Gomphrena claussenii, a novel metal‐hypertolerant bioindicator species, sequesters cadmium, but not zinc, in vacuolar oxalate crystals

Abstract

SummaryGomphrena claussenii is a recently described zinc (Zn)-and cadmium (Cd)-hypertolerant Amaranthaceae species displaying a metal bioindicator Zn/Cd accumulation response. We investigated the Zn and Cd distribution in stem and leaf tissues of G. claussenii at the cellular level, and determined metabolite profiles to investigate metabolite involvement in Zn and Cd sequestration.Gomphrena claussenii plants exposed to high Zn and Cd supply were analysed by scanning electron microscopy with energy-dispersive X-ray (SEM-EDX) and micro-proton-induced X-ray emission (micro-PIXE). In addition, gas chromatography-time of flight-mass spectrometry (GC-TOF-MS) was used to determine metabolite profiles on high Zn and Cd exposure.Stem and leaf tissues of G. claussenii plants exposed to control and high Cd conditions showed the abundant presence of calcium oxalate (CaOx) crystals, but on high Zn exposure, their abundance was strongly reduced. Ca and Cd co-localized to the CaOx crystals in Cd-exposed plants. Citrate, malate and oxalate levels were all higher in shoot tissues of metal-exposed plants, with oxalate levels induced 2.6-fold on Zn exposure and 6.4-fold on Cd exposure.Sequestration of Cd in vacuolar CaOx crystals of G. claussenii is found to be a novel mechanism to deal with Cd accumulation and tolerance.

Proteaceae from phosphorus‐impoverished habitats preferentially allocate phosphorus to photosynthetic cells: An adaptation improving phosphorus‐use efficiency

“…Our results do not support the current model of cell‐specific P allocation patterns in eudicot leaves; this discrepancy may be explained by the fact that most studies in this field have focused on metal‐hyperaccumulating species and/or crop species (Ager, Ynsa, Domínguez‐Solís, Gotor, et al, ; Ager, Ynsa, Domínguez‐Solís, López‐Martín, et al, ; Bidwell et al, ; Fernando et al, ; Fernando et al, ; Küpper, et al, ; Küpper, Lombi, Zhao, & McGrath, ; Küpper, Lombi, Zhao, Wieshammer, et al, ; Mesjasz‐Prybylowicz & Pineda, ; Mesjasz‐Przybylowicz et al, ; Mesjasz‐Przybyłowicz et al, ; Regvar et al, ; Rios et al, ; Treeby et al, ; Villafort Carvalho et al, ; Vogel‐Mikuš et al, , ; Zhao et al, ). These species likely function very differently in their environment, compared with native species from nutrient‐poor habitats.…”

“…Many studies have assessed cell‐specific nutrients in leaves of metal‐hyperaccumulating and crop species, from which the current model (Conn & Gilliham, ) is largely based (Ager, Ynsa, Domínguez‐Solís, Gotor, et al, ; Ager, Ynsa, Domínguez‐Solís, López‐Martín, et al, ; Bidwell, Crawford, Woodrow, Sommer‐Knudsen, & Marshall, ; Fernando, et al, ; Fernando et al, ; Küpper, Zhao, & McGrath, ; Küpper, Lombi, Zhao, & McGrath, ; Küpper, Lombi, Zhao, Wieshammer, & McGrath, ; Mesjasz‐Prybylowicz & Pineda, ; Mesjasz‐Przybyłowicz, Balkwill, Przybyłowicz, & Annegarn, ; Mesjasz‐Przybylowicz, Przybylowicz, Rama, & Pineda, ; Regvar et al, ; Rios et al, ; Treeby, van Steveninck, & de Vries, ; Villafort Carvalho et al, ; Vogel‐Mikuš et al, ; Vogel‐Mikuš, Pongrac, & Pelicon, ; Zhao, Lombi, Breedon, & McGrath, ). However, few studies have quantitatively assessed cellular [P], and no study has yet assessed it across a wide range of naturally occurring species, covering an extreme range in soil [P].…”

Henk Schat

“…159, issue 2; http://nph.onlinelibrary.wiley.com/hub/issue/10.1111/nph.2003.159.issue-2/) contains several ‘groundbreaking’ papers. Of the more recent papers on metal tolerance, I would like to mention one on cadmium sequestration in Gomphrena claussenii (Villafort Carvalho et al ., ) and, although I am a co‐author myself, another one on HMA5‐like copper transporters in Silene vulgaris (Li et al ., ). I am also fond of the Tansley review on selenium hyperaccumulation (Schiavon & Pilon‐Smits, ).…”

A Biostimulant Seed Treatment Improved Heat Stress Tolerance During Cucumber Seed Germination by Acting on the Antioxidant System and Glyoxylate Cycle

“…Targeted and untargeted metabolomics was performed on KIEM R in order to identify polar metabolites as previously described by Lisec et al (2006). Some adaptations were made to the protocol according to Villafort Carvalho (Villafort Carvalho et al, 2015). Briefly, polar metabolites were extracted from 50 mg of the biostimulant using methanol, followed by a 2phase separation using chloroform.…”