Genome-Wide Characterization and Analysis of Metallothionein Family Genes That Function in Metal Stress Tolerance in Brassica napus L.

Abstract

Brassica plants exhibit both high biomass productivity and high rates of heavy metal absorption. Metallothionein (MT) proteins are low molecular weight, cysteine-rich, metal-binding proteins that play crucial roles in protecting plants from heavy metal toxicity. However, to date, MT proteins have not been systematically characterized in Brassica. In this study, we identified 60 MTs from Arabidopsis thaliana and five Brassica species. All the MT family genes from Brassica are closely related to Arabidopsis MTs, encoding putative proteins that share similar functions within the same clades. Genome mapping analysis revealed high levels of synteny throughout the genome due to whole genome duplication and segmental duplication events. We analyzed the expression levels of 16 Brassica napus MTs (BnaMTs) by RNA-sequencing and real-time RT-PCR (RT-qPCR) analysis in plants under As3+ stress. These genes exhibited different expression patterns in various tissues. Our results suggest that BnaMT3C plays a key role in the response to As3+ stress in B. napus. This study provides insight into the phylogeny, origin, and evolution of MT family members in Brassica, laying the foundation for further studies of the roles of MT proteins in these important crops.

Phytoremediation of Cadmium: Physiological, Biochemical, and Molecular Mechanisms

“…MT gene regulation is different in various plants and abiotic stress conditions, including heavy metal-induced expression ( Figure 5) [239]. So far, four types of MTs have been recognized in plants, containing MT1, MT2, MT3, and MT4 types, which are categorized according to the arrangement of Cys residues in their C-and N-terminal domains [240]. Regarding the diversity of plants as well as the organization or distribution of Cys residues in the MT structure, there may be different isoforms for each type of MT, e.g., in A. thaliana, two isoforms (MT4a and MT4b) have been identified for MT4 [241].…”

“…MTs have a great tendency to bind to heavy metals containing Cd, Zn, Cu, and As, and can eliminate them even at a low amount; nevertheless, in terms of the importance as a Cd chelator, MT is considered after PCs [242]. Generally, MTs play multiple roles in plants, such as tolerance and maintenance of the cellular ion balance by detoxification of heavy metals, ROS scavenging, damaged DNA repair, and as well as various physiological processes, including seed germination and fruit ripening in plants [240,243]. However, the mechanism of action of MT plants in stressful conditions relative to mammalian MT remains unknown.…”

Peer Review #1 of "Genome-wide identification of C2H2 zinc-finger genes and their expression patterns under heat stress in tomato (Solanum lycopersicum L.) (v0.1)"

“…The phylogenetic trees were constructed using different methods with 1000 replicate bootstrap tests. The ML trees was calculated using the ProtML program under the JTT model (Guo et al, 2008), NJ trees was obtained using the JTT+I+G substitution model (Pan et al, 2018), UPGMA and MP trees were generated in MEGA v6.0 (Tamura et al, 2013) with the default parameters. Finally, the phylogenetic trees were visualized using FigTree v1.4.2 (http://tree.bio.ed.ac.uk/software/figtree/).…”

“…Gene structure, conserved motif and functional annotation analyses Genome DNA and the corresponding CDSs of the putative C2H2-ZF genes were obtained from the Sol Genomics Network database (https://solgenomics.net; The Tomato Genome, 2012), then analyzed using the Gene Structure Display Server (GSDS v2.0; http://gsds.cbi.pku.edu.cn/index.php) to obtain information on the exon/intron structures. MEME v5.0.3 (http://meme-suite.org/tools/meme) was used to predict the corresponding conserved motifs (Bailey et al, 2009) with the following parameters: optimum motif widths of 6-300 residues, any repetition, and a maximum of 10 motifs (Pan et al, 2018). Each motif with an Evalue < 1 × 10 −10 was retained for motif detection.…”

Editorial for Special Issue “Plant Genetics and Molecular Breeding”

“…Manuscripts focus on the integration of different phenotypical and molecular tools for the analysis of different traits with a high interest in breeding. These multidisciplinary studies have been performed predominantly in cereal crops including rice [5,6,7,8,9,10,11,12,13] and wheat [14]; industrial crops including oilseed rape [15,16,17], sugarcane [18,19], soybean [20], sesame [21], and minor oil crops [22]; vegetable crops including cabbage [23,24], tomato [25], broccoli [26], chickpea [27], and cucumber [28]; ornamental crops including Chrysanthemum [29,30], Paeomia [31], rose [32] and Aechmea [33]; fruit and nut trees such as kiwi [34] and almond [35]; and crops with environmental [36,37] and medical uses [38].…”