The Plant Journal

31 May 2019 - By: Sheila McCormick

Ta ta for now: Thlaspi arvense (pennycress) as an emerging model for genetic analyses

Chopra R, Johns EB, Daniels E, et al. 2018. Translational genomics using Arabidopsis as a model enables the characterization of pennycress genes through forward and reverse genetics. The Plant Journal, 96, 1093–1105.

Thlaspi arvense (common name pennycress) is a weed in the family Brassicaceae. Its most remarkable feature is that it can survive very low temperatures (−25°C). Pennycress, therefore, has been proposed as a crop to potentially fill the gap between the autumn harvest and spring planting dates for corn and soybean. But will farmers adopt it as an alternative crop? Pennycress is called a weed for a reason: the seeds don’t germinate uniformly and it is not ideal come harvesting because plants can lodge (fall down), pods sometimes shatter too early, and the seeds are small. Furthermore, the erucic acid content is too high for human consumption. Several modifications to plant architecture, oil content, and quality will be needed to domesticate pennycress.

Chopra et al. present tools that will help in these domestication efforts. They aligned the draft pennycress genome to the Arabidopsis genome and showed that the synteny was substantial. They thus hypothesised that the Arabidopsis genome could be used as a guide to identify causal mutations in pennycress mutant populations. They next mutagenised seed, then screened the M2 populations for obvious phenotypes and carried out whole genome sequencing of selected lines; they present over 16,000 pennycress genes with mutations as well as the closest Arabidopsis homologue for each. There are many applications for these mutant populations and the presented gene index, both for domestication efforts and for basic research. Genes underlying differences in seed size, seed maturation, pod shattering, and flowering time are known in Arabidopsis (and/or in Brassica), so it should be straightforward to combine the analogous pennycress mutants. Furthermore, numerous genes that are duplicated in Arabidopsis are present as single copies in pennycress, suggesting that studying their function in pennycress will be easier. Pennycress is easy to grow, is larger than Arabidopsis and thus more amenable for biochemistry (more tissue), and can be used in field and environmental studies. Now is the time for pennycress!

Sheila McCormick, Research Highlights Editor

Category: Journals
Sheila McCormick

Sheila McCormick

After 29 years at the Plant Gene Expression Center, I retired from the USDA and closed my lab in January 2016. My research focused the molecular biology of plant reproduction, mostly on the male (pollen) side.  I continue as an Adjunct Professor in the Dept. of Plant and Microbial Biology at UC-Berkeley. I was an editor for Plant Journal for 14 years.  In addition to being Research Highlights Editor (since July 2017), I also manage Plant Journal's twitter feed. I am currently an editor for eLIFE and for Peer J.