Production of lytic enzymes by Trichoderma isolates during in vitro antagonism with Aspergillus niger, the causal agent of collar rot of peanut

Twelve isolates of Trichoderma (six of T. harzianum, five of T. viride, one of T. virens), which reduced variably the incidence of collar rot disease caused in peanut by Aspergillus niger Van Tieghem, were evaluated for their potential to produce lytic enzymes during in vitro antagonism. T. viride 60 inhibited highest (86.2%) growth of test fungus followed by T. harzianum 2J (80.4%) at 6 days after inoculation (DAI) on PDA media. The specific activities of chitinase, â-1,3-glucanase and protease were 11, 3.46 and 9 folds higher in T6 antagonist (T. viride 60 and A. niger interactions) followed by 8.72, 2.85 and 9 folds in T8 antagonist (T. harzianum 2J and A. niger interactions), respectively, compared to the activity produced by control petri plate T13 (A. niger alone) at 6 DAI. Activity of these lytic enzymes induced in antagonists' plates comprises the growth of Trichoderma isolates. However, cellulase and poly galacturonase were found least amount in these antagonists treatment. A significant positive correlation (p=0.01) between percentage growth inhibition of test fungus and lytic enzymes - (chitinase, â-1,3-glucanase and protease) in the culture medium of antagonist treatment established a relationship to inhibit growth of fungal pathogen by increasing the levels of these enzymes. Among the Trichoderma isolates, T. viride 60 was found best strain to be used in biological control of plant pathogen A. niger.

Cloning and expression analysis of peanut (Arachis hypogaea L. ) CHI gene

Chalcone isomerase (CHI) is the key enzyme that catalyzes chalcone into (2S)-flavanol or (2S)-5-desoxidation flavanol. The full length cDNA (1050 bp) of AhCHI (Arachis hypogaea CHI gene) was cloned by large scale EST sequencing using a peanut immature seed cDNA library. Sequence analysis results indicated that it was a type I CHI gene (with the accession number JN660794). The ORF of AhCHI was 768 bp, encoding a peptide of 255 amino acids with a pI of 5.189. Sequence alignment showed that the coding region of AhCHI gene is highly conserved to compare with CHI genes from other plant species. Peanut cDNA microarray and semi-quantitative RT-PCR analysis indicated that AhCHI was highly expressed in pegs. The expression level in flower and root was higher than the expression level in stem and leaf. AhCHI was expressed in a high level in seeds with a purple seed coat, while its expression was low in seed with white seed coat.

Sodium azide mutagenesis resulted in a peanut plant with elevated oleate content

Screening of peanut seeds resulting from 0.39 percent sodium azide treatment with NIRS calibration equation for bulk seed samples identified a plant with more than 60 percent oleate. Oleate content in individual seeds of the plant, as predicted by NIRS calibration equation for intact single peanut seeds, ranged from 50.05 percent ~ 68.69 percent. Three seeds with >60 percent oleate thus identified were further confirmed by gas chromatography. Multiple sequence alignments of the FAD2B gene from Huayu 22 (wild type) and peanut seeds with elevated oleate (mutant type) revealed a C281T transition in the coding region causing an I94T substitution in the oleoyl-PC desaturase, which may be responsible for reduction in the enzyme activity.

Calidad nutricional en variedades de maní tegua y granoleico: estabilidad y aceptabilidad de sus aceites: efecto de su ingesta sobre niveles de lípidos plasmáticos en ratones / Nutritional quality tegua peanut varieties and granola: stability and acceptability of their oils: effect of intake on plasma lipid levels in mice

El maní es una de las principales oleaginosas del mundo y Argentina es uno de sus principales productores y exportadores. En la provincia de Córdoba se concentra el 94,63% del cultivo. Las variedades del tipo Runner: cultivar Tegua y Granoleico, presentan perfiles muy diferentes de ácidos grasos. El alto contenido en ácido graso nonoinsaturado en los productos derivados de maní lo hace muy estable ante los procesos de oxidación y altamente beneficioso para la prevención de enfermedades cardiovasculares. El objetivo de este estudio fue valorar la calidad nutricional de los maníes de las variedades Tegua (T) y Granoleico (GO) mediante el análisis de la estabilidad y aceptabilidad de sus aceites y en especial la evaluación de sus efectos sobre los lípidos plasmáticos en ratones Albino swiss. Materiales y métodos: Se utilizaron granos de maní de las variedades citadas, se determinaron macronutrientes, humedad, minerales y tocoferoles. Se obtuvo aceite de maní por método de prensado en frío. Se evaluó la composición de ácidos grasos y se la comparó con las de otros aceites vegetales (girasol, maíz, soja, canola y oliva). Estabilidad. Se analizaron índice de peróxido(IP), índice de p‐anisidina (IA) y dienos conjugados (DC) en aceites puros (T‐GO 100‐0 y T‐GO 0‐ 100) y en mezclas de las variedades: al 25% (T‐GO 75‐25), al 50% (T‐GO 50‐50) y al 75% (T‐GO 25‐ 75) almacenados en estufa a 60 ºC. Lípidos plasmáticos. Se realizó un modelo experimental conratones Albino swiss (n=81), se utilizaron dietas semisintéticas con la adición de aceites refinados de girasol, oliva, maní GO y dieta comercial. Se controló el peso semanalmente. A los 77 y 126 días de tratamiento se los sacrificó y midieron los lípidos plasmáticos: triglicéridos, colesterol total, cHDL y cLDL. Análisis sensorial. Se comparó la aceptabilidad de los aceites de maní, girasol y oliva extravirgen. Estadística. Varianza, test de LSD Fisher (α=0,05) y regresión.

A rapid and cheap protocol for preparation of PCR templates in peanut

This paper describes a simple, low cost and reliable DNA template preparation protocol for polymerase chain reaction (PCR) using immature leaves from peanut seeds or leaves from field-grown plants. The technique may find wide utility in studies involving PCR-based molecular markers, rapid screening for transformants and gene cloning.

Influence of selected insecticides on phosphatase activity in groundnut (Arachis hypogeae L.) soils.

Selected insecticides, Chloropyrifos, Dichlorovos, Methyl parathion, Phorate and Methomyl, at concentrations ranging from 0 to 10 kg ha(-1) were tested for their non-target effects towards activity of phosphatases in two soils. In soil samples receiving 2.5 kg ha(-1) of the insecticides Dichlorovos, Phorate and Methomyl and also in soil samples receiving 5.0 kg ha(-1) of the insecticides, Chloropyrifos and Methyl parathion, the activity of phosphatase was significantly more at 20 days period of incubation and decreased progressively with increasing period of incubation.

A soluble preparation from developing groundnut seeds (Arachis hypogaea) catalyzes de novo synthesis of long chain fatty acids.

A 100,000 x g supernatant fraction prepared from developing groundnut seeds (30-35 days after flowering) catalyzed the synthesis of fatty acids from [l-14C]acetate at a rate of 120nmoles of acetate incorporated per hr per gram fresh weight of tissue. 90% of this incorporated label was associated with fatty acids. The major fatty acids formed were stearic- (77%) and palmitic acids (14%) with 4% of oleic acid. The fatty acid synthetase activity was stable when stored at 0-4 degrees C for at least fifteen days. It is concluded from these results that acetyl-coA carboxylase and all the enzymes of fatty acid synthetase from developing groundnut seeds are soluble.