Plant reproductive development

Papaya is a trioecious species with XX females, XY males, and XY^h hermaphrodites, and the combination of Y and Y^h chromosomes is lethal. Here, the authors identify the degeneration of the YY lethality gene on the Y chromosome as the causal balancing lethal factor that reenforces dioecy and stabilizes balanced sex ratios.

Pollen vegetative cells undergo epigenetic reprogramming, including DNA demethylation. In these cells, the authors show that the methyl readers MBD5 and MBD6 help prevent excessive demethylation by antagonizing MBD7-mediated active demethylation.

In patchouli (Pogostemon cablin), anther-derived somatic embryos were profiled by single-cell RNA-seq to define eight cell types, identifying PcNAC048 that drives embryonic cell differentiation, promotes lateral root development in Arabidopsis, and negatively regulates patchouli alcohol biosynthesis.

In plants, the MMC represents the precursor of the female germline. Here, the authors show that SPL/NZZ, together with ovule-identity MADS-domain transcription factors, controls MMC differentiation by acting on an auxin-dependent downstream network.

Shimotohno et al. demonstrated a BAM1–GHR1–CLE5p/SnRK2 signal transduction module that regulates primary drought responses without stimulating ABA biosynthesis in Arabidopsis.

This work shows that two H3K4me2/me3 readers recruit PRC2 to timely represses FT expression following daily rhythmic FT activation under inductive long days, which prevents excessive FT expression to precisely control flowering time in Arabidopsis.

ChIP-seq and transcriptomic analyses reveal that LEC1 dynamically regulates endosperm development in Arabidopsis, with functions distinct from in the embryo, targeting genes in a stage-specific manner; its loss leads to defects in storage lipid accumulation.

A study on rice pollination using single-cell metabolomics and microscopy reports a discovery such that pollen grains attached show “Roly-poly toy”-like physical motion subsequently after exudation, leading to pollen adhesion and germination to facilitate rapid pollination.

Epigenetic modifications are crucial for plant development. Here, the authors find an epigenetically mediated double negative cascade for pollen formation and anther dehiscence, offering new insights into epigenetic regulation of anther development.

H3K9me2, a canonical heterochromatin epigenetic mark, is less in the companion vegetative cell than in sperm cells. Li et al. uncover that ARID1, a pollen-specific transcription factor, reinforces H3K9me2 maintenance in sperm cells.

In flowering plants, hermaphroditism is widespread. Here the authors identified a transposon insertion that triggers plant sexual transition. This study highlights the role of transposons in plant adaptation and evolution.

In Arabidopsis, the pollen vegetative cell is regarded as a source of mobile siRNAs that guide male germline reprogramming. This study demonstrates that siRNA triggers of triploid seed lethality originate in germline companion cells after meiosis.

Population genomic and epigenomic study in a facultatively asexual plant indicates that natural selection can act on the controls of asexual reproduction during range expansion, which in turn might reduce genetic and epigenetic diversity in the population.

The phosphorylated pathway of serine biosynthesis plays a critical role in growth and development, and affects the tricarboxylic acid cycle, the amino acid and nucleotide metabolism and lipid metabolism in Marchantia polymorpha.

A study on a soybean DNA demethylase reveals that seed size is negatively regulated by GmDMEa, which is closely linked to methylation on transposon elements.