CbMYB108 integrates the regulation of diterpene biosynthesis and trichome development in Conyza blinii against UV-B.

Plants synthesize abundant terpenes through glandular trichomes (GTs), thereby protecting themselves from environmental stresses and increasing the economic value in some medicinal plants. However, the potential mechanisms for simultaneously regulating terpenes synthesis and GTs development remain unclear. Here, we showed that terpenes in Conyza blinii could be synthesized through capitate GTs. By treating with appropriate intensity of UV-B, the density of capitate GTs and diterpene content can be increased. Through analyzing corresponding transcriptome, we identified a MYB transcription factor CbMYB108 as a positive regulator of both diterpene synthesis and capitate GT density. Transiently overexpressing/silencing CbMYB108 on C. blinii leaves could increase diterpene synthesis and capitate GT density. Further verification showed that CbMYB108 upregulated CbDXS and CbGGPPS expression in diterpene synthesis pathway. Moreover, CbMYB108 could also upregulated the expression of CbTTG1, key WD40 protein confirmed in this study to promote GT development, rather than through interaction between CbMYB108 and CbTTG1 proteins. Thus, results showed that the UV-B-induced CbMYB108 owned dual-function of simultaneously improving diterpene synthesis and GT development. Our research lays a theoretical foundation for cultivating C. blinii with high terpene content, and broadens the understanding of the integrated mechanism on terpene synthesis and GT development in plants.

VrMYB90 Functions Synergistically with VrbHLHA and VrMYB3 to Regulate Anthocyanin Biosynthesis in Mung Bean.

Mung bean is an important grain-legume crop and its sprout is an economical and nutrient vegetable for the public, but the genetic regulation of anthocyanin production, which is an antioxidant in mung bean, remains elusive. In our study, we characterized a subgroup (SG) 6 R2R3-MYB anthocyanin activator VrMYB90 and a SG 4 R2R3-MYB anthocyanin repressor VrMYB3, which synergistically function in regulating anthocyanin synthesis with VrbHLHA transcription factor. The overexpressed VrMYB90 protein activates the expression of VrMYB3 and VrbHLHA in mung bean hair roots, and also promotes VrDFR and VrANS transcript levels by directly binding to the corresponding promoters at specific motifs (CAACTG and CCGTTG). VrMYB90 interacts with VrbHLHA to enhance its regulatory activities on VrDFR and VrANS. Furthermore, the interaction between VrMYB3 with VrMYB90 and VrbHLHA could result in the restriction of anthocyanin synthesis to prevent excessive anthocyanin accumulation. Our results demonstrate that the VrMYB90 protein, in conjunction with VrMYB3 and VrbHLHA, forms a key regulatory module to fine-tune anthocyanin synthesis in mung bean.

Abdominal obesity increases the risk of reflux esophagitis: a systematic review and meta-analysis.

BACKGROUND AND OBJECTIVES: The association between abdominal obesity and reflux esophagitis (RE) has been extensively evaluated, but the current findings are mixed and more convincing epidemiological evidence urgently needs to be established. To thoroughly explore this relationship, we summarized the latest studies, performed an updated meta-analysis, and examined the dose-response relationship. METHODS: We performed a systematic search of PubMed, Web of Science, and Embase up to 28 March 2021, using prespecified terms to identify studies investigating the association between abdominal obesity and RE. Odds ratios (ORs) with 95% confidence intervals (CIs), mean differences (MDs) or standardized mean differences (SMDs) with 95% CIs were taken as effect-size estimates. RESULTS: Forty-two observational studies, including 11 cohort studies, were meta-analyzed. Overall, a statistically significant association was observed between abdominal obesity and RE, by both the pooled OR (adjusted OR = 1.51, 95% CI: 1.37-1.66, p < .001) and the pooled SMD (SMD = 0.36, 95% CI: 0.30-0.42, p < .001). Moreover, this significant relationship persisted with subgroup stratification. In subgroup analyses, we found that study design, abdominal obesity measurement, adjustment for covariates and sex were possible sources of between-study heterogeneity. For the dose-response analyses, the risk of RE increased with the degree of abdominal obesity, and the increasing trend accelerated when waist circumference (WC) reached 87.0 cm. CONCLUSION: This meta-analysis indicated a significant association between abdominal obesity and RE, and the risk of RE increased with abdominal obesity especially when the WC was over 87.0 cm.

Involvement of Auxin-Mediated CqEXPA50 Contributes to Salt Tolerance in Quinoa (Chenopodium quinoa) by Interaction with Auxin Pathway Genes.

Soil salinization is a global problem that limits crop yields and threatens agricultural development. Auxin-induced expansins contribute to plant salt tolerance through cell wall loosening. However, how auxins and expansins contribute to the adaptation of the halophyte quinoa (Chenopodium quinoa) to salt stress has not yet been reported. Here, auxin was found to contribute to the salt tolerance of quinoa by promoting the accumulation of photosynthetic pigments under salt stress, maintaining enzymatic and nonenzymatic antioxidant systems and scavenging excess reactive oxygen species (ROS). The Chenopodium quinoa expansin (Cqexpansin) family and the auxin pathway gene family (Chenopodium quinoa auxin response factor (CqARF), Chenopodium quinoa auxin/indoleacetic acid (CqAux/IAA), Chenopodium quinoa Gretchen Hagen 3 (CqGH3) and Chenopodium quinoa small auxin upregulated RNA (CqSAUR)) were identified from the quinoa genome. Combined expression profiling identified Chenopodium quinoa α-expansin 50 (CqEXPA50) as being involved in auxin-mediated salt tolerance. CqEXPA50 enhanced salt tolerance in quinoa seedlings was revealed by transient overexpression and physiological and biochemical analyses. Furthermore, the auxin pathway and salt stress-related genes regulated by CqEXPA50 were identified. The interaction of CqEXPA50 with these proteins was demonstrated by bimolecular fluorescence complementation (BIFC). The proteins that interact with CqEXPA50 were also found to improve salt tolerance. In conclusion, this study identified some genes potentially involved in the salt tolerance regulatory network of quinoa, providing new insights into salt tolerance.

Plasma membrane-localized protein BcHIPP16 promotes the uptake of copper and cadmium in planta.

Cadmium (Cd) is one of the toxic heavy metals in soil, which not only suppresses crop production but also threatens human health. In this study, we aim to clarify the biological function of Cd-related gene BcHIPP16, so as to provide potential genetic solutions to decrease the Cd levels of pak choi. Tissue expression analysis showed that BcHIPP16 expressed in almost all the plant bodies. The transcriptional level of BcHIPP16 in roots was higher than that in shoots, which was significantly induced by copper (Cu) deficiency and Cd exposure conditions. Subcellular localization revealed that BcHIPP16 localized in plasma membrane. Expressing BcHIPP16 in yeast cells improved the sensitivity to Cu and Cd and improved their accumulation in yeast. Furthermore, the Cu and Cd content of Arabidopsis seedlings were increased and complemented, respectively when expressing BcHIPP16 in wild type (WT) and hip16 mutants. Non-invasive Micro-test Technology (NMT) was used to measure the real-time Cd2+ influx from the root surface of BcHIPP16 transgenic Arabidopsis lines, and the result demonstrated that BcHIPP16 promoted Cd2+ influx into Arabidopsis root cells. Taken together, our study showed that BcHIPP16 contributed to absorbing nutrient metal Cu and heavy metal Cd in planta.

Ferrous iron-induced increases in capitate glandular trichome density and upregulation of CbHO-1 contributes to increases in blinin content in Conyza blinii.

MAIN CONCLUSION: Ferrous iron can promote the development of glandular trichomes and increase the content of blinin, which depends on CbHO-1 expression. Conyza blinii (C. blinii) is a unique Chinese herbal medicine that grows in Sichuan Province, China. Because the habitat of C. blinii is an iron ore mining area with abundant iron content, this species can be used as one of the best materials to study the mechanism of plant tolerance to iron. In this study, C. blinii was treated with ferrous-EDTA solutions at different concentrations, and it was found that the tolerance value of C. blinii to iron was 200 µM. Under this concentration, the plant height, root length, biomass, and iron content of C. blinii increased to the maximum values, and the effect was dependent on the upregulated expression of CbHO-1. At the same time, under ferrous iron, the photosynthetic capacity and capitate glandular trichome density of C. blinii also significantly increased, providing precursors and sites for the synthesis of blinin, thus significantly increasing the content of blinin. These processes were also dependent on the high expression of CbHO-1. Correlation analysis showed that there were strong positive correlations between iron content, capitate glandular trichome density, CbHO-1 gene expression, and blinin content. This study explored the effects of ferrous iron on the physiology and biochemistry of C. blinii, greatly improving our understanding of the mechanism of iron tolerance in C. blinii.

Insights into the correlation between Physiological changes in and seed development of tartary buckwheat (Fagopyrum tataricum Gaertn.).

BACKGROUND: Tartary buckwheat (Fagopyrum tataricum Gaertn.) is a widely cultivated medicinal and edible crop with excellent economic and nutritional value. The development of tartary buckwheat seeds is a very complex process involving many expression-dependent physiological changes and regulation of a large number of genes and phytohormones. In recent years, the gene regulatory network governing the physiological changes occurring during seed development have received little attention. RESULTS: Here, we characterized the seed development of tartary buckwheat using light and electron microscopy and measured phytohormone and nutrient accumulation by using high performance liquid chromatography (HPLC) and by profiling the expression of key genes using RNA sequencing with the support of the tartary buckwheat genome. We first divided the development of tartary buckwheat seed into five stages that include complex changes in development, morphology, physiology and phytohormone levels. At the same time, the contents of phytohormones (gibberellin, indole-3-acetic acid, abscisic acid, and zeatin) and nutrients (rutin, starch, total proteins and soluble sugars) at five stages were determined, and their accumulation patterns in the development of tartary buckwheat seeds were analyzed. Second, gene expression patterns of tartary buckwheat samples were compared during three seed developmental stages (13, 19, and 25 days postanthesis, DPA), and 9 765 differentially expressed genes (DEGs) were identified. We analyzed the overlapping DEGs in different sample combinations and measured 665 DEGs in the three samples. Furthermore, expression patterns of DEGs related to phytohormones, flavonoids, starch, and storage proteins were analyzed. Third, we noted the correlation between the trait (physiological changes, nutrient changes) and metabolites during seed development, and discussed the key genes that might be involved in the synthesis and degradation of each of them. CONCLUSION: We provided abundant genomic resources for tartary buckwheat and Polygonaceae communities and revealed novel molecular insights into the correlations between the physiological changes and seed development of tartary buckwheat.

The Potential Role of Auxin and Abscisic Acid Balance and FtARF2 in the Final Size Determination of Tartary Buckwheat Fruit.

Tartary buckwheat is a type of cultivated medicinal and edible crop with good economic and nutritional value. Knowledge of the final fruit size of buckwheat is critical to its yield increase. In this study, the fruit development of two species of Tartary buckwheat in the Polygonaceae was analyzed. During fruit development, the size/weight, the contents of auxin (AUX)/abscisic acid (ABA), the number of cells, and the changes of embryo were measured and observed; and the two fruit materials were compared to determine the related mechanisms that affected fruit size and the potential factors that regulated the final fruit size. The early events during embryogenesis greatly influenced the final fruit size, and the difference in fruit growth was primarily due to the difference in the number of cells, implicating the effect of cell division rate. Based on our observations and recent reports, the balance of AUX and ABA might be the key factor that regulated the cell division rate. They induced the response of auxin response factor 2 (FtARF2) and downstream small auxin upstream RNA (FtSAURs) through hormone signaling pathway to regulate the fruit size of Tartary buckwheat. Further, through the induction of fruit expansion by exogenous auxin, FtARF2b was significantly downregulated. The FtARF2b is a potential target for molecular breeding or gene editing.

Genome-Wide Investigation of the Auxin Response Factor Gene Family in Tartary Buckwheat (Fagopyrum tataricum).

Auxin signaling plays an important role in plant growth and development. It responds to various developmental and environmental events, such as embryogenesis, organogenesis, shoot elongation, tropical growth, lateral root formation, flower and fruit development, tissue and organ architecture, and vascular differentiation. However, there has been little research on the Auxin Response Factor (ARF) genes of tartary buckwheat (Fagopyrum tataricum), an important edible and medicinal crop. The recent publication of the whole-genome sequence of tartary buckwheat enables us to study the tissue and expression profile of the FtARF gene on a genome-wide basis. In this study, 20 ARF (FtARF) genes were identified and renamed according to the chromosomal distribution of the FtARF genes. The results showed that the FtARF genes belonged to the related sister pair, and the chromosomal map showed that the duplication of FtARFs was related to the duplication of the chromosome blocks. The duplication of some FtARF genes shows conserved intron/exon structure, which is different from other genes, suggesting that the function of these genes may be diverse. Real-time quantitative PCR analysis exhibited distinct expression patterns of FtARF genes in various tissues and in response to exogenous auxin during fruit development. In this study, 20 FtARF genes were identified, and the structure, evolution, and expression patterns of the proteins were studied. This systematic analysis laid a foundation for the further study of the functional characteristics of the ARF genes and for the improvement of tartary buckwheat crops.

Assessment of the clinical value of five noninvasive predictors of metabolic dysfunction-associated steatotic liver disease in Han Chinese adults.

BACKGROUND: Fatty Liver Index (FLI), Triglyceride-Glucose Index (TyG), Lipid Accumulation Product (LAP), Zhejiang University Index (ZJU), and Visceral Adiposity Index (VAI) are five classical predictive models for fatty liver disease. Our cross-sectional study aimed to identify the optimal predictors by comparing the predictive value of five models for metabolic dysfunction-associated steatotic liver disease (MASLD) risk. METHODS: Data on 2687 participants were collected from West China Hospital of Sichuan University. Controlled attenuation parameters assessed by transient elastography were used to effectively diagnose MASLD. Logistic regression analysis was used to estimate the odd ratios and 95% confidence intervals between indices and MASLD risk. Receiver operating characteristic curves were plotted to evaluate the predictive value of indices. RESULTS: This study included 1337 normal and 1350 MASLD samples. The average age of MASLD patients is 47 years old, and the prevalence was higher in males (39.3%) than in females (10.9%). Five indices were positively correlated with MASLD risk, with the strongest correlation for TyG. Overall, the area under the curve of the indicators was: ZJU 0.988, FLI 0.987, LAP 0.982, TyG 0.942, and VAI 0.941. In the gender stratification, ZJU (0.989) performed best in males. FLI (0.988) and ZJU (0.987) had similar predictive ability in females. In the age stratification, FLI performed better in predicting the middle-aged group aged 30-40 years (0.991). CONCLUSION: For Chinese Han adults, ZJU is the best predictive index for initial screening of MASLD. FLI can serve as an alternative tool for ZJU to predict females.

Recent progress on the application of compound formulas of traditional Chinese medicine in clinical trials and basic research in vivo for chronic liver disease.

ETHNOPHARMACOLOGICAL RELEVANCE: Chronic liver diseases mainly include chronic viral liver disease, metabolic liver disease, cholestatic liver disease (CLD), autoimmune liver disease, and liver fibrosis or cirrhosis. Notably, the compound formulas of traditional Chinese medicine (TCM) is effective for chronic liver diseases in clinical trials and basic research in vivo, which provide evidence of chronic liver disease treatment with integrated TCM and traditional Western medicine. AIM OF THE REVIEW: This paper aims to provide a comprehensive review of the compound formulas of TCM for treating different chronic liver diseases to elucidate the composition, main curative effects, and mechanisms of these formulas and research methods. MATERIALS AND METHODS: Different keywords related to chronic liver diseases and keywords related to the compound formulas of TCM were used to search the literature. PubMed, Scopus, Web of Science, and CNKI were searched to screen out original articles about the compound formulas of TCM related to the treatment of chronic liver diseases, mainly including clinical trials and basic in vivo research related to Chinese patent drugs, classic prescriptions, proven prescriptions, and hospital preparations. We excluded review articles, meta-analysis articles, in vitro experiments, articles about TCM monomers, articles about single-medicine extracts, and articles with incomplete or uncertain description of prescription composition. Plant names were checked with MPNS (http://mpns.kew.org). RESULTS: In this review, the clinical efficacy and mechanism of compound formulas of TCM were summarized for the treatment of chronic viral hepatitis, nonalcoholic fatty liver disease, CLD, and liver fibrosis or cirrhosis developed from these diseases and other chronic liver diseases. For each clinical trial and basic research in vivo, this review provides a detailed record of the specific composition of the compound formulas of TCM, type of clinical research, modeling method of animal experiments, grouping methods, medication administration, main efficacy, and mechanisms. CONCLUSION: The general development process of chronic liver disease can be summarized as chronic hepatitis, liver fibrosis or cirrhosis, and hepatocellular carcinoma. The compound formulas of TCM have some applications in these stages of chronic liver diseases. Owing to the continuous progress of medical technology, the benefits of the compound formulas of TCM in the treatment of chronic liver diseases are constantly changing and developing.

Selenium treatment promotes anthocyanin accumulation in radish sprouts (Raphanus sativus L.) by its regulation of photosynthesis and sucrose transport.

Red radish sprout become a popular dietary vegetable because of its unique flavor, abundant nutrients and short production cycle. As a cruciferous plant, it has strong ability to absorb and assimilate Se which can promote the content of anthocyanin in plants. However, the mechanisms of Se on anthocyanin accumulation are still unclear. In this study, we explored that appropriate Se promoted growth, antioxidant system and nutrients in radish sprouts. The enhancement of photosynthesis by Se treatment resulted in more sucrose synthesis in radish sprouts. And the transport of sucrose from cotyledon to hypocotyl promoted by Se through up-regulating the gene expression of sucrose transporters, and more sucrose increased the expression of anthocyanin biosynthesis genes to promote anthocyanin accumulation in hypocotyl. These results reveal the beneficial effect of Se on radish sprouts quality, and provide a new insight into the function of Se on sucrose-induced anthocyanin accumulation in radish sprouts.

The Tartary buckwheat bHLH gene ALCATRAZ contributes to silique dehiscence in Arabidopsis thaliana.

Tartary buckwheat is popular because of its rich nutrients. However, the difficulty in shelling restricts food production. The gene ALCATRAZ (AtALC) plays a key role in silique dehiscence in Arabidopsis thaliana. In this study, an atalc mutant was obtained by CRISPR/Cas9, and a FtALC gene homologous to AtALC was complemented into the atalc mutant to verify its function. Phenotypic observations showed that three atalc mutant lines did not dehiscence, while ComFtALC lines recovered the dehiscence phenotype. The contents of lignin, cellulose, hemicellulose, and pectin in the siliques of all the atalc mutant lines were significantly higher than those in the wild-type and ComFtALC lines. Moreover, FtALC was found to regulate the expression of cell wall pathway genes. Finally, the interaction of FtALC with FtSHP and FtIND was verified by yeast two-hybrid, bimolecular fluorescent complimentary (BIFC) and firefly luciferase completion imaging assays (LCIs). Our findings enrich the silique regulatory network and lay the foundation for the cultivation of easily shelled tartary buckwheat varieties.

The Relationship Between Plant-Based Diet and Risk of Digestive System Cancers: A Meta-Analysis Based on 3,059,009 Subjects.

Background and Objectives: Diets containing red or processed meat are associated with a growing risk of digestive system cancers. Whether a plant-based diet is protective against cancer needs a high level of statistical evidence. Methods: We performed a meta-analysis of five English databases, including PubMed, Medline, Embase, Web of Science databases, and Scopus, on October 24, 2021 to identify published papers. Cohort studies or case-control studies that reported a relationship between plant-based diets and cancers of the digestive system were included. Summary effect-size estimates are expressed as Risk ratios (RRs) or Odds ratios (ORs) with 95% confidence intervals and were evaluated using random-effect models. The inconsistency index (I2) and τ2 (Tau2) index were used to quantify the magnitude of heterogeneity derived from the random-effects Mantel-Haenszel model. Results: The same results were found in cohort (adjusted RR = 0.82, 95% CI: 0.78-0.86, P < 0.001, I2 = 46.4%, Tau2 = 0.017) and case-control (adjusted OR = 0.70, 95% CI: 0.64-0.77, P < 0.001, I2 = 83.8%, Tau2 = 0.160) studies. The overall analysis concluded that plant-based diets played a protective role in the risk of digestive system neoplasms. Subgroup analyses demonstrated that the plant-based diets reduced the risk of cancers, especially pancreatic (adjusted RR = 0.71, 95% CI: 0.59-0.86, P < 0.001, I2 = 55.1%, Tau2 = 0.028), colorectal (adjusted RR = 0.76, 95% CI: 0.69-0.83, P < 0.001, I2 = 53.4%, Tau2 = 0.023), rectal (adjusted RR = 0.84, 95% CI: 0.78-0.91, P < 0.001, I2 = 1.6%, Tau2 = 0.005) and colon (adjusted RR = 0.88, 95% CI: 0.82-0.95, P < 0.001, I2 = 0.0%, Tau2 = 0.000) cancers, in cohort studies. The correlation between vegan and other plant-based diets was compared using Z-tests, and the results showed no difference. Conclusions: Plant-based diets were protective against cancers of the digestive system, with no significant differences between different types of cancer. Systematic Review Registration: https://www.crd.york.ac.uk/prospero/display_record.php?ID=CRD42022322276, Identifier: CRD42022322276.

Obesity in children and adolescents and the risk of ovarian cancer: A systematic review and dose‒response meta-analysis.

OBJECTIVE: The relationship between obesity in children and adolescents and the risk of ovarian cancer remains controversial. The aim of this meta-analysis was to explore the exact shape of this relationship. METHODS: We conducted dose‒response meta-analyses of cohort and case‒control studies, including published studies derived from searches in the PubMed, Embase, Web of Science and Cochrane Library databases until October 2022. Pooled effect size estimates are expressed as relative risks (RRs) or odds ratios (ORs) with 95% confidence intervals (CIs) and were evaluated by fixed-effect models. A nonlinear dose‒response meta-analysis was performed by using a restricted cubic spline model. RESULTS: After screening 4215 publications, 10 studies were included in the present meta-analysis. Overall analyses revealed statistically significant associations of obesity in children and adolescents with ovarian cancer (adjusted RR = 1.19, 95% CI: 1.11 to 1.28, P < 0.001). Moreover, the association was consistently significant in most subgroup analyses, for example, using geographic stratification, the results remained stable both in the Americas(RR = 1.11; 95% CI: 1.01 to 1.21; P = 0.022) and Europe (RR = 1.46; 95% CI: 1.21 to 1.77; P<0.001). For the dose‒response analyses, the risk of ovarian cancer increased with the degree of obesity, and the trend increased rapidly when body mass index (BMI) was over 25.95 kg/m2. CONCLUSION: Our findings indicate that obesity in children and adolescents is a risk factor for ovarian cancer, and the risk increases with increasing BMI.

Mechanisms of calcium sulfate in alleviating cadmium toxicity and accumulation in pak choi seedlings.

Gypsum (calcium sulfate dihydrate, CaSO4 ·2H2O) is commonly applied to improve soil quality and nutrient supply. Previous studies also suggested it is a cost-effective soil amendment in alleviating cadmium (Cd) toxicity and accumulation in plants. The aim of this study was to investigate how this is achieved. We used pak choi as our research material because it is a popular vegetable in Asia, and as a leafy vegetable, it accumulates higher Cd level than other types of vegetable. Under Cd stress, application of CaSO4 promoted pak choi seedling growth, decreased the oxidative stress in roots, reduced Cd accumulation, and enhanced the photosynthesis in shoots. We revealed the inhibition of Cd2+ absorption by CaSO4 is largely due to the competition between Ca2+ and Cd2+ for ion channels or transporter. Moreover, under Cd stress, CaSO4 facilitated the sulphate assimilation, increased the biosynthesis of phytochelatins, and activated the expression of transporters for vacuolar sequestration. Together, CaSO4 could benefit plant growth and enhance Cd tolerance by suppressing Cd root uptake and lowering the Cd content in cytoplasm.

Malate-mediated CqMADS68 enhances aluminum tolerance in quinoa seedlings through interaction with CqSTOP6, CqALMT6 and CqWRKY88.

Aluminum (Al) stress in acidic soils has severe negative effects on crop productivity. In this study, the alleviating effect and related mechanism of malate on Al stress in quinoa (Chenopodium quinoa) seedlings were investigated. The findings indicated that malate alleviated the growth inhibition of quinoa seedlings under Al stress, maintained the enzymatic and nonenzymatic antioxidant systems, and aided resistance to the damage caused by excessive reactive oxygen species (ROS). Under Al stress, malate significantly increased the contents of chlorophyll and carotenoids in quinoa shoots by 103.8% and 240.7%, and significantly increased the ratios of glutathione (GSH)/oxidized glutathione (GSSG), and ascorbate (AsA)/dehydroascorbate (DHA) in roots by 59.9% and 699.2%, respectively. However, malate significantly decreased the superoxide radical (O2•-), hydrogen peroxide (H2O2), malondialdehyde (MDA) and Al contents in quinoa roots under Al stress by 32.7%, 60.9%, 63.1% and 49%, respectively. Moreover, the CqMADS family and the Al stress-responsive gene families (CqSTOP, CqALMT, and CqWRKY) were identified from the quinoa genome. Comprehensive expression profiling identified CqMADS68 as being involved in malate-mediated Al resistance. Transient overexpression of CqMADS68 increased Al tolerance in quinoa seedlings. More importantly, we found that CqMADS68 regulated the expression of CqSTOP6, CqALMT6 and CqWRKY88 and further demonstrated the interaction of CqMADS68 with CqSTOP6, CqALMT6 and CqWRKY88 by bimolecular fluorescence complementation (BIFC) experiments. Moreover, transient overexpression and physiological and biochemical analyses demonstrated that CqSTOP6, CqALMT6 and CqWRKY88 could also improve Al tolerance by maintaining the antioxidant capacity of quinoa seedlings. Taken together, these findings reveal that CqMADS68, CqSTOP6, CqALMT6 and CqWRKY88 may be important contributors to the Al tolerance regulatory network in quinoa, providing new insights into Al stress resistance.

CqZF-HD14 enhances drought tolerance in quinoa seedlings through interaction with CqHIPP34 and CqNAC79.

Drought stress is a key agricultural problem that restricts plant development and crop yield. Research on quinoa (Chenopodium quinoa), a nutrient-rich crop with strong stress resistance, has been limited in terms of the molecular regulation of its adaptation to drought stress. This study identified the zinc finger-homeodomain (ZF-HD) family in quinoa and a drought-responsive Chenopodium quinoa ZF-HD14 (CqZF-HD14) through expression profiles. Transient overexpression of CqZF-HD14 promotes photosynthetic pigment accumulation under drought stress, strengthens the antioxidant system, and in turn enhances drought tolerance. Comprehensive genome-wide family analysis and expression profiling identified CqNAC79 and CqHIPP34 regulated by CqZF-HD14, and their interactions were further determined by bimolecular fluorescence complementation (BIFC). Moreover, physiological and biochemical analyses and transient overexpression also revealed that CqNAC79 and CqHIPP34 resist drought by promoting the accumulation of photosynthetic pigments and maintaining antioxidant capacity under drought stress. The synergistic effect of CqZF-HD14 with CqNAC79 or CqHIPP34 further enhanced the drought tolerance of quinoa seedlings. Taken together, the results indicate that CqZF-HD14, CqNAC79 and CqHIPP34 may be important contributors to the drought tolerance regulatory network in quinoa, and these findings add new members to the drought tolerance gene pool.

Hemin-induced increase in saponin content contributes to the alleviation of osmotic and cold stress damage to Conyza blinii in a heme oxygenase 1-dependent manner.

Hemin can improve the stress resistance of plants through the heme oxygenase system. Additionally, substances contained in plants, such as secondary metabolites, can improve stress resistance. However, few studies have explored the effects of hemin on secondary metabolite content. Therefore, the effects of hemin on saponin synthesis and the mechanism of plant injury relief by hemin in Conyza blinii were investigated in this study. Hemin treatment promoted plant growth and increased the antioxidant enzyme activity and saponin content of C. blinii under osmotic stress and cold stress. Further study showed that hemin could provide sufficient precursors for saponin synthesis by improving the photosynthetic capacity of C. blinii and increasing the gene expression of key enzymes in the saponin synthesis pathway, thus increasing the saponin content. Moreover, the promotion effect of hemin on saponin synthesis is dependent on heme oxygenase-1 and can be reversed by the inhibitor Zn-protoporphyrin-IX (ZnPPIX). This study revealed that hemin can increase the saponin content of C. blinii and alleviate the damage caused by abiotic stress, and it also broadened the understanding of the relationship between hemin and secondary metabolites in plant abiotic stress relief.

Involvement of several putative transporters of different families in ß-cyclocitral-induced alleviation of cadmium toxicity in quinoa (Chenopodium quinoa) seedlings.

Cadmium (Cd) has a serious negative impact on crop growth and human food security. This study investigated the alleviating effect of ß-cyclocitral, a potential heavy metal barrier, on Cd stress in quinoa seedlings and the associated mechanisms. Our results showed that ß-cyclocitral alleviated Cd stress-induced growth inhibition in quinoa seedlings and promoted quinoa seedling root development under Cd stress. Moreover, it maintained the antioxidant system of quinoa seedlings, including the enzymatic, i.e., superoxide dismutase (SOD), peroxidase (POD), catalase (CAT), ascorbate peroxidase (APX), and nonenzymatic, i.e., reduced glutathione (GSH) and ascorbic acid (ASA), antioxidants, which eliminate the damage from excessive reactive oxygen species (ROS). Our results showed that ß-cyclocitral could reduce the amount of Cd absorbed by roots. Furthermore, we systematically identified five transporter families from the quinoa genome, and the RT-qPCR results showed that ZIP, Nramp and YSL gene families were downregulated by ß-cyclocitral to reduce Cd uptake by roots. Thus, ß-cyclocitral promoted the growth, photosynthetic capacity and antioxidant capacity of the aboveground parts of quinoa seedlings. Taken together, these results suggested that the ß-cyclocitral-induced decrease in Cd uptake may be caused by the downregulation of several selected transporter genes.