Genome-wide identification and expression analysis of the R2R3-MYB gene family in tobacco (Nicotiana tabacum L.).

BACKGROUND: The R2R3-MYB transcription factor is one of the largest gene families in plants and involved in the regulation of plant development, hormone signal transduction, biotic and abiotic stresses. Tobacco is one of the most important model plants. Therefore, it will be of great significance to investigate the R2R3-MYB gene family and their expression patterns under abiotic stress and senescence in tobacco. RESULTS: A total of 174 R2R3-MYB genes were identified from tobacco (Nicotiana tabacum L.) genome and were divided into 24 subgroups based on phylogenetic analysis. Gene structure (exon/intron) and protein motifs were especially conserved among the NtR2R3-MYB genes, especially members within the same subgroup. The NtR2R3-MYB genes were distributed on 24 tobacco chromosomes. Analysis of gene duplication events obtained 3 pairs of tandem duplication genes and 62 pairs of segmental duplication genes, suggesting that segmental duplications is the major pattern for R2R3-MYB gene family expansion in tobacco. Cis-regulatory elements of the NtR2R3-MYB promoters were involved in cellular development, phytohormones, environmental stress and photoresponsive. Expression profile analysis showed that NtR2R3-MYB genes were widely expressed in different maturity tobacco leaves, and however, the expression patterns of different members appeared to be diverse. The qRT-PCR analysis of 15 NtR2R3-MYBs confirmed their differential expression under different abiotic stresses (cold, salt and drought), and notably, NtMYB46 was significantly up-regulated under three treatments. CONCLUSIONS: In summary, a genome-wide identification, evolutionary and expression analysis of R2R3-MYB gene family in tobacco were conducted. Our results provided a solid foundation for further biological functional study of NtR2R3-MYB genes in tobacco.

Epidemiological characteristics and influencing factors of scoliosis in primary and secondary school students in Guangdong Province / 中国学校卫生

Objective@#To investigate the epidemiological characteristics and associated factors of scoliosis in primary and secondary school students in Guangdong, and to provide guidance for scoliosis control.@*Methods@#Using a stratified cluster random sampling method, a total of 38 649 students aged 9-18 were selected from 132 primary and secondary schools in the Pearl River Delta and non Pearl River Delta cities for scoliosis screening and related associated factors questionnaire survey from September to October 2020.@*Results@#A total of 1 440 students were detected with scoliosis, with a detection rate of 3.73%. The detection rate of girls was 4.90%, which was higher than that of boys at 2.66%( χ 2=386.89, P <0.01). The detection rate in the Pearl River Delta region was 4.09%, which was higher than the non Pearl River Delta region at 3.38%( χ 2=13.22, P <0.01). The detection rate in urban areas was 4.51%, which was higher than counties at 2.79%( χ 2=78.70, P <0.01). The detection rate increased with the increase of the school period, high school (5.94%)>junior high school (4.50%)>elementary school (1.35%)( χ 2=386.89, P <0.01). Multivariate Logistic regression analysis showed that region, urbanicity, gender, educational stage, exercise, using electronic mobile devices, nutritional status are the influencing factors for scoliosis ( OR=0.41-3.78, P <0.05).@*Conclusion@#The detection rate of scoliosis in primary and secondary school students in Guangdong Province varies by gender, urbanicity and educational stages. Female students, as well as junior and senior high school students should be paid more attention.

Trends of substance abuse behavior among adolescents in Guangdong Province, 2007-2016 / 中国学校卫生

Objective@#To analyle prevalence and trend of substance abuse behaviors among adolescents in Guangdong province and to provide theoretical evidence for effective interventions.@*Methods@#Data regarding smoking, drinking, drugs abuse from Adolescents Health Risk Behavior Survey in 2007, 2010, 2013 and 2016 were collected and comparatively analyzed.@*Results@#The incidences of tried smoking(27.37%), current smoking(8.32%), passive smoking(45.52%), current drinking(27.97%) and drug using(0.75%) in 2016 were lower than that in 2007(32.40%, 10.81%, 52.69%, 31.97%, 1.35%), and the average annual decrease rate were 1.89%, 2.95%, 1.64%, 1.50%, 6.75%, respectively(χ2=152.73, 92.50, 313.92, 46.48, 46.64, P<0.01). During the past decate, the incidences of current smoking in rural adolescents(12.02%, 10.64%, 9.99%, 10.10%) were significantly higher than that in urban adolescents(8.88%, 8.52%, 8.17%, 6.56%)(χ2=54.46, 26.62, 25.23, 100.43, P<0.01); the incidences of current drinking in urban adolescents(33.57%, 30.37%, 35.76%, 30.46%) were significantly higher than that in rural adolescents(30.97%, 28.48%, 28.47%, 25.32%)(χ2=16.71, 10.13, 153.47, 81.76, P<0.01); the incidence of current drinking was the highest among college students in each monitoring year(47.71%, 41.76%, 42.36%, 37.77%)(χ2=583.37, 681.25, 610.04, 729.02, P<0.01); the incidence of current smoking was the highest among vocational school students in each monitoring year(16.36%, 17.00%, 14.90%, 16.71%)(χ2=256.45, 515.61, 339.63, 742.52, P<0.01); In addition to the incidence of drug abuse was the highest among college students in 2010(2.02%), vocational school students were the highest in other years(χ2=66.92, 34.38, 23.08, 20.55, P<0.01).@*Conclusion@#Smoking and drug abuse among adolescents in Guangdong showed a declining trend by years, as well as the prevalence of drinking behavior. Strengthened intervention should be targeted on smoking behavior among rural students, drinking behavior among urban students, and smoking behavior and drug abuse among vocational school students.