H⁺‐pyrophosphatase IbVP1 promotes efficient iron use in sweet potato [Ipomoea batatas (L.) Lam.]

Abstract

SummaryIron (Fe) deficiency is one of the most common micronutrient deficiencies limiting crop production globally, especially in arid regions because of decreased availability of iron in alkaline soils. Sweet potato [Ipomoea batatas (L.) Lam.] grows well in arid regions and is tolerant to Fe deficiency. Here, we report 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 Fe‐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 up‐regulation of Fe uptake genes, e.g. FRO2,IRT1 and FIT. 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 in β‐amylase gene expression. Improved antioxidant capacities were also detected in the transgenic plants, which showed reduced H2O2 accumulation associated with up‐regulated ROS‐scavenging activity. Therefore, H+‐PPase plays a key role in the response to Fe deficiency by sweet potato and effectively improves the Fe acquisition by overexpressing IbVP1 in crops cultivated in micronutrient‐deficient soils.

Humic Acid-Induced Hairy Root Growth in Basil Ismodulated by Nitric Oxide and Reactive Oxygen Species

“…served in the tissues of transformed basil roots ( In the present study, HA and SNP application significantly increased plasma membrane (PM) ATPase activity compared to the controls under both N- root primordia and cell differentiation [46]. In the present study, the application of HA and SNP increased the H + -PPase activity, in agreement with [5].…”

VvVHP1; 2 Is Transcriptionally Activated by VvMYBA1 and Promotes Anthocyanin Accumulation of Grape Berry Skins via Glucose Signal

“…Second, sugar signals originated from different sources, including active photosynthetic cells, dynamic storage reservoir, and organs for nutrient remobilization ( Li and Sheen, 2016 ). It has been identified that VHPs overexpression can promote soluble sugar accumulation in berry skin ( Figure 8E ), sweet potato leaves ( Fan et al, 2017 ) and apple callus ( Yao et al, 2011 ). The enhanced sugar concentration in vacuoles might elicit feedback signaling in the photosynthetic source to ensure the balance of carbon flow ( McCormic et al, 2009 ).…”

“…Third, SUT1 (also designated SUC1) plays a critical role in sucrose phloem loading and transport as well as cellular sugar partitioning ( Fan et al, 2017 ); loss of SUT1 function results in reduced sucrose transport, while increased SUT1 expression results in increased sucrose transport ( Kühn and Grof, 2010 ). The expression of SUT1 was up-regulated in the VvVHP1; 2 -overexpressing berry skins, IbVP1 -overexpressing sweet potato ( Fan et al, 2017 ) and AVP1 -overexpressing Arabidopsis ( Gaxiola et al, 2012 ). Therefore, VvVHP1; 2 might promote translocation of sucrose from source to sink tissues, at least partially, via up-regulation of VvSUT1 , and thereby induced modifications of sugar status.…”

Trifunctional cross‐linker trimethylol melamine enhancing adhesive force of PVA hydrogels

“…TMCPVA could be divided into physical and chemical hydrogels . Generally, TMCPVA were obtained by a cross‐linking process of polymers, which might be achieved through a chemical reaction using high energy irradiation or through a physical reaction of polymer crystallization and/or hydrogen bonds. For chemically cross‐linking PVA hydrogels, glutaraldehyde as a traditional bifunctional cross‐linker could joint two PVA molecular chains so that the polymer network structure wasn't enough stable.…”