Advances in genetic modification of cassava

Zhang, P.; Ma, Q.; Naconsie, Maliwan; Wu, Xiaoyan; Zhou, W; Yang, Ji-Yeon

doi:10.19103/as.2016.0014.17

Cited by 7 publications

(7 citation statements)

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“…Several steps and sub-culturing procedures make FEC production a highly resource demanding and time-consuming task, in addition to the low-quality regeneration frequencies and high somaclonal variation (Raemakers et al, 2001; Taylor et al, 2001; Bull et al, 2009, 2011; Zainuddin et al, 2012; Ma et al, 2015). Recently efforts have been conducted to enhance FEC induction and transformation of more cassava cultivars (reviewed by Zhang et al, 2017). Nevertheless, in most cases, the efficiency needs improvement to be comparable with the one achieved with cv.…”

Section: Introductionmentioning

confidence: 99%

Arabidopsis LEC1 and LEC2 Orthologous Genes Are Key Regulators of Somatic Embryogenesis in Cassava

et al. 2019

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High genotype-dependent variation in friable embryogenic callus (FEC) induction and subsequent somaclonal variation constitute bottlenecks for the application and scaling of genetic transformation (GT) technology to more farmer- and industry-preferred cassava varieties. The understanding and identification of molecular factors underlying embryogenic development in cassava may help to overcome these constraints. Here, we described the Arabidopsis thaliana LEAFY COTYLEDON (LEC) LEC1 and LEC2 orthologous genes in cassava, designated as MeLEC1 and MeLEC2 , respectively. Expression analyses showed that both, MeLEC1 and MeLEC2 , are expressed at higher levels in somatic embryogenic (SE) tissues in contrast with differentiated mature tissues. The rapid expression increase of MeLEC genes at early SE induction times strongly suggests that they are involved in the transition from a somatic to an embryonic state, and probably, in the competence acquisition for SE development in cassava. The independent overexpression of the MeLEC genes resulted in different regenerated events with embryogenic characteristics such as MeLEC1 OE plants with cotyledon-like leaves and MeLEC2 OE plants with somatic-like embryos that emerged over the surface of mature leaves. Transcript increases of other embryo-specific regulating factors were also detected in MeLEC OE plants, supporting their mutual interaction in the embryo development coordination. The single overexpression of MeLEC2 was enough to reprogram the vegetative cells and induce direct somatic embryogenesis, which converts this gene into a tool that could improve the recovery of transformed plants of recalcitrant genotypes. The identification of MeLEC genes contributes not only to improve our understanding of SE process in cassava, but also provides viable alternatives to optimize GT and advance in gene editing in this crop, through the development of genotype-independent protocols.

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Section: Introductionmentioning

confidence: 99%

Arabidopsis LEC1 and LEC2 Orthologous Genes Are Key Regulators of Somatic Embryogenesis in Cassava

et al. 2019

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“…To meet the growing industrial demands for value‐added starches, the native starch with novel physico‐chemical property is needed in cassava (Zhang et al 2017). Unlike the traditional physical and/or chemical starch modifications, breeders intend to produce new cassava varieties with modified starches to expand their application spectrum through genetic approaches, such as starch‐related mutant identification and reverse‐genetic/biotechnological approaches (Schwall et al 2000; Jobling et al 2002; Raemakers et al 2005; Ceballos et al 2007; Zhao et al 2011; Bull et al 2018).…”

Section: Introductionmentioning

confidence: 99%

“…Unlike the traditional physical and/or chemical starch modifications, breeders intend to produce new cassava varieties with modified starches to expand their application spectrum through genetic approaches, such as starch‐related mutant identification and reverse‐genetic/biotechnological approaches (Schwall et al 2000; Jobling et al 2002; Raemakers et al 2005; Ceballos et al 2007; Zhao et al 2011; Bull et al 2018). Therefore, the development of cassava varieties having novel starches including waxy (amylose‐free) and high‐amylose starches are important objectives for cassava breeders (Zhang et al 2017). The target genes are mainly involved in starch biosynthesis, such as ADP‐glucose pyrophosphorylase, granule bound starch synthases (GBSS), soluble starch synthases (SSS), starch branching enzyme (SBE or BE), debranching enzyme (DBE), and related kinases (Zeeman et al 2010; Bahaji et al 2014; Wei et al 2017; Cai et al 2018).…”

Section: Introductionmentioning

confidence: 99%

“…In cassava, studies related to cloning and expression analysis of BE genes have been previously reported (Salehuzzaman et al 1992; Baguma et al 2003; Pei et al 2015). With the recent release of the cassava genome sequence (Prochnik et al 2012; Wang et al 2014; Bredeson et al 2016) and development of cassava transformation technology (Liu et al 2011; Zhang et al 2017), we now have the capacity to breed novel cassava cultivars with desirable traits using state‐of‐the‐art technologies including CRISPR/Cas9‐based genome editing (Odipio et al 2017; Sun et al 2017; Bull et al 2018; Gomez et al 2019).…”

Section: Introductionmentioning

confidence: 99%

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Production of very‐high‐amylose cassava by post‐transcriptional silencing of branching enzyme genes

Zhou

Zhao

et al. 2019

JIPB

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High amylose starch can be produced by plants deficient in the function of branching enzymes (BEs). Here we report the production of transgenic cassava (Manihot esculenta Crantz) with starches containing up to 50% amylose due to the constitutive expression of hair-pin dsRNAs targeting the BE1 or BE2 genes. All BE1-RNAi plant lines (BE1i) and BE2-RNAi plant lines (BE2i) were grown up in the field, but with reduced total biomass production. Considerably high amylose content in the storage roots of BE2i plant lines was achieved. Storage starch granules of BE1i and BE2i plants had similar morphology as wild type (WT), however, the size of BE1i starch granules were bigger than that of WT. Comparisons of amylograms and thermograms of all three sources of storage starches revealed dramatic changes to the pasting properties and a higher melting temperature for BE2i starches. Glucan chain length distribution analysis showed a slight increase in chains of DP>36 in BE1i lines and a dramatic increase in glucan chains between DP 10-20 and DP>40 in BE2i lines. Furthermore, BE2i starches displayed a B-type X-ray diffraction pattern instead of the A-type pattern found in BE1i and WT starches. Therefore, cassava BE1 and BE2 function differently in storage root starch biosynthesis.This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited.

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“…Vitamin B6 biofortified transgenic cassava showed 4-14 folds and 3-15 folds increase in vitamin B6 concentration in leaves and storage starchy roots, respectively [50,51]. Similarly, vitamin B1 (thiamine) and B9 (folate) has been enhanced in rice, although affected by processing such as polished rice of which normal practices people consume polished rice [52].…”

Section: Vitaminsmentioning

confidence: 99%

Staple Crops Biofortification Linking Agriculture, Food and Nutrition towards Eliminating Hidden Hunger

Zikankuba¹,

Mteremko

James

2019

EJNFS

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Agriculture is the mainstay of most of people globally. Despite the fact that agriculture has been a traditionally food and nutrition source, people go to bed without food and suffer from malnutrition even within the same households. Similarly, hunger and hidden hunger remains a worldwide widespread challenge. In response, researchers have tried to enhance micronutrients through staple food crops biofortification. The promotion of biofortified crops and unintended narrowed food choices might have been the underlying factor for the coexisting forms of malnutrition: undernutrition, obesity and increased incidence of non-communicable diseases; a malnutrition double burden problem. Therefore, this paper provides views to rethinking critically in order to take steps towards integrating nutrition education in modern agriculture crop biofortification programs more effectively.

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Advances in genetic modification of cassava

Cited by 7 publications

References 0 publications

Arabidopsis LEC1 and LEC2 Orthologous Genes Are Key Regulators of Somatic Embryogenesis in Cassava

Arabidopsis LEC1 and LEC2 Orthologous Genes Are Key Regulators of Somatic Embryogenesis in Cassava

Production of very‐high‐amylose cassava by post‐transcriptional silencing of branching enzyme genes

Staple Crops Biofortification Linking Agriculture, Food and Nutrition towards Eliminating Hidden Hunger

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