Inhibition of SIZ1-mediated SUMOylation of HOOKLESS1 promotes light-induced apical hook opening in Arabidopsis.

The apical hook protects cotyledons and the shoot apical meristem from mechanical injuries during seedling emergence from the soil. HOOKLESS1 (HLS1) is a central regulator of apical hook development, as a terminal signal onto which several pathways converge. However, how plants regulate the rapid opening of the apical hook in response to light by modulating HLS1 function remains unclear. In this study, we demonstrate that the small ubiquitin-like modifier (SUMO) E3 ligase SAP AND MIZ1 DOMAIN-CONTAINING LIGASE1 (SIZ1) interacts with HLS1 and mediates its SUMOylation in Arabidopsis thaliana. Mutating SUMO attachment sites of HLS1 results in impaired function of HLS1, indicating that HLS1 SUMOylation is essential for its function. SUMOylated HLS1 was more likely to assemble into oligomers, which are the active form of HLS1. During the dark-to-light transition, light induces rapid apical hook opening, concomitantly with a drop in SIZ1 transcript levels, resulting in lower HLS1 SUMOylation. Furthermore, ELONGATED HYPOCOTYL5 (HY5) directly binds to the SIZ1 promoter and suppresses its transcription. HY5-initiated rapid apical hook opening partially depended on HY5 inhibition of SIZ1 expression. Taken together, our study identifies a function for SIZ1 in apical hook development, providing a dynamic regulatory mechanism linking the post-translational modification of HLS1 during apical hook formation and light-induced apical hook opening.

Brassinosteroids enhance BES1-required thermomemory in Arabidopsis thaliana.

Heat stress (HS) caused by ambient high temperature poses a threat to plants. In the natural and agricultural environment, plants often encounter repeated and changeable HS. Moderate HS primes plants to establish a molecular 'thermomemory' that enables plants to withstand a later-and possibly more extreme-HS attack. Recent years, brassinosteroids (BRs) have been implicated in HS response, whereas the information is lacking on whether BRs signal transduction modulates thermomemory. Here, we uncover the positive role of BRs signalling in thermomemory of Arabidopsis thaliana. Heat priming induces de novo synthesis and nuclear accumulation of BRI1-Ethyl methyl sulfon-SUPPRESSOR (BES1), which is the key regulator of BRs signalling. BRs promote the accumulation of dephosphorylated BES1 during memory phase, and stoppage of BRs synthesis impairs dephosphorylation. During HS memory, BES1 is required to maintain sustained induction of HS memory genes and directly targets APX2 and HSFA3 for activation. In summary, our results reveal a BES1-required, BRs-enhanced transcriptional control module of thermomemory in Arabidopsis thaliana.

The deubiquitinating enzymes UBP12 and UBP13 positively regulate recovery after carbon starvation by modulating BES1 stability in Arabidopsis thaliana.

BRI1-EMS-SUPPRESSOR1 (BES1), a core transcription factor in the brassinosteroid (BR) signaling pathway, primarily regulates plant growth and development by influencing BR-regulated gene expression. Several E3 ubiquitin (Ub) ligases regulate BES1 stability, but little is known about BES1 deubiquitination, which antagonizes E3 ligase-mediated ubiquitination to maintain BES1 homeostasis. Here, we report that two Arabidopsis thaliana deubiquitinating enzymes, Ub-SPECIFIC PROTEASE (UBP) 12 and UBP13, interact with BES1. UBP12 and UBP13 removed Ub from polyubiquitinated BES1 to stabilize both phosphorylated and dephosphorylated forms of BES1. A double mutant, ubp12-2w ubp13-3, lacking UBP12 and UBP13 function showed both BR-deficient and BR-insensitive phenotypes, whereas transgenic plants overexpressing UBP12 or UBP13 exhibited an increased BR response. Expression of UBP12 and UPB13 was induced during recovery after carbon starvation, which led to BES1 accumulation and quick recovery of stressed plants. Our work thus establishes a mechanism by which UBP12 and UBP13 regulate BES1 protein abundance to enhance BR-regulated growth during recovery after carbon starvation.

Evaluation of canthaxanthin in eggs and its subsequent dietary risks to Chinese consumers.

Canthaxanthin is a colourant widely used in medicine, food and cosmetics, which is closely related to human eye dysfunction. The EU determines that the daily acceptable intake of canthaxanthin (ADI) is 0.03 mg canthaxanthin per kg body weight. In order to protect people's diet health and avoid the occurrence of food safety accidents, this paper measured the content of canthaxanthin in 114 egg samples sourced from different regions of China using ultrahigh-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS). The dietary exposure assessment method was used to evaluate the dietary risk to Chinese consumers. Results showed that the content of canthaxanthin varies significantly across regions of origin, with eggs produced in Beijing having a lower amount than those from other regions. The average dietary exposure of children (2-10 years old) was 0.242 ~ 0.653 µg/(kg bw∙d), and the dietary exposure of 95/97.5/99 percentile was 0.246 ~ 1.779 µg/(kg bw∙d). The maximum exposure was 3.089 µg/(kg bw∙d), and its risk quotient was 0.103 (<1), which was an acceptable risk. For the teenager group (11-18 years old), the average dietary exposure was 0.141 ~ 0.247 µg/(kg bw∙d), and the dietary exposure at the 95/97.5/99 percentile was 0.143 ~ 0.671 µg/(kg bw∙d), presenting an acceptable risk. For adults, the dietary risk of eating eggs with canthaxanthin is the lowest among the three age groups.

[G6PD deficiency among children under 7 years old from Yunnan with unique ethnic minority origin].

OBJECTIVE: To investigate the epidemiological status of glucose-6-phosphate dehydrogenase (G6PD) deficiency among children from Yunnan with unique ethnic origins. METHODS: DNA samples from 11759 children were tested with fluorescent spot test, G6PD/6PGD quantitative ratio assay and hemoglobin electrophoresis. RESULTS: The detection rate of G6PD deficiency was 2.5%, for which boys were significantly greater than girls (3.5% vs. 1.4%, P<0.05). Significant differences were also detected among children from different ethnic groups and different regions. For ethnic Han Chinese, the detection rate was 0.7%, which was lower than the majority of ethnic minorities. By regression analysis, altitude of residence and family history both have significant influence on the calculated rate. CONCLUSION: Occurrence of G6PD deficiency seems to be influenced by gender. It also varies substantially between different ethnic groups as well as regions, e.g., more common in south. It also showed a declining trend after years of diagnosis and intervention. This survey may provide a valuable basis for counseling of G6PD deficiency in Yunnan.

[A survey on anemia among children under 7 years of age from 15 minority ethnic groups in Yunnan].

OBJECTIVE: To investigate the level and distribution characteristics of anemia of the minority ethnic group children in Yunnan. METHOD: The cases with anemia were surveyed from 13 336 samples of 15 minority ethnic groups and Han children in Yunnan by Taking the method of random cluster sampling. RESULT: The prevalence of anemia among the children under 7 years of age of 15 ethnic groups of minority in Yunnan was 13.6%. There are differences among the different ethnic groups (χ(2) = 716.33, P < 0.01), the highest was 26.6% in Jingpo, the lowest was 3.5% in Bai. There were differences among the different regions, the prevalence of anemia was high in the border regions City, the highest was 23.8% in Dehong; the prevalence of anemia was low in inland cities, the lowest was 2.7% in Fugong, and was higher in border areas. The prevalence of anemia was higher in boys (13.6%) than in girls (12.1%). There were differences among the different age in the different ethnic groups (6 months to 1 years old: χ(2) = 70.52, P < 0.01; 1 - 2 years old:χ(2) = 185.86, P < 0.01; 2 - 5 years old: χ(2) = 296.12, P < 0.01; 5 - 6 years old:χ(2) = 107.11, P < 0.01; 6 - 7 years old:χ(2) = 185.02, P < 0.01), the highest was 59.0% of Deang in 1 to 2 years old children. The trend of change was that the highest prevalence was seen in 6 months to 1 year old children, the prevalence gradually declined among older children, but rose again in children 6 years of age or older. CONCLUSION: The prevalence of anemia was 13.6% among the children of 15 ethnic minority under 7 years of age in Yunnan. There were differences among different ethnic groups of minority in different prefectures. There were differences among different ethnic groups of different age groups, but it was highest in 6 months to 1 year old children, it declined among older children, and rose in children 6 years of age or older. The prevalence of anemia was related to the ethnic and geographic factors.

[Epidemiological study of thalasaemia among children in Xishuangbanna, Dehong and Nujiang of Yunnan province].

OBJECTIVE: To investigate the carrier rate of thalasaemia among the children of 10 minority ethnic groups in 3 border states (Xishuangbanna, Dehong and Nujiang) of Yunnan Province. METHODS: A total of 6562 samples of children under 10 years old were analyzed by blood cell automatic analysis and hemoglobin electrophoresis. RESULTS: The overall carrier frequency of thalasaemia was highest (46.2%) in Dehong, and lowest (30.6%) in Nujiang. The carrier frequency of beta-thalasaemia was the highest (40.6%) in Achang, and lowest (2.5%) in Dulong. The carrier frequency of alpha-thalasaemia was the highest (22.1%) in Dai from Xishuangbanna, followed by Dulong (19.1%). CONCLUSION: Thalasaemia carrier rates were high among the children of 10 minority ethnic groups in Yunnan. There were regional differences in their incidences. The results provide a valuable basis for thalasaemia prevention in Yunnan minorities in the three border states.

[Epidemiological study on thalassemia among the children of 0 - 7 years old among the six ethnic groups in Xishuangbanna and Dehong of Yunnan province].

OBJECTIVE: To investigate the prevalence rate of thalassemia among children of 0 - 7 years old, from six ethnic groups in Xishuangbanna and Dehong, Yunnan province. METHODS: 4973 blood samples from children under 7 years old were automatically undergone blood cell count, red cell osmotic fragility and hemoglobin electrophoresis testings. RESULTS: The incidence rates of thalassaemia, ß-thalassemia was 37.4%, and α-thalassaemia were 22.6% and 14.7% respectively. The thalassaemia incidence rates were significantly different among age groups but not in gender. The incidence of α-thalassaemia was decreasing along with the increase of age, while the incidence of ß-thalassaemia was increasing along with the increase of age. Xishuangbanna had the higher incidence than in Dehong and the differences were significant between counties, The incidence of thalassemia of Mengla ranked the first (52.2%) in Xishuangbanna, The differences between different regions and different nationalities were significant, with ß-thalassemia of Achang ranked the first (40.6%), The incidence of α-thalassemia among Han ranked the first as 45.5% while α-thalassaemia and ß-thalassemia were different in regions. α-thalassaemia and ß-thalassemia were significantly different between different ethnic people in the same regions. Multiple factor analysis showed that region seemed to be a risk factor and the mother's ethnicity was a protective factor and dependent variable on thalassaemia. CONCLUSION: The incidence of thalassaemia in Yunnan Xishuangbanna and Dehong was high among children under the age of 7 and were related to ethnic and regional differences in the areas. Specific genes were proliferated along with the extension of time. Our data provided valuable information on prevention and genetic studies on thalassaemia in the minorities of Xishuangbanna and Dehong in Yunnan province.