynthetic complex photosystem I had been assumed to require contact with its associated light-harvesting complex I to function. But a mutant Arabidopsis line lacking the components of this complex shows that a plant's photosynthetic apparatus is more adaptable to changes in its environment than previously thought.

Many plants detect bacteria by the receptor FLS2 that binds the flagellin epitope flg22. A new pattern recognition receptor FLS3 in tomato detects flagellin from a second side; a further move in the evolutionary game of ‘hide and seek’ where pathogens evade recognition and hosts evolve novel immunoreceptors to detect them.

Abscisic acid (ABA) dynamically balances plant water use and availability. It is synthesized during water deficit and quickly catabolized into breakdown products previously thought to be largely inactive. New work demonstrates that phaseic acid, a major ABA catabolite, is a weak ABA receptor agonist with its own auxiliary role in water relations.

This Review summarizes current understanding of the non-self- and self-recognition systems of self-incompatibility and their evolution. The non-self-recognition model suggests that the transition from self-compatibility to self-incompatibility could be more common than previously thought.

Little is known about how hybrid taxa become established as new species. Studying floral morphology evolution in different Nicotiana allopolyploids shows transgressive shortening and broadening of the corolla accompanies hybrid species formation/hybridization.

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.

In Arabidopsis, the Polycomb proteins mediate an epigenetic memory system that is important for gene silencing via histone methylation during development. Two novel deubiquitinases, UBP12 and UBP13, have now been identified and characterized in this regulatory network.

FLS2 is the well-known plasma membrane receptor for flg22, a specific region of bacterial flagellin. But Solanaceae can also detect flagellin through another epitope, flgII-28, thanks to the novel receptor-like kinase FLS3 now identified in tomato.

Leaves vary their temperatures to improve their physiological performance. Theoretical considerations predict, and data for diverse taxa show, a moderate level of leaf thermoregulation maximizing net carbon assimilation.

A quadruple mutant of Arabidopsis lacking all four subunits of light harvesting complex I (LHCI) compensates by binding LHCII complexes to photosystem I instead. This maintained similar excitation energy transfer efficiency but with a much reduced absorption cross-section.

The predicted rise in CO₂ levels during this century is expected to stimulate crop yields, offsetting losses from greater drought. But this study, using free-air CO₂ enrichment, shows soybean yield gains dropping to zero as drought stress increased.