Sarah Liljegren

Associate Professor of Biology

• Faculty
• Instructor

• Email:

  sjliljeg@olemiss.edu

• Office Location:

  118 Shoemaker Hall

• Phone:

  662-915-1409

Dr. Liljegren investigates the molecular circuits that regulate plant development in Arabidopsis.

Research Interests

Plants rely on abscission zones to release their leaves, floral organs, fruit and seeds at specific points in their life cycles or in response to environmental cues. Over the past decade, research using the model plant Arabidopsis has revealed multiple components that regulate the programmed loss of cell adhesion in organ abscission zones. However, little is currently known about the mechanisms that determine where abscission zones are located or what genes are necessary for their development. In Arabidopsis flowers, abscission zones form at boundary regions between the outer floral organs and underlying stem. Complex genetic networks establish these lateral organ boundaries as well as the inter-organ boundaries between individual floral organs.

The focus of the Liljegren lab is to investigate whether a subset of the molecular circuits that regulate organ boundaries also specify the location and identity of abscission zone cells. Advances made in understanding the basis of abscission zone development may lead to novel technologies to modify organ abscission in crop plants. This direction of research is supported by a five year National Science Foundation CAREER award to Dr. Liljegren.

Publications

Groner WD, Christy ME, Kreiner CM, and Liljegren SJ (2016) Allele-specific interactions between CAST AWAY and NEVERSHED control abscission in Arabidopsis flowers. Frontiers in Plant Science 7: 1588.

An advantage of analyzing abscission in genetically tractable model plants is the ability to make use of classic genetic tools such as suppression analysis. We have investigated the regulation of organ abscission by carrying out suppression analysis in Arabidopsis flowers. Plants carrying mutations in the NEVERSHED (NEV) gene, which encodes an ADP-ribosylation factor GTPase-activating protein, retain their outer floral organs after fertilization. Mutant alleles of CAST AWAY (CST), which encodes a receptor-like cytoplasmic kinase, were found to restore organ abscission in nev flowers in an allelespecific manner. To further explore the basis of the interactions between CST and NEV, we tested whether the site of a nev mutation is predictive of its ability to be suppressed. Our results suggest instead that the strength of a nev allele influences whether organ abscission can be rescued by a specific allele of CST.

Gubert CM, Christy ME, Ward DL, Groner WD, and Liljegren SJ (2014) ASYMMETRIC LEAVES1 regulates abscission zone placement in Arabidopsis flowers. BMC Plant Biology 14: 195.

Gubert CM and Liljegren SJ (2014) HAESA and HAESA-LIKE2 activate organ abscission downstream of NEVERSHED and EVERSHED in Arabidopsis flowers. Plant Signaling & Behavior 9: e29115.

Liu B, Butenko MA, Shi CL, Bolivar JL, Winge P, Stenvik GE, Vie AK, Leslie ME, Brembu T, Kristiansen W, Bones AM, Patterson SE, Liljegren SJ, and Aalen RB (2013) NEVERSHED and INFLORESCENCE DEFICIENT IN ABSCISSION are differentially required for cell expansion and cell separation during floral organ abscission in Arabidopsis thaliana. Journal of Experimental Botany 64: 5345-5357.

Sauer MB, Delgadillo MO, Zouhar J, Reynolds GD, Pennington JG, Jiang L, Liljegren SJ, Stierhof YD, De Jaeger G, Otegui MS, Bednarek SY, and Rojo E (2013) MTV1 and MTV4 encode plant-specific ENTH and ARF GAP proteins that mediate clathrin-dependent trafficking of vacuolar cargo from the trans-Golgi network. Plant Cell 25: 2217-2235.

Liljegren SJ (2012) Organ abscission: exit strategies require signals and moving traffic. Current Opinion in Plant Biology  15: 670-676.

Bryan A, Racolta A, Tax F, and Liljegren S (2012) The social network: receptor kinases and cell fate determination. In Kemmerling B and Tax F (editors) Receptor-Like Kinases in Plants: From Signaling to Development. Springer Publishing, New York, NY.