Breeding strategies for metal accumulation in maize – from conventional breeding to cisgenesis
Domagoj ŠimićMario FranićHrvoje FulgosiZdenko LončarićRoberta SorićAntun JambrovićTatjana LedenčanZvonimir ZdunićVlado KovačevićIvan Brkić
1
Citation
0
Reference
20
Related Paper
Citation Trend
Abstract:
Although major crops have been investigated for decades for altering metal concentrations in various tissues, the interest has been recently intensified because of biofortification and phytoremediation programs. The particular goals are enhancing concentrations of beneficial metals such as iron (Fe) and zinc (Zn) and/or reducing concentrations of toxic elements (e.g. cadmium - Cd). Our results in maize showed that metal accumulation in leaf and grain are mostly controlled by numerous small-effect quantitative trait loci (QTLs), indicating long-term conventional breeding as a breeding strategy. However, we identified, validated and confirmed a major QTL for leaf Cd concentration on chromosome 2 (bin 2.06). We detected a putative candidate gene of known function on the basis of co- location with the major QTL. Our findings could aid rapid development of maize genotypes with decreased/increased Cd accumulation in leaves by manipulation of the gene. Using the detected gene in maize breeding via the new cisgenic approach will be discussed.Keywords:
Biofortification
Plant Breeding
Germ plasm
Cite
Cadmium (Cd), as a heavy metal, presents substantial biological toxicity and has harmful effects on human health. To lower the ingress levels of human Cd, it is necessary for Cd content in food crops to be reduced, which is of considerable significance for ensuring food safety. This review will summarize the genetic traits of Cd accumulation in rice and examine the mechanism of Cd uptake and translocation in rice. The status of genes related to Cd stress and Cd accumulation in rice in recent years will be summarized, and the genes related to Cd accumulation in rice will be classified according to their functions. In addition, an overview of quantitative trait loci (QTLs) mapping populations in rice will be introduced, aiming to provide a theoretical reference for the breeding of rice varieties with low Cd accumulation. Finally, existing problems and prospects will be put forward.
Cite
Citations (76)
Billions of people worldwide consume insufficient calcium (Ca) or magnesium (Mg) for adequate health. Dietary Ca and Mg intakes can potentially be increased through crop biofortification. Recently, we reported sufficient natural genetic variation and heritability in a leafy crop plant (Brassica oleracea; C-genome, 1n=9; cabbage, cauliflower, kale etc.) to indicate that genetic biofortification is feasible in vegetable Brassica. We also reported loci affecting shoot Ca and Mg concentration (shoot-Ca and Mg). Here, we extend the previous study to explore the closely related species B. rapa (A-genome, 1n=10; Chinese cabbage, pak choi, a more tractable species genetically, and the amphidiploid species B. napus(AC-genome, 1n=19; canola/oilseed rape etc.). Wide variation in shoot/leaf-Ca and Mg occurs among all three species. Shoot/leaf-Ca and Mg is significantly and highly heritable. Quantitative trait loci (QTL) affecting shoot/leaf Ca and Mg concentration occur in potentially paralogous regions of B. oleracea and B. rapa. If confirmed, allelic variation at such loci could be used in biofortification breeding programs for vegetable Brassica. As genome sequencing and marker generation improves, it will be possible to resolve these (and other) putative loci to the gene level. Further studies on the regulation, interaction and function of these genes will enable us to understand Ca and Mg dynamics in plants.
Brassica rapa
Biofortification
Leafy
Cite
Citations (0)
Cite
Citations (0)
Cite
Citations (6)
Background Aluminum (Al) toxicity is a major worldwide constraint to crop productivity on acidic soils. Al becomes soluble at low pH, inhibiting root growth and severely reducing yields. Maize is an important staple food and commodity crop in acidic soil regions, especially in South America and Africa where these soils are very common. Al exclusion and intracellular tolerance have been suggested as two important mechanisms for Al tolerance in maize, but little is known about the underlying genetics. Methodology An association panel of 282 diverse maize inbred lines and three F2 linkage populations with approximately 200 individuals each were used to study genetic variation in this complex trait. Al tolerance was measured as net root growth in nutrient solution under Al stress, which exhibited a wide range of variation between lines. Comparative and physiological genomics-based approaches were used to select 21 candidate genes for evaluation by association analysis. Conclusions Six candidate genes had significant results from association analysis, but only four were confirmed by linkage analysis as putatively contributing to Al tolerance: Zea mays AltSB like (ZmASL), Zea mays aluminum-activated malate transporter2 (ALMT2), S-adenosyl-L-homocysteinase (SAHH), and Malic Enzyme (ME). These four candidate genes are high priority subjects for follow-up biochemical and physiological studies on the mechanisms of Al tolerance in maize. Immediately, elite haplotype-specific molecular markers can be developed for these four genes and used for efficient marker-assisted selection of superior alleles in Al tolerance maize breeding programs.
Candidate gene
Genetic linkage
Inbred strain
Association mapping
Marker-Assisted Selection
Genetic Association
Plant Breeding
Cite
Citations (99)
Evaluation of wild barley introgression lines for agronomic traits related to nitrogen fertilization
Abstract In the coming decades, climate change and resources constraints will make profitable and economically reliable agriculture more and more challenging. To evaluate the potential of exotic alleles to maintain performance under low nitrogen input, we investigated a set of 41 introgression lines (S42ILs) originating from the hybridization of the German spring barley ‘Scarlett’ and the Israeli wild barley ‘ISR42-8’. These lines were assessed in field trials for yield, yield components, grain protein content and chlorophyll content during growing seasons 2015 and 2016 in two different test sites in Germany under low and high nitrogen supply levels, N 0 and N 1 . Our analyses revealed 17 regions for putative quantitative trait loci (QTL), linked to one or multiple traits, across all chromosomes. In particular, lines S42IL_119 and S42IL_121 exhibited an enhanced thousand grain weight of 7% and 9% under N 1 and N 0 , respectively. In addition, six QTL were found for grain number per ear leading to a decline of grain number of up to 20%. Furthermore, three new QTL for chlorophyll content could be identified on chromosomes 1H and 2H. The present study revealed QTL effects of wild barley introgressions in a spring barley elite background, especially under low nitrogen. The selection for nitrogen efficient lines with beneficial exotic alleles represents the first step towards the development of spring barley cultivars genetically adapted to nitrogen limitations.
Introgression
Plant Breeding
Marker-Assisted Selection
Cite
Citations (12)
Wheat is an important staple that acts as a primary source of dietary energy, protein, and essential micronutrients such as iron (Fe) and zinc (Zn) for the world's population. Approximately two billion people suffer from micronutrient deficiency, thus breeders have crossed high Zn progenitors such as synthetic hexaploid wheat, T. dicoccum, T. spelta, and landraces to generate wheat varieties with competitive yield and enhanced grain Zn that are being adopted by farmers in South Asia. Here we report a genome-wide association study (GWAS) using the wheat Illumina iSelect 90 K Infinitum SNP array to characterize grain Zn concentrations in 330 bread wheat lines. Grain Zn phenotype of this HarvestPlus Association Mapping (HPAM) panel was evaluated across a range of environments in India and Mexico. GWAS analysis revealed 39 marker-trait associations for grain Zn. Two larger effect QTL regions were found on chromosomes 2 and 7. Candidate genes (among them zinc finger motif of transcription-factors and metal-ion binding genes) were associated with the QTL. The linked markers and associated candidate genes identified in this study are being validated in new biparental mapping populations for marker-assisted breeding.
Biofortification
Genome-wide Association Study
Candidate gene
Molecular breeding
Plant Breeding
Genetic Association
Common wheat
Marker-Assisted Selection
Cite
Citations (120)
The development of high-yielding wheat genotypes containing micronutrient-dense grains are the main priorities of biofortification programs. At the International Maize and Wheat Improvement Center, breeders have successfully crossed high zinc progenitors including synthetic hexaploid wheat, T. dicoccum, T. spelta and landraces to generate high-zinc varieties. In this study, we report a genome-wide association using a wheat diversity panel to dissect the genetics controlling zinc, iron, copper, manganese and phosphorus concentrations in the grain and rachis during grain development and at physiological maturity. Significant marker-trait associations (MTAs) were identified for each nutrient using multi-locus mixed model methodologies. For mature grain, markers that showed significant pleiotropic effects were found on chromosomes 1A, 3B and 5B, of which those on chromosome 5B at ∼95.5 cM were consistent over two growing seasons. Co-located MTAs were identified for the nutrient concentrations in developing grain, rachis and mature grain on multiple chromosomes. The identified genomic regions included putative candidate genes involved in metal uptake and transport and storage protein processing. These findings add to our understanding of the genetics of the five important nutrients in wheat grain and provide information on genetic markers for selecting high micronutrient genotypes.
Biofortification
Cite
Citations (76)
Rice is a staple food for more than half the world’s population. It has highest global production next to wheat. With global climate change, most rice growing regions are experiencing extreme environmental fluctuations. Rice is susceptible to a variety of abiotic stresses including cold stress. In the temperate regions, rice growth is constrained by limited period that favours growth, where it needs optimum temperature between 25 0C to 35 0C. As the temperatures goes below 15oC, rice crop shows a wide range of chilling injury depending on the length of exposure and the developmental stage. Seedlings subjected to prolonged exposure (i.e. several days to weeks) can exhibit necrosis and mortality while shorter or intermittent exposure often leads to yellowing (chlorosis) and stunting, thus greatly reducing rice yields. Many QTLs related to cold tolerance at different stages have been identified by different researchers using mapping populations like recombinant inbred lines (RILs), doubled haploids (DH), F2:F3 lines, backcrosses and introgression lines. Therefore, the development of cold tolerant plants by the introduction of molecular breeding is assuredly a meaningful approach to hasten the breeding for improved plants. Intuitively, molecular breeding would be a faster way to mapping of beneficial QTL than through conventional breeding. The QTLs identified could be brought together by pyramiding into the breeders’ material and thus reduce the negative effect of cold stress.
Introgression
Staple food
Chlorosis
Cold stress
Cold tolerance
Cite
Citations (1)
The development of nutritionally enhanced wheat ( Triticum aestivum L.) with higher levels of grain iron (Fe) and zinc (Zn) offers a sustainable solution to micronutrient deficiency among resource-poor wheat consumers. One hundred and ninety recombinant inbred lines (RILs) from ‘Kachu’ × ‘Zinc-Shakti’ cross were phenotyped for grain Fe and Zn concentrations and phenological and agronomically important traits at Ciudad Obregon, Mexico in the 2017–2018, 2018–2019, and 2019–2020 growing seasons and Diversity Arrays Technology (DArT) molecular marker data were used to determine genomic regions controlling grain micronutrients and agronomic traits. We identified seven new pleiotropic quantitative trait loci (QTL) for grain Zn and Fe on chromosomes 1B, 1D, 2B, 6A, and 7D. The stable pleiotropic QTL identified have expanded the diversity of QTL that could be used in breeding for wheat biofortification. Nine RILs with the best combination of pleiotropic QTL for Zn and Fe have been identified to be used in future crossing programs and to be screened in elite yield trials before releasing as biofortified varieties. In silico analysis revealed several candidate genes underlying QTL, including those belonging to the families of the transporters and kinases known to transport small peptides and minerals (thus assisting mineral uptake) and catalyzing phosphorylation processes, respectively.
Biofortification
Candidate gene
Inbred strain
Cite
Citations (29)