Genetius

Leaf venation density has increased through plant evolution, reaching its highest levels in recently diverged C4 species such as maize. Using diverse Mexican maize varieties and a MAGIC population, the study finds that higher densities of small intermediate veins correlate with higher photosynthetic rates, and identifies 12 QTLs and candidate genes linked to vein patterning. These results illuminate the genetic architecture of vein density and its role in water use efficiency and photosynthetic performance in C4 plants.

The authors exploit maize haploid pollen carrying Ds‑GFP insertional mutations to associate specific genes with quantitative fitness effects measured by transmission bias. Using interpretable machine‑learning models that combine genomic sequence features and expression specificity, they predict genes influencing pollen fitness with AUROC values up to 90% and demonstrate genome‑wide applicability.

The study assessed 17 morphological, biochemical, and salt‑stress tolerance traits in 19 maize (Zea mays) landrace accessions from Northern Argentina, revealing substantial phenotypic diversity both within and among accessions. Although regional differences were not significant, altitude was linked to phenotypic variation, underscoring the potential of these landraces as reservoirs of valuable traits for breeding and conservation.

The study profiled the maize endosperm transcriptome during the first four days after pollination using laser-capture microdissection, revealing temporal co‑expression modules activated after fertilization. By analyzing cis‑regulatory elements and transcription factor families, the authors constructed gene networks linking MYB‑related TFs to BETL differentiation and E2F TFs to early endosperm proliferation, highlighting sugar‑sensing TOR pathways that influence kernel size. These findings provide a framework for improving seed composition and yield.

The study profiled transcriptomes, small RNAs, and proteomes across four stages of maize tassel development to elucidate regulatory programs governing anther cell specification. Dynamic gene expression shifts and stage‑specific microRNA patterns, especially those targeting auxin signaling and meiocyte‑associated miRNAs, reveal fine‑tuned hormonal and reproductive pathways during meristem transition and early anther differentiation.

The study quantified bioactive gibberellins GA1 and GA4 in multiple commercial Zea mays hybrids grown across diverse field sites using high‑throughput LC‑MS/MS, revealing significant variation due to environment, genotype, and their interaction. Site effects were significant for most GA‑tissue combinations, while genetic effects were limited to GA4 in grain, and GA1 and GA4 levels were positively correlated in most tissues.

The study examined how elevated CO2 (550 ppm) affects disease susceptibility in the C4 crop maize (Zea mays L.) by inoculating plants with a range of bacterial, viral, fungal, and oomycete pathogens. Results showed increased vulnerability to sugarcane mosaic virus, decreased susceptibility to several bacterial and fungal pathogens, and no change for a rust and an oomycete, indicating pathogen‑specific modulation of immunity under eCO2. These findings lay groundwork for dissecting CO2‑responsive defense pathways in crops.

The study shows that maize autophagy-defective atg10 mutants exhibit delayed flowering and produce smaller, lighter, and fewer kernels, resulting in lower grain yield. Reciprocal crossing experiments indicate that the maternal plant, rather than seed genotype, primarily drives the kernel defects, likely due to impaired nutrient remobilization during seed development.

The study tests whether heavy metal (copper and cadmium) stress contributed to maize domestication by exposing teosinte parviglumis and maize to sublethal metal concentrations and analyzing selection on three chromosome‑5 heavy‑metal response genes (ZmHMA1, ZmHMA7, ZmSKUs5). Transcriptomic and phenotypic data show that metal stress induces a maize‑like architecture and up‑regulates Tb1, while genomic scans reveal strong positive selection on these genes, linking volcanic‑related heavy‑metal exposure to the evolutionary transition from teosinte to maize.

The study evaluated how four decades of maize breeding and increased planting density have reshaped root system architecture, finding that modern hybrids develop smaller, thinner crowns but explore more soil volume and share a larger proportion of topsoil with neighbors compared to older varieties. This suggests an adaptation toward less competitive, more intertwined root systems under high-density conditions. The findings have implications for breeding strategies aimed at improving root efficiency and crop productivity.