Effects of a color gradient and emoji in AR-HUD warning interfaces in autonomous vehicles on takeover performance and driver emotions.

OBJECTIVE: This study examined the effects of color gradients and emojis in an augmented reality-head-up display (AR-HUD) warning interface on driver emotions and takeover performance. METHODS: A total of 48 participants were grouped into four different warning interfaces for a simulated self-driving takeover experiment. Two-way analysis of variance and the Kruskal-Wallis test was used to analyze takeover time, mood, task load, and system availability. RESULTS: Takeover efficiency and task load did not significantly differ among the interfaces, but the interfaces with a color gradient and emoji positively affected drivers' emotions. Emojis also positively affected emotional valence, and the color gradient had a high emotional arousal effect. Both the color gradient and the emoji interfaces had an inhibitory effect on negative emotions. The emoji interface was easier to learn, reducing driver learning costs. CONCLUSIONS: These findings offer valuable insights for designing safer and more user-friendly AR-HUD interfaces for self-driving cars.

Targeted mutagenesis of flavonoid biosynthesis pathway genes reveals functional divergence in seed coat colour, oil content and fatty acid composition in Brassica napus L.

Yellow-seed is widely accepted as a good-quality trait in Brassica crops. Previous studies have shown that the flavonoid biosynthesis pathway is essential for the development of seed colour, but its function in Brassica napus, an important oil crop, is poorly understood. To systematically explore the gene functions of the flavonoid biosynthesis pathway in rapeseed, several representative TRANSPARENT TESTA (TT) genes, including three structural genes (BnaTT7, BnaTT18, BnaTT10), two regulatory genes (BnaTT1, BnaTT2) and a transporter (BnaTT12), were selected for targeted mutation by CRISPR/Cas9 in the present study. Seed coat colour, lignin content, seed quality and yield-related traits were investigated in these Bnatt mutants together with Bnatt8 generated previously. These Bnatt mutants produced seeds with an elevated seed oil content and decreased pigment and lignin accumulation in the seed coat without any serious defects in the yield-related traits. In addition, the fatty acid (FA) composition was also altered to different degrees, i.e., decreased oleic acid and increased linoleic acid and α-linolenic acid, in all Bnatt mutants except Bnatt18. Furthermore, gene expression analysis revealed that most of BnaTT mutations resulted in the down-regulation of key genes related to flavonoid and lignin synthesis, and the up-regulation of key genes related to lipid synthesis and oil body formation, which may contribute to the phenotype. Collectively, our study generated valuable resources for breeding programs, and more importantly demonstrated the functional divergence and overlap of flavonoid biosynthesis pathway genes in seed coat colour, oil content and FA composition of rapeseed.

Fine mapping and candidate gene analysis of a major QTL for oil content in the seed of Brassica napus.

KEY MESSAGE: By integrating QTL fine mapping and transcriptomics, a candidate gene responsible for oil content in rapeseed was identified. The gene is anticipated to primarily function in photosynthesis and photosystem metabolism pathways. Brassica napus is one of the most important oil crops in the world, and enhancing seed oil content is an important goal in its genetic improvement. However, the underlying genetic basis for the important trait remains poorly understood in this crop. We previously identified a major locus, OILA5 responsible for seed oil content on chromosome A5 through genome-wide association study. To better understand the genetics of the QTL, we performed fine mapping of OILA5 with a double haploid population and a BC3F2 segregation population consisting of 6227 individuals. We narrowed down the QTL to an approximate 43 kb region with twelve annotated genes, flanked by markers ZDM389 and ZDM337. To unveil the potential candidate gene responsible for OILA5, we integrated fine mapping data with transcriptome profiling using high and low oil content near-isogenic lines. Among the candidate genes, BnaA05G0439400ZS was identified with high expression levels in both seed and silique tissues. This gene exhibited homology with AT3G09840 in Arabidopsis that was annotated as cell division cycle 48. We designed a site-specific marker based on resequencing data and confirmed its effectiveness in both natural and segregating populations. Our comprehensive results provide valuable genetic information not only enhancing our understanding of the genetic control of seed oil content but also novel germplasm for advancing high seed oil content breeding in B. napus and other oil crops.

Targeted mutagenesis of BnaSTM leads to abnormal shoot apex development and cotyledon petiole fusion at the seedling stage in Brassica napus L.

The Arabidopsis homeodomain transcription factor SHOOT MERISTEMLESS (STM) is crucial for shoot apical meristem (SAM) function, which cooperates with CLAVATA3 (CLV3)/WUSCHEL (WUS) feedback regulation loops to maintain the homeostasis of stem cells in SAM. STM also interacts with the boundary genes to regulate the tissue boundary formation. However, there are still few studies on the function of STM in Brassica napus, an important oil crop. There are two homologs of STM in B. napus (BnaA09g13310D and BnaC09g13580D). In the present study, CRISPR/Cas9 technology was employed to create the stable site-directed single and double mutants of the BnaSTM genes in B. napus. The absence of SAM could be observed only in the BnaSTM double mutants at the mature embryo of seed, indicating that the redundant roles of BnaA09.STM and BnaC09.STM are vital for regulating SAM development. However, different from Arabidopsis, the SAM gradually recovered on the third day after seed germination in Bnastm double mutants, resulting in delayed true leaves development but normal late vegetative and reproductive growth in B. napus. The Bnastm double mutant displayed a fused cotyledon petiole phenotype at the seedling stage, which was similar but not identical to the Atstm in Arabidopsis. Further, transcriptome analysis showed that targeted mutation of BnaSTM caused significant changes for genes involved in the SAM boundary formation (CUC2, CUC3, LBDs). In addition, Bnastm also caused significant changes of a sets of genes related to organogenesis. Our findings reveal that the BnaSTM plays an important yet distinct role during SAM maintenance as compared to Arabidopsis.

Precise A∙T to G∙C base editing in the allotetraploid rapeseed (Brassica napus L.) genome.

Rapeseed is an important source of oilseed crop in the world. Achieving genetic improvement has always been the major goal in rapeseed production. Single nucleotide substitution is the basis of most genetic variation underpinning important agronomic traits. Nowadays, Cas-base editing acts as an efficient tool to mediate single-base substitution at the target site. In this study, four adenine base editors (ABE) were modified to achieve adenosine base editing at different genome sites in allotetraploid Brassica napus. We designed 18 small guide RNAs to target phytoene desaturase (PDS), acetolactate synthase (ALS), CLAVATA3 (CLV3), CLV2, TRANSPARENT TESTA12 (TT12), carotenoid isomerase (CRTISO), designated de-etiolated-2 (DET2), BRANCHED1 (BRC1), zeaxanthin epoxidase (ZEP) genes, respectively. Among the four ABE systems, pBGE17 had the highest base-editing efficiency, with an average editing efficiency of 3.51%. Target sequencing results revealed that the editing window ranged from A5 to A8 of the protospacer-adjacent motif (PAM) sequence. Moreover, the ABEmax-nCas9NG system with NG PAM was developed, with a base-editing efficiency of 1.22%. These results revealed that ABE system developed in this study could efficiently induce A to G substitution and the ABE-nCas9NG system could broaden editing window in oilseed rape.

Site-Directed Mutagenesis of the Carotenoid Isomerase Gene BnaCRTISO Alters the Color of Petals and Leaves in Brassica napus L.

The diversity of petal and leaf color can improve the ornamental value of rapeseed and promote the development of agriculture and tourism. The two copies of carotenoid isomerase gene (BnaCRTISO) in Brassica napus (BnaA09.CRTISO and BnaC08.CRTISO) was edited using the CRISPR/Cas9 system in the present study. The mutation phenotype of creamy white petals and yellowish leaves could be recovered only in targeted mutants of both BnaCRTISO functional copies, indicating that the redundant roles of BnaA09.CRTISO and BnaC08.CRTISO are vital for the regulation of petal and leaf color. The carotenoid content in the petals and leaves of the BnaCRTISO double mutant was significantly reduced. The chalcone content, a vital substance that makes up the yellow color, also decreased significantly in petals. Whereas, the contents of some carotenes (lycopene, α-carotene, γ-carotene) were increased significantly in petals. Further, transcriptome analysis showed that the targeted mutation of BnaCRTISO resulted in the significant down-regulation of important genes BnaPSY and BnaC4H in the carotenoid and flavonoid synthesis pathways, respectively; however, the expression of other genes related to carotenes and xanthophylls synthesis, such as BnaPDS3, BnaZEP, BnaBCH1 and BCH2, was up-regulated. This indicates that the molecular mechanism regulating petal color variation in B. napus is more complicated than those reported in Arabidopsis and other Brassica species. These results provide insight into the molecular mechanisms underlying flower color variation in rapeseed and provides valuable resources for rapeseed breeding.

Influence of Multi-Modal Warning Interface on Takeover Efficiency of Autonomous High-Speed Train.

As a large-scale public transport mode, the driving safety of high-speed rail has a profound impact on public health. In this study, we determined the most efficient multi-modal warning interface for automatic driving of a high-speed train and put forward suggestions for optimization and improvement. Forty-eight participants were selected, and a simulated 350 km/h high-speed train driving experiment equipped with a multi-modal warning interface was carried out. Then, the parameters of eye movement and behavior were analyzed by independent sample Kruskal-Wallis test and one-way analysis of variance. The results showed that the current level 3 warning visual interface of a high-speed train had the most abundant warning graphic information, but it failed to increase the takeover efficiency of the driver. The visual interface of the level 2 warning was more likely to attract the attention of drivers than the visual interface of the level 1 warning, but it still needs to be optimized in terms of the relevance of and guidance between graphic-text elements. The multi-modal warning interface had a faster response efficiency than the single-modal warning interface. The auditory-visual multi-modal interface had the highest takeover efficiency and was suitable for the most urgent (level 3) high-speed train warning. The introduction of an auditory interface could increase the efficiency of a purely visual interface, but the introduction of a tactile interface did not improve the efficiency. These findings can be used as a basis for the interface design of automatic driving high-speed trains and help improve the active safety of automatic driving high-speed trains, which is of great significance to protect the health and safety of the public.

Fine mapping and candidate gene analysis of a major locus controlling ovule abortion and seed number per silique in Brassica napus L.

KEY MESSAGE: A major QTL controlling ovule abortion and SN was fine-mapped to a 80.1-kb region on A8 in rapeseed, and BnaA08g07940D and BnaA08g07950D are the most likely candidate genes. The seed number per silique (SN), an important yield determining trait of rapeseed, is the final consequence of a complex developmental process including ovule initiation and the subsequent ovule/seed development. To explore the genetic mechanism regulating the natural variation of SN and its related components, quantitative trait locus (QTL) mapping was conducted using a doubled haploid (DH) population derived from the cross between C4-146 and C4-58B, which showed significant differences in SN and aborted ovule number (AON), but no obvious differences in ovule number (ON). QTL analysis identified 19 consensus QTLs for six SN-related traits across three environments. A novel QTL on chromosome A8, un.A8, which associates with multiple traits, except for ON, was stably detected across the three environments. This QTL explained more than 50% of the SN, AON and percentage of aborted ovules (PAO) variations as well as a moderate contribution on silique length (SL) and thousand seed weight (TSW). The C4-146 allele at the locus increases SN and SL but decreases AON, PAO and TSW. Further fine mapping narrowed down this locus into an 80.1-kb interval flanked by markers BM1668 and BM1672, and six predicted genes were annotated in the delimited region. Expression analyses and DNA sequencing showed that two homologs of Arabidopsis photosystem I subunit F (BnaA08g07940D) and zinc transporter 10 precursor (BnaA08g07950D) were the most promising candidate genes underlying this locus. These results provide a solid basis for cloning un.A8 to reduce the ovule abortion and increase SN in the yield improvement of rapeseed.

Precision Genome Engineering Through Cytidine Base Editing in Rapeseed (Brassica napus. L).

Rapeseed is one of the world's most important sources of oilseed crops. Single nucleotide substitution is the basis of most genetic variation underpinning important agronomic traits. Therefore, genome-wide and target-specific base editing will greatly facilitate precision plant molecular breeding. In this study, four CBE systems (BnPBE, BnA3A-PBE, BnA3A1-PBE, and BnPBGE14) were modified to achieve cytidine base editing at five target genes in rapeseed. The results indicated that genome editing is achievable in three CBEs systems, among which BnA3A1-PBE had the highest base-editing efficiency (average 29.8% and up to 50.5%) compared to all previous CBEs reported in rapeseed. The editing efficiency of BnA3A1-PBE is ~8.0% and fourfold higher, than those of BnA3A-PBE (averaging 27.6%) and BnPBE (averaging 6.5%), respectively. Moreover, BnA3A1-PBE and BnA3A-PBE could significantly increase the proportion of both the homozygous and biallelic genotypes, and also broaden the editing window compared to BnPBE. The cytidine substitution which occurred at the target sites of both BnaA06.RGA and BnaALS were stably inherited and conferred expected gain-of-function phenotype in the T1 generation (i.e., dwarf phenotype or herbicide resistance for weed control, respectively). Moreover, new alleles or epialleles with expected phenotype were also produced, which served as an important resource for crop improvement. Thus, the improved CBE system in the present study, BnA3A1-PBE, represents a powerful base editor for both gene function studies and molecular breeding in rapeseed.

Targeted mutagenesis of BnTT8 homologs controls yellow seed coat development for effective oil production in Brassica napus L.

Yellow seed is a desirable trait with great potential for improving seed quality in Brassica crops. Unfortunately, no natural or induced yellow seed germplasms have been found in Brassica napus, an important oil crop, which likely reflects its genome complexity and the difficulty of the simultaneous random mutagenesis of multiple gene copies with functional redundancy. Here, we demonstrate the first application of CRISPR/Cas9 for creating yellow-seeded mutants in rapeseed. The targeted mutations of the BnTT8 gene were stably transmitted to successive generations, and a range of homozygous mutants with loss-of-function alleles of the target genes were obtained for phenotyping. The yellow-seeded phenotype could be recovered only in targeted mutants of both BnTT8 functional copies, indicating that the redundant roles of BnA09.TT8 and BnC09.TT8b are vital for seed colour. The BnTT8 double mutants produced seeds with elevated seed oil and protein content and altered fatty acid (FA) composition without any serious defects in the yield-related traits, making it a valuable resource for rapeseed breeding programmes. Chemical staining and histological analysis showed that the targeted mutations of BnTT8 completely blocked the proanthocyanidin (PA)-specific deposition in the seed coat. Further, transcriptomic profiling revealed that the targeted mutations of BnTT8 resulted in the broad suppression of phenylpropanoid/flavonoid biosynthesis genes, which indicated a much more complex molecular mechanism underlying seed colour formation in rapeseed than in Arabidopsis and other Brassica species. In addition, gene expression analysis revealed the possible mechanism through which BnTT8 altered the oil content and fatty acid composition in seeds.