Generation of cyanogen-free transgenic cassava

Siritunga, Dimuth; Sayre, Richard T.

doi:10.1007/s00425-003-1005-8

Cited by 168 publications

(169 citation statements)

References 22 publications

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“…We show that this oxidative burst is due to cyanide production, which is rapidly induced when cassava is mechanically damaged. Cassava produces potentially toxic levels of cyanogenic glycosides that break down to release cyanide following cellular disruption and release of the cyanogens from the vacuole (Miller and Conn, 1980;McMahon et al, 1995;Siritunga and Sayre, 2003;Siritunga et al, 2004). During cyanogenesis, Glc is cleaved from linamarin by the enzyme linamarase.…”

Section: Discussionmentioning

confidence: 99%

“…Cyanide is a potent cellular toxin that inhibits the mitochondrial electron transport chain by tightly binding to the heme iron within cytochrome c oxidase, potentially leading to the accumulation of ROS (Boveris and Cadenas, 1982;Yip and Yang, 1998). The availability of transgenic lowcyanogen plants (Siritunga and Sayre, 2003) allowed us to investigate whether there was a causal link between cyanogenesis and the oxidative burst associated with PPD. Our results show that the oxidative burst is initiated by cyanide release occurring with mechanical wounding.…”

Section: Discussionmentioning

confidence: 99%

“…The intensity of the resulting brown coloration was quantified as a measure of hydrogen peroxide levels. Transgenic low-cyanogen plants with less than 1% of wild-type linamarin levels (Cab1-1, Cab1-2, and Cab1-3; Siritunga and Sayre, 2003) had 2-to 8-fold lower dye-detectable hydrogen peroxide levels relative to wild-type plants (Fig. 1A).…”

Section: The Oxidative Burst In Damaged Cassava Roots Is Cyanogen Indmentioning

confidence: 99%

“…We hypothesized that cyanide release (Mkpong et al, 1990;McMahon et al, 1995;Siritunga and Sayre, 2003) was the primary event leading to ROS production, via cyanide-induced inhibition of mitochondrial electron transfer and overreduction of the upstream electron transfer complexes leading to ROS production (Møller, 2001). In root tissues, there is an additional potential source of ROS production, the plasma membrane NADPH oxidase (Bhattacharjee, 2005).…”

Section: The Oxidative Burst In Damaged Cassava Roots Is Cyanogen Indmentioning

confidence: 99%

“…A, Plasmid construct of AOX. The codonoptimized Arabidopsis AOX, AtAox1A, was cloned into a pBI121-based three-dimensional vector in which the cauliflower mosaic virus 35S promoter was replaced by the root-specific patatin promoter followed by the NOS terminator (Siritunga and Sayre, 2003;Ihemere et al, 2006). B, AOX expression in roots of transgenic lines as determined by RT-PCR.…”

Section: Expression Of Arabidopsis Aox Delays Ppd In Cassava Tubersmentioning

confidence: 99%

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Extending Cassava Root Shelf Life via Reduction of Reactive Oxygen Species Production

Zidenga

Leyva-Guerrero²,

Moon³

et al. 2012

Plant Physiology

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138

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One of the major constraints facing the large-scale production of cassava (Manihot esculenta) roots is the rapid postharvest physiological deterioration (PPD) that occurs within 72 h following harvest. One of the earliest recognized biochemical events during the initiation of PPD is a rapid burst of reactive oxygen species (ROS) accumulation. We have investigated the source of this oxidative burst to identify possible strategies to limit its extent and to extend cassava root shelf life. We provide evidence for a causal link between cyanogenesis and the onset of the oxidative burst that triggers PPD. By measuring ROS accumulation in transgenic low-cyanogen plants with and without cyanide complementation, we show that PPD is cyanide dependent, presumably resulting from a cyanide-dependent inhibition of respiration. To reduce cyanide-dependent ROS production in cassava root mitochondria, we generated transgenic plants expressing a codon-optimized Arabidopsis (Arabidopsis thaliana) mitochondrial alternative oxidase gene (AOX1A). Unlike cytochrome c oxidase, AOX is cyanide insensitive. Transgenic plants overexpressing AOX exhibited over a 10-fold reduction in ROS accumulation compared with wild-type plants. The reduction in ROS accumulation was associated with a delayed onset of PPD by 14 to 21 d after harvest of greenhouse-grown plants. The delay in PPD in transgenic plants was also observed under field conditions, but with a root biomass yield loss in the highest AOX-expressing lines. These data reveal a mechanism for PPD in cassava based on cyanideinduced oxidative stress as well as PPD control strategies involving inhibition of ROS production or its sequestration.

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Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Section: The Oxidative Burst In Damaged Cassava Roots Is Cyanogen Indmentioning

confidence: 99%

Section: The Oxidative Burst In Damaged Cassava Roots Is Cyanogen Indmentioning

confidence: 99%

Section: Expression Of Arabidopsis Aox Delays Ppd In Cassava Tubersmentioning

confidence: 99%

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Extending Cassava Root Shelf Life via Reduction of Reactive Oxygen Species Production

Zidenga

Leyva-Guerrero²,

Moon³

et al. 2012

Plant Physiology

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138

168

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Cassava Genetic Improvement

Ceballos¹,

Fregene²,

Carlos³

et al. 2007

Breeding Major Food Staples

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PREFACEThis Handbook is the result of a combined effort by several current and previous cassava researchers at CIAT to review and summarize the most important results of cassava research during the past 40 years. Most of the chapters are based on the various presentations during the Regional Cassava Training Course, held in Thailand from October 6 to 17, 2008. This course was organized upon the realization that many people that were actively involved with cassava research in the 1970s and 80s, both at CIAT and in national programs, have now retired or will soon do so, and that a whole new generation of cassava researchers are currently being hired to take their place.As cassava is now becoming a very important, and mostly industrial, crop in Asia, there are many new opportunities, but also a host of new problems and challenges. These include the appearance in Asia of new cassava diseases and pests; the decreasing availability and increasing cost of rural labor, resulting in the need for partial or complete mechanization of cassava production; the rapidly increasing demand for cassava roots for production of food, feed and fuel, and the unavailability in many countries of new land for any expansion of cassava area, thus requiring a rapid increase in cassava yields to increase supplies. This requires a renewed focus on cassava research for the development of new higher-yielding varieties and more sustainable production practices.While many cassava researchers in national programs in Asia received individual or group training at CIAT-Colombia during the 1970s and 80s, this training was greatly reduced during the following two decades due to funding limitations. Thus, the objective of the Regional Cassava Training Course in 2008 was to provide a new training opportunity for young scientists in Asian countries, and to hand over the knowledge and experience of the older cassava researchers, mostly from CIAT, to a new generation that will have to face the new challenges. Thus, the course was taught mostly by current or already retired CIAT cassava researchers, while the 60-plus participants of the course included cassava researchers from Cambodia, China, East Timor, India, Indonesia, Lao PDR, Malaysia, Myanmar, the Philippines, Thailand and Vietnam. The training course not only provided knowledge -from physiology and biotechnology to animal feeding and production of fuelethanol -but also an opportunity for people from different institutions and countries to get to know each other, which will greatly facilitate future collaboration.Course participants returned home with a CD containing the PowerPoint presentations of the course. However, it was felt that a more comprehensive review of all the topics covered was warranted, as this would provide more in-depth knowledge for those working in the various specialized fields. Most of this information is available in many refereed journals, in workshop proceedings and old CIAT annual reports, but many of these are now out of print or otherwise difficult to obtain. Thus, the Cas...

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Transgenic Vegetable Crops: Progress, Potentials, and Prospects

Dias

Ortíz

2011

Plant Breeding Reviews

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Generation of cyanogen-free transgenic cassava

Cited by 168 publications

References 22 publications

Extending Cassava Root Shelf Life via Reduction of Reactive Oxygen Species Production

Extending Cassava Root Shelf Life via Reduction of Reactive Oxygen Species Production

Cassava Genetic Improvement

Transgenic Vegetable Crops: Progress, Potentials, and Prospects

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