Iron biofortification and homeostasis in transgenic cassava roots expressing the algal iron assimilatory gene, FEA1

Ihemere, Uzoma; Narayanan, Narayanan N.; Sayre, Richard T.

doi:10.3389/fpls.2012.00171

Cited by 28 publications

(15 citation statements)

References 77 publications

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“…Next generation sequencing information has allowed genome sequencing of the most important crops to human consumption. There has also been progress in identifying genes that are involved in the movement of Fe and Zn in plants and using these genes for biofortification of rice (Goto et al, 1999), cassava (Ihemere, 2012), wheat (Borg et al, 2012), maize (Kanobe et al, 2013), lettuce (Goto et al, 2000) and soybean (Vasconcelos et al, 2014).…”

Section: Discussionmentioning

confidence: 99%

Meta-QTL analysis of seed iron and zinc concentration and content in common bean (Phaseolus vulgaris L.)

et al. 2018

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Twelve meta-QTL for seed Fe and Zn concentration and/or content were identified from 87 QTL originating from seven population grown in sixteen field trials. These meta-QTL include 2 specific to iron, 2 specific to zinc and 8 that co-localize for iron and zinc concentrations and/or content. Common bean (Phaseolus vulgaris L.) is the most important legume for human consumption worldwide and it is an important source of microelements, especially iron and zinc. Bean biofortification breeding programs develop new varieties with high levels of Fe and Zn targeted for countries with human micronutrient deficiencies. Biofortification efforts thus far have relied on phenotypic selection of raw seed mineral concentrations in advanced generations. While numerous quantitative trait loci (QTL) studies have been conducted to identify genomic regions associated with increased Fe and Zn concentration in seeds, these results have yet to be employed for marker-assisted breeding. The objective of this study was to conduct a meta-analysis from seven QTL studies in Andean and Middle American intra- and inter-gene pool populations to identify the regions in the genome that control the Fe and Zn levels in seeds. Two meta-QTL specific to Fe and two meta-QTL specific to Zn were identified. Additionally, eight Meta QTL that co-localized for Fe and Zn concentration and/or content were identified across seven chromosomes. The Fe and Zn shared meta-QTL could be useful candidates for marker-assisted breeding to simultaneously increase seed Fe and Zn. The physical positions for 12 individual meta-QTL were identified and within five of the meta-QTL, candidate genes were identified from six gene families that have been associated with transport of iron and zinc in plants.

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Section: Discussionmentioning

confidence: 99%

Meta-QTL analysis of seed iron and zinc concentration and content in common bean (Phaseolus vulgaris L.)

et al. 2018

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“…All commonly used genetic transformation systems in cassava rely on the induction of somatic embryogenesis. In some cases, OES produced from explants is used directly for transgene integration (Ihemere et al, 2012;Ntui et al, 2015). Alternatively, OES can be matured to generate caulogenic cotyledon tissues (Jorgensen et al, 2005;Li et al, 1996), or converted to a highly disorganized FEC, which can then be subjected to Agrobacterium or direct gene transfer technologies (Liu et al, 2011;Taylor et al, 2004).…”

Section: Discussionmentioning

confidence: 99%

“…Constructs p718, p5001 and p5003 consisted of inverted repeat sequences from the CP genes of UCBSV (p718), CBSV (p5003) and both CPs (p5001). pRS26 was designed to elevate iron content in cassava storage roots by expression of the FEA1 gene under control of the Patatin type-1 promoter (Ihemere et al, 2012).…”

Section: Methodsmentioning

confidence: 99%

Loss of CMD2‐mediated resistance to cassava mosaic disease in plants regenerated through somatic embryogenesis

Beyene

Chauhan

Wagaba

et al. 2016

Molecular Plant Pathology

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SummaryCassava mosaic disease (CMD) and cassava brown streak disease (CBSD) are the two most important viral diseases affecting cassava production in Africa. Three sources of resistance are employed to combat CMD: polygenic recessive resistance, termed CMD1, the dominant monogenic type, named CMD2, and the recently characterized CMD3. The farmer‐preferred cultivar TME 204 carries inherent resistance to CMD mediated by CMD2, but is highly susceptible to CBSD. Selected plants of TME 204 produced for RNA interference (RNAi)‐mediated resistance to CBSD were regenerated via somatic embryogenesis and tested in confined field trials in East Africa. Although micropropagated, wild‐type TME 204 plants exhibited the expected levels of resistance, all plants regenerated via somatic embryogenesis were found to be highly susceptible to CMD. Glasshouse studies using infectious clones of East African cassava mosaic virus conclusively demonstrated that the process of somatic embryogenesis used to regenerate cassava caused the resulting plants to become susceptible to CMD. This phenomenon could be replicated in the two additional CMD2‐type varieties TME 3 and TME 7, but the CMD1‐type cultivar TMS 30572 and the CMD3‐type cultivar TMS 98/0505 maintained resistance to CMD after passage through somatic embryogenesis. Data are presented to define the specific tissue culture step at which the loss of CMD resistance occurs and to show that the loss of CMD2‐mediated resistance is maintained across vegetative generations. These findings reveal new aspects of the widely used technique of somatic embryogenesis, and the stability of field‐level resistance in CMD2‐type cultivars presently grown by farmers in East Africa, where CMD pressure is high.

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“…Previously it was shown that transgenic expression of FEA1, from the unicellular algae Chlymadomonas reinhardtii, resulted in a threefold accumulation of iron in greenhouse-grown cassava storage roots [38]. FEA1 functions as an iron assimilatory protein and complements the Arabidopisis irt1 mutant [68] and is thought to enhance iron uptake and transport from the soil.…”

Section: Discussionmentioning

confidence: 99%

“…Recently, the iron-specific assimilatory protein FEA1 from Chlamydomonas reinhardtii was integrated into cassava and expressed under control of the storage organ specific type I patatin promoter. Regenerated plants showed an approximate three-fold increase in iron in their storage roots compared with the non-transgenic control plants when grown under greenhouse conditions [38]).…”

Section: Introductionmentioning

confidence: 99%

Overexpression of Arabidopsis VIT1 increases accumulation of iron in cassava roots and stems

et al. 2015

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Iron is extremely abundant in the soil, but its uptake in plants is limited due to low solubility in neutral or alkaline soils. Plants can rely on rhizosphere acidification to increase iron solubility. AtVIT1 was previously found to be involved in mediating vacuolar sequestration of iron, which indicates a potential application for iron biofortification in crop plants. Here, we have overexpressed AtVIT1 in the starchy root crop cassava using a patatin promoter. Under greenhouse conditions, iron levels in mature cassava storage roots showed 3-4 times higher values when compared with wild-type plants. Significantly, the expression of AtVIT1 showed a positive correlation with the increase in iron concentration of storage roots. Conversely, young leaves of AtVIT1 transgenic plants exhibit characteristics of iron deficiency such as interveinal chlorosis of leaves (yellowing) and lower iron concentration when compared with the wild type plants. Interestingly, the AtVIT1 transgenic plants showed 4 and 16 times higher values of iron concentration in the young stem and stem base tissues, respectively. AtVIT1 transgenic plants also showed 2-4 times higher values of iron content when compared with wild-type plants, with altered partitioning of iron between source and sink tissues. These results demonstrate vacuolar iron sequestration as a viable transgenic strategy to biofortify crops and to help eliminate micronutrient malnutrition in at-risk human populations.

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Iron biofortification and homeostasis in transgenic cassava roots expressing the algal iron assimilatory gene, FEA1

Cited by 28 publications

References 77 publications

Meta-QTL analysis of seed iron and zinc concentration and content in common bean (Phaseolus vulgaris L.)

Meta-QTL analysis of seed iron and zinc concentration and content in common bean (Phaseolus vulgaris L.)

Loss of CMD2‐mediated resistance to cassava mosaic disease in plants regenerated through somatic embryogenesis

Overexpression of Arabidopsis VIT1 increases accumulation of iron in cassava roots and stems

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