Summary: Trees are capable of tremendous architectural plasticity, allowing them to maximize their light exposure under highly competitive environments. One key component of tree architecture is the branch angle, yet little is known about the molecular basis for the spatial patterning of branches in trees. Here, we report the identification of a candidate gene for the br mutation in Prunus persica (peach) associated with vertically oriented growth of branches, referred to as ‘pillar’ or ‘broomy’. Ppa010082, annotated as hypothetical protein in the peach genome sequence, was identified as a candidate gene for br using a next generation sequence‐based mapping approach. Sequence similarity searches identified rice TAC1 (tiller angle control 1) as a putative ortholog, and we thus named it PpeTAC1. In monocots, TAC1 is known to lead to less compact growth by increasing the tiller angle. In Arabidopsis, an attac1 mutant showed more vertical branch growth angles, suggesting that the gene functions universally to promote the horizontal growth of branches. TAC1 genes belong to a gene family (here named IGT for a shared conserved motif) found in all plant genomes, consisting of two clades: one containing TAC1‐like genes; the other containing LAZY1, which contains an EAR motif, and promotes vertical shoot growth in Oryza sativa (rice) and Arabidopsis through influencing polar auxin transport. The data suggest that IGT genes are ancient, and play conserved roles in determining shoot growth angles in plants. Understanding how IGT genes modulate branch angles will provide insights into how different architectural growth habits evolved in terrestrial plants.

Quinoa (Chenopodium quinoa Willd.) is an ancient Andean crop that produces edible seeds and leaves. Quinoa's tolerance to salinity and other types of abiotic stresses provides it with high potential in a world where scarcity of water and increased soil salinization are important causes of crop failures. Due to its traditionally broad cultivation area (from Colombia to southern Chile), there is a wide range of quinoa cultivars adapted to specific conditions displaying a broad genetic variability in stress tolerance. In addition, being practically unique as a halophytic seed-producing crop with amazing nutritional properties, it is ideal as a model species for investigating morphological, cellular, physiological, and bio-molecular mechanisms of salinity tolerance. This review summarizes current knowledge of genotype-dependent variability in salinity responses and adaptive salt-tolerance mechanisms in quinoa. These include anatomical features and physiological aspects, such as osmotic adjustment through accumulation of ions, osmoprotectants, and sodium loading, transport, and storage, including the activity and gene expression of plasma and vacuolar membrane transporters. Finally, current knowledge regarding the effect of salinity on the nutritional properties of quinoa is discussed.

Chenopodium quinoa Willd. (quinoa) is a halophyte for which some parameters linked to salt tolerance have been investigated separately in different genotypes and under different growth conditions. In this study, several morphological and metabolic responses were analysed in parallel after exposure to salinity. In vitro seed germination was initially delayed by a 150 mM NaCl treatment but eventually reached the same level as the control (0 mM NaCl), whereas seedling root growth was enhanced; both parameters were moderately inhibited (~35–50%) by 300 mM NaCl. In pot grown plants, plant size was reduced by increasing salinity (0–750 mM NaCl). Transpiration and stomatal conductance were decreased at the highest salinity levels tested, consistent with reduced stomatal density and size. The density of epidermal bladder cells (EBCs) on the leaf surface remained unaffected up to 600 mM NaCl. Tissue contents of Na+ and Cl– increased dramatically with salt treatment, but resulted in only a 50% increase in Na+ from 150 to 750 mM NaCl. Internal K+ was unaffected up to 450 mM NaCl but increased at the highest salinity levels tested. Excretion through sequestration into EBCs was limited (generally =20%) for all ions. A modest dose-dependent proline accumulation, and concomitant reduction in total polyamines and putrescine efflux occurred in NaCl-treated plants. Results confirm the importance of inorganic ions for osmotic adjustment, the plant’s ability to maintain K+ levels and the involvement of putrescine efflux in maintaining ionic balance under high salinity conditions. Conversely, ion excretion and proline appear to play a minor role. Taken together these results indicate which parameters could be used for future comparison among different genotypes.