Wang, W, Haberer G, Gundlach H, Gläßer C, Nussbaumer T, Luo MC, Lomsadze A, Borodovsky M, Kerstetter RA, Shanklin J et al..  2014.  The Spirodela polyrhiza genome reveals insights into its neotenous reduction fast growth and aquatic lifestyle. 5 AbstractWebsite
The subfamily of the Lemnoideae belongs to a different order than other monocotyledonous species that have been sequenced and comprises aquatic plants that grow rapidly on the water surface. Here we select Spirodela polyrhiza for whole-genome sequencing. We show that Spirodela has a genome with no signs of recent retrotranspositions but signatures of two ancient whole-genome duplications, possibly 95 million years ago (mya), older than those in Arabidopsis and rice. Its genome has only 19,623 predicted protein-coding genes, which is 28% less than the dicotyledonous Arabidopsis thaliana and 50% less than monocotyledonous rice. We propose that at least in part, the neotenous reduction of these aquatic plants is based on readjusted copy numbers of promoters and repressors of the juvenile-to-adult transition. The Spirodela genome, along with its unique biology and physiology, will stimulate new insights into environmental adaptation, ecology, evolution and plant development, and will be instrumental for future bioenergy applications.
Wang, W, Wu Y, Messing J.  2014.  RNA-Seq transcriptome analysis of Spirodela dormancy without reproduction. BMC Genomics. 15(60) Abstract
Higher plants exhibit a remarkable phenotypic plasticity to adapt to adverse environmental changes. The Greater Duckweed Spirodela, as an aquatic plant, presents exceptional tolerance to cold winters through its dormant structure of turions in place of seeds. Abundant starch in turions permits them to sink and escape the freezing surface of waters. Due to their clonal propagation, they are the fastest growing biomass on earth, providing yet an untapped source for industrial applications.
Wang, W, Messing J.  2012.  Analysis of ADP-glucose pyrophosphorylase expression during turion formation induced by abscisic acid in Spirodela polyrhiza (greater duckweed). BMC Plant Biology. 12(5) Abstract
Aquatic plants differ in their development from terrestrial plants in their morphology and physiology, but little is known about the molecular basis of the major phases of their life cycle. Interestingly, in place of seeds of terrestrial plants their dormant phase is represented by turions, which circumvents sexual reproduction. However, like seeds turions provide energy storage for starting the next growing season.
Wang, W, Wu Y, Messing J.  2012.  The mitochondrial genome of an aquatic plant, Spirodela polyrhiza. PLoS ONE. 7(10) Abstract
Spirodela polyrhiza is a species of the order Alismatales, which represent the basal lineage of monocots with more ancestral features than the Poales. Its complete sequence of the mitochondrial (mt) genome could provide clues for the understanding of the evolution of mt genomes in plant.
Wang, W, Kerstetter R, Michael TP..  2011.  Evolution of Genome Size in Duckweeds (Lemnaceae).. Journal of Botany.
Wang, W, Wu Y, Ermakova M, Kerstetter R, Messing J.  2010.  DNA barcoding of the Lemnaceae, a family of aquatic monocots. BMC Plant Biology. 10:205.