Variations in cadmium and nitrate co-accumulation among water spinach genotypes and implications for screening safe genotypes for human consumption

Abstract

Abstract:Vegetables are important constituents of the human diet. Heavy metals and nitrate are among the major contaminants of vegetables. Consumption of vegetables and fruits with accumulated heavy metals and nitrate has the potential to damage different body organs leading to unwanted effects. Breeding vegetables with low heavy metal and nitrate contaminants is a cost-effective approach. We investigated 38 water spinach genotypes for low Cd and nitrate co-accumulation. Four genotypes, i.e. JXDY, GZQL, XGDB, and B888, were found to have low co-accumulation of Cd (<0.71 mg/kg dry weight) and nitrate (<3100 mg/kg fresh weight) in the edible parts when grown in soils with moderate contamination of both Cd (1.10 mg/kg) and nitrate (235.2 mg/kg). These genotypes should be appropriate with minimized risk to humans who consume them. The Cd levels in the edible parts of water spinach were positively correlated with the concentration of Pb or Zn, but Cd, Pb, or Zn was negatively correlated with P concentration. These results indicate that these three heavy metals may be absorbed into the plant in similar proportions or in combination, minimizing the influx to aerial parts. Increasing P fertilizer application rates appears to prevent heavy metal and nitrate translocation to shoot tissues and the edible parts of water spinach on co-contaminated soils.

Molecular-Assisted Breeding of Cadmium Pollution-Safe Cultivars

“…36 Among 38 genotypes of water spinach, JXDY, GZQL, XGDB, and B888 exhibited low Cd accumulation (<0.71 mg/kg DW) in edible parts in moderately Cd-contaminated soil (1.10 mg/kg). 37 Five soybean cultivars among 25 tested Chinese soybean cultivars accumulated less Cd (<0.20 mg/kg), with enrichment factor (EF) and translocation factor (TF) lower than 1.0 in Cd contaminated soil. 38 In another experiment involving 28 lettuce cultivars, SJDT, YLGC, N518, and KR17 genotypes were identified as Cd-safe lettuce cultivars (Cd < 0.2 mg kg, FW).…”

“…In a field experiment involving 32 oilseed rape cultivars, Nanchongjie, Pengzhoubai, and J-25 were identified as high Cd accumulators with Cd concentrations over 0.5 mg/kg DW, while cultivars 72A and 47 were identified as low Cd accumulators with high yield, low Cd concentration (Cd concentration 0.3 mg/kg DW), and low food safety risk . Among 38 genotypes of water spinach, JXDY, GZQL, XGDB, and B888 exhibited low Cd accumulation (<0.71 mg/kg DW) in edible parts in moderately Cd-contaminated soil (1.10 mg/kg) . Five soybean cultivars among 25 tested Chinese soybean cultivars accumulated less Cd (<0.20 mg/kg), with enrichment factor (EF) and translocation factor (TF) lower than 1.0 in Cd contaminated soil .…”

The Fate of Nitrogen from Soil to Plants: Influence of Agricultural Practices in Modern Agriculture

“…If nitrate is absorbed without being reduced, it accumulates in plant cells [123]. Many factors influence this accumulation, such as the physical and chemical characteristics of soil [123,124], the plant species [123,[125][126][127][128], the fertilization regime [129,130], and the growing season and climatic conditions [131]. Since nitrate accumulates mainly in the leaves, leafy vegetables are considered the richest sources of nitrates among vegetables [132].…”

Breeding crops by design for future agriculture

“…Food safety problems, such as those posed by heavy metal contamination, are other key challenges for future agriculture (Tang et al, 2018). In the following review, Chen and Wu (2020) summarize the genes mediating Cd transport (ion transporters and chelates) and molecular markers for low-Cd accumulation and discuss methodologies for breeding low-Cd cultivars.…”

“…It is a formidable challenge for future agriculture to maintain sustainable food production and satisfy the requirements for biofortification and safety of edible crops under a changing climate (Tang et al, 2018;Fernie and Yan, 2019). In a recent report, "Science Breakthroughs to Advance Food and Agricultural Research by 2030" (National Academies of Sciences, Engineering, and Medicine, 2019), genomics and precision breeding were identified as scientific breakthrough areas that will have the greatest positive impact on food and agriculture.…”