Abstract The coupling between sugar availability and shoot branching is well established, yet the underlying molecular mechanisms remain largely unknown. Here, using genome-wide profiling, we characterized the sugar signalling pathways by identifying 10 microRNAs (miRNAs) repressed by glycolysis, the tricarboxylic acid (TCA) cycle, and/or the oxidative pentose phosphate pathway (OPPP) in rose buds. Focusing on RhmiR319, a miRNA repressed under active sugar metabolism, we demonstrate that disruption of both glycolysis/TCA cycle and the OPPP induces RhmiR319 accumulation, leading to the concomitant repression of its targets, RhTCP4a and RhTCP4b. We additionally reveal that the miR319–TCP4 module regulates shoot branching in Arabidopsis, as miR319 overexpression impairs shoot branching, whereas TCP4 promotes it. Altered branching patterns in Rose and Arabidopsis were associated with the expression of the branching integrator BRC1. Finally, we provide molecular evidence supporting that RhTCP4a/b directly binds to RhBRC1 promoter and represses its transcription. Together, these results establish the miR319–TCP4–BRC1 module as a key component in the regulation of shoot branching in response to sugar status. We propose that the miR319–TCP4–BRC1 module is conserved between annual and perennial species and may integrate multiple hormonal and metabolic signals to shape shoot branching in plants.
The seed-to-seedling transition is a key step of plant microbiota assembly, where the seed microbiota meets the soil microbiota. Seed germination triggers profound physiological changes, including exudate release and oxidative bursts, which generate selective pressures shaping microbial survival and interactions. Here, we investigated how host selection and community composition influence bacterial colonization during this transition using a Synthetic Community (SynCom) approach on common bean (Phaseolus vulgaris) seeds. Specifically, we tested the importance of microbial interactions by applying 30 bacterial SynComs spawning a phylogenetic diversity gradient. Seedling colonization success was primarily determined by strain identity but was strongly modulated by the SynCom context. Strains that were highly effective colonizers when inoculated alone often exhibited reduced transmission within SynComs, indicating that microbial interactions can either inhibit or facilitate colonization. Random forest models confirmed that colonization outcomes could not be predicted from single-strain performance alone. Instead, both phylogenetic relatedness and metabolic similarity among SynCom members emerged as key predictors of strain success, supporting the competition, relatedness hypothesis and highlighting the importance of community-dependent effects in shaping colonization success. Genomic analyses identified microbial traits linked to efficient seedling colonization, notably amino acid transport and metabolism, stress tolerance, ROS detoxification, and biofilm formation, highlighting the strong selective pressures acting during the seed-to-seedling transition. Besides key adaptative traits, our findings underscore the importance of microbial interactions to survive and colonize seedlings, bringing a novel perspective for the successful engineering of seed and seedling microbiota. ### Competing Interest Statement The authors have declared no competing interest. Agence Nationale de la Recherche, https://ror.org/00rbzpz17, ANR-20-PCPA- 0009
Understanding the molecular evolution of genes involved in parasite adaptation and the role of transposable elements (TEs) in driving their diversification is key to unraveling how populations adapt to their environments. In phytophagous insects like aphids, olfactory (OR) and gustatory receptor (GR) genes are crucial for host recognition, yet their post-duplication evolution remains insufficiently explored. Here, we analyzed 521 OR and 399 GR genes, alongside TEs, across 12 aphid genomes with varying host ranges. Aphid lineages with broader host ranges exhibited higher evolutionary rates, driven by gene family expansions linked to host interaction, including lipid metabolism, immune function, and transposase activity. The evolution of OR and GR genes post-duplication was shaped by diversifying selection, with bursts of positive selection followed by long periods of purifying selection, consistent with adaptation to new hosts. OR and GR genes originated from proximal and tandem duplications, with younger TE activity enriched near these genes compared to other genomic regions, suggesting a role for TEs in catalyzing tandem duplications and fueling diversification. The star-like topology of the OR phylogenetic tree, low synteny, and recent TE activity around OR genes support a faster evolutionary rate for ORs than GRs - a trend observed in other insect taxa. This study provides insights into molecular mechanisms underlying host adaptation in aphids and presents the first high-quality genome assembly of Dysaphis plantaginea , a major apple pest, with a comprehensive annotation of chemosensory genes and TEs. These resources offer a foundation for research on aphid genome evolution, insect–plant interactions. ### Competing Interest Statement The authors have declared no competing interest.
The extensive survey was carried out across various locations of Northern (Bagalkot, Raichur, Arabhavi, Sirsi) and Southern Karnataka (Bangalore, Mudigere, Kolar, Hassan), India to collect gelechiid moths. Fourty species were collected, belonging to six families within superfamily Gelechioidea and the Gelechiidae being the most represented family recorded twenty-seven species belonging to five subfamilies. Species belonging to other families included Batrachedridae (one species), Cosmopterigidae (five species), Depressariidae (four species), Elachistidae (one species) and Stathmopodidae (two species), respectively.
Street trees have gained attention for improving thermal comfort in cities, yet seasonal changes in tree services in relation to the evolution of tree architecture are not well understood. This study hypothesizes that over a growing season and for sunny days, changes in climate services primarily rely on tree architecture influence on castshadow, especially during summer droughts. Two alignments of ornamental apple trees were grown in a reduced-scale street canyon, with a non-vegetated control zone. All trees were well watered until July 5th, 2022, after which one alignment experienced moderate water restriction while the other remained well-watered. The street microclimate was characterized, the universal thermal climate index (UTCI) calculated, and tree architecture at the organ and crown scales was measured. On sunny days, well-watered trees improved thermal comfort from 5.8 degrees C UTCI in mid-May to 7.9 degrees C in late August, while water restriction reduced this benefit by up to 2.7 degrees C UTCI after 8 weeks. The changes in thermal comfort were primarily linked to tree architectural development and cast-shadow, although these effects were moderate due to leaf area index high enough in May to ensure 87.5 % of interception of radiation. Increases in crown projected area and volume enhanced tree services, with larger effects on the side than just below the tree canopy. Water restriction diminished thermal comfort by inhibiting stem growth and accelerating leaf fall, thus reducing light interception. This study highlights the significant role of architectural plasticity in tree climate services under water restriction, warranting further research in other species.
