Direct use of spent mushroom substrate from Pleurotus pulmonarius as a readily delignified feedstock for cellulase production

The feasibility of spent mushroom substrate (SMS) as an alternative fermentation feedstock for cellulase production has been demonstrated in this work. Utilization of SMS as a substrate has been attempted widely due to its high cellulose content and readily available in smaller particle size. On top of that, the availability of delignified SMS by the action of Pleurotus pulmonarius during mushroom cultivation offers another benefit to its use whereby no chemical pretreatment would be required prior to fermentation. The recovery of crude laccase and manganese peroxidase from delignified SMS were found to be 3 and 1.4 U/g, respectively. Further to this, the cellulase production from SMS by Trichoderma asperellum UPM 1 under solid state fermentation was optimized by applying central composite design, resulted in increment of 1.4-fold in CMCase (171.21 U/g) and 1.5-fold in β-glucosidase (6.83 U/g), with the optimum temperature of 27.5 °C, initial moisture content 81% and initial pH of fermentation 4.5. Therefore, this study showed that the direct utilization of SMS is feasible for promising cellulase production by T. asperellum UPM 1

The potential of shifting recombination hotspots to increase genetic gain in livestock breeding

International audienceAbstractBackgroundThis study uses simulation to explore and quantify the potential effect of shifting recombination hotspots on genetic gain in livestock breeding programs.MethodsWe simulated three scenarios that differed in the locations of quantitative trait nucleotides (QTN) and recombination hotspots in the genome. In scenario 1, QTN were randomly distributed along the chromosomes and recombination was restricted to occur within specific genomic regions (i.e. recombination hotspots). In the other two scenarios, both QTN and recombination hotspots were located in specific regions, but differed in whether the QTN occurred outside of (scenario 2) or inside (scenario 3) recombination hotspots. We split each chromosome into 250, 500 or 1000 regions per chromosome of which 10% were recombination hotspots and/or contained QTN. The breeding program was run for 21 generations of selection, after which recombination hotspot regions were kept the same or were shifted to adjacent regions for a further 80 generations of selection. We evaluated the effect of shifting recombination hotspots on genetic gain, genetic variance and genic variance.ResultsOur results show that shifting recombination hotspots reduced the decline of genetic and genic variance by releasing standing allelic variation in the form of new allele combinations. This in turn resulted in larger increases in genetic gain. However, the benefit of shifting recombination hotspots for increased genetic gain was only observed when QTN were initially outside recombination hotspots. If QTN were initially inside recombination hotspots then shifting them decreased genetic gain.DiscussionShifting recombination hotspots to regions of the genome where recombination had not occurred for 21 generations of selection (i.e. recombination deserts) released more of the standing allelic variation available in each generation and thus increased genetic gain. However, whether and how much increase in genetic gain was achieved by shifting recombination hotspots depended on the distribution of QTN in the genome, the number of recombination hotspots and whether QTN were initially inside or outside recombination hotspots.ConclusionsOur findings show future scope for targeted modification of recombination hotspots e.g. through changes in zinc-finger motifs of the PRDM9 protein to increase genetic gain in production species

Analysis of genome-wide DNA arrays reveals the genomic population structure and diversity in autochthonous Greek goat breeds

Goats play an important role in the livestock sector in Greece. The national herd consists mainly of two indigenous breeds, the Eghoria and Skopelos. Here, we report the population structure and genomic profiles of these two native goat breeds using Illumina's Goat SNP50 BeadChip. Moreover, we present a panel of candidate markers acquired using different genetic models for breed discrimination. Quality control on the initial dataset resulted in 48,841 SNPs kept for downstream analysis. Principal component and admixture analyses were applied to assess population structure. The rate of inbreeding within breed was evaluated based on the distribution of runs of homozygosity in the genome and respective coefficients, the genomic relationship matrix, the patterns of linkage disequilibrium, and the historic effective population size. Results showed that both breeds exhibit high levels of genetic diversity. Level of inbreeding between the two breeds estimated by the Wright's fixation index FST was low (Fst = 0.04362), indicating the existence of a weak genetic differentiation between them. In addition, grouping of farms according to their geographical locations was observed. This study presents for the first time a genome-based analysis on the genetic structure of the two indigenous Greek goat breeds and identifies markers that can be potentially exploited in future selective breeding programs for traceability purposes, targeted genetic improvement schemes and conservation strategies

A novel approach for simultaneous detection of<i style=""> Citrus yellow mosaic virus</i> and Citrus greening bacterium by multiplex polymerase chain reaction

528-533A method of multiplex polymerase chain reaction (PCR) was developed for the simultaneous detection of Citrus yellow mosaic virus (CYMV) and fastidious Citrus greening bacterium, Candidatus Liberibacter asiaticus (CLa) in sweet orange trees. Initially total DNA from individual CLa and CYMV infected citrus plants were mixed and both pathogens were detected simultaneously by multiplex PCR. Subsequently, both pathogens were detected from the total DNA obtained after mixing midribs of CLa-infected and CYMV-infected leaf lamina of the sweet oranges. The finally adopted multiplex PCR protocol simultaneously detected CLa and CYMV from the total DNA extracted from the midrib of leaf of citrus plants infected by both the pathogens. Thus, the present protocol demonstrated the presence of mixed infections of CLa and CYMV in citrus orchards trees. The technique would also prove highly useful in disease survey, nursery certification and quarantine applications

Effective management of legumes for maximizing biological nitrogen fixation and other benefits

The importance of legumes in sustainable crop production systems is well recognized. In the rice and wheat cropping systems of the Indo-Gangetic Plain, several legumes such as chickpea, lentil, pea, soybean, groundnut, mung bean, black gram, cowpea, and pigeonpea are grown depending upon rainfall pattern, water resources, geo-morphological features, domestic needs, and cropping systems. In the rice-wheat sequential cropping, short-duration legumes such as mung bean and cowpea offer great promise, but at present their adoption is negligible due to several management and social constraints. The productivity of legumes in general is low due to low genetic yield potential and sub-optimal management practices. Several studies under the All India Coordinated Pulses Improvement Project (AICPIP) have clearly shown that with better management, the present level of productivity of most of the legumes could be almost doubled. Tillage, planting time, plant population, plant nutrition, irrigation, and weed management considerably influence biological nitrogen fixation and productivity of legumes and therefore their management needs to be optimized for the agroecological regions and production systems. A decrease in nodulation and nitrogenase activity in many legumes has been observed due to late planting, high plant population, drought, excess moisture, high dose of mineral nitrogen, and soil application of herbicides (oxyfluorfen, linuron, oxadiazon, and metribuzin). Enhanced nodulation and higher yield have been reported with timely planting, application of 20-40 kg sulfur ha-1 along with 17.5-26.5 kg phosphorus ha-1, dual inoculation with Rhizobium and vesicular-arbuscular mycorrhizal fungi, irrigation at critical growth stages under moisture stress conditions, and efficient weed management. Deficiency of micronutrients such as zinc, molybdenum, and iron, which impair nodulation and grain yield, have been observed in some of the area