Evolution of HMA-integrated tandem kinases accompanied by expansion of target pathogens
Authors: Asuke, S., Tagle, A. G., Hyon, G.-S., Koizumi, S., Murakami, T., Horie, A., Niwamoto, D., Katayama, E., Shibata, M., Takahashi, Y., Islam, M. T., Matsuoka, Y., Yamaji, N., Shimizu, M., Terauchi, R., Hisano, H., Sato, K., Tosa, Y.
The study cloned the resistance genes Rmo2 and Rwt7 from barley and wheat, revealing them as orthologous tandem kinase proteins (TKPs) with an N‑terminal heavy metal‑associated (HMA) domain. Domain‑swapping experiments indicated that the HMA domain dictates effector specificity, supporting a model of TKP diversification into paralogs and orthologs that recognize distinct pathogen effectors.
Mutations in the plastid division gene PARC6 and the granule initiation gene BGC1 were combined to generate wheat plants with dramatically enlarged A-type starch granules, some exceeding 50 µm, without affecting plant growth, grain size, or overall starch content. The parc6 bgc1 double mutant was evaluated in both glasshouse and field trials, and the giant granules displayed altered viscosity and pasting temperature, offering novel functional properties for food and industrial applications.
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.
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.
Glycosylated diterpenes associate with early containment of Fusarium culmorum infection across wheat (Triticum aestivum L.) genotypes under field conditions
Authors: Pieczonka, S. A., Dick, F., Bentele, M., Ramgraber, L., Prey, L., Kupczyk, E., Seidl-Schulz, J., Hanemann, A., Noack, P. O., Asam, S., Schmitt-Kopplin, P., Rychlik, M.
The researchers performed a large‑scale field trial with 105 wheat (Triticum aestivum) genotypes inoculated by Fusarium culmorum, combining quantitative deoxynivalenol (DON) profiling and untargeted metabolomics to uncover molecular signatures of infection. Sesquiterpene‑derived metabolites tracked toxin accumulation, whereas glycosylated diterpene conjugates were enriched in low‑DON samples, indicating a potential defensive metabolic pathway.
The study examined the pre‑activation state of the rice NLR pair Pik‑1 (sensor) and Pik‑2 (helper) when transiently expressed in Nicotiana benthamiana leaves. Both wild‑type and engineered Pik‑1 variants constitutively associate with Pik‑2 to form ~1 MDa hetero‑oligomeric complexes that localize to the plasma membrane in the absence of effector. These results reveal that some NLRs exist as pre‑assembled membrane‑associated complexes prior to pathogen perception.
The study evaluated a transgenic soybean line (VPZ-34A) expressing Arabidopsis VDE, PsbS, and ZEP for combined improvements in light‑use efficiency and carbon assimilation under ambient and elevated CO2 in a FACE experiment. While VPZ‑34A showed enhanced maximum quantum efficiency of PSII under fluctuating light, it did not increase carbon assimilation efficiency or yield, and transcriptome analysis revealed limited gene expression changes. The results suggest that VPZ‑mediated photosynthetic gains are insufficient to boost productivity under elevated CO2.
The study performed a meta‑transcriptomic analysis of over twenty drought versus control experiments in Vitis vinifera and two hybrid rootstocks, identifying a core set of 4,617 drought‑responsive genes. Using transcription factor binding motif enrichment and random‑forest machine learning, gene regulatory networks were built, revealing key regulators such as ABF2, MYB30A, and a novel HMG‑box protein. These regulators and network hierarchies provide candidate targets for breeding and biotechnological improvement of grapevine drought tolerance.
The study reveals that the Arabidopsis O-GlcNAc transferase SEC is essential for timely ABA‑induced stomatal closure and drought tolerance, with sec-5 mutants showing delayed closure and increased water loss, while SEC overexpression enhances responsiveness. SEC influences guard‑cell microtubule remodeling, as loss of SEC impairs microtubule reorganization and SEC directly interacts with tubulin α‑4, suggesting tubulin as a target of O‑GlcNAcylation.