Hee Jin Park

To control net sodium (Na + ) uptake, Arabidopsis plants utilize the plasma membrane (PM) Na + /H + antiporter SOS1 to achieve Na + efflux at the root and Na + loading into the xylem, and the channel-like HKT1;1 protein that mediates the reverse flux of Na + unloading off the xylem. Together, these opposing transport systems govern the partition of Na + within the plant yet they must be finely co-regulated to prevent a futile cycle of xylem loading and unloading. Here, we show that the Arabidopsis SOS3 protein acts as the molecular switch governing these Na + fluxes by favoring the recruitment of SOS1 to the PM and its subsequent activation by the SOS2/SOS3 kinase complex under salt stress, while commanding HKT1;1 protein degradation upon acute sodic stress. SOS3 achieves this role by direct and SOS2-independent binding to previously unrecognized functional domains of SOS1 and HKT1;1. These results indicate that roots first retain moderate amounts of salts to facilitate osmoregulation, yet when sodicity exceeds a set point, SOS3-dependent HKT1;1 degradation switches the balance toward Na + export out of the root. Thus, SOS3 functionally links and co-regulates the two major Na + transport systems operating in vascular plants controlling plant tolerance to salinity.

Throughout the history of crop domestication, desirable traits have been selected in agricultural products. However, such selection often leads to crops and vegetables with weaker vitality and viability than their wild ancestors when exposed to adverse environmental conditions. Considering the increasing human population and climate change challenges, it is crucial to enhance crop quality and quantity. Accordingly, the identification and utilization of diverse genetic resources are imperative for developing disease‐resistant plants that can withstand unexpected epidemics of plant diseases. In this review, we provide a brief overview of recent progress in genome‐editing technologies, including zinc‐finger nucleases (ZFNs), transcription activator‐like effector nucleases (TALENs), and clustered regularly interspaced short palindromic repeats (CRISPR)‐associated protein 9 (Cas9) technologies. In particular, we classify disease‐resistant mutants of Arabidopsis thaliana and several crop plants based on the roles or functions of the mutated genes in plant immunity and suggest potential target genes for molecular breeding of genome‐edited disease‐resistant plants. Genome‐editing technologies are resilient tools for sustainable development and promising solutions for coping with climate change and population increases.

Flowering time in plants is a complex process regulated by environmental conditions such as photoperiod and temperature, as well as nutrient conditions. While the impact of major nutrients like nitrogen, phosphorus, and potassium on flowering time has been well recognized, the significance of micronutrient imbalances and their deficiencies should not be neglected because they affect the floral transition from the vegetative stage to the reproductive stage. The secondary major nutrients such as calcium, magnesium, and sulfur participate in various aspects of flowering. Micronutrients such as boron, zinc, iron, and copper play crucial roles in enzymatic reactions and hormone biosynthesis, affecting flower development and reproduction as well. The current review comprehensively explores the interplay between microelements and flowering time, and summarizes the underlying mechanism in plants. Consequently, a better understanding of the interplay between microelements and flowering time will provide clues to reveal the roles of microelements in regulating flowering time and to improve crop reproduction in plant industries.