ARTICLE | doi:10.20944/preprints202110.0228.v1
Subject: Biology, Agricultural Sciences & Agronomy Keywords: flax; Fusarium oxysporum; differential expression genes; GO enrichment analysis; KEGG enrichment analysis
Online: 15 October 2021 (14:32:42 CEST)
A plant’s early response to pathogen stress is a vital indicator of its disease resistance. In order to study the response mechanism of resistant and susceptible flax cultivars to Fusarium oxysporum f. sp. lini (Foln), we applied RNA-sequencing to analyze transcriptomes of flax with Foln 0.5, 2 and 8 hours post inoculation (hpi). We found a significant difference in the number of differential expression genes (DEGs) between resistant and susceptible flax clutivars. The number of DEGs in the Fusarium-resistant cultivar increased dramatically at 2 hpi, and a large number of DEGs participated in the Fusarium-susceptible cultivar response to Foln infection 0.5 hpi. GO enrichment analysis determined that the up-regulated DEGs of both flax cultivars were enriched such as oxidoreductase activity and oxidation-reduction process. At the same time, the genes involved in diterpenoid synthesis were up-regulated in resistant cultivar, while those involved in extracellular region, cell wall and organophosphate ester transport were down-regulated in susceptible cultivar. KEGG enrichment analysis showed the genes encoded WRKY 22 and WRKY33 which involved in MAPK signaling pathway were up-regulated expressed in S-29 and down-regulated expressed in R-7, negatively regulated the disease resistance of flax; The genes encoded Hsp 90 family which in involved in plant pathogen interaction pathway were up-regulated in R-7 and down-regulated in S-29, which positively regulated the disease resistance of flax; The genes encoded MYC2 transcription factor and TIFY proteins which involved in plant hormone signaling pathway were up-regulated in R-7, and regulated the jasmonic acid metabolism of flax and the signal transduction of plant hormones. Meanwhile seven regulatory genes with the most correlation were screened out, Among Lus10025000.g and Lus10026447.g regulated other genes expressed both in plant hormone signal transduction pathway and MAPK signal pathway. In conclusion, these findings will facilitate further studies on the function of these candidate genes in flax of response to Fusarium stress, and the breeding of disease-resistant flax cultivar.
ARTICLE | doi:10.20944/preprints202010.0603.v1
Subject: Earth Sciences, Atmospheric Science Keywords: Consequential LCA; System expansion; Life Cycle Assessment; flax fiber biobased materials; bioeconomy
Online: 29 October 2020 (09:27:42 CET)
Flax fiber appears as a suitable feedstock in the endeavor of deploying a sustainable biobased economy. Its environmental performance as reinforcement in composite materials has been studied in previous Life Cycle Assessments (LCAs). However, these studies only present a coarse Life cycle Inventory (LCI) and often fail to detail all processes of the supply chain or to represent the co-products. This paper aims to bridge this gap and provide data for future LCAs on flax fiber production and transformation.The study focuses on the impacts of producing a bio-based reinforcement material (a fabric product for non-aesthetic purposes) with a system expansion perspective. The functional unit is defined as the production of 2400 m² flax-based technical textile per year, this corresponds to one hectare of cultivated land. The geographical scope considers that the production occurs in France and that some manufacturing process are outsourced in China. A Sensitivity Analysis was carried out to assess the influence of the electricity mix in the various countries involved in the manufacturing cycle.A detailed life cycle inventory for flax fiber production and transformation was built and the environmental performance of a flax technical textile was assessed as a cradle-to-gate LCA. The fate of co-products was documented and was shown to contribute to the reduction of the generated environmental impacts. Through a cradle-to-gate LCA, a broader understanding of the environmental performance of a flax-based technical textile was presented by including the valorization of co-products and a wider set of analyzed impact categories, going therefore beyond the existing state-of-the-art. Results show agricultural activities and electricity production to be the biggest contributors to the environmental impacts of flax technical textile; contributions due to land use changes were minor in comparison. Very specifically for this case study, a sensibility analysis showed the influence of an all-French production to be more efficient from an environmental point of view.
ARTICLE | doi:10.20944/preprints202010.0610.v1
Subject: Keywords: Life Cycle Assessment; Bio-based materials; Flax fibre; Climate change; Aviation; Interior fittings
Online: 29 October 2020 (12:23:03 CET)
As part of the efforts to reduce the environmental impacts caused by the aviation sector, the use of bio-based instead of fossil-based materials has been assessed as a possible mitigation option. Natural Fibre Polymer Composites have proven to have a higher environmental performance in the automotive sector and are emerging as an option for weight reduction in aircraft. This study quantifies, though Life Cycle Assessment, the environmental performance of specific flax-based composite panels intended for aircrafts as interior fitting elements (i.e. partition panels, tray tables, baggage compartments) compared to a glass fibre/epoxy composite with a honeycomb core. Through system expansion, the fate of co-products issued from the production of the flax fibre technical textile used as reinforcement in the biocomposite material were considered in the assessment. Results showed that for an application in the aeronautics sector, the weight of the panels is the upmost critical parameter shaping the overall environmental performance of panels. Focusing on the panel production only, the biocomposite panel showed a higher environmental performance in the categories of climate change and marine eutrophication compared to the conventional panel, and the fire suppressant agent was identified as the main contributor to the environmental impacts of the bio-based panel. Yet these gains were negligible when considering the full life cycle of the panels, due to the higher weight (14%) of the bio-based panels; which is linked to the bio-based panel being at a prototype stage.In order to improve the environmental performance of the biocomposite panel and thus reduce its weight, it was shown relevant to optimize geometry of the panel itself, especially its core, so less resin could be used.
ARTICLE | doi:10.20944/preprints201811.0336.v1
Subject: Biology, Plant Sciences Keywords: pasmo resistance, pasmo severity, quantitative trait loci (QTL), quantitative trait nucleotides (QTNs), fiber, linseed, core collection, flax, Linum usitatissimum
Online: 14 November 2018 (10:45:20 CET)
Pasmo is one of the most widespread diseases threatening flax production. To identify genetic regions associated with pasmo resistance (PR), a genome-wide association study was performed on 370 accessions from the flax core collection. Evaluation of pasmo severity was performed in the field from 2012 to 2016 in Morden, MB, Canada. Genotyping-by-sequencing has identified 258,873 single nucleotide polymorphisms (SNPs) distributed on all 15 flax chromosomes. Marker-trait associations were identified using ten different statistical models. A total of 692 unique quantitative trait nucleotides (QTNs) associated with 500 putative quantitative trait loci (QTL) were detected from six phenotypic PR datasets (five individual years and average across years). Different QTNs were identified with various statistical models and from individual PR datasets, indicative of the complementation between analytical methods and/or genotype × environment interactions of the QTL effects. The single-locus models tended to identify large-effect QTNs while the multi-loci models were able to detect QTNs with smaller effects. Among the putative QTL, 67 had large effects (3-23%), were stable across all datasets and explained 32-64% of the total variation for PR in the various datasets. Forty-five of these QTL spanned 85 resistance gene analogs including a large toll interleukin receptor, nucleotide-binding site, leucine-rich repeat (TNL) type gene cluster on chromosome 8. The number of positive effect QTL (NPQTL) in accessions was significantly correlated with PR (R2=0.55), suggesting additive effects. NPQTL was also significantly associated with morphotype (R2=0.52) and major positive effect QTL were present in the fiber type accessions. The 67 large effect QTL are suited for marker-assisted selection and the 500 QTL for effective genomic prediction in PR molecular breeding.
ARTICLE | doi:10.20944/preprints201811.0623.v1
Subject: Biology, Plant Sciences Keywords: genomic selection; genomic prediction; genotyping by sequencing; pasmo resistance; pasmo severity; quantitative trait loci; single nucleotide polymorphism; Septoria linicola; flax
Online: 30 November 2018 (08:39:11 CET)
Pasmo (Septoria linicola) is a fungal disease causing major losses in seed yield and quality, and stem fibre quality in flax. Pasmo resistance (PR) is quantitative and has low heritability. To improve PR breeding efficiency, the accuracy of genomic prediction (GP) was evaluated using a diverse worldwide core collection of 370 accessions. Four marker sets, including three defined by 500, 134, and 67 previously identified quantitative trait loci (QTL) and one of 52,347 PR-correlated genome-wide single nucleotide polymorphisms, were used to build ridge regression best linear unbiased prediction (RR-BLUP) models using pasmo severity (PS) data collected from field experiments performed during five consecutive years. With five-fold random cross-validation, GP accuracy as high as 0.92 was obtained from the models using the 500 QTL when the average PS was used as the training dataset. GP accuracy increased with training population size, reaching values >0.9 with training population size greater than 185. Linear regression of the observed PS with the number of positive-effect QTL in accessions provided an alternative GP approach with an accuracy of 0.86. The results demonstrate the GP models based on marker information from all identified QTL and the 5-year PS average is highly effective for PR prediction.
TECHNICAL NOTE | doi:10.20944/preprints201901.0126.v1
Subject: Life Sciences, Genetics Keywords: flax; association mapping; genome-wide association study (GWAS); simple sequence repeat (SSR); single nucleotide polymorphism (SNP); quantitative trait loci (QTL); chromosome-scale pseudomolecules
Online: 14 January 2019 (07:19:08 CET)
Quantitative trait loci (QTL) are genomic regions associated with phenotype variation of quantitative traits in a population. To date, a total of 267 QTL for 29 quantitative traits have been reported in 13 studies on flax. Of these, 200 QTL from 12 studies were identified based on genetic maps, scaffold sequences, or pre-released chromosome-scale pseudomolecules. Molecular markers for QTL identification differed across studies but were mainly based on simple sequence repeat (SSR) or single nucleotide polymorphism (SNP) markers. This article provides methods with software tools and database files to uniquely map SSR and SNP markers from different references onto the recently released chromosome-scale pseudomolecules. Using these methods, 195 QTL were successfully sorted onto the 15 flax chromosomes and grouped into 133 co-located QTL clusters. Mapping of QTL from different studies to the same reference enables comparisons and facilitates genome-wide QTL analysis, candidate gene scanning, and breeding applications.
ARTICLE | doi:10.20944/preprints201807.0397.v2
Subject: Biology, Agricultural Sciences & Agronomy Keywords: flax; genome-wide association study (GWAS); selective sweep; genotyping by sequencing (GBS); bi-parental population; single nucleotide polymorphism (SNP); seed yield; plant height; maturity; fatty acid composition
Online: 3 August 2018 (15:34:24 CEST)
A genome-wide association study (GWAS) was performed on a set of 260 lines which belong to three different bi-parental flax mapping populations. These lines were sequenced to an averaged genome coverage of 19× using the Illumina Hi-Seq platform. Phenotypic data for 11 seed yield and oil quality traits were collected in eight year/location environments. A total of 17,288 single nucleotide polymorphisms were identified, which explained more than 80% of the phenotypic variation for days to maturity (DTM), iodine value (IOD), palmitic (PAL), stearic, linoleic (LIO) and linolenic (LIN) acid contents. Twenty-three unique genomic regions associated with 33 QTL for the studied traits were detected, thereby validating four genomic regions previously identified. The 33 QTL explained 48-73% of the phenotypic variation for oil content, IOD, PAL, LIO and LIN but only 8-14% for plant height, DTM and seed yield. A genome-wide selective sweep scan for selection signatures detected 114 genomic regions that accounted for 7.82% of the flax pseudomolecule and overlapped with the 11 GWAS-detected genomic regions associated with 18 QTL for 11 traits. The results demonstrate the utility of GWAS combined with selection signatures for dissection of the genetic structure of traits and for pinpointing genomic regions for breeding improvement.