Photosynthetic organisms convert light energy into chemical energy stored in carbohydrates. To perform this process, an adequate supply of essential mineral elements, such as iron, is required in the chloroplast. Because iron plays a crucial role during electron transport and chlorophyll formation, iron deficiency alters photosynthesis and promotes chlorosis, or the yellowing of leaves. Intriguingly, iron deficiency-induced chlorosis can be reverted by the depletion of other micronutrients [i.e., manganese (Mn)] or macronutrients [i.e., sulfur (S) or phosphorus (P)], raising the question of how plants integrate nutrient status to control photosynthesis. Here, we review how improving our understanding of the complex relationship between nutrient homeostasis and photosynthesis has great potential for crop improvement.

Body size varies widely among species, populations and individuals, depending on the environment. Transitioning between proliferation and differentiation is a crucial determinant of final organ size, but how the timing of this transition is established and maintained remains unknown. Using cell proliferation markers and genetic analysis, we show that CHIQUITA1 (CHIQ1) is required to maintain the timing of the transition from proliferation to differentiation in Arabidopsis thaliana. Combining kinematic and cell lineage-tracking studies, we found that the number of actively dividing cells in chiquita1-1 plants decreases prematurely compared with wild-type plants, suggesting CHIQ1 maintains the proliferative capacity in dividing cells and ensures that cells divide a specific number of times. CHIQ1 belongs to a plant-specific gene family of unknown molecular function and genetically interacts with three close members of its family to control the timing of proliferation exit. Our work reveals the interdependency between cellular and organ-level processes underlying final organ size determination.

Plants produce a vast array of metabolites, the biosynthetic routes of which remain largely undetermined. Genome-scale enzyme and pathway annotations and omics technologies have revolutionized research to decrypt plant metabolism and produced a growing list of functionally characterized metabolic genes and pathways. However, what is known is still a tiny fraction of the metabolic capacity harbored by plants. Here, we review plant enzyme and pathway annotation resources and cutting-edge omics approaches to guide discovery and characterization of plant metabolic pathways. We also discuss strategies for improving enzyme function prediction by integrating protein 3D structure information and single cell omics. This review aims to serve as a primer for plant biologists to leverage omics datasets to facilitate understanding and engineering plant metabolism.

Understanding the molecular and physiological mechanisms of how plants respond to drought is paramount to breeding more drought resistant crops. Certain mutations or allelic variations result in plants with altered water-use requirements. To correctly identify genetic differences which confer a drought phenotype, plants with different genotypes must be subjected to equal levels of drought stress. Many reports of advantageous mutations conferring drought resistance do not control for soil water content variations across genotypes and may therefore need to be re-examined. Here, we reassessed the drought phenotype of the Arabidopsis (Arabidopsis thaliana) dwarf mutant, chiquita1-1 (chiq1-1, also called constitutively stressed 1 (cost1)), by growing mutant seedlings together with the wild type to ensure uniform soil water availability across genotypes. Our results demonstrate that the dwarf phenotype conferred by loss of CHIQ1 function results in constitutively lower water usage per plant, but not increased drought resistance. Our study provides an easily reproducible, low-cost method to measure and control for soil water content and to compare drought resistant genotypes more accurately.

The densities of RNA-seq reads (in reads per kilo-bases per million reads, RPKM) were normalized to the library size and the number of sites in 20bp sliding windows along the genome.

The densities of RNA-seq reads (in reads per kilo-bases per million reads, RPKM) were normalized to the library size and the number of sites in 20bp sliding windows along the genome.

The densities of RNA-seq reads (in reads per kilo-bases per million reads, RPKM) were normalized to the library size and the number of sites in 20bp sliding windows along the genome.

The core pluripotency factors (Oct4, Sox2, and Nanog), the Myc network, and the chromatin-modifying complexes such as PRC2 ensure the pluripotency and self-renewal of ES cells (ESC). How these factors coordinate with one another remains poorly understood. We report that Utf1, a target of Oct4 and Sox2, is a new bivalent chromatin component that buffers poised states of bivalent genes. By limiting PRC2 loading and Histone 3 lysine-27 trimethylation, Utf1 sets proper activation thresholds for bivalent genes. It also promotes nuclear tagging of mRNAs transcribed from insufficiently silenced bivalent genes for cytoplasmic degradation through mRNA de-capping. Whereas these opposing functions of Utf1 allow proper execution of ESC pluripotency, the mRNA pruning function also ensures rapid cell proliferation by blocking the Myc-Arf feedback regulation. Thus, Utf1 is an important regulator that couples the core pluripotency factors with Myc and PRC2 networks to promote proliferation and pluripotency execution of ESCs.

The densities of RNA-seq reads (in reads per kilo-bases per million reads, RPKM) were normalized to the library size and the number of sites in 20bp sliding windows along the genome.

The densities of RNA-seq reads (in reads per kilo-bases per million reads, RPKM) were normalized to the library size and the number of sites in 20bp sliding windows along the genome.