Selection for low-cadmium cultivars and cadmium subcellular distribution comparison between two selected cultivars of eggplant (Solanum melongena L.)

Abstract

Excessive accumulation of cadmium (Cd) in vegetables poses a serious threat to human health; therefore, it is urgent to screen and cultivate vegetable cultivars with low Cd accumulation in the edible parts. Eggplant has a high tendency for Cd accumulation, but research on its low Cd accumulation cultivars is still rare. In this study, to screen low-Cd cultivars, 30 eggplant cultivars were screened using soils containing 0.22 mg/kg, 2.9 mg/kg (low-Cd), and 4.7 mg/kg of Cd (high-Cd). MYCQ and ZGQ were con rmed as low-Cd cultivars, BXGZ and WCCQ were con rmed as high-Cd cultivars, and a 2.52-3.88 fold difference in Cd concentration was observed in their fruits. The subcellular distribution revealed that the root cell wall and vacuole Cd concentrations of a typical low-Cd cultivar (MYCQ) were signi cantly higher than those of a typical high-Cd cultivar (BXGZ); however, the Cd concentrations in the cell wall and vacuole in fruits, leaves, and stems were signi cantly lower in MYCQ than in BXGZ. These results indicated that the low-Cd cultivars of eggplant could lessen Cd toxicity through the elevated Cd retention and sequestration levels of root cell walls and vacuoles, thus reducing Cd transport from roots to aboveground tissues, leading to low Cd accumulation. The ndings of this study can provide a physiological and biochemical foundation for the screening and breeding of low-Cd cultivars of fruit vegetables and demonstrates that the application of low-Cd cultivars is necessary for food safety in humans.

Characterization of cadmium accumulation mechanism between eggplant (Solanum melongena L.) cultivars

“…In Brassica chinensis L., approximately 14.1% of Cd was adsorbed by lignin in the high-Cd cultivar, while 14.5% of Cd was adsorbed by the lignin of the low-Cd cultivar ( Wang et al., 2020 ). The lignin synthesis-related genes ( CADs and PODs ), lignin content as well as FTIR analyses of lignin (peaks at 1238 and 1157 cm -1 ) in MYQZ were significantly higher ( p <0.05) than that of BXGZ in this study, which are consistent with our previous study ( Shen et al., 2021 ), revealing that the distribution of Cd in the root cell wall is significantly higher in MYQZ than in BXGZ. Collectively, differences in lignin should also be an important factor in determining the Cd accumulation characteristics of eggplant.…”

“…Comparative studies of high- and low-Cd cultivars in potato and hot pepper revealed that high-Cd cultivar possessed longer root length, more root tips, larger root surface area and root volume, which should contribute to its higher Cd uptake and translocation ( Huang et al., 2015 ; Xin et al., 2017 ). Our previous study revealed that the Cd net uptake via root of BXGZ under low and high Cd treatment was were significantly higher than those of MYQZ ( Shen et al., 2021 ). In this study, with the significantly higher expression of root development genes ( ARF19 , GATA4 , 5 , 11 and PIN5 ), BXGZ showed a more developed root system of BXGZ under Cd treatment, indicting the root development of eggplant should be a key factor affecting the Cd net uptake via roots.…”

“…However, eggplant has a tendency to accumulate excessive Cd, even when growing in lightly contaminated soils ( Yuan et al., 2019 ). To control the Cd accumulation level of eggplant in a safe range through pollution-safe cultivar (PSC) strategy, a low-Cd cultivar (MYQZ) and a high-Cd cultivar (BXGZ) were obtained in our previous study ( Shen et al., 2021 ). The low-Cd cultivar showed high Cd retention and sequestration ability in the root, leading to reduced Cd transportation from roots to fruits in eggplants.…”

Bulk Segregant Analysis Sequencing and RNA-Seq Analyses Reveal Candidate Genes Associated with Sepal Color Phenotype of Eggplant (Solanum melongena L.)

“…Purple sepal eggplant varieties have higher anthocyanin concentrations compared to other darker colored fruits and vegetables. In brilliant flowering plants, color changes in the floral organs are closely associated with anthocyanins natural pigments that are widely found in plants [45]. They not only confer plants' vivid colors to attract pollinators and seed dispersers, but also enhance plants' resistance to stress [45].…”

“…In brilliant flowering plants, color changes in the floral organs are closely associated with anthocyanins natural pigments that are widely found in plants [45]. They not only confer plants' vivid colors to attract pollinators and seed dispersers, but also enhance plants' resistance to stress [45]. Anthocyanin synthesis and transport are intricately regulated processes that engage a multitude of structural genes and transcription factors, along with regulatory mechanisms at various levels, including RNA processing and protein modification [46].…”