Genetic mapping of semi-polar metabolites in pepper fruits (Capsicum sp.): towards unravelling the molecular regulation of flavonoid quantitative trait loci

Untargeted LCMS profiling of semi-polar metabolites followed by metabolite quantitative trait locus (mQTL) analysis was performed in ripe pepper fruits of 113 F2 plants derived from a cross between Capsicum annuum AC1979 (no. 19) and Capsicum chinense No. 4661 Selection (no. 18). The parental accessions were selected based on their variation in fruit morphological characteristics and fruit content of some target phytonutrients. Clear segregation of fruit colour and fruit metabolite profiles was observed in the F2 population. The F2 plants formed three clusters based on their metabolite profiles. Of the total of 542 metabolites, 52 could be annotated, including a range of flavonoids, such as flavone C-glycosides, flavonol O-glycosides and naringenin chalcone, as well as several phenylpropanoids, a capsaicin analogue, fatty acid derivatives and amino acid derivatives. Interval mapping revealed 279 mQTLs in total. Two mQTL hotspots were found on chromosome 9. These two chromosomal regions regulated the relative levels of 35 and 103 metabolites, respectively. Analysis also revealed an mQTL for a capsaicin analogue, located on chromosome 7. Confirmation of flavonoid mQTLs using a set of six flavonoid candidate gene markers and their corresponding expression data (expression QTLs) indicated the Ca-MYB12 transcription factor gene on chromosome 1 and the gene encoding flavone synthase (FS-2) on chromosome 6 as likely causative genes determining the variation in naringenin chalcone and flavone C-glycosides, respectively, in this population. The combination of large-scale metabolite profiling and QTL analysis provided valuable insight into the genomic regions and genes important for the production of (secondary) metabolites in pepper fruit. This will impact breeding strategies aimed at optimising the content of specific metabolites in pepper frui

Field testing and exploitation of genetically modified cassava with low-amylose or amylose-free starch in Indonesia

The development and testing in the field of genetically modified -so called- orphan crops like cassava in tropical countries is still in its infancy, despite the fact that cassava is not only used for food and feed but is also an important industrial crop. As traditional breeding of cassava is difficult (allodiploid, vegetatively propagated, outbreeding species) it is an ideal crop for improvement through genetic modification. We here report on the results of production and field testing of genetically modified low-amylose transformants of commercial cassava variety Adira4 in Indonesia. Twenty four transformants were produced and selected in the Netherlands based on phenotypic and molecular analyses. Nodal cuttings of these plants were sent to Indonesia where they were grown under biosafety conditions. After two screenhouse tests 15 transformants remained for a field trial. The tuberous root yield of 10 transformants was not significantly different from the control. Starch from transformants in which amylose was very low or absent showed all physical and rheological properties as expected from amylose-free cassava starch. The improved functionality of the starch was shown for an adipate acetate starch which was made into a tomato sauce. This is the first account of a field trial with transgenic cassava which shows that by using genetic modification it is possible to obtain low-amylose cassava plants with commercial potential with good root yield and starch quality

Somatic embryogenesis and plant regeneration in cassava

SIGLEAvailable from British Library Document Supply Centre- DSC:DX93721 / BLDSC - British Library Document Supply CentreGBUnited Kingdo

Establishment of biochemical genetic markers techniques for Shorea spp.- tropical forest tree species

Two types of materials, six compositions of extractions buffer and three electrophoretic buffer system were studied to establish optimum procedures for obtaining good resolution of 14 enzyme systems in 12 species of Shorea which belongs to the family of Dipterocarpaceace. Thirteen (13) enzyme systems could be detected in S.seminis and S.parvifolia, 10 of that in S. laevis, S.leprosula, S.selanica, S.aquminata, S.gibbosa, S.palembanica, and S.pauciflora, 7 of that in S.paquetiana and 4 of that in S.johorensis. The use of W extraction buffer in combination with the use of MC electrophoretic buffer systems led to the best results of using twigs were almost the same as leaves, better resolution of certain enzyme system such as PER, PGI, SDH, and MDH was obtained from leaves. Results obtained from this study would benefit further study on various aspects such as genetic diversity assessment of Shorea species and genetic improvement

Development of RAPD protocol for Shorea laevis

To study genetic diversity of Shorea leavis using RAPD, optimization of the method is necessary to obtain good resolution. Two kinds of PCR conditions, emplyoing 109 random primers of Kit B, C,E, F, G and H from Operon Technology Ltd. were tried on S. laevis DNA extracted by CTAB miniprep method. It was found out that the most suitable PCR condition for S. laevis is condition, which require more PCR cycles, compunded with higher MgCl2, concentration, employed more DNA sample and primer. Further survey using two primers on 110 individuals from natural habitat showed that S.laevis has considerable amount of genetic variatio

Characterization of cassava starch attributes of different genotypes

The genetic variation of starch of Indonesian cassava genotypes with various morphological characteristics of roots and eco-geographical origin was characterized and compared. The morphological characteristics of the roots of 71 collected cassava genotypes were classified into yellow and white for flesh colors, purple, pink, light brown, yellow, cream and white for cortex colors, dark brown and light brown for external colors, as well as conical and cylindrical for root shapes. Starch samples extracted from 17 genotypes showed that the amylose content varied from 17.1 to 21.3%. The mean particle size was around 7.3 to 9.7 mu m, and the gelatinization onset temperature was in the range of 63.5-66.1 degrees C. Seven genotypes were analyzed in more detail for their physicochemical properties. The granule size distribution was in the range of 3.2 mu m to 17.6 mu m for d10 and d90 (i.e. 90% of the granules were bigger than 3.2 pm and 90% were smaller than 17.6 mu m), respectively, and the median granule size was around 7.7-10.8 mu m. The gelatinization temperatures of the different cassava starches were in the range of 63.5-66.1 degrees C. The phosphate content varied from 23.5-25.3 nmol/mg starch. Particle size distribution and gelatinization temperature as well as the phosphate content of the starch of the selected seven genotypes also showed minor differences among the genotypes. The swelling power of all starches showed some differences between genotypes, but the profiles were similar. The opacity of starch of all the tested genotypes increased twofold within six days, but no large differences among the different genotypes could be detected except for the genotype Ketan. Strength of the gels, which are indicated with force, adhesiveness, cohesiveness, and elasticity, also did not show large differences

Metabolite biodiversity in pepper (Capsicum) fruits of thirty-two diverse accessions : variation in health-related compounds and impliciations for breeding

A comprehensive study on morphology and biochemical compounds of 32 Capsicum spp. accessions has been performed. Accessions represented four pepper species, Capsicum annuum, Capsicum frutescens, Capsicum chinense and Capsicum baccatum which were selected by their variation in morphological characters such as fruit color, pungency and origin. Major metabolites in fruits of pepper, carotenoids, capsaicinoids (pungency), flavonoid glycosides, and vitamins C and E were analyzed and quantified by high performance liquid chromatography. The results showed that composition and level of metabolites in fruits varied greatly between accessions and was independent of species and geographical location. Fruit color was determined by the accumulation of specific carotenoids leading to salmon, yellow, orange, red and brown colored fruits. Levels of both O- and C-glycosides of quercetin, luteolin and apigenin varied strongly between accessions. All non-pungent accessions were devoid of capsaicins, whereas capsaicinoid levels ranged from 0.07 up to 80 mg/100 g fr. wt. in fruit pericarp. In general, pungent accessions accumulated the highest capsaicinoid levels in placenta plus seed tissue compared to pericarp. The non-pungent capsaicinoid analogs, capsiates, could be detected at low levels in some pungent accessions. All accessions accumulated high levels of vitamin C, up to 200 mg/100 g fr. wt. The highest vitamin E concentration found was 16 mg/100 g fr. wt. Based on these metabolic data, five accessions were selected for further metabolic and molecular analysis, in order to isolate key genes involved in the production of these compounds and to assist future breeding programs aimed at optimizing the levels of health-related compounds in pepper fruit