Assessment of the profile of free amino acids and reducing sugars of cacao beans from local Cameroonian Trinitario (SNK varieties) and Forastero (TIKO varieties) using fermentation-like incubation

This study investigated the profile of cacao beans from the local Cameroonian Trinitario (SNK) and Forastero (TIKO) in terms of aroma precursors (amino acids and reducing sugars) through fermentation-like incubations. Treatments consisted of incubating beans in acetic acid, 100 mmol/L for two days followed by 200 mmol/L of acetic acid for three days (Treatment T1) and in 100 mmol/L of lactic acid for two days followed by 200 mmol/L of acetic acid for three days (Treatment T2). Both treatments resulted in an increase of free amino acids content by 1.5 - 2.5 times in SNK and TIKO varieties. The ratio of the hydrophobic amino acids over the rest of amino acids showed the preponderance of T1 on the hydrophobic amino acids released in TIKO while in the SNK, some varieties displayed the highest ratio in T2. Glucose and fructose content in TIKO and SNK beans increased 2 to 3 times during incubation. Galactose and raf-finose were found in unfermented beans. After incubation, raffinose was missing while at the same time a raise of galactose content could be seen. These results highlighted that acidification remains the factor inducing the releasing of free hydrophobic amino acids, the genotype being less involved

Domestication syndrome is investigated by proteomic analysis between cultivated cassava (Manihot esculenta Crantz) and its wild relatives

Cassava (Manihot esculenta Crantz) wild relatives remain a largely untapped potential for genetic improvement. However, the domestication syndrome phenomena from wild species to cultivated cassava remain poorly understood. The analysis of leaf anatomy and photosynthetic activity showed significantly different between cassava cultivars SC205, SC8 and wild relative M. esculenta ssp. Flabellifolia (W14). The dry matter, starch and amylose contents in the storage roots of cassava cultivars were significantly more than that in wild species. In order to further reveal the differences in photosynthesis and starch accumulation of cultivars and wild species, the globally differential proteins between cassava SC205, SC8 and W14 were analyzed using 2-DE in combination with MALDI-TOF tandem mass spectrometry. A total of 175 and 304 proteins in leaves and storage roots were identified, respectively. Of these, 122 and 127 common proteins in leaves and storage roots were detected in SC205, SC8 and W14, respectively. There were 11, 2 and 2 unique proteins in leaves, as well as 58, 9 and 12 unique proteins in storage roots for W14, SC205 and SC8, respectively, indicating proteomic changes in leaves and storage roots between cultivated cassava and its wild relatives. These proteins and their differential regulation across plants of contrasting leaf morphology, leaf anatomy pattern and photosynthetic related parameters and starch content could contribute to the footprinting of cassava domestication syndrome. We conclude that these global protein data would be of great value to detect the key gene groups related to cassava selection in the domestication syndrome phenomena

Proteomic analysis of injured storage roots in cassava (<i>Manihot esculenta</i> Crantz) under postharvest physiological deterioration - Fig 7

<p><b>The expressed levels of genes including <i>MeHSC70-1</i> (A), <i>MeCPN60B</i> (B), <i>MeCPN20B</i> (C), <i>MeCaM</i> (D), <i>MeAPX</i> (E), <i>MeRas</i> (F) and <i>MeENO</i> (G) in cassava injured storage roots using qRT-PCR.</b> Each bar represents the mean of three independent replicates with standard error. Different letters on the columns indicate the statistical difference at p< 0.05 by SPSS to Duncan’s multiple comparison tests.</p

Biological networks generated from a combination of 19 differential proteins involved with photosynthesis (a) in cassava leaves and 11 differential proteins related with starch accumulation (b) in storage roots.

<p>Nineteen differentially up-(a red and upward arrow) and down-(a blue and downward arrow) regulated proteins including ribulose-bisphosphate carboxylase, phosphoribulokinase, ribulose- phosphate-3-epimerase, ribose-5-phosphate isomerase, RCA, transketolase, ATP synthase subunit beta, phosphoglycerate kinase, malate dehydrogenase, alcohol dehydrogenase and enoyl-ACP reductase, ethylene receptor, peroxiredoxin, heat shock protein, glucokinase, glutaredoxin, superoxide dismutase, beta-glucosidase and APX2 in cassava cultivars were used to generate a protein-protein interaction network about photosynthesis through Pathway Studio analysis. Eleven differentially up-(a red and upward arrow) and down-(a blue and downward arrow) regulated proteins including succinate dehydrogenase, dihydrolipoyllysine-residue succinyltransferase, UDP- glucosyltrans-ferase, transaldolase, uroporphyrinogen decarboxylase, pectinesterase, triosephosphate isomerase, N-acetyltransferase, aldo-keto reductase, annexin and pyruvate dehydrogenase in cassava cultivars were used to generate a protein-protein interaction network regarding starch accumulation through Pathway Studio analysis. Regulation is marked as an arrow with R, Chemical Reaction as an arrow with C, MolTransport as an arrow with M, Expression as an arrow with E and Binding as an arrow without any marks. The entity table and relation table were presented in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0152154#pone.0152154.s006" target="_blank">S1</a> and <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0152154#pone.0152154.s007" target="_blank">S2</a> Tables.</p

Venn diagrams of 175 proteins identified (a) and their functional classification (b) in leaves of SC205, SC8 and W14.

<p>Functional categorization was performed according to the MIPS database (<a href="http://mips.gsf.de" target="_blank">http://mips.gsf.de</a>).</p