Volume 8 Issue 7, July 2022

Comparative and evolutionary genomics analyses for more than 1,600 re-sequenced maize lines identified vast amounts of differentially and complementary selected regions and genes among female and male heterotic groups used in modern hybrid maize breeding.

Regulation of organ growth involves multiple pathways that coordinate cell number and size in a process that is highly dependent on nutrient supply and energy levels. The simplicity of the Arabidopsis root tip provides a suitable model for the genetic dissection of plant organ growth regulation.

Organisms living at elevation are exposed to a constant state of hypoxia compared to those at low altitude. A recent study¹ has shown that flowering plants acclimatize to high altitude through natural variation in molecular oxygen (O₂) sensing, with high-altitude populations exhibiting increased O₂ sensitivity to balance physiological and metabolic outputs. This finding demonstrates convergent mechanisms for altitude adaptation across eukaryotic kingdoms despite differences in the hypoxia-signalling pathways of plants and animals.

In the phloem of vascular plants, distinct cell types are arranged in precise positions to ensure effective loading, transport and unloading of photosynthates and signalling molecules. Feedback between transcription factors and mobile peptides triggers and controls the differentiation of phloem at the growing root tip.

CLE peptides control stem-cell activity in meristems. Recent studies in Marchantia and Arabidopsis support the idea that an ancestral function of CLE peptides was to promote stem cells. After gene duplication in angiosperms, a subset of CLE peptides became stem-cell suppressors.

The development of root nodules implies tissue-specific epigenetic modifications of the plant genome, key for proper symbiotic gene expression and nodule activity. This study reveals the DNA methylation dynamics during nodule development.

This study reports the genomic changes underlying the convergent and divergent agronomic improvement of the female and male heterotic groups during modern hybrid maize breeding, laying a foundation for the dissection and utilization of maize heterosis.

The chromosomal-level genome assembly of a species from the earliest branching monocot, Acorus tatarinowii, provides evidence to trace the ancestral monocot chromosomes, and hints that the monocot ancestor might have an aquatic or wetland origin.

Heat stress transcription factors (HSFs) play critical roles in response to heat stress. This study reveals a new regulatory mechanism in Arabidospis by which ALBA proteins stabilize HSFs in cytoplasmic granules under heat stress.

Photosynthesis promotes the expression of TOPOISOMERASE1α, which in turn represses TARGET OF RAPAMYCIN (TOR) expression at the root tip. Glucose-TOR regulates cell division at the quiescent centre, and phosphorylates and stabilizes PLETHORA2 in columella cells to maintain root tip homeostasis.

How the plant immune signalling hub EDS1 is activated by pathogen elicitors remains enigmatic. Li et al. show that fungal elicitor perception can induce EDS1 phosphorylation by a plasma membrane tethering kinase after elegant subcellular coordination.

This study shows that Dof transcription factors in the phloem precursors not only induce formation of phloem, but also cause secretion of CLE peptides, which in turn inhibit phloem formation in neighbourhing cells by post-transcriptionally decreasing Dofs.

Mitochondrial ascorbate peroxidase (PtomtAPX) is relocated to cell walls undergoing programmed cell death and catalyses lignin polymerization. These results show how xylem cells provide autonomous enzymes needed for lignin polymerization.

Genetic, biochemical and high-resolution structural studies of chloroplast protein SOQ1 reveal the existence of a C-terminal lumenal domain with potential redox function and its essential role for suppressing photoprotection in plants.