High prevalence of maternal mosaic monosomy X in pregnant women in Vietnam.

OBJECTIVE: To demonstrate the prevalence of maternal mosaic monosomy X (MMXO) in a cohort of pregnant women in Vietnam. METHODS: All 105,594 singleton pregnant women undergoing noninvasive prenatal screening (NIPS) between January 2019 and February 2021 in Vietnam were analyzed by measuring discordance between size- and count-based z-scores for chromosome X (ChrX) to identify suspected cases of MMXO and validated by fluorescence in situ hybridization (FISH) on maternal blood. RESULTS: We identified 295 (0.279%) suspected MMXO cases. After FISH analysis, MMXO was confirmed in 125 cases (42.37%), revealing the MMXO prevalence of 0.118% (95% CI: 0.097-0.139%) in this cohort. CONCLUSION: We found a relatively high prevalence of MMXO in Vietnamese pregnant women and demonstrated a strong influence of MMXO on the ChrX z-score using a count-based method, resulting in false positives. The size-based method is not sensitive to MMXO and therefore achieves higher PPV.

Effect of a peer-led education intervention on dietary behaviour and physical activity among adolescents in Ho Chi Minh City, Vietnam: a pilot study.

This pilot study aimed to evaluate the effectiveness of peer-led education intervention on physical activity, sedentary behaviours, and dietary behaviours among adolescents in HCM city, Vietnam. Among students in the intervention arm after a 9-month follow-up, total energy intake was reduced by 304 kcal/day, fat by 13 g/day, carbohydrate by 39 g/day, and sweet foods by 20 g/day, compared to pre-intervention figures (p < 0.05, adjusted for age, BMI at baseline, gender, the interaction between measurement time and intervention groups, and cluster effect in schools). Only total energy intake was significantly lower in the intervention than control students (p < 0.05, after adjustment). Our pilot project has established the feasibility of a peer-led intervention to improve lifestyles among adolescents in HCM city and evidence of improvements in dietary intake. Australian New Zealand Clinical Trials Registry: ACTRN12619000421134.

Systematic deletion of the ER lectin chaperone genes reveals their roles in vegetative growth and male gametophyte development in Arabidopsis.

Calnexin (CNX) and calreticulin (CRT) are homologous lectin chaperones in the endoplasmic reticulum (ER) that facilitate glycoprotein folding and retain folding intermediates to prevent their transit via the secretary pathway. The Arabidopsis genome has two CNX (CNX1 and CNX2) and three CRT (CRT1, CRT2 and CRT3) homologs. Despite growing evidence of the biological roles of CNXs and CRTs, little is understood about their function in Arabidopsis growth and development under normal conditions. Here, we report that the deletion of CNX1, but not of CNX2, in the crt1 crt2 crt3 triple mutation background had an adverse effect on pollen viability and pollen tube growth, leading to a significant reduction in fertility. The cnx1 crt1 crt2 crt3 quadruple mutation also conferred severe defects in growth and development, including a shortened primary root, increased root hair length and density, and reduced plant height. Disruption of all five members of the CNX/CRT family was revealed to be lethal. Finally, the abnormal phenotype of the cnx1 crt1 crt2 crt3 quadruple mutants was completely rescued by either the CNX1 or CNX2 cDNA under the control of the CNX1 promoter, suggesting functional redundancy between CNX1 and CNX2. Taken together, these results provide genetic evidence that CNX and CRT play essential and overlapping roles during vegetative growth and male gametophyte development in Arabidopsis.

Loss of all three calreticulins, CRT1, CRT2 and CRT3, causes enhanced sensitivity to water stress in Arabidopsis.

KEY MESSAGE: The calreticulin triple knockout mutant shows growth defects in response to abiotic stress. The endoplasmic reticulum (ER) is an essential organelle that is responsible for the folding and maturation of proteins. During ER stress, unfolded protein aggregates accumulate in the cell, leading to the unfolded protein response (UPR). The UPR up-regulates the expression of ER-stress-responsive genes encoding calreticulin (CRT), an ER-localized Ca2+-binding protein. To understand the function of plant CRTs, we generated a triple knockout mutant, t123, which lacks CRT1, CRT2 and CRT3 and examined the roles of calreticulins in abiotic stress tolerance. A triple knockout mutant increased sensitivity to water stress which implies that calreticulins are involved in the Arabidopsis response to water stress. We identified that the cyclophilin AtCYP21-2, which is located in the ER, was specifically enhanced in the t123 mutants. Seed germination of the atcyp21-1 mutant was retarded by water stress. Taken together, these results suggest that regulatory proteins that serve to protect plants from water stress are folded properly in part with the help of calreticulins. The AtCYP21-2 may also participate in this protein-folding process in association with calreticulins.

Loss of the R2R3 MYB, AtMyb73, causes hyper-induction of the SOS1 and SOS3 genes in response to high salinity in Arabidopsis.

Environmental stressors, including high salt, drought, and low or high temperatures, are often associated with significant losses in agricultural productivity. Plants have evolved a diverse array of signaling pathways to modulate their development in response to various environmental challenges. Here, we report the characterization of a member of the R2R3-MYB transcription factor family, AtMyb73. The expression of AtMyb73 was up-regulated by salt stress but not by other stresses. The maximum level of AtMyb73 expression occurred at 6h of 300mM NaCl treatment. Under salt stress, atmyb73 ko mutant plants exhibited higher survival rates compare to wild type (Col-0) plants. Using quantitative reverse transcription-polymerase chain reaction (qRT-PCR) analysis, we determined that the accumulation of salt overly sensitive (SOS) transcripts, SOS1 and SOS3, was higher in atmyb73 ko and atmyb73 eko plants than in wild type plants in response to 300mM NaCl treatment. These results indicate that AtMyb73 is a negative regulator of SOS induction in response to salt stress in Arabidopsis thaliana.

TTG1-mediated flavonols biosynthesis alleviates root growth inhibition in response to ABA.

KEY MESSAGE: Our results demonstrate that the flavonoids biosynthetic pathway can be effectively manipulated to confer enhanced plant root growth under water-stress conditions. Abscisic acid (ABA) is one of most important phytohormones. It functions in various processes during the plant lifecycle. Previous studies indicate that ABA has a negative effect on root growth and branching. Auxin is another key plant growth regulator that plays an essential role in plant growth and development. In contrast to ABA, auxin is a positive regulator of root growth and development at low concentrations. This study was performed to help understand whether flavonoids can suppress the effect of ABA on lateral root growth. The recessive TRANSPARENT TESTA GLABRA 1 (ttg1) mutant was characterized on ABA and sucrose treatments. It was determined that auxin mobilization could be altered by modifying flavonoids biosynthesis, which resulted in alterations of root architecture in response to ABA treatment. Moreover, transgenic TTG1-overexpression (TTG1-OX) seedlings exhibited enhanced root length and lateral root number compared to wild-type seedlings grown under normal or stress conditions. Genetic manipulation of the flavonoids biosynthetic pathway could therefore be employed successfully for the improvement of plant root systems by overcoming the inhibition of ABA and some abiotic stresses.