Artificially cultivated duckweed: a high-efficiency starch producer

The increasing demand for starch has been a social struggle. We report a new technology that efficiently produces starch from duckweed. Although Landoltia punctata has a dramatic contraction of gene families, its starch content and productivity reached 72.2% (dry basis) and 10.4 g m-2 d-1 in 10 days, equivalent to a yield of 38.0 t ha-1 y-1 under nutrient limitation and CO2 elevation treatment. Meanwhile, we also examined the mechanism of duckweed's high starch accumulation. This is exhibited in the regulation of DNA methylation and transcription factors as well as the significantly up-regulated transcription levels and the increased enzyme activities of key genes in starch biosynthesis. Meantime, while nitrogen redistribution was enhanced, sucrose biosynthesis and transportation, and lignocellulose biosynthesis were all reduced. These alterations led to a reduction in lignocellulose and protein content and ultimately an increase in an accumulation of starch in the chloroplast. This work demonstrates duckweed's potential of being a highly efficient starch producer.