A mathematical model of kin selection in floral displays

Altruism or selfishness: floral behaviour based on genetic relatedness with neighbouring plants

Kin recognition in plants may lead to plastic changes in their behaviour, such as altering their floral display size. In this study, we conducted evolutionary simulations of the 2 floral tactics utilized by plants depending on the genetic relatedness of their neighbouring plants. We found that the evolutionary consequences of the floral display size in plants can be classified into 4 types, based on whether the floral display size increased or decreased in comparison with the case of plants disabled of kin recognition. As a typical result, the plants that grew with kin behaved altruistically by increasing their floral display size, whereas those that coexisted with strangers behaved selfishly by reducing their floral display size, as is observed in the field. The kin recognition and resultant evolution of the floral display size had a spillover effect on the population scale. Kin recognition generally increased the intraspecific variation in the floral display size and seed production and decreased the genetic diversity of plant populations.

Kin discrimination causes plastic responses in floral and clonal allocation

The composition of a plant's neighbourhood shapes its competitive interactions. Neighbours may be related individuals due to limited seed dispersal or clonal growth, so that the ability to recognize and respond to the presence of kin is beneficial. Here, we ask whether plants plastically adjust their floral and clonal allocation in response to their neighbour's identity. In a species that reproduces both sexually and clonally, we test the following predictions in response to neighbouring kin: (i) a reduction in floral display will occur to minimize costly floral structures and pollinator competition, as well as to mitigate inbreeding; and (ii) a decrease in clonality will occur to minimize resource competition and overcrowding among kin. We grew focal individuals of Mimulus guttatus (syn. Erythranthe guttata) surrounded by neighbours of varying relatedness (non-kin, outcross siblings or self siblings) and measured a suite of vegetative, floral and clonal traits. Consistent with our predictions, focal plants reduced floral and clonal allocation in the presence of kin. Moreover, focal plants increased their floral and clonal allocation when surrounded by non-kin neighbours that were high-performing. Together, we demonstrate a clear and predictable response to kin, which has general implications for the structure and function of plant neighbourhoods.

Discrimination of relatedness drives rice flowering and reproduction in cultivar mixtures

The improvement of performance and yield in both cultivar and species mixtures has been well established. Despite the clear benefits of crop mixtures to agriculture, identifying the critical mechanisms behind performance increases are largely lacking. We experimentally demonstrated that the benefits of rice cultivar mixtures were linked to relatedness-mediated intraspecific neighbour recognition and discrimination under both field and controlled conditions. We then tested biochemical mechanisms of responses in incubation experiments involving the addition of root exudates and a root-secreted signal, (-)-loliolide, followed by transcriptome analysis. We found that closely related cultivar mixtures increased grain yields by modifying root behaviour and accelerating flowering over distantly related mixtures. Importantly, these responses were accompanied by altered concentration of signalling (-)-loliolide that affected rice transcriptome profiling, directly regulating root growth and flowering gene expression. These findings suggest that beneficial crop combinations may be generated a-priori by manipulating neighbour genetic relatedness in rice cultivar mixtures and that root-secreted (-)-loliolide functions as a key mediator of genetic relatedness interactions. The ability of relatedness discrimination to regulate rice flowering and yield raises an intriguing possibility to increase crop production.

Development and applications of metabolic models in plant multi-omics research

Plant growth and development are characterized by systematic and continuous processes, each involving intricate metabolic coordination mechanisms. Mathematical models are essential tools for investigating plant growth and development, metabolic regulation networks, and growth patterns across different stages. These models offer insights into secondary metabolism patterns in plants and the roles of metabolites. The proliferation of data related to plant genomics, transcriptomics, proteomics, and metabolomics in the last decade has underscored the growing importance of mathematical modeling in this field. This review aims to elucidate the principles and types of metabolic models employed in studying plant secondary metabolism, their strengths, and limitations. Furthermore, the application of mathematical models in various plant systems biology subfields will be discussed. Lastly, the review will outline how mathematical models can be harnessed to address research questions in this context.

Effects of the Relatedness of Neighbours on Floral Colour

The reproductive success of plants depends both on their phenotype and the local neighbourhood in which they grow. Animal-pollinated plants may benefit from increased visitation when surrounded by attractive conspecific individuals, via a “magnet effect.” Group attractiveness is thus potentially a public good that can be exploited by individuals, with selfish exploitation predicted to depend on genetic relatedness within the group. Petal colour is a potentially costly trait involved in floral signalling and advertising to pollinators. Here, we assessed whether petal colour was plastically sensitive to the relatedness of neighbours in the annual herb Moricandia moricandioides, which produces purple petals through anthocyanin pigment accumulation. We also tested whether petal colour intensity was related to nectar volume and sugar content in a context-dependent manner. Although both petal colour and petal anthocyanin concentration did not significantly vary with the neighbourhood configuration, plants growing with kin made a significantly higher investment in petal anthocyanin pigments as a result of the greater number and larger size of their flowers. Moreover the genetic relatedness of neighbours significantly modified the relationship between floral signalling and reward quantity: while focal plants growing with non-kin showed a positive relationship between petal colour and nectar production, plants growing with kin showed a positive relationship between number of flowers and nectar volume, and sugar content. The observed plastic response to group relatedness might have important effects on pollinator behaviour and visitation, with direct and indirect effects on plant reproductive success and mating patterns, at least in those plant species with patchy and genetically structured populations.