Oil Crop Science最新文献

Peanut (Arachis hypogaea L.) is a thermophilic crop, and low temperature leads to a significant reduction in annual yields. Despite a few cold tolerant germplasms or cultivars have been discovered and developed, molecular mechanisms governing peanut cold tolerance is poorly understood. Identification of keys genes involved in cold tolerance is the first step to address the underlying mechanism. In this study, we isolated and characterized 157 genes with potentials to confer cold tolerance in peanut by using a yeast functional screening system. GO (Gene ontology) and KEGG (Kyoto encyclopedia of genes and genomes) enrichment analysis of these genes revealed that ribosome and photosynthesis proteins might play essential roles in peanut cold response. Transcriptome results indicated that 60 cold tolerance candidate genes were significantly induced or depressed by low temperature. qRT-PCR analysis demonstrated that several candidate genes could be also regulated by salt or drought stress. Individual overexpression of two UDP-glycosyltransferases (AhUGT2 and AhUGT268) in transgenic yeast cells could enhance their tolerance to multiple abiotic stress. In conclusion, this study advances our understanding of the mechanisms associated with the cold stress responses in peanut, and offers valuable gene resources for genetic improvement of abiotic stress tolerance in crops.

Trehalose and its precursor, trehalose-6-phosphate, play critical roles in plant metabolism and response to abiotic stresses. Trehalose-6-phosphate synthase (TPS) is a key enzyme in the trehalose synthesis pathway. Hence this study identified TPS genes in sesame (SiTPSs) and examined their expression patterns under various abiotic stresses. Totally, ten SiTPSs were identified and comprehensively characterized. SiTPSs were found to be unevenly distributed on five out of 13 sesame chromosomes and were predicted to be localized in chloroplasts and vacuoles of cells. Phylogenetic analysis classified SiTPS proteins into two groups (I and II), which was supported by gene structure and conserved motif analyses. Analysis of cis-acting elements in promoter regions of SiTPSs revealed that they might primarily involve developmental and environmental responses. SiTPSs exhibited different expression patterns in different tissues and under different abiotic stresses. Most group II SiTPS genes (SiTPS4 - SiTPS10) were strongly induced by drought, salt, waterlogging, and osmotic stress. Particularly, SiTPS10 was the most significantly up-regulated under various abiotic stresses, indicating it is a candidate gene for improving sesame tolerance to multiple abiotic stresses. Our results provide insight into the TPS gene family in sesame and fundamental resources for genomics studies towards dissecting SiTPS genes’ functions.

Fusarium wilt is a common fungal disease in sesame caused by Fusarium oxysporum f. sp. sesami (FOS). To determine the toxin production profiles of the FOS isolates with different pathogenicity levels under various culture conditions, we assessed the content variation of fusaric acid (FA) and 9, 10-dehydrofusaric acid (9, 10-DFA) produced by the four representative FOS isolates. Results indicated that the concentration of FA reached to a maximum of 2848.66 ​μg/mL in Czapek medium, while 9, 10-DFA was mainly produced in Richard and Low-carbon Richard medium. The concentration of 9, 10-DFA on Richard culture medium varied from 0 ​μg/mL to 716.89 ​μg/mL. Of the five culture media used in this study, Czapek culture medium was the most conductive to produce FA. FA production was significantly affected by culture medium, culture time, and their interactions. Results suggest that there is no correlation between toxin production and pathogenicity level of FOS isolates. These findings provide key information for the mechanism analysis of FOS- sesame interaction and pathogen control.

The sunflower has the potential to be a highly competitive crop owing to its diversity market and the valuable oil it produces. Nevertheless, the amount of sunflower seed oil – a key factor for the crushing industry – is affected by genotype and environment, which sometimes is difficult to predict. The paper analyzes the theoretical principles of sunflower growth in Ukraine, highlights the current trends in the sowing of this crop, the influence of climatic factors of the environment on the prospects of the oilseed sunflower yield. The results of the research are presented for 3 years (2014–2016), during the authors conducted a grain quality observatory at the regional level, taking into account the climatic conditions of sunflower growth in different natural zones of Ukraine (from 45° to 51° north latitude and from 22° to 37° east longitude). Additionally, the research includes the coefficient of significance of the deviation from long-term climatic indicators, which makes it possible to forecast sunflower yield in the future. The analyzed data was obtained from the commercial fields with a minimum area of 40 ​ha in all Ukrainian regions except Crimea peninsula, Donetsk and Luhansk regions. The results obtained in research show the great diversity of oil content index as per both latitude and longitude meaning. If we consider the entire country, this survey shows that the seed oil content can change dramatically from year to year: e.g. 47.5% in one year versus 45.7% in another year. Regionally, these changes have a completely different dynamic with a gradual decrease in seed oil content in the southern part of the country. The main goal of the research was to identify the best sunflower growing areas in Ukraine according to the oil content index.

In order to grasp the distribution of Aspergillus flavus in the soil of peanut production areas in China, A. flavus biomarkers were tested on 555 soil samples from 37 sampling points in 17 provinces, peanut fields in four agroecological zones (Southern area, Yangtze River Basin, Northern area, Northeast area). The results showed that (1) the cultivation amount of A. flavus per gram of soil in the Yangtze River Basin is 1.30 times that of the southern area, 1.56 times that of the northern area, and 6.20 times that of the northeast area, with obvious regional characteristics. (2) In the Yangtze River basin, the change of longitude in the east-west direction has no direct impact on the cultivation amount of A. flavus per gram of soil. (3) In the east coast, the A. flavus cultivated per gram of soil increased first and then decreased with the increase of latitude from south to north. (4) A. flavus can be isolated in the soil samples above 1000 ​m. Field pollution is an important source of aflatoxin contamination in peanut. The study on the distribution of A. flavus in soil in China could provide theoretical support for the early warning and prevention and control measures of aflatoxin contamination in peanut.

In 2020, diseased seedlings of winter oilseed rape (Brassica napus) with cankered taproots as well as abundant sclerotium-like structures in the soil surrounding the roots were found in Longxi County of Gansu province of northwestern China. A fungus with production of pycnidia was isolated from the diseased roots, and it was identified based on morphological characteristics, molecular phylogeny (ITS, LSU) and PCR detection with the specific primers. The fungus was identified as Leptosphaeria sclerotioides Gruyter, Aveskamp & Verkley [anamorph: Phoma sclerotioides (Preuss) ex Sacc.]. Re-inoculation of isolates of P9 and P10 of L. sclerotioides on winter oilseed rape (B. napus cultivar ‘Zhongshuang No. 9’) in Wuhan caused formation of abundant sclerotium-like structures in soil surrounding the roots, but failed to produce root cankers as those observed in Gansu possibly due to lack of long peroid of low-temperature conditioning in Wuhan. In spite of this, plant height, pod number and seed yield of oilseed rape were significantly reduced in the treatment with L. sclerotioides P9 and P10, compared to the control treatment. To the best of our knowledge, this is the first report of L. sclerotioides on B. napus in China and the finding broadened our understanding about the natural distribution of this psychrophilic fungus.

In recent years, peanut yield and quality are more seriously affected by pod rot disease in China. However, managing this disease has proven challenging due to the wide host range of its pathogens. In this study, four soil samples were collected from fields with pod rot disease in Hebei Province, and 454 pyrosequencing was used to analyze the fungal communities structure within them. All 38 490 ITS high-quality sequences were grouped into 1203 operational taxonomic units, the fungal community diversity of four soil samples was evaluated and compared using Shannon index and Simpson index. The results showed that members of Ascomycota were dominant, followed by Basidiomycota. According to the BLAST results at the species level, Guehomyces had the highest abundance, accounting for about 7.27%, followed by Alternaria, Fusarium, and Davidiella. The relative abundance of Fusarium oxysporum isolated from rotting peanuts in soil with peanut rot was higher than that in the control, indicating that Fusarium oxysporum might be one of the main pathogenic fungus of peanut rot in this area. This study delved into the broader fungal community associated with peanut pod rot, providing a theoretical foundation for preventing and treating this disease in agriculture.

In order to understand the pathogenic mechanisms of Sclerotium rolfsii on peanut and to analyze the variation of virulence in S. rolfsii strains, the highly virulent strain (ZY2) and weakly virulent strain (GP3-1) were investigated under both in vivo and in vitro conditions. The results indicated that S. rolfsii directly infected peanut by producing infection cushions. ZY2 formed infection cushions earlier than GP3-1, and ZY2 produced a greater number of infection cushions compare to GP3-1. Both strains could utilize cellulose, xylose, or polygalacturonic acid in the Czapek medium. The activities of cellulase (CL) and polygalacturonase (PG) in the inoculated peanut stems increased significantly at 9 ​h after inoculation. The activities of CL and PG produced by ZY2 in the inoculated stems were significantly higher than that produced by GP3-1. Both strains could produce oxalic acid (OA), and the content of OA produced by ZY2 in the inoculated stems was higher than that produced by GP3-1. In summary, it suggested that S. rolfsii destroyed peanut cells through physical and biochemical factors by secreting a large amount of OA, CL and PG during the formation of infection cushions. The difference in OA content, activity of CL and PG produced by highly and weakly virulent strains played important roles in variation of virulence.

WRKY transcription factors (TFs) have been identified as important core regulators in the responses of plants to biotic and abiotic stresses. Cultivated peanut (Arachis hypogaea) is an important oil and protein crop. Previous studies have identified hundreds of WRKY TFs in peanut. However, their functions and regulatory networks remain unclear. Simultaneously, the AdWRKY40 TF is involved in drought tolerance in Arachis duranensis and has an orthologous relationship with the AhTWRKY24 TF, which has a homoeologous relationship with AhTWRKY106 TF in A. hypogaea cv. Tifrunner. To reveal how the homoeologous AhTWRKY24 and AhTWRKY106 TFs regulate the downstream genes, DNA affinity purification sequencing (DAP-seq) was performed to detect the binding sites of TFs at the genome-wide level. A total of 3486 downstream genes were identified that were collectively regulated by the AhTWRKY24 and AhTWRKY106 TFs. The results revealed that W-box elements were the binding sites for regulation of the downstream genes by AhTWRKY24 and AhTWRKY106 TFs. A gene ontology enrichment analysis indicated that these downstream genes were enriched in protein modification and reproduction in the biological process. In addition, RNA-seq data showed that the AhTWRKY24 and AhTWRKY106 TFs regulate differentially expressed genes involved in the response to drought stress. The AhTWRKY24 and AhTWRKY106 TFs can specifically regulate downstream genes, and they nearly equal the numbers of downstream genes from the two A. hypogaea cv. Tifrunner subgenomes. These results provide a theoretical basis to study the functions and regulatory networks of AhTWRKY24 and AhTWRKY106 TFs.

The optimal process conditions for solvent-free microwave extraction (SFME) of essential oils from Cinnamomum longepaniculatum deciduous leaves after moisture conditioning were established by response surface methodology (RSM). A Box-Behnken design (BBD) was applied to evaluate the effects of three independent variables: moisture content (A: 54%–74%), microwave power (B: 300–500 ​W) and microwave time (C: 20–40 ​min), on the extraction yield of essential oil. The compounds of the essential oils obtained by SFME, hydro-distillation and microwave-assisted hydro-distillation (MADE) were identified by gas chromatography-mass spectrometry (GC-MS), and the total lipids of C. longepaniculatum fresh leaves and deciduous leaves were analyzed. The correlation analysis of the response regression model indicated that quadratic polynomial model could be employed to optimize the extraction of essential oil. The optimal extraction condition was A: 58%, B: 400 ​W and C: 28 ​min. In the optimal condition, the maximum extraction yield was 4.475 mL/100 ​g dw and higher than that by MADE. The main compound of the essential oil was eucalyptol (63.54%), and total oxygenated compounds was 78.95%, mainly caused by SFME and the metabolism of endophytic bacteria with decreasing content of phospholipids and fatty acids. Analysis of variance under the extraction condition illustrated high fitness of the model and the success of RSM for optimizing and reflecting the expected process condition. SFME combined with moisture regulation was an effective method for extracting essential oil from C. longepaniculatum deciduous leaves.