Whole-genome sequencing reveals the molecular basis of sex determination in the dioecious wild yam Dioscorea tokoro
Authors: Kudoh, A., Natsume, S., Sugihara, Y., Kato, H., Abe, A., Oikawa, K., Shimizu, M., Itoh, K., Tsujimura, M., Takano, Y., Sakai, T., Adachi, H., Ohta, A., Ohtsu, M., Ishizaki, T., Terachi, T., Terauchi, R.
The study reveals that the dioecious monocot Dioscorea tokoro employs a male heterogametic (XY) sex-determination system with sex-determining regions on chromosome 3, including X- and Y-specific pericentromeric regions. Two Y-specific candidate genes, BLH9 (a homeobox protein) and HSP90 (a molecular chaperone), are identified as likely mediators of female organ suppression and pollen development, respectively, providing insight into the evolution of dioecy in plants.
The study examines how the SnRK1 catalytic subunit KIN10 integrates carbon availability with root growth regulation in Arabidopsis thaliana. Loss of KIN10 reduces glucose‑induced inhibition of root elongation and triggers widespread transcriptional reprogramming of metabolic and hormonal pathways, notably affecting auxin and jasmonate signaling under sucrose supplementation. These findings highlight KIN10 as a central hub linking energy status to developmental and environmental cues in roots.
The study generated high‑quality genome assemblies for 12 indica and japonica rice accessions and demonstrated that structural variants (SVs) are abundant and strongly associated with heterosis across 17 agronomic traits. Correlation analyses revealed that SV count between parental lines predicts hybrid performance, and functional validation of SVs in S5‑ORF5 and OsBZR1 confirmed their contributions to seed setting rate and yield heterosis, supporting an overdominance model for inter‑subspecific hybrid vigor.
Four isolates of Pythium aphanidermatum obtained from infected amaranth seedlings were confirmed by morphology and ITS rDNA sequencing and shown to cause severe root loss and damping‑off in both plate and soil assays, with up to 100% disease incidence in susceptible genotypes. The genome of isolate PT2-1-1 was sequenced, revealing a 51.55 Mb assembly with 14,453 protein‑coding genes, including numerous plant cell wall‑degrading enzymes and candidate intracellular and apoplastic effectors such as Crinkler and YxSL[RK] proteins. This second genome assembly and the demonstrated pathogenic variation provide a foundation for studying host‑pathogen interactions in amaranth.
The study generated a high-quality genome assembly for Victoria cruziana and used comparative transcriptomics to identify anthocyanin biosynthesis genes and their transcriptional regulators that are differentially expressed between white and light pinkish flower stages. Differential expression of structural genes (VcrF3H, VcrF35H, VcrDFR, VcrANS, VcrarGST) and transcription factors (VcrMYB123, VcrMYB-SG6_a, VcrMYB-SG6_b, VcrTT8, VcrTTG1) correlates with the observed flower color change.