High‐throughput sequencing of maize dwarf mosaic virus from common reed in a wetland

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Abstract

Common reed is a widespread aquatic grass in wetland areas of Turkey. In reed samples, RNAs with the sequence of the Maize dwarf mosaic virus (MDMV) were found using high-throughput sequencing. The nearly complete genome sequence comprised 9514 nucleotides. It contains a 5′ UTR of at least 145 nucleotides, a 3′ UTR of at least 237 nucleotides, and an ORF encoding a single polyprotein of 3041 amino acid residues. Two partial sequences were 7709 nt and 7858 nt long, respectively. Three reed sequences contained 22 nt, 25 nt, and 80 nt insertions in the 5′UTR, respectively. The coding region of MDMV TR-34 (49%) was more conserved than UTRs (34.3%) compared to Johnsongrass mosaic virus (JGMV), Sugarcane mosaic virus (SCMV), and Sorghum mosaic virus (SrMV). MDMV-TR34 reed isolate shares 91%–53.1% nucleotide identity and 98.2%–49% amino acid sequence similarity with other MDMV and three potyvirus sequences, respectively. Recombination analysis indicated six putative recombination events. In 2020–2022, the survey studies showed that 25 of 260 reed samples were infected with MDMV at the infection rate of 9.6% in Tekirdag province. This result is the first report of the complete nucleotidesequence of MDMV in the common reed, a reservoir host for cereals growing areas in Turkey.

The effect of silicon fertilizers on agronomic performance of bread wheat under drought stress and non‐stress conditions

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Abstract

Drought is one of the major constraints of wheat production, especially in rainfed wheat production systems. The objective of this study was to evaluate the effects of different silicon fertilizer formulations on the agronomic performance of diverse wheat genotypes under drought-stressed conditions. Twenty wheat genotypes were evaluated in field and greenhouse environments under non-stressed and drought-stressed and two silicon fertilizer formulations (granular and liquid potassium silicate) and untreated control. The four-way interaction involving genotype, environment, water regime and silicon formulation had a significant effect (p < .05) for aboveground biomass, productive spike number, hundred seed weight and grain yield. Granular silicon application was the most effective treatment both under non-stressed and drought-stressed conditions compared to the liquid and control treatments. Under field and drought conditions, the highest yielding genotype was MC18, which exhibited a mean grain yield of 4.17 t ha−1 with granular silicon, 2.56 t ha−1 with liquid silicon and 2.18 t ha−1 without silicon. The yield of genotype MC18 improved by 91.3% using granular silicon under drought-stressed and by 44.6% under non-stressed conditions compared with the untreated control. Granular silicon positively affected the drought stress tolerance indices compared to the liquid silicon and untreated control. The principal component biplot analysis revealed that liquid and granular silicon positively impact yield response for all test genotypes under drought-stressed and non-stressed conditions compared with the control. Silicon application reduced genotype variation for agronomic traits and enhanced agronomic trait relationships under drought-stressed conditions. Drought stress tolerance indices are influenced by silicon application. The effect of silicon has a direct and indirect effect on yield and yield components. Silicon fertilization can be considered as a mitigation measure to cope with the adverse effect of drought stress on wheat.

Maize and heat stress: Physiological, genetic, and molecular insights

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Abstract

Global mean temperature is increasing at a rapid pace due to the rapid emission of greenhouse gases majorly from anthropogenic practices and predicted to rise up to 1.5°C above the pre-industrial level by the year 2050. The warming climate is affecting global crop production by altering biochemical, physiological, and metabolic processes resulting in poor growth, development, and reduced yield. Maize is susceptible to heat stress, particularly at the reproductive and early grain filling stages. Interestingly, heat stress impact on crops is closely regulated by associated environmental covariables such as humidity, vapor pressure deficit, soil moisture content, and solar radiation. Therefore, heat stress tolerance is considered as a complex trait, which requires multiple levels of regulations in plants. Exploring genetic diversity from landraces and wild accessions of maize is a promising approach to identify novel donors, traits, quantitative trait loci (QTLs), and genes, which can be introgressed into the elite cultivars. Indeed, genome wide association studies (GWAS) for mining of potential QTL(s) and dominant gene(s) is a major route of crop improvement. Conversely, mutation breeding is being utilized for generating variation in existing populations with narrow genetic background. Besides breeding approaches, augmented production of heat shock factors (HSFs) and heat shock proteins (HSPs) have been reported in transgenic maize to provide heat stress tolerance. Recent advancements in molecular techniques including clustered regularly interspaced short palindromic repeats (CRISPR) would expedite the process for developing thermotolerant maize genotypes.

Bioactive peptides in preterm human milk: Impact of maternal characteristics and their association to neonatal outcomes

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Bioactive peptides in preterm human milk: Impact of maternal characteristics and their association to neonatal outcomes

Hormone content of very preterm human milk is partially determined by maternal factors most of them regarding metabolic health and obstetric characteristics. Human milk concentration impacts on growth and development of preterm infants during their stay in the neonatal unit.


Abstract

Human milk adipokines in term babies seem partially determined by maternal factors and affect infant's development. We aimed to describe bioactive peptide concentration in very preterm human milk and associations to maternal characteristics and postnatal growth. Mothers delivering ≤32 weeks of gestation and their infant/s were recruited. At 4 weeks of lactation, an aliquot of 24-h-pooled milk was collected for exclusively breastfeeding dyads. Insulin, leptin, adiponectin, and milk fat globule epidermal growth factor-8 (MFG-E8) were measured by enzyme-linked immunoabsorbent assay in skimmed milk. One hundred mothers (28.8 ± 2.3 weeks at delivery) provided a milk sample. Milk insulin was related to gestational age, pre-pregnancy body mass index (BMI), and galactagogue treatment (final model: adjusted R 2: 0.330, p < 0.0001; adjusted β coefficients: galactagogue treatment: 0.348, p 0.001; pre-pregnancy BMI: 0.274, p 0.009; gestational age: −0.290, p 0.007). Adiponectin was higher in mothers with gestational diabetes (30.7 ± 6.5 vs. 24.8 ± 8 ng/mL, p 0.044). Leptin was associated with pre-pregnancy BMI (Spearman's ρ: 0.648, p < 0.0001) and MFG-E8 to presence of labor and multiple pregnancy (final linear regression model, R 2: 0.073, p 0.028, adjusted β coefficients: presence of labor −0.229, p 0.050; twins: −0.192, p 0.099). Milk adiponectin was associated with a greater decrease in length z-scores from birth to 28 days (Pearson's r: −0.225, p 0.032) and to discharge (Pearson's r: −0.290, p 0.003). Milk MFG-E8 was lower in milk of mothers whose babies experienced late-onset sepsis (13.3 ± 5.8 vs. 16.8 ± 6.3 μg/mL, p 0.023). Adipokines levels in preterm human milk are partially related to maternal metabolic status. Milk peptide concentration associates with early neonatal growth trajectories.

Characterization of sugarcane mosaic virus from Cymbopogon spp. plants in Brazil

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Abstract

In April 2022, virus-like symptoms were observed in a Cymbopogon spp. plant grown in the backyard of a house and in Java citronella (C. winterianus) plants in a flower shop in Piracicaba, São Paulo State, Brazil. In April 2023, ca. 700,000 Ceylon citronella (C. nardus) plants showing symptoms of mosaic were observed in a field crop in Dois Corrégos (SP). Evidence for a possible potyvirus infection was revealed by electron microscopy and confirmed by molecular assays. Nucleotide sequencing of amplicons from RT-PCR identified the potyvirus infecting a Cymbopogon spp. plant, Java and Ceylon citronella as sugarcane mosaic virus (SCMV, genus Potyvirus). Phylogenetic analysis of the coat protein gene indicated that the SCMV isolates from Cymbopogon (C1), Java (JC1), and Ceylon citronella (CC) belong to the clade of SCMV from sugarcane. The C1 isolate, and an isolate from sugarcane (SCMV-SU) (control) were mechanically transmitted to Java citronella, sorghum, sugarcane and maize plants. Aphis gossypii transmitted the C1 and SU isolates to Java citronella plants, while Melanaphis sacchari transmitted only the SU isolate to Java citronella plants. This is the first molecular characterization of SCMV from Cymbopogon spp. plants.

Morphomolecular identification and pathogenicity of Colletotrichum species associated with avocado anthracnose in northern Thailand

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Morphomolecular identification and pathogenicity of Colletotrichum species associated with avocado anthracnose in northern Thailand

11 Colletotrichum Isolates were identified based on a polyphasic approach from avocado orchards in northern Thailand, and the pathogenicity was assessed for each species on avocado fruits and leaves.


Abstract

Avocado production is restricted globally by the anthracnose disease caused by Colletotrichum species. In Thailand, anthracnose symptoms can be found on avocado leaves and fruits, and it is an important postharvest disease, reducing the shelf life of the fruits and causing huge economic losses. Avocado leaves and fruits showing anthracnose disease were collected from Chiang Rai province, located in northern Thailand, and the Colletotrichum species isolated from the samples were identified based on morphological examination and multigene phylogenetic analyses. Phylogenetic analyses using five loci (ITS, ACT, CHS-1, GAPDH and TUB2) coupled with the morphology of 11 isolates showed that they belonged to four known species of Colletotrichum. Colletotrichum endophytica, C. fructicola and C. siamense are illustrated as new geographical records, and C. henanense is characterized as a new host record. Furthermore, the pathogenicity of these species in avocado fruits and leaves (West Indian variety) has been proven. In addition, this study provides further evidence for the synonymization of C. pandanicola and C. parvisporum with C. siamense.

Overexpression of BnNAC19 in Brassica napus enhances resistance to Leptosphaeria maculans, the blackleg pathogen of canola

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Overexpression of BnNAC19 in Brassica napus enhances resistance to Leptosphaeria maculans, the blackleg pathogen of canola

Overexpression of BnNAC19 in canola (Brassica napus) can enhance disease resistance against blackleg, caused by Leptosphaeria maculans, providing a valuable genetic resource for disease breeding.


Abstract

Leptosphaeria maculans is a fungal pathogen that causes blackleg disease in canola (Brassica napus), resulting in significant yield and economic losses in Canada and many parts of the world. Plant NAC transcription factors play critical roles in plant development and response to biotic or abiotic stress. In this study, we identified and characterized a BnNAC19 gene from Brassica napus. The overexpression of BnNAC19 in transgenic canola plants contributed to the improvement of seedling resistance against L. maculans. The mycelial growth of a green fluorescent protein-tagged strain of L. maculans and production of pycnidiospores were shown to be inhibited in the transgenic canola plants overexpressing BnNAC19. In addition, the canola transgenic line overexpressing BnNAC19 showed increased disease resistance in the adult plant, which was determined by quantitative resistance. Both increased seedling and adult plant resistance in transgenic canola plants overexpressing BnNAC19 indicate that the BnNAC19 gene plays a positive role against L. maculans. The expression pattern of genes BnNAC19 upstream and downstream of BnNAC19 that participate in plant defence pathways were investigated to elucidate the B. napus resistance mechanisms to L. maculans infection, and hence to aid the long-term blackleg disease-resistant breeding programmes.

Meloidogyne arenaria infecting Matricaria chamomilla in Brazil

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Abstract

Plants of Matricaria chamomilla L. (Asteraceae), well-known medicinal species, showing root galls, were collected in Pelotas, state of Rio Grande do Sul (Brazil). Based on morphological (perineal patterns and males), morphometric (males) and esterase phenotypes (Est A2), we identified the infecting nematode as the root-knot nematode M. arenaria. Under greenhouse conditions, four M. chamomilla plants were inoculated with about 1000 specimens obtained from the isolate. We observed about 207 ± 72 nematodes g−1 of roots, confirming its pathogenicity. To the best of our knowledge, this is the first record of M. arenaria parasitizing M. chamomilla in Brazil and elsewhere.