Expression of zinc and cadmium responsive genes in leaves of willow (Salix caprea L.) genotypes with different accumulation characteristics

Abstract

Salix caprea is well suited for phytoextraction strategies. In a previous survey we showed that genetically distinct S. caprea plants isolated from metal-polluted and unpolluted sites differed in their zinc (Zn) and cadmium (Cd) tolerance and accumulation abilities. To determine the molecular basis of this difference we examined putative homologues of genes involved in heavy metal responses and identified over 200 new candidates with a suppression subtractive hybridization (SSH) screen. Quantitative expression analyses of 20 genes in leaves revealed that some metallothioneins and cell wall modifying genes were induced irrespective of the genotype's origin and metal uptake capacity while a cysteine biosynthesis gene was expressed constitutively higher in the metallicolous genotype. The third and largest group of genes was only induced in the metallicolous genotype. These data demonstrate that naturally adapted woody non-model species can help to discover potential novel molecular mechanisms for metal accumulation and tolerance.

Transcriptome Sequencing and Expression Analysis of Cadmium (Cd) Transport and Detoxification Related Genes in Cd-Accumulating Salix integra

“…Hybrid aspen ( P. trichocarpa × deltoides ) PtdMT2B conferred Cd tolerance to a Cd sensitive yeast strain (Kohler et al, 2004), and the MT2B expression levels of P. tremula × tremuloides correlated with foliar Zn and Cd concentrations on metal contaminated soil (Hassinen et al, 2009). Konlechner et al (2013) also reported induced metallothionein expression might constitute a general metal response in S. caprea leaves allowing higher Zn and Cd uptake. S. integra could accumulate 90–288 mg Cd Kg −1 dry weight in their leaves, however, molecular mechanisms underlying the high accumulation of Cd in leaves were still uncovered.…”

“…Although fast growing woody plants have been widely used for cleaning up HM contaminated soils, limited information is available about the physiological and molecular mechanisms of HM tolerance and detoxification in woody plants (Konlechner et al, 2013; Luo et al, 2016). To date, most of genes involving in HM uptake, transport, sequestration, and detoxification in woody plants were restricted to Populus (Marmiroli et al, 2011; Luo et al, 2016).…”

“…Members of the ZIP gene family are capable of transporting a variety of cations, including Cd, iron, manganese and zinc (Guerinot, 2000), but very few members were characterized and functioned in Salix . Konlechner et al (2013) detected overexpression of ZIP6 in leaves of S. caprea by Zn and Cd, suggesting ZIP family gene play an important role in Zn/Cd transportation in Salix . In this study, we identified ZIP1 and ZIP8 , which might be involved in the Cd transport respectively in the leaves and the roots of S. integra .…”

Meta-transcriptomics indicates biotic cross-tolerance in willow trees cultivated on petroleum hydrocarbon contaminated soil

“…Several trials have investigated the gene expression or transcriptomic response of willow, and similar crops, to a number of inorganic contaminants applied in isolation, such as: chromium [ 17 ], copper [ 18 ], zinc [ 19 ] and cadmium [ 20 ]. Little research, however, has investigated the transcriptomic response of woody crops to organic contamination.…”

Selection of suitable reference genes for quantitative real-time PCR gene expression analysis in Salix matsudana under different abiotic stresses

“…Physiological and biochemical properties have been characterized in S. matsudana 3435. Meanwhile, some key genes have been identified to regulate stress response factors in stressed plants at the molecular level363738. Understanding the expression patterns of key stress response genes will help elucidate the mechanisms involved in various stresses of S. matsudana .…”