Project Details
Projekt
Adaptation to selfing in the genus Capsella: Inferring the evolutionary history and adaptive value of selfing-syndrome alleles
Applicant
Professor Dr. Michael Lenhard, since 9/2017
Subject Area
Plant Genetics and Genomics
Plant Cell and Developmental Biology
Plant Cell and Developmental Biology
Term
from 2014 to 2019
Project identifier
Deutsche Forschungsgemeinschaft (DFG) - Project number 260499038
A common event in the evolution of flowering plants is the transition from outbreeding to selfing. In many cases, this transition has been followed by convergent evolution of the floral morphology towards a dramatically reduced flower size and less open structure. Several adaptive hypotheses have been formulated to explain the emergence of this so-called selfing syndrome. They have however been difficult to test rigorously up to now due to the lack of identified casual underlying genes. Also, the extent to which recurrent mutations in orthologous loci have contributed to the frequent independent emergence of the selfing syndrome is currently unknown. The genus Capsella has recently emerged as a model to study the evolution of the selfing syndrome. The transition to selfing has occurred independently twice in this genus, and in both cases this has been followed by a strong reduction of flower size. Using a quantitative-genetics approach, I have identified a gene underlying the reduction of petal size in the selfing species C. rubella relative to the closely related outbreeding species C. grandiflora. Population-genetic analyses indicate that the small-petal allele has been captured from standing genetic variation in the outcrossing species. This proposal will pursue two major objectives: (1) to investigate the effects of the small-petal allele on fitness and (2) to assess whether the independent emergence of the selfing syndrome in C. orientalis involved mutations to the same loci identified in C. rubella. The effect of the small-petal allele on plant reproductive success in a natural environment will be investigated by association studies in natural populations and a common-garden experiment, and its allele frequency and geographical distribution in the descendants of the ancestral outcrossing species will be studied. The genetic basis of the selfing syndrome in C. orientalis will be compared to that in C. rubella by comparative QTL mapping, comparative transcriptomic analyses and direct testing of C. orientalis alleles by transgenic experiments. As a result, the proposed project will help to understand why selfing-syndrome alleles become fixed in selfing species, and will define the genetic basis underlying the convergent evolution of floral morphology after the transition to selfing.
DFG Programme
Priority Programmes
Participating Person
Dr. Christian Kappel
Ehemaliger Antragsteller
Dr. Adrien Sicard, until 8/2017
