Modeling of flaxseed protein, oil content, linoleic acid, and lignan content prediction based on hyperspectral imaging.

Protein, oil content, linoleic acid, and lignan are several key indicators for evaluating the quality of flaxseed. In order to optimize the testing methods for flaxseed's nutritional quality and enhance the efficiency of screening high-quality flax germplasm resources, we selected 30 flaxseed species widely cultivated in Northwest China as the subjects of our study. Firstly, we gathered hyperspectral information regarding the seeds, along with data on protein, oil content, linoleic acid, and lignan, and utilized the SPXY algorithm to classify the sample set. Subsequently, the spectral data underwent seven distinct preprocessing methods, revealing that the PLSR model exhibited superior performance after being processed with the SG smoothing method. Feature wavelength extraction was carried out using the Successive Projections Algorithm (SPA) and the Competitive Adaptive Reweighted Sampling (CARS). Finally, four quantitative analysis models, namely Partial Least Squares Regression (PLSR), Support Vector Regression (SVR), Multiple Linear Regression (MLR), and Principal Component Regression (PCR), were individually established. Experimental results demonstrated that among all the models for predicting protein content, the SG-CARS-MLR model predicted the best, with and of 0.9563 and 0.9336, with the corresponding Root Mean Square Error Correction (RMSEC) and Root Mean Square Error Prediction (RMSEP) of 0.4892 and 0.5616, respectively. In the optimal prediction models for oil content, linoleic acid and lignan, the Rp2 was 0.8565, 0.8028, 0.9343, and the RMSEP was 0.8682, 0.5404, 0.5384, respectively. The study results show that hyperspectral imaging technology has excellent potential for application in the detection of quality characteristics of flaxseed and provides a new option for the future non-destructive testing of the nutritional quality of flaxseed.

Phosphorus and naphthalene acetic acid increased the seed yield by regulating carbon and nitrogen assimilation of flax.

To evaluate the impact of phosphorus (P) combined with exogenous NAA on flax yield, enhance flax P utilization efficiency and productivity, minimize resource inputs and mitigate negative environmental and human effects. Therefore, it is crucial to comprehend the physiological and biochemical responses of flax to P and naphthylacetic acid (NAA) in order to guide future agronomic management strategies for increasing seed yield. A randomized complete block design trial was conducted under semi-arid conditions in Northwest China, using a factorial split-plot to investigate the effects of three P (0, 67.5, and 135.0 kg P2O5 ha-1) and three exogenous spray NAA levels (0, 20, and 40 mg NAA L-1) on sucrose phosphate synthase (SPS) and diphosphoribulose carboxylase (Rubisco) activities as well as nitrogen (N) and P accumulation and translocation in flax. Results indicated that the SPS and Rubisco activities, N and P accumulation at flowering and maturity along with assimilation and translocation post-flowering, fruiting branches per plant, tillers per plant, capsules per plant, and seed yield were 95, 105, 14, 27, 55, 15, 13, 110, 103, 82, 16, 61, 8, and 13% greater in the P treatments compared to those in the zero P treatment, respectively. Moreover, those characteristics were observed to be greater with exogenous spray NAA treatments compared to that no spray NAA treatment. Additionally, the maximum SPS and Rubisco activities, N and P accumulation, assimilation post-flowering and translocation, capsules per plant, and seed yield were achieved with the application of 67.5 kg P2O5 ha-1 with 20 mg NAA L-1. Therefore, these findings demonstrate that the appropriate combination of P fertilizer and spray NAA is an effective agronomic management strategy for regulating carbon and nitrogen assimilation by maintaining photosynthetic efficiency in plants to increase flax productivity.

Genome-Wide Identification and Expression Analysis of Auxin Response Factor Gene Family in Linum usitatissimum.

Auxin response factors (ARFs) are critical components of the auxin signaling pathway, and are involved in diverse plant biological processes. However, ARF genes have not been investigated in flax (Linum usitatissimum L.), an important oilseed and fiber crop. In this study, we comprehensively analyzed the ARF gene family and identified 33 LuARF genes unevenly distributed on the 13 chromosomes of Longya-10, an oil-use flax variety. Detailed analysis revealed wide variation among the ARF family members and predicted nuclear localization for all proteins. Nineteen LuARFs contained a complete ARF structure, including DBD, MR, and CTD, whereas the other fourteen lacked the CTD. Phylogenetic analysis grouped the LuARFs into four (I-V) clades. Combined with sequence analysis, the LuARFs from the same clade showed structural conservation, implying functional redundancy. Duplication analysis identified twenty-seven whole-genome-duplicated LuARF genes and four tandem-duplicated LuARF genes. These duplicated gene pairs' Ka/Ks ratios suggested a strong purifying selection pressure on the LuARF genes. Collinearity analysis revealed that about half of the LuARF genes had homologs in other species, indicating a relatively conserved nature of the ARFs. The promoter analysis identified numerous hormone- and stress-related elements, and the qRT-PCR experiment revealed that all LuARF genes were responsive to phytohormone (IAA, GA3, and NAA) and stress (PEG, NaCl, cold, and heat) treatments. Finally, expression profiling of LuARF genes in different tissues by qRT-PCR indicated their specific functions in stem or capsule growth. Thus, our findings suggest the potential functions of LuARFs in flax growth and response to an exogenous stimulus, providing a basis for further functional studies on these genes.

Phenotypic analysis of Longya-10 × pale flax hybrid progeny and identification of candidate genes regulating prostrate/erect growth in flax plants.

Flax is a dual-purpose crop that is important for oil and fiber production. The growth habit is one of the crucial targets of selection during flax domestication. Wild hybridization between cultivated flax and wild flax can produce superior germplasms for flax breeding and facilitate the study of the genetic mechanism underlying agronomically important traits. In this study, we used pale flax, Linum grandiflorum, and L. perenne to pollinate Longya-10. Only pale flax interspecific hybrids were obtained, and the trait analysis of the F1 and F2 generations showed that the traits analyzed in this study exhibited disparate genetic characteristics. In the F1 generation, only one trait, i.e., the number of capsules per plant (140) showed significant heterosis, while the characteristics of other traits were closely associated with those of the parents or a decline in hybrid phenotypes. The traits of the F2 generation were widely separated, and the variation coefficient ranged from 9.96% to 146.15%. The quantitative trait locus underlying growth habit was preliminarily found to be situated on chromosome 2 through Bulked-segregant analysis sequencing. Then linkage mapping analysis was performed to fine-map GH2.1 to a 23.5-kb interval containing 4 genes. Among them, L.us.o.m.scaffold22.109 and L.us.o.m.scaffold22.112 contained nonsynonymous SNPs with Δindex=1. Combined with the qRT-PCR results, the two genes might be possible candidate genes for GH2.1. This study will contribute to the development of important germplasms for flax breeding, which would facilitate the elucidation of the genetic mechanisms regulating the growth habit and development of an ideal architecture for the flax plant.

Overexpression of WRINKLED1 improves the weight and oil content in seeds of flax (Linum usitatissimum L.).

Seeds of flax (Linum usitatissimum L.) are highly rich in both oil and linolenic acid (LIN). It is crucial for flax agricultural production to identify positive regulators of fatty acid biosynthesis. In this study, we find that WRINKLED1 transcription factors play important positive roles during flax seed oil accumulation. Two WRINKLED1 genes, LuWRI1a and LuWRI1b, were cloned from flax, and LuWRI1a was found be expressed predominantly in developing seeds during maturation. Overexpression of LuWRI1a increased seed size, weight, and oil content in Arabidopsis and increased seed storage oil content in transgenic flax without affecting seed production or seed oil quality. The rise in oil content in transgenic flax seeds was primarily attributable to the increase in seed weight, according to a correlational analysis. Furthermore, overexpression or interference of LuWRI1a upregulated the expression of genes in the fatty acid biosynthesis pathway and LAFL genes, and the expression level of WRI1 was highly significantly positively associated between L1L, LEC1, and BCCP2. Our findings give a theoretical scientific foundation for the future application of genetic engineering to enhance the oil content of plant seeds.

Genomic Comparison and Population Diversity Analysis Provide Insights into the Domestication and Improvement of Flax.

Flax has been cultivated for its oil and fiber for thousands of years. However, it remains unclear how the modifications of agronomic traits occurred on the genetic level during flax cultivation. In this study, we conducted genome-wide variation analyses on multiple accessions of oil-use, fiber-use, landraces, and pale flax to identify the genomic variations during flax cultivation. Our findings indicate that, during flax domestication, genes relevant to flowering, dehiscence, oil production, and plant architecture were preferentially selected. Furthermore, regardless of origins, the improvement of the modern oil-use flax preceded that of the fiber-use flax, although the dual selection on oil-use and fiber-use characteristics might have occurred in the early flax domestication. We also found that the expansion of MYB46/MYB83 genes may have contributed to the unique secondary cell wall biosynthesis in flax and the directional selections on MYB46/MYB83 may have shaped the morphological profile of the current oil-use and fiber-use flax.

A reverse transcription loop-mediated isothermal amplification assay to rapidly diagnose foot-and-mouth disease virus C.

A reverse transcription loop-mediated isothermal amplification (RT-LAMP) assay was developed to rapidly detect foot-and-mouth disease virus serotype C (FMDV C). By testing 10-fold serial dilutions of FMDV C samples, sensitivity of the FMDV C RT-LAMP was found to be 10 times higher than that of conventional reverse transcription- PCR (RT-PCR). No cross-reactivity with A, Asia 1, or O FMDV or swine vesicular disease virus (SVDV) indicated that FMDV C RT-LAMP may be an exciting novel method for detecting FMDV C.