FRIEDMAN LAB

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BIOLOGYhttp://biology.syr.edu
 

We are interested in understanding the ecological and genetic mechanisms that encompass the key life history transition between perenniality and annuality. Life history traits controlling the timing of individuals’ growth, reproduction, and death represent some of the most spectacular adaptive differences among plants and animals. One of the main differences between annuals and perennials is when and how they switch from vegetative growth to flowering, a decision that has direct implications for reproduction and fitness. New research on the genetics of flowering allows us to ask mechanistic questions about the adaptive significance of the cues used by plants to transition between vegetative and floral phases and shed light on
the genetic changes that might occur during evolutionary transitions between annual and perennial life strategies.

The Western North American wildflower, Mimulus guttatus, is an ideal system to investigate life history transitions. The species encompasses both facultative annual and perennial populations that are geographically widespread. Perennial populations are widespread in areas with permanent streams with year-round moisture. Annual populations are typically located in habitats that have abundant soil moisture in the spring and early summer, but little during the late summer. Previous common garden experiments consistently show that plants from annual populations tend to flower earlier and have smaller floral and vegetative sizes than plants from perennial populations, allowing them to flower rapidly before the onset of summer drought.  Perennial plants are larger and more competitive in their native sites, and they cycle repeatedly through vegetative and reproductive modes.

We have identified extensive variation in critical photoperiod between annual and perennial populations, with most annual populations requiring substantially shorter day lengths to initiate flowering than perennial populations. We have also discovered a novel type of vernalization requirement in perennial populations that is contingent on plants experiencing short days first (2013 New Phyt).  Current research funded by NSF includes a large common garden experiment on Vancouver Island, British Columbia with annual-perennial mapping populations, to map QTL associated with perenniality in the field. In collaboration with Jill Preston we are characterizing the flowering response using candidate gene expression and comparative transcriptomics in different photoperiod and vernalization treatments.

We have identified phenotypic and genetic trade-offs between flowering and vegetative growth that distinguish the different life history strategies. These results provide insight on the genetic nature of variation in flowering and resource allocation, and their role in local adaptation and ecotypic differentiation in life history strategies.

Transitions between annual and perennial reproductive strategies

Friedman Lab, Syracuse University | 256 Life Sciences |
Office: 315.443.1564 Lab: 315.443.8193 | friedman@syr.edu

BIOLOGYhttp://biology.syr.edu

photo: G. Pilch

photo: G. Pilch

photo: G. Pilch

photo: G. Pilch