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Thaikert R.,Mahidol University | Sraphet S.,Mahidol University | Boonchanawiwat A.,Mahidol University | Boonseng O.,Rayong Field Crops Research Center | And 3 more authors.
Journal of Crop Improvement

Cassava anthracnose disease (CAD), caused by Colletotrichum gloeosporioides f. sp. manihotis infection, is a major disease of cassava (Manihot esculenta Crantz). The objective of this study was to identify proteins differentially regulated in resistant (‘Huaybong 60’) and susceptible (‘Hanatee’) cultivars in response to C. gloeosporioides f. sp. manihotis infection. Total proteins were extracted and resolved via 2-dimensional gel electrophoresis. Fourteen differentially expressed proteins were identified in ‘Huaybong 60’, of which eight were up-regulated and seven down-regulated. In ‘Hanatee’, seven proteins were identified, of which one was up-regulated and six were down-regulated. Proteins associated with carbohydrate metabolism were down-regulated, whereas reactive oxygen species-generating and cyanogenic pathways were up-regulated in the resistant cultivar. This study provided new insights into the mechanisms underlying pathogen resistance in cassava and suggested that pathogen resistance might arise from an integrated mechanism that arises from only a few initiating events. Copyright © Taylor & Francis Group, LLC. Source

Charoenkul N.,King Mongkuts University of Technology Thonburi | Charoenkul N.,Kagoshima University | Uttapap D.,King Mongkuts University of Technology Thonburi | Pathipanawat W.,Rayong Field Crops Research Center | Takeda Y.,Kagoshima University
LWT - Food Science and Technology

Starches and flours from 12 cassava varieties having differences in cooked root texture - mealy, firm and mealy & firm - were investigated, with a particular focus on aspects of physicochemical characteristics. It was found that chemical composition (protein, lipid, fiber, ash), pasting properties, firmness of gel, thermal properties, morphology and granular size distribution and crystalline pattern of starches from the 12 varieties were not significantly different. On the contrary, cassava flours which consisted of both starch and non-starch components exhibited wider variations in these properties, especially pasting properties and firmness of gel, than the starches. All flour samples had lower paste viscosities than their corresponding starches. Pasting temperatures of flours were in a range of 70-74 °C, which was higher than those of starches (67-70 °C). Fluctuation in the values of pasting parameters of flours among the varieties was associated with the variations in the chemical composition and α-amylase activity, i.e. paste viscosity and setback were positively correlated to starch content and negatively correlated to α-amylase activity, while protein, lipid and fiber did not show correlation with pasting parameters. Cassava starches from all varieties, except the F-18 variety, had higher firmness of gels than their corresponding flours. Firmness values (except the F-18 variety) of starches were in a range of 149-207 g, whereas those of flours were 75-163 g. Firmness of flour gels was negatively correlated to lipid and fiber content, while strong positive correlation was found with the amylase activity. © 2011 Elsevier Ltd. Source

Boonchanawiwat A.,Mahidol University | Sraphet S.,Mahidol University | Boonseng O.,Rayong Field Crops Research Center | Lightfoot D.A.,Southern Illinois University Carbondale | Triwitayakorn K.,Mahidol University
Field Crops Research

Cassava, Manihot esculenta Crantz subsp. Esculenta was a major food crop across Asia and Africa. The crop was a highly heterozygous perennial woody shrub cultivated from stem cuttings. Cassava improvement for starchy tuberous roots requires about 5-6 years from F1 hybrid seed germination to the selection of superior genotypes. Early selection with DNA markers could increase the number of elite genotypes identified. The aim here was to identify DNA markers associated with loci underlying plant and first branch height. In this study, 640 SSR primer pairs were used to screen for polymorphisms in two parental lines, cv. 'Huaybong60' (female) and cv. 'Hanatee' (male). There were 235 informative polymorphic markers used to genotype 100 individuals of an F1 mapping population. Genotype data was analyzed by JoinMap® version 3.0 software in order to construct a genetic linkage map. The map consisted of 156 linked SSR markers distributed across 25 linkage groups. The total length of the map was 845.2cM (Kosambi cM) with 6.2 loci per linkage group, and an average distance between markers of 7.9cM. Plant and first branch height of stem cuttings from the F1 mapping population were collected from individual lines planted in 2007-2009. Quantitative Trait Loci (QTL) underlying these traits were identified using mapQTL®/version 4.0. A total of seven QTL placed on four linkage groups were found for plant height. Of these, one major QTL was discovered on linkage group 2 near the marker SSRY155 with 17.9% of phenotypic variation explained (PVE). For first branch height, five QTL located on five linkage groups were identified. The two major QTL were located on linkage groups 2, and 20 at the loci SSRY323 and SSRY236 with 23.5% and 22.6% PVE, respectively. The QTL for plant and first branch height will serve as useful molecular markers in a cassava breeding program and may allow identification of the underlying genes in future. © 2011 Elsevier B.V. Source

BOONCHANAWIWAT A.,Mahidol University | SRAPHET S.,Mahidol University | WHANKAEW S.,Mahidol University | BOONSENG O.,Rayong Field Crops Research Center | And 2 more authors.
Journal of Agricultural Science

Cassava (Manihot esculenta Crantz) is an economically important root crop in Thailand, which is ranked the world's top cassava exporting country. Production of cassava can be hampered by several pathogens and pests. Cassava anthracnose disease (CAD) is an important disease caused by the fungus Colletotrichum gloeosporioides f. sp. manihotis. The pathogen causes severe stem damage resulting in yield reductions and lack of stem cuttings available for planting. Molecular studies of cassava response to CAD will provide useful information for cassava breeders to develop new varieties with resistance to the disease. The current study aimed to identify quantitative trait loci (QTL) and DNA markers associated with resistance to CAD. A total of 200 lines of two F1 mapping populations were generated by reciprocal crosses between the varieties Huabong60 and Hanatee. The F1 samples were genotyped based on simple sequence repeat (SSR) and expressed sequence tag-SSR markers and a genetic linkage map was constructed using the JoinMap®/version3·0 program. The results showed that the map consisted of 512 marker loci distributed on 24 linkage groups with a map length of 1771·9 centimorgan (cM) and a mean interval between markers of 5·7 cM. The genetic linkage map was integrated with phenotypic data for the response to CAD infection generated by a detached leaf assay test. A total of three QTL underlying the trait were identified on three linkage groups using the MapQTL®/version4·0 program. Those DNA markers linked to the QTL that showed high statistically significant values with the CAD resistance trait were identified for gene annotation analysis and 23 candidate resistance genes to CAD infection were identified. Copyright © Cambridge University Press 2015 Source

Thanyasiriwat T.,Mahidol University | Sraphet S.,Mahidol University | Whankaew S.,Mahidol University | Boonseng O.,Rayong Field Crops Research Center | And 5 more authors.
Plant Biology

Starch pasting viscosity is an important quality trait in cassava (Manihot esculenta Crantz) cultivars. The aim here was to identify loci and candidate genes associated with the starch pasting viscosity. Quantitative trait loci (QTL) mapping for seven pasting viscosity parameters was carried out using 100 lines of an F1 mapping population from a cross between two cassava cultivars Huay Bong 60 and Hanatee. Starch samples were obtained from roots of cassava grown in 2008 and 2009 at Rayong, and in 2009 at Lop Buri province, Thailand. The traits showed continuous distribution among the F1 progeny with transgressive variation. Fifteen QTL were identified from mean trait data, with Logarithm of Odds (LOD) values from 2.77-13.01 and phenotype variations explained (PVE) from10.0-48.4%. In addition, 48 QTL were identified in separate environments. The LOD values ranged from 2.55-8.68 and explained 6.6-43.7% of phenotype variation. The loci were located on 19 linkage groups. The most important QTL for pasting temperature (PT) (qPT.1LG1) from mean trait values showed largest effect with highest LOD value (13.01) and PVE (48.4%). The QTL co-localised with PT and pasting time (PTi) loci that were identified in separate environments. Candidate genes were identified within the QTL peak regions. However, the major genes of interest, encoding the family of glycosyl or glucosyl transferases and hydrolases, were located at the periphery of QTL peaks. The loci identified could be effectively applied in breeding programmes to improve cassava starch quality. Alleles of candidate genes should be further studied in order to better understand their effects on starch quality traits. © 2013 German Botanical Society and The Royal Botanical Society of the Netherlands. Source

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