Arabidopsis H ⁺ -PPase AVP1 Regulates Auxin-Mediated Organ Development

Abstract

The transport of auxin controls developmental events in plants. Here, we report that in addition to maintaining vacuolar pH, the H+-pyrophosphatase, AVP1, controls auxin transport and consequently auxin-dependent development. AVP1 overexpression results in increased cell division at the onset of organ formation, hyperplasia, and increased auxin transport. In contrast, avp1-1 null mutants have severely disrupted root and shoot development and reduced auxin transport. Changes in the expression of AVP1 affect the distribution and abundance of the P-adenosine triphosphatase and Pinformed 1 auxin efflux facilitator, two proteins implicated in auxin distribution. Thus, AVP1 facilitates the auxin fluxes that regulate organogenesis.

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

“…Accordingly, IAA content was significantly increased in the roots of IA transgenic plants (Figure 4e). No significant difference in leaf IAA content was found between IA plants and WT, indicating that the enhanced root growth was due to increased auxin transport from shoot into root in transgenic plants, which is consistent with the previous observations of AVP1 ‐overexpressing Arabidopsis plants (Li et al ., 2005). …”

“…Increased biomass, especially root system, has been reported in plants overexpressing type I H + ‐PPases, under deficiencies of phosphate (Gaxiola et al ., 2012; Pei et al ., 2012; Yang et al ., 2007, 2014) and nitrogen (Lv et al ., 2015; Paez‐Valencia et al ., 2013). The type I H + ‐PPase AVP1 triggers auxin efflux by up‐regulating the expression of Pinformed 1 auxin efflux facilitator and P‐adenosine triphosphatase, in Arabidopsis (Li et al ., 2005) and AUX1 , PIN1a and PIN1b in maize (Pei et al ., 2012). In this study, the expression of IbVP1 was also induced by auxin (IAA) treatment (Figure 2c,d).…”

“…Up‐regulated H + ‐PPases induce plant tolerance to various stresses, such as drought, high salinity, and N and Pi deprivation (Arif et al ., 2013; Paez‐Valencia et al ., 2013; Yang et al ., 2007). It also affects auxin and sugar transport and accumulation during root and shoot growth (Gaxiola et al ., 2012; Khadilkar et al ., 2016; Li et al ., 2005; Pasapula et al ., 2011; Pizzio et al ., 2015). …”

“…The H + ‐PPase overexpression enhances apoplastic acidification by increasing the abundance and activity of H + ‐ATPase at the plasma membrane (Gaxiola et al ., 2016; Li et al ., 2005; Undurraga et al ., 2012). It increases root and shoot biomass, photosynthetic capacity and nutrient uptake under normal or nutrient‐limited conditions, such as low NO 3− and Pi (Khadilkar et al ., 2016; Li et al ., 2005; Lv et al ., 2015; Paez‐Valencia et al ., 2013; Pizzio et al ., 2015; Yang et al ., 2007, 2014).…”

The Sink-Specific Plastidic Phosphate Transporter PHT4;2 Influences Starch Accumulation and Leaf Size in Arabidopsis

“…Indeed, the phenotypes of lines evaluated in this study differ from each other and from pht4;2, primarily with respect to leaf positions. For example, overexpression of AVP1, a vacuolar pyrophosphatedependent H + pump that is involved in auxin transport (Li et al, 2005), yields rosettes with a greater number of leaves, all of which are enlarged. Overexpression of JAW1, which is involved in the regulation of jasmonate biosynthesis (Palatnik et al, 2003;Schommer et al, 2008), leads to the enlargement of only the first rosette leaves, and these have a characteristic uneven shape.…”