Telomere-to-telomere assembly of cassava genome reveals the evolution of cassava and divergence of allelic expression.

Cassava is a crucial crop that makes a significant contribution to ensuring human food security. However, high-quality telomere-to-telomere cassava genomes have not been available up to now, which has restricted the progress of haploid molecular breeding for cassava. In this study, we constructed two nearly complete haploid resolved genomes and an integrated, telomere-to-telomere gap-free reference genome of an excellent cassava variety, 'Xinxuan 048', thereby providing a new high-quality genomic resource. Furthermore, the evolutionary history of several species within the Euphorbiaceae family was revealed. Through comparative analysis of haploid genomes, it was found that two haploid genomes had extensive differences in linear structure, transcriptome features, and epigenetic characteristics. Genes located within the highly divergent regions and differentially expressed alleles are enriched in the functions of auxin response and the starch synthesis pathway. The high heterozygosity of cassava 'Xinxuan 048' leads to rapid trait segregation in the first selfed generation. This study provides a theoretical basis and genomic resource for molecular breeding of cassava haploids.

Fear of COVID-19 and the career maturity of Chinese international high school students: The mediating effect of the intolerance of uncertainty.

This study examined the influencing mechanism underlying the relationship between the fear of COVID-19 and Chinese international high school students' career maturity by investigating the mediating role of the intolerance of uncertainty. The results indicated that the fear of COVID-19 and the intolerance of uncertainty are negatively associated with international high school students' career maturity. Moreover, intolerance of uncertainty plays a mediating role in the relationship between the fear of COVID-19 and career maturity. The findings contribute to the literature on mental health and have important practical implications for international high school students' mental health and career development.

Chromosome-level and graphic genomes provide insights into metabolism of bioactive metabolites and cold-adaption of Pueraria lobata var. montana.

Pueraria lobata var. montana (P. montana) belongs to the genus Pueraria and originated in Asia. Compared with its sister P. thomsonii, P. montana has stronger growth vigour and cold-adaption but contains less bioactive metabolites such as puerarin. To promote the investigation of metabolic regulation and genetic improvement of Pueraria, the present study reports a chromosome-level genome of P. montana with length of 978.59 Mb and scaffold N50 of 80.18 Mb. Comparative genomics analysis showed that P. montana possesses smaller genome size than that of P. thomsonii owing to less repeat sequences and duplicated genes. A total of 6,548 and 4,675 variety-specific gene families were identified in P. montana and P. thomsonii, respectively. The identified variety-specific and expanded/contracted gene families related to biosynthesis of bioactive metabolites and microtubules are likely the causes for the different characteristics of metabolism and cold-adaption of P. montana and P. thomsonii. Moreover, a graphic genome was constructed based on 11 P. montana accessions. Total 92 structural variants were identified and most of which are related to stimulus-response. In conclusion, the chromosome-level and graphic genomes of P. montana will not only facilitate the studies of evolution and metabolic regulation, but also promote the breeding of Pueraria.

DNA Methylome and LncRNAome Analysis Provide Insights Into Mechanisms of Genome-Dosage Effects in Autotetraploid Cassava.

Whole genome duplication (WGD) increases the dosage of all coding and non-coding genes, yet the molecular implications of genome-dosage effects remain elusive. In this study, we generated integrated maps of the methylomes and lncRNAomes for diploid and artificially generated autotetraploid cassava (Manihot esculenta Crantz). We found that transposable elements (TEs) suppressed adjacent protein coding gene (PCG)-expression levels, while TEs activated the expression of nearby long non-coding RNAs (lncRNAs) in the cassava genome. The hypermethylation of DNA transposons in mCG and mCHH sites may be an effective way to suppress the expression of nearby PCGs in autotetraploid cassava, resulting in similar expression levels for most of PCGs between autotetraploid and diploid cassava. In the autotetraploid, decreased methylation levels of retrotransposons at mCHG and mCHH sites contributed to reduced methylation of Gypsy-neighboring long intergenic non-coding RNAs, potentially preserving diploid-like expression patterns in the major of lncRNAs. Collectively, our study highlighted that WGD-induced DNA methylation variation in DNA transposons and retrotransposons may be as direct adaptive responses to dosage of all coding-genes and lncRNAs, respectively.

Effects of Leader-Follower Extraversion Congruence and Sectoral Difference on Leader-Member Exchange: A Cross-Sectional Study.

PURPOSE: Drawing upon self-categorization theory and the comparative literature on public and private sectors, the purpose of this study is to examine whether leader-follower extraversion congruence is positively related to leader-member exchange (LMX) and whether congruence at high levels of extraversion results in higher LMX than congruence at low levels. Furthermore, the study aims to investigate the moderating role of sectoral difference in the relationship between extraversion fit and LMX. METHODS: Participants were 320 leader-follower dyads (53 leaders and 320 followers) from various public and private sectors in the Chinese cultural context. The extraversion part of the Revised NEO Personality Inventory (NEO-PI-R) and leader-member exchange multidimensional measure (LMX-MDM) were used to measure extraversion and LMX, respectively. Hypotheses were tested using cross-level moderated polynomial regression and response surface analysis. RESULTS: Leader-follower extraversion congruence was not significantly associated with LMX, and there was no significant difference in LMX between congruence at high levels of extraversion and congruence at low levels. However, sectoral difference moderated the relationship between extraversion fit and LMX. Specifically, in the public sector, leader-follower extraversion congruence was positively related to LMX, and LMX was higher when leader and follower extraversion were both at a high level compared to when they were at a low level. In the private sector, this fit effect vanished. PRACTICAL IMPLICATIONS: The results suggest that, in the public sector, when organizations deal with the deployment of staff, taking leader-follower extraversion fit into account may mitigate possible later relationship conflicts. However, in the private sector, by not emphasizing extraversion fit, organizations can focus resources on more crucial factors. ORIGINALITY/VALUE: By considering sectoral difference as the boundary condition of leader-follower extraversion fit, this study extends the comparative literature on public and private sectors and supports self-categorization theory.

Identification of Nutritional Ingredients and Medicinal Components of Pueraria lobata and Its Varieties Using UPLC-MS/MS-Based Metabolomics.

Pueraria lobata and its variety P. lobata var. thomsonii are both traditional Chinese medicines that have high nutritional and medical value; whereas another variety, P. lobata var. montana has low nutritional and medicinal value and can cause ecological disasters. The material basis of different nutritional and medicinal values, which are caused by metabolite differences among these varieties, remains to be further clarified. Here, we performed ultra performance liquid chromatography-tandem mass spectrometry based widely targeted metabolome analysis on Pueraria lobata, P. lobata var. thomsonii, and P. lobata var. montana. Among them, a total of 614 metabolites were identified, and distinguished from each other using orthogonal partial least squares discriminant analysis. Our results suggest that the nutritional differences between P. lobata and its varieties can be explained by variations in the abundance of amino acids, nucleotides, saccharides, and lipids; differences in flavonoids, isoflavones, phenolic acids, organic acids, and coumarins contents caused the differences in the medicinal quality of P. lobata and its varieties. Additionally, the key metabolites responsible for the classification of the three Pueraria varieties were identified. This study provides new insights into the underlying metabolic causes of nutritional and medicinal variation in P. lobata and its varieties.

Transcriptome Profiling Reveals B-Lineage Cells Contribute to the Poor Prognosis and Metastasis of Clear Cell Renal Cell Carcinoma.

Although immune therapy can improve the treatment of clear cell renal cell carcinoma (ccRCC) significantly, there are still a large proportion of ccRCC patients who progress to metastasis. Targeting the pro-metastatic immune cell in the ccRCC microenvironment could provide a solution to this problem. In this study, B cells in ccRCC biopsies were identified by using scRNA-seq and flow cytometry. The findings indicated the presence of a pro-metastatic B cell type which could be further classified into 3 subpopulations, MARCH3, B2M and DTWD1, based on their large-scaled genetic profiles, rather than traditional Immature/Mature ones. Although all of the 3 subpopulations appeared to contribute to distant metastasis, B cell (B2M) was deemed to be the most essential. Moreover, STX16, CLASRP, ATIC, ACIN1 and SEMA4B, were genes found to be commonly up-regulated in the 3 subpopulations and this was correlated to a poor prognosis of ccRCC. Furthermore, the heterogeneity of plasma cells in ccRCC was also found to contribute to metastasis of the disease. This study offers potential novel therapeutic targets against distant metastasis of cancers, and can help to improve the therapeutic efficiency of ccRCC patients.

Ego-Resiliency and Perceived Social Support in Late Childhood: A Latent Growth Modeling Approach.

This study explored the change trajectory of schoolchildren's ego-resiliency and perceived social support and investigated the effect of perceived social support on ego-resiliency across four time points. A sample of 437 children aged 8-13 years (M = 10.99, SD = 0.70, 51.5% boys) completed assessments at four time points. The results indicated that ego-resiliency showed an increasing linear trend and perceived social support showed a declining linear trend. Perceived social support had a positive effect on ego-resiliency over time. In addition, the initial status of perceived social support negatively predicted the growth trend of ego-resiliency, and the initial status of ego-resiliency negatively predicted the declining trend of perceived social support. The implications for theory and practice are discussed.

Relationships Among Leaders' and Followers' Work Engagement and Followers' Subjective Career Success: A Multilevel Approach.

Using a sample of 52 work teams (52 work team leaders and their 348 followers) in China, we investigated the influence mechanism of leaders' work engagement on their followers' work engagement and subjective career success. A multilevel structural equation model (MSEM) was applied to analyze the survey data. The results of this study indicated that leaders' work engagement positively influenced their followers' subjective career success, and this relationship was mediated by the followers' work engagement. Implications of these findings, limitations, and directions for future research are discussed in the final section of the paper.

Metabolomic and transcriptomic profiling reveals distinct nutritional properties of cassavas with different flesh colors.

Cassava is a significant food security crop in several developing countries. Metabolites in cassava roots provide numerous nutrients essential for human health. Exploiting the diversity of nutritional ingredients present in cassavas is vital for improving its nutritional value. To address this problem, root metabolomes of three cassava cultivars with white-flesh, light-yellow-flesh and yellow-flesh were comprehensively measured, respectively. A total of 508 metabolites were detected in cassava roots, including 300 primary metabolites and 185 secondary metabolites. There were 22.6% to 34.1% metabolites exhibiting significant variations among the three cassava cultivars. The light-yellow-flesh cassava contained higher contents of secondary metabolites, especially flavone, phenylpropanoids and alkaloids, and lower contents of primary metabolites except lipids, alcohols, vitamins and derivatives. Compared with light-yellow-flesh cassava, the yellow-flesh cassava contained higher contents of amino acid and derivatives, but lower contents of phenylpropanoids, nucleotide and derivates. White-flesh cassava contained higher contents of primary metabolites, especially amino acid and derivatives, but lower contents of secondary metabolites except flavonoid and indole derivatives. Transcriptome analyses were parallelly performed to decipher the potential mechanisms regulating the accumulations of related metabolites. Several pathways were both enriched by differentially expressed genes and differentially accumulated metabolites, supporting that metabolisms of these metabolites were regulated at transcriptional level. These results expand the knowledge on metabolite compositions in cassava roots and provide substantial information for genetic improvement of cassavas with high nutritional values.

Comparative physiology and transcriptome analysis allows for identification of lncRNAs imparting tolerance to drought stress in autotetraploid cassava.

BACKGROUND: Polyploidization, pervasive among higher plant species, enhances adaptation to water deficit, but the physiological and molecular advantages need to be investigated widely. Long non-coding RNAs (lncRNAs) are involved in drought tolerance in various crops. RESULTS: Herein, we demonstrate that tetraploidy potentiates tolerance to drought stress in cassava (Manihot esculenta Crantz). Autotetraploidy reduces transpiration by lesser extent increasing of stomatal density, smaller stomatal aperture size, or greater stomatal closure, and reducing accumulation of H2O2 under drought stress. Transcriptome analysis of autotetraploid samples revealed down-regulation of genes involved in photosynthesis under drought stress, and less down-regulation of subtilisin-like proteases involved in increasing stomatal density. UDP-glucosyltransferases were increased more or reduced less in dehydrated leaves of autotetraploids compared with controls. Strand-specific RNA-seq data (validated by quantitative real time PCR) identified 2372 lncRNAs, and 86 autotetraploid-specific lncRNAs were differentially expressed in stressed leaves. The co-expressed network analysis indicated that LNC_001148 and LNC_000160 in autotetraploid dehydrated leaves regulated six genes encoding subtilisin-like protease above mentioned, thereby result in increasing the stomatal density to a lesser extent in autotetraploid cassava. Trans-regulatory network analysis suggested that autotetraploid-specific differentially expressed lncRNAs were associated with galactose metabolism, pentose phosphate pathway and brassinosteroid biosynthesis, etc. CONCLUSION: Tetraploidy potentiates tolerance to drought stress in cassava, and LNC_001148 and LNC_000160 mediate drought tolerance by regulating stomatal density in autotetraploid cassava.