Ecotypic divergence in Senecio lautus - Field experiment on Stradbroke Island, Queensland, Australia.
The plant genus Senecio comprises approximately 1,000 species and is increasingly used in research on plant adaptation and evolution. The genus includes leaf, stem and tuber succulents, annuals, perennials, aquatics, climbers, shrubs and small trees. Some species produce natural biocides (especially alkaloids) to deter or even kill animals that would eat them, and several species are notable weeds of agriculture and horticulture (e.g. Senecio vulgaris), while others are successful invaders of pastures, wasteground and roadsides (e.g. S. inaequidens, S. madagascariensis and S. squalidus).
Some Senecio species are self-compatible, whereas others exhibit strong self-incompatibility. Interspecific hybridization is common and there are notable examples of recent introgression and hybrid speciation in the genus resulting in the origin of new introgressant taxa, and allopolyploid and homoploid hybrid species. Ecotypic divergence is also marked in some species (e.g. S. lautus and S. vulgaris), raising questions on how new species originate via ecological speciation.
Because Senecio species are now being used to investigate a wide range of questions in ecology and evolution in different labs around the world, several labs thought it desirable to establish a network to enhance collaborative research and to access and exchange valuable information and resources. This led to the first meeting of the network in August 2010 (Programme & Abstracts) and to the establishment of this website.
People
Flower head variation in Senecio vulgaris. In the first genetic study on Senecio, Trow (1912) showed that presence/absence of ray florets in flower heads of S. vulgaris was controlled by a single genetic locus. Almost a century later, Kim et al. (2008) showed that this locus comprised at least two cycloidea-like, regulatory genes, RAY 1 and RAY2. The radiate morph originated within the last 200 years in Britain after introgression of alleles at the RAY locus from the radiate invasive species, S. squalidus, into the formerly non-radiate S. vulgaris. Presence of ray florets increases pollinator attraction and outcrossing rate in S. vulgaris.
Senecio eboracensisLendal Bridge site, York, where S. eboracensis once grew
Senecio eboracensis a new allotetraploid species discovered in York in 1979 is now extinct in the wild. Seed of this species is stored in Kew's Millenium Seed Bank. Enquiries should be directed to the UK Collections Coordinator, Royal Botanic Gardens Kew, Millenium Seed Bank, Wakehurst Place, Ardingly, West Sussex RH17 6TN.
Genome Resources
SenecioDB is an online database curated at the University of Bristol which currently hosts in excess of 11,000 ESTs from floral and leaf tissue of five Senecio taxa.
The draft genome sequence of Senecio squalidus is being produced using several different sequencing approaches through a collaboration between the Hiscock (Bristol) and Filatov (Oxford) labs. More details to appear soon.
Genetic maps of S. squalidus and its parent species, S. aethnensis and S. chrysanthemifolius, are being produced by Adrian Brennan (Edinburgh) and Richard Abbott (St Andrews) using SSR and AFLP markers. Work to expand and improve these maps is being carried out by Dmitri Filatov (Oxford) and Mark Chapman (Southampton).
Genetic maps of Senecio jacobaea and S. aquaticus (now Jacobaea vulgaris and J. aquaticus, respectivey,) are being produced by the Klinkhamer and Vrieling labs (Leiden University) from a cross between these two species.
Network Meetings
The First Senecio Research Network meeting was held at St Andrews University, UK, on 20 August 2010. Programme & Abstracts. You can view pdfs of presentations given by speakers at the meeting by clicking on their names in the following list:
Kirk H, Vrieling K, Pelser PB, Schaffner U (2012) Can plant resistance to specialist herbivores be explained by plant chemistry or resource use strategy? Oecologia 168: 1043-1055.
Kirk H, Cheng DD, Choi YH, Vrieling K, Klinkhamer P (2012) Transgressive segregation of primary and secondary metabolites in F-2 hybrids between Jacobaea aquatica and J. vulgaris. Metabolomics 8: 211-219.
Allen AM, Thorogood, CJ, Hegarty MJ, Lexer C, Hiscock SJ (2011) Pollen-pistil interactions and self-incompatibility in the Asteraceae: new insights from studies of Senecio squalidus (Oxford ragwort). Annals of Botany 108: 687-698.
Brennan AC, Tabah DA, Harris SA, Hiscock SJ (2011) Sporophytic self-incompatibility in Senecio squalidus (Asteraceae): S allele dominance interactions and modifiers of cross-compatibility and selfing rates. Heredity 106: 113-123.
Cheng DD, Vrieling K, Klinkhamer PGL (2011) The effect of hybridization on secondary metabolites and herbivore resistance: implications for the evolution of chemical diversity in plants. Phytochemistry Reviews 10: 107-117.
Cheng DD, Kirk H, Mulder PPJ, Vrieling K, Klinkhamer PGL (2011) Pyrrolizidine alkaloid variation in shoots and roots of segregating hybrids between Jacobaea vulgaris and Jacobaea aquatica. New Phytologist 192: 1010-1023.
Klinkhamer PGL (2011) Special Issue: Pyrrolizidine alkaloids in Senecio: In honour of the eremitate of Prof. Eddy van der Meijden (Institute of Biology IBL, University of Leiden, the Netherlands) Introduction. Phytochemistry Reviews 10: 1-2.
Langel D, Ober D, Pelser PB (2011) The evolution of pyrrolizidine alkaloid biosynthesis and diversity in the Senecioneae. Phytochemistry Reviews 10: 3-74.
Allen AM, Lexer C, Hiscock SJ (2010) Comparative analysis of pistil transcriptomes reveals conserved and novel genes expressed in dry, wet, and semidry stigmas. Plant Physiology 154: 1347-1360.
Allen AM, Lexer C, Hiscock SJ (2010) Characterisation of sunflower-21 (SF21) genes expressed in pollen and pistil of Senecio squalidus (Asteraceae) and their relationship with other members of the SF21 gene family. Sexual Plant Reproduction 23: 173-186.
Brennan AC, Hiscock SJ (2010) Expression and inheritance of sporophytic self-incompatibility in synthetic allohexaploid Senecio cambrensis (Asteraceae). New Phytologist 186: 251-261
Kirk H, Vrieling K, Van Der Meijden E, Klinkhamer PGL (2010) Species by environment interactions affect pyrrolizidine alkaloid expression in Senecio jacobaea, Senecio aquaticus, and their hybrids. J. Chemical Ecology 36: 378-387.
Langel D, Ober D, Pelser P (2010) The evolution of pyrrolizidine alkaloid biosynthesis and the diversity in the Senecioneae.
Phytochemistry Reviews 10: 3-74
Pelser PB, Tepe EJ, Kennedy AH, Watson LE (2010) The fate of Robinsonia (Asteraceae): sunk in Senecio, but still monophyletic? Phytotaxa 5: 31-46.
Prentis PJ, Woolfit M, Thomas-Hall SR, Ortiz-Barrientos D, Pavasovic A, Lowe AJ, Schenk PM (2010) Massively parallel sequencing and analysis of expressed sequence tags in a successful invasive plant. Annals of Botany 106: 1009-1017.
Rapo C, Muller-Scharer H, Vrieling K, Schaffner U (2010) Is there rapid evolutionary response in introduced populations of tansy ragwort, Jacobaea vulgaris, when exposed to biological control? Evolutionary Ecology 24: 1081-1099
