Plant-on-Chip: core morphogenesis processes in the tiny plantWolffia australiana

Abstract

A plant can be thought of as a colony comprising numerous growth buds, each developing to its own rhythm. Such lack of synchrony impedes efforts to describe core principles of plant morphogenesis, dissect the underlying mechanisms, and identify regulators. Here, we use the tiniest known angiosperm to overcome this challenge and provide an ideal model system for plant morphogenesis. We present a detailed morphological description of the monocot Wolffia australiana, as well as high-quality genome information. Further, we developed the Plant-on-Chip culture system and demonstrate the application of advanced technologies such as snRNA-seq, protein structure prediction, and gene editing. We provide proof-of-concept examples that illustrate how W. australiana can open a new horizon for deciphering the core regulatory mechanisms of plant morphogenesis.

Atypical epigenetic and small RNA control of transposons in clonally reproducingSpirodela polyrhiza

“…In contrast to stem cells in other angiosperms, contained in a well-organized shoot apical meristem (SAM) that generates new organs [178], meristems in Spirodela and all duckweeds are formed by unstructured groups of few undifferentiated cells, which generate new meristems that develop into daughter fronds. [42,43,[179][180][181]. In order to maintain genome integrity along the clonal lineage, RdDM might be expressed in the few stem cells within the budding pockets or during the developmental window between the formation of a new meristem and its development into a new frond with its own stem cells.…”

The “Duckweed Dip”: AquaticSpirodela polyrhizaPlants Can Efficiently Uptake Dissolved, DNA-Wrapped Carbon Nanotubes from Their Environment for Transient Gene Expression

“…[5][6][7][8][9][10][11] While they are capable of flowering under certain conditions, in general duckweeds survive in a juvenile state, and S. polyrhiza primarily propagates vegetatively by continuously budding off clonal "daughter" plantlets from two meristematic pads asexually every 1 -3 days (Figure 1A). 5,12 Their simplicity to culture in large numbers (with exponential population growth of genetically identical plants) and their ability to efficiently extract material like radiolabeled metabolites from their aquatic environments made them ideal as a model higher plant in the decades before Arabidopsis, 13 but duckweeds have largely been overlooked in this emerging era of synthetic biology, where new approaches have the power to truly unleash their immense biotechnological potential. With regards to their biotechnological potential, engineered Spirodela species can exhibit very high levels of transgene protein expression: in one report stable, transgenic, GFP yield was >25% of total soluble protein, [14][15] among the highest in all plant expression systems.…”