Trichoderma atroviride suppresses Fusarium graminearum by altering primary and secondary metabolite biosynthesis profiling

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Trichoderma atroviride suppresses Fusarium graminearum by altering primary and secondary metabolite biosynthesis profiling

Trichoderma atroviride seems to be a potential biocontrol agent against Fusarium graminearum by altering the expression of genes related to vital processes in fungal life cycle.


Abstract

The use of Trichoderma spp. offers an ecologically friendly tool for the struggle with mycotoxigenic Fusarium spp. Here, the alterations in transcriptome level were investigated in 6-day-old Fusarium graminearum cultures treated with Trichoderma atroviride and nontreated with T. atroviride (FGc), using whole transcriptome sequencing to better understand the associated biological processes. Transcriptome analysis indicated a total of 55 up-regulated genes and 728 down-regulated genes with p adj < 0.05. Enrichment analysis revealed that the up-regulated genes were related to fatty acid biosynthesis, AMP-dependent biosynthesis, amino acid recognition/activation processes and secondary metabolite production, whereas down-regulated genes were involved in amino acid synthesis, oxidation–reduction processes, metal ion-binding and metabolic/catalytic activities. Among the down-regulated genes, the expression of pigmentation-related genes such as aurO, gip1 and aurR2 was remarkable. Similarly, the expression levels of key enzyme-coding genes involved in deoxynivalenol mycotoxin production were significantly decreased in the range of −1.77 and −2.94. For up-regulated genes, nonribosomal peptide synthetase and polyketide synthase genes were notably distinguished from the remaining down-regulated genes as these genes can be involved in biosynthesis of common secondary metabolites. The results clearly emphasize that T. atroviride repressed the biosynthesis of primary metabolites in F. graminearum while simultaneously up-regulating the expression of genes involved in the synthesis of secondary metabolites. This is the first report showing how T. atroviride leads to transcriptome alterations and the findings suggest that T. atroviride could serve as an effective fungus by employing a wide variety of strategies against phytopathogenic fungi.

Lentil (Lens culinaris), a new host of Alternaria chlamydosporigena

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Abstract

During a survey conducted in June 2019, chlorosis symptoms were observed on lentil leaves in a field located at Relizane, Algeria. Based on morphological and molecular identification, the pathogen was identified as Alternaria chlamydosporigena. A pathogenicity test was carried out and Koch's postulates were verified and fulfilled. To our best knowledge, this is the first report of A. chlamydosporigena as new pathogen on lentil worldwide.

Genetic loci associated with Fusarium wilt resistance in tomato (Solanum lycopersicum L.) discovered by genome‐wide association study

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Abstract

Fusarium wilt (FW), caused by Fusarium oxysporum f. sp. lycopersici (Fol), has impacted global tomato production. This study aims to identify single nucleotide polymorphisms (SNPs) and candidate genes associated with FW resistance against different Fol isolates in tomato accessions using genome-wide association studies (GWAS). Ninety-four tomato accessions were evaluated for FW resistance and subjected to GWAS analysis. Broad-spectrum tomato accessions demonstrated resistance to Fol in at least two isolates, exhibiting a disease severity index (DSI) of 0%. Thirty-two SNP loci were significantly linked to the DSI of Fol isolates TFPK401, BK2269 and NP-T4, clustering on chromosome 6. Among these, 12 common significant SNPs were associated with the DSI of at least two Fol isolates, while four unique SNPs were specific to TFPK401 or NP-T4. Furthermore, candidate genes associated with disease response to Fol infection were identified within a 37.9–41 Mb region flanking the SNPs. These findings contribute to a deeper understanding of resistance mechanisms against Fol infection in tomatoes, potentially aiding the development of effective breeding strategies for Fusarium wilt resistance.

Varietal effects on Greenhouse Gas emissions from rice production systems under different water management in the Vietnamese Mekong Delta

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Abstract

Rice production accounts for 15% of the national Greenhouse Gas (GHG) emissions and Vietnam aims at reducing emissions from rice production by focusing on changing farming practices. However, the potential for mitigation through the selection of different rice varieties is still poorly understood. A two-year field screening of 20 rice varieties under continuous flooding (CF) and alternate wetting and drying (AWD) irrigation was conducted in the Vietnamese Mekong Delta (VMD), Vietnam, employing the closed chamber method for assessing GHG emissions. The results confirmed that varietal variation was the largest for methane (CH4) emissions under CF. Across the varietal spectrum, CH4 emissions were more important than nitrous oxide (N2O) (accounts for less than 2% of the CO2e) with the lowest emitting variety showing 243 kg CH4 ha−1 and the highest emitting variety showing 398 kg CH4 ha−1 emissions as compared to 0.07 kg N2O ha−1 and 0.76 kg N2O ha−1 emissions, respectively. Under AWD, CH4 emissions were generally strongly reduced with the varietal effect being of minor importance. Compared with IPCC default values, the data set from the two seasons yielded higher Emission Factors (EFs) under CF (2.92 and 3.00 kg ha−1 day−1) as well as lower Scaling Factors (SFs) of AWD (0.41 and 0.38). In the context of future mitigation programs in the VMD, the dry season allows good control of the water table, so varietal selection could maximize the mitigation effect of AWD that is either newly introduced or practised in some locations already. In the wet seasons, AWD may be difficult to implement whereas other mitigation options could be implemented such as selecting low-emitting cultivars.

Pioneers of post‐agricultural forest successions are adapted for herbivory avoidance but not biotic seed dispersal

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Pioneers of post-agricultural forest successions are adapted for herbivory avoidance but not biotic seed dispersal

Natural reforestation through secondary succession in marginal agricultural land is an important component of climate mitigation and adaptation, but the fundamental ecological processes promoting or constraining it are poorly understood. This study provides national-scale evidence that species accumulation in post-agricultural forest successions may be slowed by intense mammalian herbivory and low rates of biotic seed dispersal. Naturally reforesting post-agricultural land, South Island, New Zealand.


Abstract

Question

Natural reforestation is an important component of climate mitigation and adaptation, but the ecological processes promoting or constraining it are poorly understood. In this study we employ a stand reconstruction approach (which uses ages of extant trees to estimate year of establishment for each individual tree) to test for general trait-based effects on tree species arrival order in post-agricultural forest successions.

Location

Naturally reforesting post-agricultural landscapes throughout New Zealand.

Methods

Ages were obtained for 2434 individuals spanning 30 tree species across a nationwide network of 128 plots in 14 naturally reforesting post-agricultural sites. These ages were used to calculate individual-level arrival times (relative to the oldest individual in each plot). We estimated species-level arrival times by fitting linear mixed-effects (LME) regressions (with species identity as the fixed effect, and plots nested within sites as the random effects) to individual arrival time data. We used back-casting (where arrival time data are used to document individual-level presence in plots through time) to track annual changes in species abundance and community-weighted mean (CWM) trait values.

We used standardised major axis (SMA) regressions to examine the effect of traits related to resource use strategy, herbivory avoidance, seed dispersal and disturbance response on species-level arrival times. We used LME regressions to test for changes in CWM trait values with stand age.

Results

The earliest-arriving species had traits associated with herbivory avoidance, were abiotically dispersed and had short predicted dispersal distances. There was no evidence that traits linked to resource use strategy or disturbance response affected species arrival times. Every significant species-level relationship was recovered in community-level LME analyses.

Conclusions

Our findings suggest that mammalian herbivore control and enhancement of biotic (bird) seed dispersal may be key management interventions in realising the full climate mitigation and adaptation potential of natural reforestation in post-agricultural landscapes.

Gut microbiota contribution to selenium deficiency‐induced gut–liver inflammation

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Gut microbiota contribution to selenium deficiency-induced gut–liver inflammation

Se deficient imbalance the intestinal microbiota. Se deficient effects gut–liver axis via lipopolysaccharide. Lactobacillus reuteri could alleviate selenium deficiency-induced gut–liver axis injury.


Abstract

There is limited knowledge about the factors that drive gut–liver axis changes after selenium (Se) deficiency-induced gut or liver injuries. Thus, we tested Se deficiency in mice to determine its effects on intestinal bacterial balance and whether it induced liver injury. Serum Se concentration, lipopolysaccharide (LPS) level, and liver injury biomarkers were tested using a biochemical method, while pathological changes in the liver and jejunum were observed via hematoxylin and eosin stain, and a fluorescence spectrophotometer was used to evaluate intestinal permeability. Tight junction (TJ)-related and toll-like receptor (TLR) signaling-related pathway genes and proteins were tested using quantitative polymerase chain reaction, western blotting, immunohistochemistry, and 16S ribosomal ribonucleic acid gene-targeted sequencing of jejunum microorganisms. Se deficiency significantly decreased glutathione peroxidase activity and disrupted the intestinal flora, with the most significant effect being a decrease in Lactobacillus reuteri. The expression of TJ-related genes and proteins decreased significantly with increased treatment time, whereas supplementation with Se, fecal microbiota transplantation, or L. reuteri reversed these decreases. Signs of liver injury and LPS content were significantly increased after intestinal flora imbalance or jejunum injury, and the levels of TLR signaling-related genes were significantly increased. The results indicated that Se deficiency disrupted the microbiota balance, decreased the expression of intestinal TJ factors, and increased intestinal permeability. By contrast, LPS increased due to a bacterial imbalance, which may induce inflammatory liver injury via the TLR4 signaling pathway.

Development of KASP fingerprinting panel for clonal identification in red raspberry (Rubus idaeus L.)

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Abstract

Red raspberry is an economically important horticultural crop that is known for its fruit's sweet flavour and nutritional value. A reliable and economic genotyping platform is needed to facilitate clonal/variety identification. Previous attempts for clonal identification utilized morphological traits or low-throughput, difficult to score dinucleotide-containing simple sequence repeat molecular markers. Single nucleotide polymorphisms (SNPs), despite having lower allelic diversity, are numerous across the genome and more easily converted to high-throughput assays restoring differential power. In this study, we use the kompetitive allele-specific PCR (KASP™) chemistry, an affordable and high-throughput platform, to develop a panel of SNPs to distinguish a diverse collection of red raspberry accessions for clonal identification. The panel consists of 48 KASP assays that show high concordance with whole genome sequencing, allelic balance, and recovery rate and a minimal set of 24 assays that distinguished the same accessions differentiated by the larger panel.