Microsatellite markers used for genome-wide association mapping of partial resistance to <Emphasis Type="Italic">Sclerotinia sclerotiorum</Emphasis> in a world collection of <Emphasis Type="Italic">Brassica napus</Emphasis>

The fungal pathogen Sclerotinia sclerotiorum causes stem rot of oilseed rape (Brassica napus) worldwide. In preparation for genome-wide association mapping (GWAM) of sclerotinia resistance in B. napus, 152 accessions from diverse geographical regions were screened with a single Canadian isolate, #321. Plants were inoculated by attaching mycelium plugs to the main stem at full flower. Lesion lengths measured 7, 14 and 21 days after inoculation were used to calculate the area under the disease progress curve (AUDPC). Depth of penetration was noted and used to calculate percent soft and collapsed lesions (% s + c). The two disease traits were highly correlated (r = 0.93). Partially resistant accessions (AUDPC <7 and % s + c <2) were identified primarily from South Korea and Japan with a few from Pakistan, China and Europe. Genotyping of accessions with 84 simple sequence repeat markers provided 690 polymorphic loci for GWAM. The general linear model in TASSEL best fitted the data when adjusted for population structure (STRUCTURE), GLM + Q. After correction for positive false discovery rate, 34 loci were significantly associated with both disease traits of which 21 alleles contributed to resistance, while the remaining enhanced susceptibility. The phenotypic variation explained by the loci ranged from 6 to 25 %. Five loci mapped to published quantitative trait loci conferring sclerotinia resistance in Chinese lines.     

Intermittent electrical stimulation redistributes pressure and promotes tissue oxygenation in loaded muscles of individuals with spinal cord injury

Deep tissue injury (DTI) is a severe form of pressure ulcer that originates at the bone-muscle interface. It results from mechanical damage and ischemic injury due to unrelieved pressure. Currently, there are no established clinical methods to detect the formation of DTI. Moreover, despite the many recommended methods for preventing pressure ulcers, none so far has significantly reduced the incidence of DTI. The goal of this study was to assess the effectiveness of a new electrical stimulation-based intervention, termed intermittent electrical stimulation (IES), in ameliorating the factors leading to DTI in individuals with compromised mobility and sensation. Specifically, we sought to determine whether IES-induced contractions in the gluteal muscles can 1) reduce pressure in tissue surrounding bony prominences susceptible to the development of DTI and 2) increase oxygenation in deep tissue. Experiments were conducted in individuals with spinal cord injury, and two paradigms of IES were utilized to induce contractions in the gluteus maximus muscles of the seated participants. Changes in surface pressure around the ischial tuberosities were assessed using a pressure-sensing mattress, and changes in deep tissue oxygenation were indirectly assessed using T?*-weighted magnetic resonance imaging (MRI) techniques. Both IES paradigms significantly reduced pressure around the bony prominences in the buttocks by an average of 10-26% (P < 0.05). Furthermore, both IES paradigms induced significant increases in T?* signal intensity (SI), indicating significant increases in tissue oxygenation, which were sustained for the duration of each 10-min trial (P < 0.05). Maximal increases in SI ranged from 2-3.3% (arbitrary units). Direct measurements of oxygenation in adult rats revealed that IES produces up to a 100% increase in tissue oxygenation. The results suggest that IES directly targets factors contributing to the development of DTI in people with reduced mobility and sensation and may therefore be an effective method for the prevention of deep pressure ulcers.     

Multiomics approach reveals a role of translational machinery in shaping maize kernel amino acid composition

Maize (Zea mays) seeds are a good source of protein, despite being deficient in several essential amino acids. However, eliminating the highly abundant but poorly balanced seed storage proteins has revealed that the regulation of seed amino acids is complex and does not rely on only a handful of proteins. In this study, we used two complementary omics-based approaches to shed light on the genes and biological processes that underlie the regulation of seed amino acid composition. We first conducted a genome-wide association study to identify candidate genes involved in the natural variation of seed protein-bound amino acids. We then used weighted gene correlation network analysis to associate protein expression with seed amino acid composition dynamics during kernel development and maturation. We found that almost half of the proteome was significantly reduced during kernel development and maturation, including several translational machinery components such as ribosomal proteins, which strongly suggests translational reprogramming. The reduction was significantly associated with a decrease in several amino acids, including lysine and methionine, pointing to their role in shaping the seed amino acid composition. When we compared the candidate gene lists generated from both approaches, we found a nonrandom overlap of 80 genes. A functional analysis of these genes showed a tight interconnected cluster dominated by translational machinery genes, especially ribosomal proteins, further supporting the role of translation dynamics in shaping seed amino acid composition. These findings strongly suggest that seed biofortification strategies that target the translation machinery dynamics should be considered and explored further.

An integrated approach reveals the key role of translational machinery in maize kernel amino acid natural variation and homeostasis, highlighting targets for seed amino acid biofortification.     

Genome wide association studies (GWAS) of spot blotch resistance at the seedling and the adult plant stages in a collection of spring barley

Spot blotch (SB) in barley is caused by the fungal pathogen Cochliobolus sativus and considered one of the major constraints to successful barley production. Resistance to C. sativus was evaluated, using a barley collection of 336 genotypes (AM-2014), at the seedling and adult stages. Seedling resistance was evaluated by using a mixture of 19 virulent isolates in Morocco. Virulent isolates prevalent in Uttar Pradesh were used for phenotyping resistance at the adult stage in India. The AM-2014 panel was genotyped with 9-K single-nucleotide polymorphism (SNP) markers using iSelect Illumina Infinium. Genome wide association studies (GWAS) were carried out using SNP markers, infection responses, disease severity, and area under the disease progress curve (AUDPC). The mixed linear model was employed in TASSEL using principal component analysis (PCA) and Kinship matrix (K) as covariates. Higher SB severity, 82.3?±?13.5 (mean?±?SD), was recorded at the Banaras Hindu University (BHU) compared to 47.6?±?15.0 at the Narendra Dev University of Agriculture and Technology (NDUAT). Nine QTL, Rcs-qtl-1H-126.9, Rcs-qtl-2H-148.16, Rcs-qtl-3H-25.27, Rcs-qtl-5H-80.35, Rcs-qtl-6H-58.24, Rcs-qtl-7H-29.62, Rcs-qtl-7H-29.72, Rcs-qtl-7H-32.81, and Rcs-qtl-7H-34.74, were detected for SB resistance at the seedling stage. For SB severity at the adult stage, a QTL, Rcs-qtl-7H-32.81, was detected at BHU while seven QTL, Rcs-qtl-2H-91.09, Rcs-qtl-3H-145.64, Rcs-qtl-4H-14.43, Rcs-qtl-6H-6.49, Rcs-qtl-7H-114.43, Rcs-qtl-7H-151.66, and Rcs-qtl-7H-150.36, were found for SB severity at NDUAT. Three QTL, Rcs-qtl-4H-18.61, Rcs-qtl-4H-67.91, and Rcs-qtl-5H-110.25, were significant for AUDPC of SB at BHU. The QTLs reported in this study are important to advance marker-assisted selection and gene pyramiding of SB resistance in South Asia and North Africa in future.     

Identification of additional sources of resistance to Puccinia striiformis f. sp. hordei (PSH) in a collection of barley genotypes adapted to the high input condition

A total of 336 barley genotypes consisting of released cultivars, advanced lines, differentials and local landraces from the ICARDA barley breeding programme were screened for seedling and adult‐plant resistances to barley stripe rust pathogen (Puccinia striiformis f. sp. hordei [PSH]). Seedling resistance tests were undertaken at Shimla, India by inoculating 336 barley genotypes with five prevalent PSH races [Q (5S0), 24 (0S0‐1), 57 (0S0), M (1S0) and G (4S0)] in India. Barley genotypes were also evaluated at the adult‐plant stage for stripe rust resistance at Durgapura (Rajasthan, India) in 2013 and 2014, and at Karnal (Haryana, India) in 2014 under artificial PSH infection in fields, using a mixture of the five races. Twelve barley genotypes (ARAMIR/COSSACK, Astrix, C8806, C9430, CLE 202, Gold, Gull, Isaria, Lechtaler, Piroline, Stirling, and Trumpf) were resistant to all five PSH races at the seedling and adult‐plant stages. Two of these genotypes, Astrix and Trumpf, were part of international differentials and reveal that five races were avirulent to genes Rps4 (yr4), rpsAst, rpsTr1 and rpsTr2. These genes were highly effective against PSH races prevalent in India. The virulence/avirulence formula reported in this study helped to determine the effectiveness of PSH resistance genes against Indian races. Forty‐five genotypes showed adult‐stage plant resistance (APR) in the field. The identified PSH resistant genotypes may possess novel resistance genes and might serve as potential donors of PSH resistance at seedling and APR in the future. Further research is needed to determine the nature of resistance genes through allelic studies and mapping of these genes.     

Seedling and adult stage resistance to net form of net blotch (NFNB) in spring barley and stability of adult stage resistance to NFNB in Morocco

This study was conducted to identify stable resistance to net form of net blotch (NFNB) in spring barley in Moroccan environments. Seedling resistance to NFNB was evaluated by inoculating 336 barley genotypes with two NFNB isolates LDNH04Ptt-19 and TD-10 in the greenhouse. These genotypes were evaluated for adult plant resistance to NFNB under seven environments in Morocco in 2015 and 2016. The disease severity was estimated at GS 77–87 on barley leaves using a double-digit scale. To investigate stability of resistance, 149 barley genotypes were subjected to AMMI analysis. At the seedling stage, differential responses of barley genotypes to different NFNB isolates were identified, whereas genotypes had variable stability to NFNB resistance at the adult stages. Five genotypes, AM-68, AM-95, AM-250, AM-267 and AM-322, were resistant to both NFNB isolates at the seedling stage. There were significant (p < .001) effects of genotype (G) and G × E interaction on NFNB severity for barley genotypes at the adult stage. The principal components, IPCA1 and IPCA2, accounted for 48.4% and 18.7% variation for NFNB severity, respectively. The AMMI stability values (ASVs) ranged from 0.01 to 15.5, and fifty-nine barley genotypes had stable responses (ASV ≤ 0.05) across all seven environments. Specifically, two stable genotypes, AM-187 and AM-244, had lower mean NFNB severities across all environments, suggesting a quantitative resistance in these genotypes. Divergent environmental responses of NFNB severity were measured in Sidi El Ayedi 2015 and Sidi Allal Tazi 2016, suggesting that these environments may be suitable to capture resistance to diverse pathotypes. These stable genotypes are valuable resources for introgression of both qualitative resistance and quantitative resistance to NFNB in future.     

Impact of plant derivatives on the growth of foodborne pathogens and the functionality of probiotics

Numerous studies have been published on the antimicrobial and antioxidant properties of various plant components. However, there is relatively little information on the impact of such components on the enhancement of probiotics and production of antimicrobial compounds from these probiotics. Hence, this paper focuses on the influence of plant-derived components against pathogens, enhancement of cell viability and functionality of probiotics, and potential applications of such components in food safety and human health.     

Activation of the Rostral Intralaminar Thalamus Drives Reinforcement through Striatal Dopamine Release

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