Chromosome-scale Solanum pennellii and Solanum cheesmaniae genome assemblies reveal structural variants, repeat content and recombination barriers of the tomato clade
Authors: van Rengs, W., Fuentes, R. R., Zangishei, Z., Primetis, E., Wang, Y., Fernandes, J., Susanto, T., Lian, Q., Effgen, S., Huettel, B., Alseekh, S., Usadel, B., Underwood, C. J.
The study generated chromosome‑scale de novo assemblies for two wild tomato relatives, Solanum pennellii and Solanum cheesmaniae, using PacBio HiFi, Oxford Nanopore ultra‑long reads, and Hi‑C scaffolding, achieving >99% completeness. Comparative analysis with nine Lycopersicon clade genomes revealed species‑specific structural variants and independent Tekay retrotransposon expansions, while recombination mapping in 709 backcross hybrids demonstrated higher female crossover rates and identified gender‑biased recombination regions and coldspots associated with large structural differences.
The study reveals that red pigmentation in quinoa (Chenopodium quinoa) epidermal bladder cells is due to a ~4‑kb genomic insertion that restores the full-length CYP76AD gene, which is the rate‑limiting enzyme for betacyanin synthesis. Cell‑type‑specific RNA‑sequencing showed that this restored CYP76AD is highly upregulated in red bladder cells, and subgenome analysis indicated B‑subgenome dominance for this gene in pigmented tissues.
Using ten Phaeodactylum tricornutum mutant strains with graded constitutive Lhcx1 expression, the study links NPQ induction under high light to physiological outcomes (oxidized QA, increased cyclic electron flow) and extensive transcriptomic reprogramming, affecting nearly half the genome. The approach demonstrates that higher NPQ mitigates PSII damage, boosts ATP production for repair, and drives distinct gene regulatory networks, providing a model framework for dissecting photosynthetic and gene expression integration.
The study establishes a tractable system using the large bloom-forming diatom Coscinodiscus granii and its natural oomycete parasite Lagenisma coscinodisci, enabling manual isolation of single host cells and stable co-cultures. High‑quality transcriptomes for both partners were assembled, revealing diverse oomycete effectors and a host transcriptional response involving proteases and exosome pathways, while also profiling the co‑occurring heterotrophic flagellate Pteridomonas sp. This tripartite platform provides a unique marine model for dissecting molecular mechanisms of oomycete‑diatom interactions.
Using a forward genetic screen of 284 Arabidopsis thaliana accessions, the study identified extensive natural variation in root endodermal suberin and pinpointed the previously unknown gene SUBER GENE1 (SBG1) as a key regulator. GWAS and protein interaction analyses revealed that SBG1 controls suberin deposition by binding type‑one protein phosphatases (TOPPs), with disruption of this interaction or TOPP loss‑of‑function altering suberin levels, linking the pathway to ABA signaling.
A comprehensive multi‑environment trial of 437 maize testcross hybrids derived from 38 MLN‑tolerant lines and 29 testers identified additive genetic effects as the primary driver of grain yield, disease resistance, and drought tolerance. Strong general combining ability and specific combining ability patterns were uncovered, with top hybrids delivering up to 5.75 t ha⁻¹ under MLN pressure while maintaining high performance under optimum and drought conditions. The study provides a framework for selecting elite parents and exploiting both additive and non‑additive effects to develop resilient maize hybrids for sub‑Saharan Africa.
The study reveals that rice perceives Xanthomonas oryzae pv. oryzae outer membrane vesicles through a rapid calcium signal that triggers plasma‑membrane nanodomain formation and the re‑organisation of defence‑related proteins, establishing an early immune response. Without this Ca2+ signal, OMVs are not recognized and immunity is weakened.
The study compares the iron-poor oceanic diatom Thalassiosira oceanica with the iron-rich coastal species T. pseudonana to uncover how diatoms adapt to low-iron conditions. Using photo‑physiological measurements, proteomic profiling, and focused ion beam scanning electron microscopy, the researchers show that each species remodels chloroplast compartments and exhibits distinct mitochondrial architectures to maintain chloroplast‑mitochondrial coupling under iron limitation.
CLPC2 plays specific roles in CLP complex-mediated regulation of growth, photosynthesis, embryogenesis and response to growth-promoting microbial compounds
Authors: Leal-Lopez, J., Bahaji, A., De Diego, N., Tarkowski, P., Baroja-Fernandez, E., Munoz, F. J., Almagro, G., Perez, C. E., Bastidas-Parrado, L. A., Loperfido, D., Caporalli, E., Ezquer, I., Lopez-Serrano, L., Ferez-Gomez, A., Coca-Ruiz, V., Pulido, P., Morcillo, R. J. L., Pozueta-Romero, J.
The study demonstrates that the plastid chaperone CLPC2, but not its paralogue CLPC1, is essential for Arabidopsis responsiveness to microbial volatile compounds and for normal seed and seedling development. Loss of CLPC2 alters the chloroplast proteome, affecting proteins linked to growth, photosynthesis, and embryogenesis, while overexpression of CLPC2 mimics CLPC1 deficiency, highlighting distinct functional roles within the CLP protease complex.
Chromosome-scale haplotype genome assemblies for the Australian mango 'Kensington Pride' 1 and a wild relative, Mangifera laurina, provide insights into anthracnose-resistance and volatile 2 compound biosynthesis genes
Authors: Wijesundara, U. K., Furtado, A., Masouleh, A., Dillon, N. L., Smyth, H., Henry, R. J.
Chromosome-level, 100% complete genomes of the Australian mango cultivar Kensington Pride and the wild relative M. laurina were assembled using high-coverage PacBio HiFi sequencing. Comparative analyses uncovered extensive structural variation, identified key genes in carotenoid, anthocyanin, and terpenoid pathways, and pinpointed a SNP in the β-1,3-glucanase 2 gene associated with anthracnose resistance. Whole-genome duplication and collinearity analyses revealed two polyploidization events and conserved gene blocks across mango genomes.