PGR News from the Pacific

Posted 1:38 PM by Tevita

Discovery of an Amylose-free Starch Mutant in Cassava
(Manihot esculenta Crantz)

From : J. Agric. Food Chem. 2007, 55, 7469-7476 7469

Authors:
HERNAN CEBALLOS,*,†,‡ TERESA SANCHEZ,† NELSON MORANTE,†MARTIN FREGENE,† DOMINIQUE DUFOUR,†,§ ALISON M. SMITH, KAY DENYER, JUAN CARLOS PEÄ REZ,† FERNANDO CALLE,† AND CHRISTIAN MESTRES§

Centro Internacional de Agricultura Tropical (CIAT), Apdo Ae´reo 6713, Cali, Colombia, Universidad Nacional de Colombia-Palmira Campus, Centre de Coope´ration Internationale en Recherche Agronomique pour le De´veloppement. (CIRAD), 73 rue Jean-Francüois Breton, TA B-95/16, 34398 Montpellier Cedex 5, France, and John Innes Centre, Norwich Research Park, Colney, Norwich NR4 7UH, U.K.

One of the objectives of the cassava-breeding project at CIAT is the identification of clones with special root quality characteristics. A large number of self-pollinations have been made in search of useful recessive traits. During 2006 harvests an S1 plant produced roots that stained brownish-red when treated with an iodine solution, suggesting that it had lower-than-normal levels of amylose in its starch. Colorimetric and DSC measurements indicated low levels (3.4%) and an absence of amylose
in the starch, respectively. SDS-PAGE demonstrated the absence of GBSS enzyme in the starch from these roots. Pasting behavior was analyzed with a rapid visco-analyzer and resulted in larger values for peak viscosity, gel breakdown, and setback in the mutant compared with normal cassava starch. Solubility was considerably reduced, while the swelling index and volume fraction of the dispersed phase were higher in the mutant. No change in starch granule size or shape was observed. This is the first report of a natural mutation in cassava that drastically reduces amylose content in root starch.

* To whom correspondence should be addressed. E-mail: h.ceballos@cgiar.org.
† Centro Internacional de Agricultura Tropical (CIAT).
‡ Universidad Nacional de Colombia-Palmira Campus.
§ Centre de Coope´ration Internationale en Recherche Agronomique pour
le De´veloppement.
^ John Innes Centre.

( Courtesy of Choo, BI Malaysia)



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Agric. Food Chem. 2007, 55, 7469-7476 7469 Authors: HERNAN CEBALLOS,,†,‡ TERESA SANCHEZ,† NELSON MORANTE,†MARTIN FREGENE,† DOMINIQUE DUFOUR,†,§ ALISON M. SMITH, KAY DENYER, JUAN CARLOS PEÄ REZ,† FERNANDO CALLE,† AND CHRISTIAN MESTRES§ Centro Internacional de Agricultura Tropical (CIAT), Apdo Ae´reo 6713, Cali, Colombia, Universidad Nacional de Colombia-Palmira Campus, Centre de Coope´ration Internationale en Recherche Agronomique pour le De´veloppement. (CIRAD), 73 rue Jean-Francüois Breton, TA B-95/16, 34398 Montpellier Cedex 5, France, and John Innes Centre, Norwich Research Park, Colney, Norwich NR4 7UH, U.K. One of the objectives of the cassava-breeding project at CIAT is the identification of clones with special root quality characteristics. A large number of self-pollinations have been made in search of useful recessive traits. During 2006 harvests an S1 plant produced roots that stained brownish-red when treated with an iodine solution, suggesting that it had lower-than-normal levels of amylose in its starch. Colorimetric and DSC measurements indicated low levels (3.4%) and an absence of amylose in the starch, respectively. SDS-PAGE demonstrated the absence of GBSS enzyme in the starch from these roots. Pasting behavior was analyzed with a rapid visco-analyzer and resulted in larger values for peak viscosity, gel breakdown, and setback in the mutant compared with normal cassava starch. Solubility was considerably reduced, while the swelling index and volume fraction of the dispersed phase were higher in the mutant. No change in starch granule size or shape was observed. This is the first report of a natural mutation in cassava that drastically reduces amylose content in root starch. To whom correspondence should be addressed. E-mail: h.ceballos@cgiar.org. † Centro Internacional de Agricultura Tropical (CIAT). ‡ Universidad Nacional de Colombia-Palmira Campus. § Centre de Coope´ration Internationale en Recherche Agronomique pour le De´veloppement. ^ John Innes Centre. ( Courtesy of Choo, BI Malaysia) * Comments: Post a Comment	Archive October 2002 November 2002 December 2002 January 2003 February 2003 March 2003 April 2003 May 2003 June 2003 July 2003 August 2003 September 2003 October 2003 November 2003 December 2003 January 2004 February 2004 March 2004 April 2004 May 2004 June 2004 July 2004 August 2004 September 2004 October 2004 November 2004 December 2004 January 2005 February 2005 March 2005 April 2005 May 2005 June 2005 July 2005 August 2005 September 2005 October 2005 November 2005 December 2005 January 2006 February 2006 March 2006 April 2006 May 2006 June 2006 July 2006 August 2006 September 2006 October 2006 November 2006 December 2006 January 2007 February 2007 March 2007 April 2007 May 2007 June 2007 July 2007 August 2007 September 2007 October 2007 November 2007 December 2007 January 2008 February 2008 March 2008 April 2008 May 2008 June 2008 July 2008 August 2008 September 2008 October 2008 November 2008 December 2008 January 2009 February 2009 March 2009 April 2009 May 2009 June 2009 July 2009 August 2009 September 2009 October 2009 November 2009 January 2010 RSS Feed Alternative feed Contact Tevita Something new: Agrobiodiversity Weblog: For discussions of conservation and sustainable use of the genetic resources of crops, livestock and their wild relatives. 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