Autistic adults in China and the Netherlands: Proxy-reported community integration and life satisfaction.

LAY ABSTRACT: Even though there are about 10 million Chinese autistic individuals, we know little about autistic adults in China. This study examined how well young autistic adults in China integrate into their communities (such as having a job, living independently and having friends) and how satisfied they are with their lives as reported by their caregivers. We compared them to autistic adults with similar characteristics (such as high support needs) from the Netherlands. We included 99 autistic adults in China and 109 in the Netherlands (18-30 years). In both countries, autistic adults were reported to have a hard time fitting into their communities. They often had no work, did not live on their own and had few close friends. Also, in both countries, caregivers reported that autistic adults felt low satisfaction with their life. Chinese adults were less satisfied with their life than Dutch adults, as indicated by their caregivers. This could be because of a lack of support for autistic adults in China, higher parental stress in Chinese caregivers, or general cross-country differences in happiness. Only in the Dutch group, younger compared with older adults fitted better into their communities, and adults without additional psychiatric conditions were reported to have higher life satisfaction. Country was a significant predictor of independent living only, with Dutch participants more likely living in care facilities than Chinese participants. In conclusion, our study shows that autistic adults with high support needs generally face similar challenges in both China and the Netherlands.

SUPPRESSOR OF MAX2 LIKE 6, 7, and 8 Interact with DDB1 BINDING WD REPEAT DOMAIN HYPERSENSITIVE TO ABA DEFICIENT 1 to Regulate the Drought Tolerance and Target SUCROSE NONFERMENTING 1 RELATED PROTEIN KINASE 2.3 to Abscisic Acid Response in Arabidopsis.

SUPPRESSOR OF MAX2-LIKE 6, 7, and 8 (SMXL6,7,8) function as repressors and transcription factors of the strigolactone (SL) signaling pathway, playing an important role in the development and stress tolerance in Arabidopsis thaliana. However, the molecular mechanism by which SMXL6,7,8 negatively regulate drought tolerance and ABA response remains largely unexplored. In the present study, the interacting protein and downstream target genes of SMXL6,7,8 were investigated. Our results showed that the substrate receptor for the CUL4-based E3 ligase DDB1-BINDING WD-REPEAT DOMAIN (DWD) HYPERSENSITIVE TO ABA DEFICIENT 1 (ABA1) (DWA1) physically interacted with SMXL6,7,8. The degradation of SMXL6,7,8 proteins were partially dependent on DWA1. Disruption of SMXL6,7,8 resulted in increased drought tolerance and could restore the drought-sensitive phenotype of the dwa1 mutant. In addition, SMXL6,7,8 could directly bind to the promoter of SUCROSE NONFERMENTING 1 (SNF1)-RELATED PROTEIN KINASE 2.3 (SnRK2.3) to repress its transcription. The mutations in SnRK2.2/2.3 significantly suppressed the hypersensitivity of smxl6/7/8 to ABA-mediated inhibition of seed germination. Conclusively, SMXL6,7,8 interact with DWA1 to negatively regulate drought tolerance and target ABA-response genes. These data provide insights into drought tolerance and ABA response in Arabidopsis via the SMXL6,7,8-mediated SL signaling pathway.

AtHSPR functions in gibberellin-mediated primary root growth by interacting with KNAT5 and OFP1 in Arabidopsis.

KEY MESSAGE: AtHSPR forms a complex with KNAT5 and OFP1 to regulate primary root growth through GA-mediated root meristem activity. KNAT5-OFP1 functions as a negative regulator of AtHSPR in response to GA. Plant root growth is modulated by gibberellic acid (GA) signaling and depends on root meristem maintenance. ARABIDOPSIS THALIANA HEAT SHOCK PROTEIN-RELATED (AtHSPR) is a vital regulator of flowering time and salt stress tolerance. However, little is known about the role of AtHSPR in the regulation of primary root growth. Here, we report that athspr mutant exhibits a shorter primary root compared to wild type and that AtHSPR interacts with KNOTTED1-LIKE HOMEOBOX GENE 5 (KNAT5) and OVATE FAMILY PROTEIN 1 (OFP1). Genetic analysis showed that overexpression of KNAT5 or OFP1 caused a defect in primary root growth similar to that of the athspr mutant, but knockout of KNAT5 or OFP1 rescued the short root phenotype in the athspr mutant by altering root meristem activity. Further investigation revealed that KNAT5 interacts with OFP1 and that AtHSPR weakens the inhibition of GIBBERELLIN 20-OXIDASE 1 (GA20ox1) expression by the KNAT5-OFP1 complex. Moreover, root meristem cell proliferation and root elongation in 35S::KNAT5athspr and 35S::OFP1athspr seedlings were hypersensitive to GA3 treatment compared to the athspr mutant. Together, our results demonstrate that the AtHSPR-KNAT5-OFP1 module regulates root growth and development by impacting the expression of GA biosynthetic gene GA20ox1, which could be a way for plants to achieve plasticity in response to the environment.

Comparing a modified simple-conditional with the conditional-only methods in teaching Chinese children with autism.

Instruction in auditory-visual conditional discriminations for young children with autism spectrum disorder is typically based on either a conditional-only or a simple-conditional method. In this study, we evaluated a modified simple-conditional method in which we removed the steps for which visual comparisons were presented in isolation. We compared this modified simple-conditional method with the conditional-only method when teaching auditory-visual conditional discriminations to six young Chinese children with autism spectrum disorder. We included two efficiency measures: total sessions and time to mastery. Our results replicated the findings of previous research in that both methods were efficacious for all but one participant. Although efficacy outcomes were similar across methods, the conditional-only method was more efficient across participants according to sessions and time to mastery. Thus, the results add to support for the use of the conditional-only method to teach auditory-visual conditional discriminations.

Using Pivotal Response Treatment to Improve Language Functions of Autistic Children in Special Schools: A Randomized Controlled Trial.

Language difficulties exert profound negative effects on the cognitive and social development of autistic children. Pivotal Response Treatment (PRT) is a promising intervention for improving social communication in autistic children, but there is a lack of a comprehensive examination of language functions. This study aimed to investigate the effectiveness of PRT in promoting the primary language functions (requesting, labeling, repeating, responding) defined by (Skinner, B. F. (1957). Verbal behavior. Martino Publishing.) theory of verbal behavior in autistic children. Thirty autistic children were randomly divided into the PRT group (Mage = 6.20, SDage = 1.21) and control group (Mage = 6.07, SDage = 1.49). The PRT group were provided with an 8-week training of the PRT motivation component in addition to treatment as usual (TAU) in their schools, whereas the control group only received TAU. Parents of the PRT group were also trained to practice the PRT motivation procedures at home. The PRT group demonstrated greater improvements in all four measured language functions compared to the control group. The improvement in language functions in the PRT group was generalized and maintained at the follow-up assessment. In addition, the PRT intervention enhanced untargeted social and communicative functioning, cognition, motor skills, imitation, and adaptive behaviors in the autistic children. In conclusion, language intervention using the motivation component of PRT is effective in promoting language functions as well as widespread untargeted cognitive and social functions in autistic children.

Hydrogen sulfide reduces cell death through regulating autophagy during submergence in Arabidopsis.

KEY MESSAGE: Hydrogen sulfide positively regulates autophagy and the expression of hypoxia response-related genes under submergence to enhance the submergence tolerance of Arabidopsis. Flooding seriously endangers agricultural production, and it is quite necessary to explore the mechanism of plant response to submergence for improving crop yield. Both hydrogen sulfide (H2S) and autophagy are involved in the plant response to submergence. However, the mechanisms by which H2S and autophagy interact and influence submergence tolerance have not been thoroughly elucidated. Here, we reported that exogenous H2S pretreatment increased the level of endogenous H2S and alleviated plant cell death under submergence. And transgenic lines decreased in the level of endogenous H2S, L-cysteine desulfurase 1 (des1) mutant and 35S::GFP-O-acetyl-L-serine(thiol)lyase A1 (OASA1)/des1-#56/#61, were sensitive to submergence, along with the lower transcript levels of hypoxia response genes, LOB DOMAIN 41 (LBD41) and HYPOXIA RESPONSIVE UNKNOWN PROTEIN 43 (HUP43). Submergence induced the formation of autophagosomes, and the autophagy-related (ATG) mutants (atg4a/4b, atg5, atg7) displayed sensitive phenotypes to submergence. Simultaneously, H2S pretreatment repressed the autophagosome producing under normal conditions, but enhanced this process under submergence by regulating the expression of ATG genes. Moreover, the mutation of DES1 aggravated the sensitivity of des1/atg5 to submergence by reducing the formation of autophagosomes under submergence. Taken together, our results demonstrated that H2S alleviated cell death through regulating autophagy and the expression of hypoxia response genes during submergence in Arabidopsis.

Exploring Cultural Differences in Autistic Traits: A Factor Analytic Study of Children with Autism in China and the Netherlands.

Autism spectrum disorders are diagnosed globally, but recognition, interpretation and reporting may vary across cultures. To compare autism across cultures it is important to investigate whether the tools used are conceptually equivalent across cultures. This study evaluated the factor structure of the parent-reported Autism Spectrum Quotient Short Form in autistic children from China (n = 327; 3 to 17 years) and the Netherlands (n = 694; 6 to 16 years). Confirmatory factor analysis did not support the two-factor hierarchical model previously identified. Exploratory factor analysis indicated culturally variant factor structures between China and the Netherlands, which may hamper cross-cultural comparisons. Several items loaded onto different factors in the two samples, indicating substantial variation in parent-reported autistic traits between China and the Netherlands.

Mental health and social support of caregivers of children and adolescents with ASD and other developmental disorders during COVID-19 pandemic.

BACKGROUND: Previous studies showed that caregivers of children with autism spectrum disorder (ASD) and other developmental disorders had higher levels of parenting stress, anxiety and depression. In the present study, the author examined the caregivers' mental health and investigated the mediating role of social support between symptoms severity and parenting stress during COVID-19. METHODS: During 20 March to 8 April 2020, 1932 caregivers of children and adolescents with ASD and other developmental disorders from China were enrolled to fill in a sociodemographic questionnaire, Depression, Anxiety and Stress Scale and Social Support Rating Scale. The author also collected children's disability severity symptoms and behavioral problems. RESULTS: The results showed that 46.01% of the caregivers reported symptoms of depression, 44.67% showed anxiety and 44.62% showed stress during COVID-19 pandemic. Fathers were found to get more subjective support than mothers (P < 0.05). Caregivers who had the highest educational attainment had the most social support (P = 0.01). People who had the more household income showed the significantly lower levels of depression and anxiety (P < 0.05). The caregivers' employment status during COVID-19 was found significantly related with their depression, anxiety, stress and social support (P < 0.05). LIMITATIONS: This study has some limitations, such as it did not conduct the longitudinal analysis of variables before COVID-19. CONCLUSIONS: The findings showed that many caregivers experienced mental health problems during COVID-19. The author suggested to promote caregivers' engagement in functional social support and the behavioral interventions for their children to reduce the impact of stress, anxiety and depression.

Chinese College Students Have Higher Anxiety in New Semester of Online Learning During COVID-19: A Machine Learning Approach.

The COVID-19 pandemic has caused tremendous loss starting from early this year. This article aims to investigate the change of anxiety severity and prevalence among non-graduating undergraduate students in the new semester of online learning during COVID-19 in China and also to evaluate a machine learning model based on the XGBoost model. A total of 1172 non-graduating undergraduate students aged between 18 and 22 from 34 provincial-level administrative units and 260 cities in China were enrolled onto this study and asked to fill in a sociodemographic questionnaire and the Self-Rating Anxiety Scale (SAS) twice, respectively, during February 15 to 17, 2020, before the new semester started, and March 15 to 17, 2020, 1 month after the new semester based on online learning had started. SPSS 22.0 was used to conduct t-test and single factor analysis. XGBoost models were implemented to predict the anxiety level of students 1 month after the start of the new semester. There were 184 (15.7%, Mean = 58.45, SD = 7.81) and 221 (18.86%, Mean = 57.68, SD = 7.58) students who met the cut-off of 50 and were screened as positive for anxiety, respectively, in the two investigations. The mean SAS scores in the second test was significantly higher than those in the first test (P < 0.05). Significant differences were also found among all males, females, and students majoring in arts and sciences between the two studies (P < 0.05). The results also showed students from Hubei province, where most cases of COVID-19 were confirmed, had a higher percentage of participants meeting the cut-off of being anxious. This article applied machine learning to establish XGBoost models to successfully predict the anxiety level and changes of anxiety levels 4 weeks later based on the SAS scores of the students in the first test. It was concluded that, during COVID-19, Chinese non-graduating undergraduate students showed higher anxiety in the new semester based on online learning than before the new semester started. More students from Hubei province had a different level of anxiety than other provinces. Families, universities, and society as a whole should pay attention to the psychological health of non-graduating undergraduate students and take measures accordingly. It also confirmed that the XGBoost model had better prediction accuracy compared to the traditional multiple stepwise regression model on the anxiety status of university students.

A Pilot Investigation of the Social Attention and Communication Surveillance (SACS) Tool for the Early Identification of Autism in Tianjin, China (SACS-C).

Introduction: Autism spectrum disorder (ASD) comprises difficulties in social communication and restrictive and repetitive behaviors. Despite an increased global prevalence, little remains known about early detection and diagnosis of autism in Mainland China. Our aim was to conduct a pilot investigation of the implementation of an Australian tool, Social Attention and Communication Surveillance (SACS), in Tianjin, China (SACS-C) by trained professionals to identify autism early compared to the Checklist for Autism in Toddlers-23 (CHAT-23) completed by parents and professionals. Materials and Methods: A total of 10,514 children were monitored across 61 Community Health Service Centres in six Tianjin districts on the SACS-C at 12, 18, and 24 months of age following a half-day training of 225 child health practitioners. Children deemed at "high likelihood" for autism on either the SACS, CHAT-23, or both, were referred for developmental assessments at the Tianjin Women and Children's Health Centre (TWCHC). Results: A total of 87 children (0.8%) were identified at "high likelihood" on the SACS-C, of whom 57 (66%) were assessed for autism; 24 children were subsequently diagnosed with autism (42.1%), and the remaining 33 (57.9%) were diagnosed with developmental and/or language delays. The SACS-C had a positive predictive value (PPV) of 42.1%, a negative predictive value (NPV) of 99.8%, and sensitivity and specificity of 53.3 and 99.7%, respectively. Only 21 children were identified at "high risk" for autism on the CHAT-23 (0.2%), over four times fewer children than the SACS-C, with 14 children assessed for autism (66%); nine were diagnosed with autism (64.3%) and the remaining five children were diagnosed with developmental and/or language delays. The CHAT-23 had an overall PPV of 64.3%, NPV of 99.6%, sensitivity of 27.3%, and specificity of 99.9%. Conclusion: This was the first large-scale study identifying autism in 12-24-month-old children in China. We ascertained the feasibility of training community health practitioners to monitor infants and toddlers for the early signs of autism, and determined the effectiveness of their use of SACS-C which had a better balance between accuracy and sensitivity in detecting autism in contrast to the CHAT-23 which missed the majority of children with autism (72.7%) vs. the SACS-C (46.7%). Given the emphasis on identifying as many children with autism as possible in Mainland China, SACS-C was identified as the tool of choice by the TWCHC. However, more work is needed to improve the psychometric properties in using the SACS-C in Mainland China so that it is comparable to its use in Australia.

NAC Transcription Factors as Positive or Negative Regulators during Ongoing Battle between Pathogens and Our Food Crops.

The NAC (NAM, ATAF1/2, and CUC2) family of proteins is one of the largest plant-specific transcription factor (TF) families and its members play varied roles in plant growth, development, and stress responses. In recent years, NAC TFs have been demonstrated to participate in crop-pathogen interactions, as positive or negative regulators of the downstream defense-related genes. NAC TFs link signaling pathways between plant hormones, including salicylic acid (SA), jasmonic acid (JA), ethylene (ET), and abscisic acid (ABA), or other signals, such as reactive oxygen species (ROS), to regulate the resistance against pathogens. Remarkably, NAC TFs can also contribute to hypersensitive response and stomatal immunity or can be hijacked as virulence targets of pathogen effectors. Here, we review recent progress in understanding the structure, biological functions and signaling networks of NAC TFs in response to pathogens in several main food crops, such as rice, wheat, barley, and tomato, and explore the directions needed to further elucidate the function and mechanisms of these key signaling molecules.

Crosstalk between Hydrogen Sulfide and Other Signal Molecules Regulates Plant Growth and Development.

Hydrogen sulfide (H2S), once recognized only as a poisonous gas, is now considered the third endogenous gaseous transmitter, along with nitric oxide (NO) and carbon monoxide (CO). Multiple lines of emerging evidence suggest that H2S plays positive roles in plant growth and development when at appropriate concentrations, including seed germination, root development, photosynthesis, stomatal movement, and organ abscission under both normal and stress conditions. H2S influences these processes by altering gene expression and enzyme activities, as well as regulating the contents of some secondary metabolites. In its regulatory roles, H2S always interacts with either plant hormones, other gasotransmitters, or ionic signals, such as abscisic acid (ABA), ethylene, auxin, CO, NO, and Ca2+. Remarkably, H2S also contributes to the post-translational modification of proteins to affect protein activities, structures, and sub-cellular localization. Here, we review the functions of H2S at different stages of plant development, focusing on the S-sulfhydration of proteins mediated by H2S and the crosstalk between H2S and other signaling molecules.

The Impact of COVID-19 on Anxiety in Chinese University Students.

COVID-19 had become a pandemic raising concerns of widespread panic and increasing anxiety and stress in individuals all over the world (World Health Organization, 2020a). Lots of countries had closed their schools. As the first country to do so, Chinese colleges and universities were making use of different modes of learning, including online-learning based on different platforms to achieve the goal suggested by Ministry of Education in China, "suspending classes without suspending learning," since middle February. This paper is the first one which aims to investigate the anxiety of Chinese university students after the outbreak of COVID-19 right before the start of new spring term. 3611 university students (female: male = 1.48:1) aged between 18 to 24 from all over China were enrolled to this study from a top university in China. The Self-Rating Anxiety Scale - SAS (Zung, 1971) was used to assess anxiety 2 days before the start of new spring term in middle February. All four-year undergraduate students were included in the study. The mean SAS score was 40.53 (SD = 10.15), significantly higher than the national norm (Mean = 29.78, SD = 10.07, and p ≤ .001), and there were still 557 (15.43%, Mean = 58.75, and SD = 8.9) students met the cutoff of 50 and were screened positive. Comparisons among sexes, grades and majors were also conducted. Significant differences were found between all males and all female (p ≤ .001), and between all students majoring arts and sciences in the anxiety sample (n = 557, p = 0.05). The results also showed that the mean SAS scores were not correlated with the regions they came from/lived in. This study concluded that the Chinese university students showed higher anxiety for COVID-19.

The SUPPRESSOR of MAX2 1 (SMAX1)-Like SMXL6, SMXL7 and SMXL8 Act as Negative Regulators in Response to Drought Stress in Arabidopsis.

Drought represents a major threat to crop growth and yields. Strigolactones (SLs) contribute to regulating shoot branching by targeting the SUPPRESSOR OF MORE AXILLARY GROWTH2 (MAX2)-LIKE6 (SMXL6), SMXL7 and SMXL8 for degradation in a MAX2-dependent manner in Arabidopsis. Although SLs are implicated in plant drought response, the functions of the SMXL6, 7 and 8 in the SL-regulated plant response to drought stress have remained unclear. Here, we performed transcriptomic, physiological and biochemical analyses of smxl6, 7, 8 and max2 plants to understand the basis for SMXL6/7/8-regulated drought response. We found that three D53 (DWARF53)-Like SMXL members, SMXL6, 7 and 8, are involved in drought response as the smxl6smxl7smxl8 triple mutants showed markedly enhanced drought tolerance compared to wild type (WT). The smxl6smxl7smxl8 plants exhibited decreased leaf stomatal index, cuticular permeability and water loss, and increased anthocyanin biosynthesis during dehydration. Moreover, smxl6smxl7smxl8 were hypersensitive to ABA-induced stomatal closure and ABA responsiveness during and after germination. In addition, RNA-sequencing analysis of the leaves of the D53-like smxl mutants, SL-response max2 mutant and WT plants under normal and dehydration conditions revealed an SMXL6/7/8-mediated network controlling plant adaptation to drought stress via many stress- and/or ABA-responsive and SL-related genes. These data further provide evidence for crosstalk between ABA- and SL-dependent signaling pathways in regulating plant responses to drought. Our results demonstrate that SMXL6, 7 and 8 are vital components of SL signaling and are negatively involved in drought responses, suggesting that genetic manipulation of SMXL6/7/8-dependent SL signaling may provide novel ways to improve drought resistance.

AtHSPR is involved in GA- and light intensity-mediated control of flowering time and seed set in Arabidopsis.

Flowering is a dynamic and synchronized process, the timing of which is finely tuned by various environmental signals. A T-DNA insertion mutant in Arabidopsis HEAT SHOCK PROTEIN-RELATED (AtHSPR) exhibited late-flowering phenotypes under both long-day (LD) and short-day (SD) conditions compared to the wild-type, while over-expression of AtHSPR promoted flowering. Exogenous application of gibberellin (GA) partially rescued the late-flowering mutant phenotype under both LD and SD conditions, suggesting that AtHSPR is involved in GA biosynthesis and/or the GA signaling that promotes flowering. Under SD or low-light conditions, the Athspr mutant exhibited late flowering together with reduced pollen viability and seed set, defective phenotypes that were partially rescued by GA treatment. qRT-PCR assays confirmed that GA biosynthetic genes were down-regulated, that GA catabolic genes were up-regulated, and that the levels of bioactive GA and its intermediates were decreased in Athspr under both SD and low-light/LD, further suggesting that AtHSPR could be involved in the GA pathway under SD and low-light conditions. Furthermore, AtHSPR interacted in vitro with OFP1 and KNAT5, which are transcriptional repressors of GA20ox1 in GA biosynthesis. Taken together, our findings demonstrate that AtHSPR plays a positive role in GA- and light intensity-mediated regulation of flowering and seed set.

Comparing and Contrasting the Multiple Roles of Butenolide Plant Growth Regulators: Strigolactones and Karrikins in Plant Development and Adaptation to Abiotic Stresses.

Strigolactones (SLs) and karrikins (KARs) are both butenolide molecules that play essential roles in plant growth and development. SLs are phytohormones, with SLs having known functions within the plant they are produced in, while KARs are found in smoke emitted from burning plant matter and affect seeds and seedlings in areas of wildfire. It has been suggested that SL and KAR signaling may share similar mechanisms. The α/ß hydrolases DWARF14 (D14) and KARRIKIN INSENSITIVE 2 (KAI2), which act as receptors of SL and KAR, respectively, both interact with the F-box protein MORE AXILLARY GROWTH 2 (MAX2) in order to target SUPPRESSOR OF MAX2 1 (SMAX1)-LIKE/D53 family members for degradation via the 26S proteasome. Recent reports suggest that SLs and/or KARs are also involved in regulating plant responses and adaptation to various abiotic stresses, particularly nutrient deficiency, drought, salinity, and chilling. There is also crosstalk with other hormone signaling pathways, including auxin, gibberellic acid (GA), abscisic acid (ABA), cytokinin (CK), and ethylene (ET), under normal and abiotic stress conditions. This review briefly covers the biosynthetic and signaling pathways of SLs and KARs, compares their functions in plant growth and development, and reviews the effects of any crosstalk between SLs or KARs and other plant hormones at various stages of plant development. We also focus on the distinct responses, adaptations, and regulatory mechanisms related to SLs and/or KARs in response to various abiotic stresses. The review closes with discussion on ways to gain additional insights into the SL and KAR pathways and the crosstalk between these related phytohormones.

Exogenous hydrogen peroxide inhibits primary root gravitropism by regulating auxin distribution during Arabidopsis seed germination.

Hydrogen peroxide (H2O2) is the key factor in many physiological and metabolic processes in plants. During seed germination, exogenous H2O2 application influences gravitropism and induces curvature of the primary root in grass pea and pea seedlings. However, it remains unclear whether and how this happens in the model plant Arabidopsis thaliana. In the present study, the effect of exogenous H2O2 on the gravitropic response of primary roots during Arabidopsis seed germination was studied using histology and molecular biology approaches. Appropriate H2O2 treatment not only restrained primary root growth, but also disrupted gravitropism and induced root curvature. Histological staining and molecular analysis demonstrated that exogenous H2O2 correlated with lack of starch-dense amyloplasts in root tip columella cells, which ultimately results in the lack of gravisensing. Detection of calcium ion (Ca2+) by a fluorescent probe showed that Ca2+ distribution changed and intracellular Ca2+ concentration increased in H2O2-treated primary root, which was consistent with alterations in auxin distribution and concentration triggered by H2O2 treatment. Furthermore, the normally polar localization of Pin-formed 1 (PIN1) and PIN2 became uniformly distributed on root tip cell membranes after treatment with H2O2. This leads to speculation that the IAA signaling pathway was affected by exogenous H2O2, causing asymmetrical distribution of IAA on both sides of the primary root, which would influence the gravitropic response.

Functional analyses of Populus euphratica brassinosteroid biosynthesis enzyme genes DWF4 (PeDWF4) and CPD (PeCPD) in the regulation of growth and development of Arabidopsis thaliana.

DWF4 and CPD are key brassinosteroids (BRs) biosynthesis enzyme genes. To explore the function of Populus euphratica DWF4 (PeDWF4) and CPD (PeCPD), Arabidopsis thaliana transgenic lines (TLs) expressing PeDWF4, PeCPD or PeDWF4 plus PeCPD, namely PeDWF4-TL, PeCPD-TL and PeCP/DW-TL, were characterized. Compared with wild type (WT), the changes of both PeDWF4-TL and PeCPD-TL in plant heights, silique and hypocotyls lengths and seed yields were similar, but in bolting time and stem diameters, they were opposite. PeCP/DW-TL was more in plant heights and the lengths of primary root, silique, and fruit stalk, but less in silique numbers and seed yields than either PeDWF4-TL or PeCPD-TL. PeDWF4 and PeCPD specially expressed in PeDWF4-TL or PeCPDTL, and the transcription level of PeDWF4 was higher than that of PeCPD. In PeCP/DW-TL, their expressions were all relatively reduced. Additionally, the expression of PeDWF4 and PeCPD differentially made the expression levels of AtDWF4, AtCPD, AtBR6OX2, AtFLC, AtTCP1 and AtGA5 change in the TLs. The total BRs contents were PeDWF4-TL greater than PeCP/DW-TL greater than WT greater than PeCPD-TL. These results imply that PeDWF4 is functionally not exactly the same as PeCPD and there may be a synergistic and antagonistic effects in physiology between both of them in the regulation of plant growth and development.

Hydrogen sulfide enhances nitric oxide-induced tolerance of hypoxia in maize (Zea mays L.).

KEY MESSAGE: Our data present H 2 S in a new role, serving as a multi-faceted transducer to different response mechanisms during NO-induced acquisition of tolerance to flooding-induced hypoxia in maize seedling roots. Nitric oxide (NO), serving as a secondary messenger, modulates physiological processes in plants. Recently, hydrogen sulfide (H2S) has been demonstrated to have similar signaling functions. This study focused on the effects of treatment with H2S on NO-induced hypoxia tolerance in maize seedlings. The results showed that treatment with the NO donor sodium nitroprusside (SNP) enhanced survival rate of submerged maize roots through induced accumulation of endogenous H2S. The induced H2S then enhanced endogenous Ca2+ levels as well as the Ca2+-dependent activity of alcohol dehydrogenase (ADH), improving the capacity for antioxidant defense and, ultimately, the hypoxia tolerance in maize seedlings. In addition, NO induced the activities of key enzymes in H2S biosynthesis, such as L-cysteine desulfhydrases (L-CDs), O-acetyl-L-serine (thiol)lyase (OAS-TL), and ß-Cyanoalanine Synthase (CAS). SNP-induced hypoxia tolerance was enhanced by the application of NaHS, but was eliminated by the H2S-synthesis inhibitor hydroxylamine (HA) and the H2S-scavenger hypotaurine (HT). H2S concurrently enhanced the transcriptional levels of relative hypoxia-induced genes. Together, our findings indicated that H2S serves as a multi-faceted transducer that enhances the nitric oxide-induced hypoxia tolerance in maize (Zea mays L.).