Long-term monoculture reduces the symbiotic rhizobial biodiversity of peanut.

Long-term monoculture (LTM) decreases the yield and quality of peanut, even resulting in changes in the microbial community. However, the effect of LTM on peanut rhizobial communities has still not been elucidated. In this study, we isolated and characterized peanut rhizobia from 6 sampling plots with different monoculture cropping durations.

Long-term continuously monocropped peanut significantly changed the abundance and composition of soil bacterial communities.

Soil sickness is the progressive loss of soil quality due to continuous monocropping. The bacterial populations are critical to sustaining agroecosystems, but their responses to long-term peanut monocropping have not been determined. In this study, based on a previously constructed gradient of continuous monocropped plots, we tracked the detailed feedback responses of soil bacteria to short- and long-term continuous monocropping of four different peanut varieties using high-throughput sequencing techniques.

[Directional breeding of high oil content peanut variety Yuhua 9 by in vitro mutagenesis and screening].

Leaf water potential of peanut subjected to drought stress is positively related to the oil content of peanut kernels. The aim of this study was to directly screen the high oil mutants of peanut and create the new peanut varieties using hydroxyproline as water potential regulator. In vitro mutagenesis was carried out with the embryonic leaflets of peanut variety Huayu 20 as explants and pingyangmycin as a mutagen added into the somatic embryo formation medium.

Sequencing of Cultivated Peanut, Arachis hypogaea, Yields Insights into Genome Evolution and Oil Improvement.

Cultivated peanut (Arachis hypogaea) is an allotetraploid crop planted in Asia, Africa, and America for edible oil and protein. To explore the origins and consequences of tetraploidy, we sequenced the allotetraploid A. hypogaea genome and compared it with the related diploid Arachis duranensis and Arachis ipaensis genomes.

Influence of Peanut Cultivars and Environmental Conditions on the Diversity and Community Composition of Pod Rot Soil Fungi in China.

Peanut yield and quality are seriously affected by pod rot pathogens worldwide, especially in China in recent years. The goals of this study are to analyze the structure of fungal communities of peanut pod rot in soil in three peanut cultivars and the correlation of pod rot with environmental variables using 454 pyrosequencing. A total of 46,723 internal transcribed spacer high-quality sequences were obtained and grouped into 1,706 operational taxonomic units at the 97% similarity cut-off level.

Isolation and functional analysis of fatty acid desaturase genes from peanut (Arachis hypogaea L.).

Background: Fatty acid desaturases are enzymes that introduce double bonds into fatty acyl chains. Extensive studies of fatty acid desaturases have been done in many plants. However, less is known about the diversity of this gene family in peanut (Arachis hypogaea L.

Transcriptome-wide sequencing provides insights into geocarpy in peanut (Arachis hypogaea L.).

A characteristic feature of peanut is the subterranean fructification, geocarpy, in which the gynophore ('peg'), a specialized organ that transitions from upward growth habit to downward outgrowth upon fertilization, drives the developing pod into the soil for subsequent development underground. As a step towards understanding this phenomenon, we explore the developmental dynamics of the peanut pod transcriptome at 11 successive stages. We identified 110 217 transcripts across developmental stages and quantified their abundance along a pod developmental gradient in pod wall.

Generation of peanut mutants by fast neutron irradiation combined with in vitro culture.

Induced mutations have played an important role in the development of new plant varieties. In this study, we investigated the effects of fast neutron irradiation on somatic embryogenesis combined with plant regeneration in embryonic leaflet culture to develop new peanut (Arachis hypogaea L.) germplasm for breeding.

Cloning and functional analysis of three diacylglycerol acyltransferase genes from peanut (Arachis hypogaea L.).

Diacylglycerol acyltransferase (DGAT) catalyzes the final and only committed acylation step in the synthesis of triacylglycerols. In this study, three novel AhDGATs genes were identified and isolated from peanut. Quantitative real-time RT-PCR analysis indicated that the AhDGAT1-2 transcript was more abundant in roots, seeds, and cotyledons, whereas the transcript abundances of AhDGAT1-1 and AhDGAT3-3 were higher in flowers than in the other tissues examined.

Dynamic succession of soil bacterial community during continuous cropping of peanut (Arachis hypogaea L.).

Plant health and soil fertility are affected by plant-microbial interactions in soils. Peanut is an important oil crop worldwide and shows considerable adaptability, but growth and yield are negatively affected by continuous cropping. In this study, 16S rRNA gene clone library analyses were used to study the succession of soil bacterial communities under continuous peanut cultivation.

Sequence similarity and functional comparisons of pheromone receptor orthologs in two closely related Helicoverpa species.

The olfactory system of moth species in subfamily Heliothinae is an attractive model to study the evolution of the pheromone reception because they show distinct differentiation in sex pheromone components or ratios that activate pheromone receptors (PRs). However, functional assessment of PRs in closely related species remains largely untried. Here we present a special cloning strategy to isolate full-length cDNAs encoding candidate odorant receptors (ORs) from Helicoverpa armigera (Harm) and Helicoverpa assulta (Hass) on the basis of Heliothis virescens ORs, and investigate the functional properties of PRs to determine how the evolution of moth PRs contribute to intraspecific mating choice and speciation extension.

Identification of 30 MYB transcription factor genes and analysis of their expression during abiotic stress in peanut (Arachis hypogaea L.).

The MYB superfamily constitutes one of the most abundant groups of transcription factors and plays central roles in developmental processes and defense responses in plants. In the work described in this article, 30 unique peanut MYB genes that contained full-length cDNA sequences were isolated. The 30 genes were grouped into three categories: one R1R2R3-MYB, nine R2R3-MYBs and 20 MYB-related members.

Characterization of peanut germin-like proteins, AhGLPs in plant development and defense.

Background: Germin-like superfamily members are ubiquitously expressed in various plant species and play important roles in plant development and defense. Although several GLPs have been identified in peanut (Arachis hypogaea L.), their roles in development and defense remain unknown.

Transcriptome identification of the resistance-associated genes (RAGs) to Aspergillus flavus infection in pre-harvested peanut (Arachis hypogaea).

Pre-harvest aflatoxin contamination caused by Aspergillus favus is a major concern in peanut. However, little is known about the resistance mechanism, so the incorporation of resistance into cultivars with commercially-acceptable genetic background has been slowed. To identify resistance-associated genes potentially underlying the resistance mechanism, we compared transcriptome profiles in resistant and susceptible peanut genotypes under three different treatments: well watered, drought stress and both A.

Deep sequencing analysis of the transcriptomes of peanut aerial and subterranean young pods identifies candidate genes related to early embryo abortion.

The failure of peg penetration into the soil leads to seed abortion in peanut. Knowledge of genes involved in these processes is comparatively deficient. Here, we used RNA-seq to gain insights into transcriptomes of aerial and subterranean pods.

Soil eukaryotic microorganism succession as affected by continuous cropping of peanut--pathogenic and beneficial fungi were selected.

Peanut is an important oil crop worldwide and shows considerable adaptability but growth and yield are negatively affected by continuous cropping. Soil micro-organisms are efficient bio-indicators of soil quality and plant health and are critical to the sustainability of soil-based ecosystem function and to successful plant growth. In this study, 18S rRNA gene clone library analyses were employed to study the succession progress of soil eukaryotic micro-organisms under continuous peanut cultivation.

Validation of reference genes for gene expression studies in peanut by quantitative real-time RT-PCR.

Quantitative real-time reverse transcription PCR (qRT-PCR), a sensitive technique for quantifying gene expression, depends on the stability of the reference gene(s) used for data normalization. Only a few studies on the reference genes have been done with peanut to date. In the present study, 14 potential reference genes in peanut were evaluated for their expression stability using the geNorm and NormFinder statistical algorithms.

Identification and characterization of microRNAs from peanut (Arachis hypogaea L.) by high-throughput sequencing.

Background: MicroRNAs (miRNAs) are noncoding RNAs of approximately 21 nt that regulate gene expression in plants post-transcriptionally by endonucleolytic cleavage or translational inhibition. miRNAs play essential roles in numerous developmental and physiological processes and many of them are conserved across species. Extensive studies of miRNAs have been done in a few model plants; however, less is known about the diversity of these regulatory RNAs in peanut (Arachis hypogaea L.

Isolation and characterization of fatty acid desaturase genes from peanut (Arachis hypogaea L.).

Fatty acid desaturases are responsible for the insertion of double bonds into pre-formed fatty acid chains in reactions that require oxygen and reducing equivalents. In this study, genes for FAB2, FAD2-2, FAD6 and SLD1, were cloned from peanut (Arachis hypogaea L.).

Comparison of the Delta(12) fatty acid desaturase gene between high-oleic and normal-oleic peanut genotypes.

Delta(12) fatty acid desaturase gene has been targeted as a logical candidate controlling the high oleate trait in peanut seeds. By RT-PCR method, the full-length cDNAs of Delta(12) fatty acid desaturase gene were isolated from peanut (Arachis hypogaea L.) genotypes with normal and high ratio of oleic to linoleic acid, which were designated AhFAD2B and AhFAD2B', respectively.