Biology subjects

Illing, N.

Publications and source records attributed to Illing, N..

6 recordsLinked to original sources

bioRxiv2026

Functional characterization of bat limb regulatory elements

Bats are the only mammals capable of powered flight and roost head-down. However, the molecular changes shaping bat limbs remain largely unknown. Here, we used comparative functional genomics coupled with mouse-bat sequence swaps to identify key regulatory elements important in bat limb development. We generated and compared bat and mouse forelimb and hindlimb genomic datasets at key wing developmental timepoints, followed by mouse enhancer assays to characterize sequences showing differences between species. We then swapped six mouse enhancer sequences with their corresponding bat sequences, obtaining a variety of bat limb associated phenotypes, including ossification delay, longer digits, thicker skin and symmetrical hindlimb digits. Our work provides a genomic catalog of genes and regulatory elements involved in bat limb development and through extensive characterization in mice shows how changes in regulatory elements lead to small phenotypic changes that together contribute to bat limb development.

developmental biology↗

bioRxiv2026

Transcriptional regulation of the response to water availability in the resurrection plant Xerophyta elegans

Vegetative desiccation tolerance (VDT) has evolved independently across vascular plants, but its genetic basis remains poorly understood. Although VDT is associated with expansion of the ELIP gene family, the contribution of other lineage-specific expansions is unclear. We assembled genomes for Xerophyta elegans and Xerophyta humilis, identifying expanded gene families largely involved in chlorophyll metabolism and abscisic acid-mediated stress responses. Using a dense dehydration-rehydration transcriptome series in X. elegans seedlings, we reconstructed the regulatory network underlying VDT. Transcription factors from the ABF, ZAT and HSFC families were associated with early responses to desiccation. Key regulators of the seed maturation programme, including NAC transcription factors (ATAF1 and ANAC032), DOG genes and the trihelix factor ASIL1, were also implicated. These findings indicate that VDT arises through integration of abiotic stress signalling with rewiring of the seed maturation network, enabling desiccation tolerance in vegetative tissues.

plant biology↗

bioRxiv2025

Selective contexts favouring asymmetry: a theoretical and empirical study of pollen transfer in mirror-image flowers

Reciprocal herkogamy has evolved multiple times in flowering plants and is thought to enhance cross-pollination and reduce reproductive interference. Mirror-image flowers represent a form of reciprocal herkogamy in which plants have either right-or left-deflected styles (dimorphic enantiostyly) or produce both stylar orientations (monomorphic enantiostyly). The ecological conditions under which these two forms of enantiostyly originate and persist remain poorly understood. Here, we investigate how floral asymmetry affects pollen transfer dynamics and mating outcomes, and under which conditions enantiostyly provides a fitness advantage over straight-styled floral morphologies. We integrate field observations of dimorphic enantiostylous Wachendorfia paniculata with a mathematical model simulating pollen transfer in plants with straight-styled, monomorphic, and dimorphic enantiostylous flowers. The model incorporates pollinator pathways, pollen carryover, and floral display size, and was parameterized using our ecological data. Enantiostylous flowers received more outcrossed pollen than straight-styled flowers, with dimorphism outperforming monomorphism. However, enantiostyly increased stochasticity in pollen transfer due to variation in pollinator pathways. Intrafloral self-pollination was extremely low in enantiostylous flowers and did not differ between monomorphic and dimorphic forms. Dimorphic enantiostylous plants exhibited longer pollen carryover curves and exported more pollen to more mates potentially increasing siring success and mate diversity. Enantiostyly, particularly in dimorphic systems, can provide a selective advantage by improving pollen receipt and export components of fitness through enhanced outcrossing. This mating advantage may be reduced under conditions of pollen limitation or when autogamy in straight-styled flowers is low. Our findings clarify the functional significance of enantiostyly and offer a framework for understanding the evolution of floral asymmetry in angiosperms.

evolutionary biology↗

bioRxiv2025

Supergene control of chiral development in mirror-image flowers

How genes determine the left-versus right-handed development of chiral structures is a fascinating question. The reciprocal placement of female and male organs on opposite sides of the midline in mirror-image flowers limits selfing and promotes efficient cross-pollination. Here we identify the molecular and developmental basis of floral handedness in butterfly lilies. Female and male organs deflect by a combination of genetically controlled chirality and gravitropism, orienting left and right with respect to an external rather than internal reference axis. Coordinated organ placement is controlled by a hemizygous supergene containing two causal loci, MIR156-R and YUCCA-R, responsible for opposite female and male organ orientation, respectively. This genomic architecture results in differential placement of the supergene alleles on the pollinators and maintenance of the reproductive polymorphism.

plant biology↗

bioRxiv2024

Style deflection is determined by the handedness of phyllotaxis and differential cell elongation in a species with mirror-image flowers

Many animals and plants show left-right (LR) asymmetry. In some animal systems, handedness has a simple genetic basis, which has allowed identifying how handedness is determined at the molecular level, even if its functional relevance often remains unclear. Mirror-image flowers represent an example of LR asymmetry of clear functional significance, with the reciprocal placement of male and female organs in left- versus right-handed flowers promoting cross-pollination. Here, we use the South African geophyte Cyanella alba to study how handedness of its mirror-image flowers is determined and elaborated during development. Inflorescences of C. alba produce flowers with a largely consistent handedness. However, we find that this handedness has no simple genetic basis, and individual plants can switch their predominant handedness between years. Rather, it is the direction of the phyllotactic spiral that determines floral handedness. Cellular analysis combined with biophysical modelling demonstrates that style deflection is driven by increased cell expansion in the adaxial carpel facing the next oldest flower compared to the other adaxial carpel. The more expanding carpel shows transcriptional signatures of increased auxin signaling compared to the less expanding one, and auxin application to the latter can reverse the orientation of style deflection. We propose that a recently described inherent LR auxin asymmetry in the initiating organs of spiral phyllotaxis determines handedness in C. alba, representing a conserved non-genetic mechanism for creating a stable floral polymorphism. This mechanism links chirality across different levels of plant development and exploits a developmental constraint in a core patterning process to produce morphological variation of ecological relevance.

plant biology↗

bioRxiv2023

Characterization of tomato canal-1 mutant using a multi-omics approach

The recently described canal-1 tomato mutant, which has a variegated leaf phenotype, has been shown to affect canalization of yield. The corresponding protein is orthologous to AtSCO2 - SNOWY COTYLEDON2, which has suggested roles in thylakoid biogenesis. Here we characterize the canal-1 mutant through a multi-omics approach, by comparing mutant to wild-type tissues. While white canal-1 leaves are devoid of chlorophyll, green leaves of the mutant appear wild-type-like, despite an impaired protein function. Transcriptomic data suggest that green mutant leaves compensate for this impaired protein function by upregulation of transcription of photosystem assembly and photosystem component genes, thereby allowing adequate photosystem establishment, which is reflected in their wild-type-like proteome. White canal-1 leaves, however, likely fail to reach a certain threshold enabling this overcompensation, and plastids get trapped in an undeveloped state, while additionally suffering from high light stress, indicated by the overexpression of ELIP homolog genes. The metabolic profile of white and to a lesser degree also green tissues revealed upregulation of amino acid levels, that was at least partially mediated by transcriptional and proteomic upregulation. These combined changes are indicative of a stress response and suggest that white tissues behave as carbon sinks. In summary, our work demonstrates the relevance of the SCO2 protein in both photosystem assembly and as a consequence in the canalization of yield. Significance statementThe variegated canalized-1 tomato mutant was recently described and the underlying gene SCO2 suggested to be a yield canalization gene. Through a multi-omics approach we show that mutants require a transcriptional upregulation of photosystem components and assembly components, likely as overcompensation for partially impaired SCO2 function, to produce a wild type-like proteome and functional photosynthetic tissue Our data, furthermore, suggest that variation of green to white leaf area from plant to plant leads to the yield variation.

plant biology↗