On Februrary 1^st, Horticulture Research, an internationally renowned horticultural journal, published a research paper from my center entitled "The H⁺-pyrophosphatase IbVP1 regulations carbon flux to influence the starch metabolism and yield of sweet potato". For the first time, sweet potato showed significantly improved quality and yield of its storage root starch only after the overexpression of H⁺- pyrophosphatase IbVP1.

Sweet potato storage root is an important underground reservoir for photosynthate and energy storage, and its starch metabolism level determines starch content and yield, and is also affected by the sugar translocation ability of above-ground source organ (leaves). The team's previous study found that the sweet potato IbVP1 played an important role in promoting nutrient absorption and fibrous root growth (Fan et al., 2017), enhancing iron acquisition through rhizosphere acidification and enhancing carbohydrate metabolic levels in sweet potato plants (Fan et al., 2017). The study further found that over-expression of the IbVP1 gene in sweet potato plants improved their photosynthesis capacity and sucrose content of leaves; using ¹³C-labeled-labeled sucrose feeding, the IbVP1 overexpressing plants showed promoted phloem loading and sucrose long-distance transport and enhances Pi-use efficiency. In the storage roots, the expression level and enzyme activity of genes such as AGPase, GBSSI and SSI were increased, showing an improved starch synthesis ability, and increased total starch and amylose content. Consequently, the storage starch was detected changes in the structure, composition, and physicochemical properties. The study reveals the important function of VP1 gene in optimizing the "Source-Sink" relationship of sweet potato, and improve the yield and quality of sweet potato through the "Yin-Yang" regulation of Pi and H⁺. It is also a new technology to increase root crop yields through single-gene expression. 

The research was funded by the National Key Research and Development Program, the National Natural Science Foundation of China and other projects.

Article Link: https://www.nature.com/articles/s41438-020-00454-2

Sweet potato overexpressing VP1 promotes storage root yield and improves starch quality. VP1 promotes photoassilimate mobilization and starch biosynthesis (a-e) through "Yin-Yang" dual regulation (f) of Pi and H⁺, to optimize the "Source-Sink" relationship of sweet potato.

References：

1.      Fan W, Wang H, Wu Y, Yang N, Yang J, Zhang P* (2017) H⁺-pyrophosphatase IbVP1 promotes efficient iron use in sweet potato [Ipomoea batatas (L.) Lam.]. Plant Biotechnology Journal 15: 698-712.

2.      Fan W, Zhang Y, Wu Y, Zhou W, Yang J, Yuan L, Zhang P*, Wang H* (2021) The H⁺-pyrophosphatase IbVP1 regulates carbon flux to influence the starch metabolism and yield of sweet potato. Horticulture Research  8: 20.