Plant Biotechnology Journal online published an article entitled “H⁺-pyrophosphatase IbVP1 promotes efficient iron use in sweet potato [Ipomoea batatas (L.) Lam.]”in Nov. 18, 2016. The work reveals the novel regulatory mechanism of sweet potato adapting to infertile soils and iron efficient uptake, which provides new technologies for nutrient utilization and iron biofortification in crops.

Sweet potato is an important root crop that provides food source and industrial material for at least 800 million people worldwide. China is the biggest producer of sweet potato with 80 million tonnes in annual production, accounting for 70% of global production. Sweet potato is tolerant to infertile soils and mainly cultivates on mountainous regions. Because of its high tolerance to iron deficiency, further understanding the mechanism is important for nutrient use and yield in root and tuber crops.

Dr. Weijuan Fan and colleagues found that the transcription of type I H⁺-pyrophosphatase (H⁺-PPase) gene IbVP1 in sweet potato plants was strongly induced by Fe deficiency and auxin in hydroponics, improving Fe acquisition via increased rhizosphere acidification and auxin regulation. When overexpressed, transgenic plants show higher pyrophosphate hydrolysis and plasma membrane H⁺-ATPase activity compared with the wild type, leading to increased rhizosphere acidification. The IbVP1-overexpressing plants showed better growth, including enlarged root systems, under Fe-sufficient or -deficient conditions. Increased ferric precipitation and ferric chelate reductase activity in the roots of transgenic lines indicate improved iron uptake, which is also confirmed by increased Fe content and upregulation of Fe uptake genes. Carbohydrate metabolism is significantly affected in the transgenic lines, showing increased sugar and starch content associated with the increased expression of AGPase and SUT1 genes and the decrease of β-amylase gene expression. Improved antioxidant capacities were also detected in the transgenic plants which showed improved stress resistance. Overall, the overexpression of H⁺-PPase gene in sweet potato increased the total biomass.

The study was supported by grates from Natural Science Foundation of China and MOST.

Article link: http://onlinelibrary.wiley.com/doi/10.1111/pbi.12667/full