Effects of sucrose on development of cultures of some accessions of Dioscorea spp

The method of micropropagation was used to establish nodal cultures of D. rotundata, D. alata, D. praehensilis, D. dumetorum, D. esculenta and D. cayenensis on 6 ml or 8 ml MS medium supplemented with 2.5 μM kinetin. The cultures were incubated at 28ºC and 16 h photoperiod at 4500 Lux, on 3%, 5%, 7%, and 10% sucrose, with a sucrose-free medium as control in a CRD design. Generally, increase in sucrose concentration significantly (P≤0.05) enhanced the rate of survival and growth of the Dioscorea cultures. Mean shoot height and root formation were high-est in D. rotundata cultures on full-strength MS medium containing 10% sucrose compared to half-strength MS medium. However, 7% sucrose stimulated the highest rate of vigorous growth of healthy cultures, leaf formation and plantlet production among the Dioscorea spp. It also enhanced development of bud primordia to regenerate plantlets in D. rotundata meristem cultures. There was a positive correlation (r=0.983) between the rate of leaf production and shoot height. It was evident that 5% and 7% sucrose were more effective for culture development towards multiple bud, lateral and terminal bud differentiation in most of the Dioscorea spp as well as re-duced the duration for plantlet development and the demand for regular sub-culturing since the growth phase of cultures could be prolonged. However, D. esculenta cultures appeared to grow better on 3% sucrose than the other Dioscorea spp tested, suggesting that the optimum sucrose concentration required to initiate and establish culture differs significantly among various Dioscorea species

Is there Avocado sunblotch Viroid in Ghana?

The prevalence of Avocado sunblotch Viroid (ASBVd) among Ghanaian accessions was investigated. One hundred and eighty five (185) symptomatic and symptomless avocado trees were tested by DIGdotblot hybridization for the presence of ASBVd. One (0.01%) accession tested positive, 158 (85.8%) tested negative, while the results of the remaining 26 (14.1%) were inconclusive (herein referred to as“possible carriers”). Only one true symptomless carrier of the viroid was identified. The viroid showed no geographical or topographical preferences. The positive and ”possible carriers” were evenly distributed around the country. The incidence of the disease in Ghana was found to be very low and hence steps must be taken to eradicate it and maintain a clean industry

Evaluation of agro-morphological diversity in some segregating lines of cowpea (Vigna un-guiculata L. WALP)

A study was conducted to evaluate agro-morphological characteristics of some segregating lines of eight accessions of cowpea (Vigna unguiculata L. Walp.) using seeds from a first cycle generation progenies. Eight cowpea accessions [GH36841 (red), GH3684B4 (mottle brown), GH 3684B5 (mottle brown), GH3684A2 (red), GH3684C2 (red), GHUCO1BL (black), GH3684BL, (black) and GH7184BL (black with spots)] and an out group IT97K-499-35 (white) were culti-vated under field conditions. Twenty three agro-morphological traits were assessed for thirty three lines of cowpea. A dendrogram generated using 23 agro-morphological characters distinguished the cowpea accessions into two lineages, with the out-group being the most diverse. Generally, morphological polymorphism revealed discriminations among the cowpea accessions studied. Seed weight, plant height, number of branches, length of branches, number of leaves, number of peduncles, length of peduncles and number of seeds per pod as well as number of pods per plant differed significantly (p ≤ 0.05) among the cowpea accessions. The evidence showed that there were variations in morphological characteristics expressed by the cowpea ac-cessions and these were segregations in one trait or the other. The cowpea accession GH UCO1BL is possibly a cross between IT97K-499-35 x SARC-LO2. The segregation lines of GH 3684 had the greatest diversity probably due to genotype environment interactions

Direct and Continuous Measurement of Phospholipase D Activities Using the Chelation-Enhanced Fluorescence Property of 8-Hydroxyquinoline

International audienc

Expression and Purification of Recombinant Vigna unguiculata Phospholipase D in Pichia pastoris for Structural Studies.

International audienceThe production of pure enzymes in high quantities is a proven strategy to study the catalytic mechanism as well as the solving of structure at the atomic scale for therapeutic or industrial purposes. Phospholipase D (PLD, EC 3.1.4.4) is found in a wide majority of living organisms and has been shown to be involved in signal transduction, vesicle trafficking, and membrane metabolism processes. Located at the membrane-cytoplasm interface, plant PLDs are soluble but also bear an evident hydrophobic aspect making challenging its expression and its purification in large quantity. So far there is no high-resolution three-dimensional structure for a eukaryotic PLD. The protocols herein describe the cloning of the eukaryotic recombinant PLDα of Vigna unguiculata (cowpea) into the yeast expression system Pichia pastoris and its two-step purification process. This allowed us to purify to homogeneity hundreds of micrograms of highly pure protein to conduct in fine structural studies