Key Research Interests

Research in our lab is focused on plant breeding systems that involve development of different forms of flowers on plants of the same species. We focus primarily on two experimental models, floral heteromorphy in the Primula species, and sex determination in Silene species with the aim of identifying and characterising the molecular genetic mechanism that underpin these reproductive strategies.

Floral heteromorphy is a characteristic of, but not limited to, the Primulaceae and epitomised by Primula vulgaris, the common primrose. Individuals develop one of two forms of flower, known as pin and thrum. Pin flowers have a long style that presents the stigma at the mouth of the flower, with anthers attached midway down the inner corolla tube. Thrum flowers have a short style and anthers attached to the inner corolla wall at the mouth of the flower. This reciprocal positioning of male and female reproductive structures, known as reciprocal herkogamy, promotes insect-mediated cross pollination. These characteristics, and other features of floral heteromorphy, including differential pollens size and a sporophytic self-incompatibility system, are controlled by a co-adapted linkage group known as the S locus. Pin plants are homozygous recessive (s/s); thrum plants are heterozygous (S/s). BBSRC funding supports our work on the Primula S locus and we are working towards the identification and characterisation of the S locus genes that orchestrate floral heteromorphy. Using a combination of classical genetic analysis, molecular genetics techniques, genome sequencing, mutagenesis and screening, alongside plant transformation approaches we have made significant progress towards identifying the key genes controlling pin and thrum flower development.

In dioecy, separate male and female flowers are produced on different individuals as exemplified by Silene dioica, red campion, and S. latifolia, white campion. Sex determination in these species is controlled by heteromorphic sex chromosomes. Females have two X chromosomes; males have an X and a Y. The dominant male determining Y chromosome suppresses carpel development, promotes stamen development, and is required for pollen production. In the absence of a Y sex chromosome, carpels develop normally but stamens arrest at the primordia stage. Infection of dioecious Silene with the anther smut fungus Microbotryum violaceum causes development of anthers in genetically female flowers; the pathogen mimics the Y chromosome-encoded signal for male reproductive development. We are working to define the sex determination genes on the male-determining Y chromosome responsible for suppression of carpel development and promotion of stamen development, and to identify the Microbotryum-derived signal for another development. Funding from the Leverhulme Trust supports work on characterisation of an unstable mutation in a flower pigment gene that leads to red and white sectored variegated flowers in S. dioica. We are working towards using the transposon responsible for this instability locus as a tool for reverse genetic approaches to identify key sex determination genes.

Our laboratory is located within the John Innes Centre on the Norwich Research Park. If you are interested in pursuing PhD or post doctoral research opportunities in our group working on either of our model systems, please email me directly

Research Group Membership

Professor Phil Gilmartin, Group Leader
Dr Jinhong Li,  Independent Research Fellow
Dr Elizabeth Ingle, Post-doctoral Research Associate
Dr Sadiye Hayte, Post-doctoral Research Associate
Mr Matthew Smith, Fourth year PhD student
Ms Olivia Kent, First year PhD student
Mr Jonathan Cocker, First year PhD student
Mrs Pamela Wells, Horticulture technician

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