Cryptochrome 1b represses gibberellin signaling to enhance lodging resistance in maize.

Maize (Zea mays L.) is one of the most important crops worldwide. Photoperiod, light quality, and light intensity in the environment can affect the growth, development, yield, and quality of maize. In Arabidopsis (Arabidopsis thaliana), cryptochromes are blue-light receptors that mediate the photocontrol of stem elongation, leaf expansion, shade tolerance, and photoperiodic flowering. However, the function of maize cryptochrome ZmCRY in maize architecture and photomorphogenic development remains largely elusive. The ZmCRY1b transgene product can activate the light signaling pathway in Arabidopsis and complement the etiolation phenotype of the cry1-304 mutant. Our findings show that the loss-of-function mutant of ZmCRY1b in maize exhibits more etiolation phenotypes under low blue light and appears slender in the field compared with wild-type plants. Under blue and white light, overexpression of ZmCRY1b in maize substantially inhibits seedling etiolation and shade response by enhancing protein accumulation of the bZIP transcription factors ELONGATED HYPOCOTYL 5 (ZmHY5) and ELONGATED HYPOCOTYL 5-LIKE (ZmHY5L), which directly upregulate the expression of genes encoding gibberellin (GA) 2-oxidase to deactivate GA and repress plant height. More interestingly, ZmCRY1b enhances lodging resistance by reducing plant and ear heights and promoting root growth in both inbred lines and hybrids. In conclusion, ZmCRY1b contributes blue-light signaling upon seedling de-etiolation and integrates light signals with the GA metabolic pathway in maize, resulting in lodging resistance and providing information for improving maize varieties.

Ethylene controls three-dimensional growth involving reduced auxin levels in the moss Physcomitrium patens.

The conquest of land by plants was concomitant with, and possibly enabled by, the evolution of three-dimensional (3D) growth. The moss Physcomitrium patens provides a model system for elucidating molecular mechanisms in the initiation of 3D growth. Here, we investigate whether the phytohormone ethylene, which is believed to have been a signal before land plant emergence, plays a role in 3D growth regulation in P. patens. We report ethylene controls 3D gametophore formation, based on results from exogenously applied ethylene and genetic manipulation of PpEIN2, which is a central component in the ethylene signaling pathway. Overexpression (OE) of PpEIN2 activates ethylene responses and leads to earlier formation of gametophores with fewer gametophores produced thereafter, phenocopying ethylene-treated wild-type. Conversely, Ppein2 knockout mutants, which are ethylene insensitive, show initially delayed gametophore formation with more gametophores produced later. Furthermore, pharmacological and biochemical analyses reveal auxin levels are decreased in the OE lines but increased in the knockout mutants. Our results suggest that evolutionarily, ethylene and auxin molecular networks were recruited to build the plant body plan in ancestral land plants. This might have played a role in enabling ancient plants to acclimate to the continental surfaces of the planet.

Metabolomic and transcriptomic analyses provide insights into variations in flavonoids contents between two Artemisia cultivars.

BACKGROUND: Plants in the genus Artemisia are rich in active ingredients and specialized metabolites. Many of these compounds, especially flavonoids, have potential medicinal and nutritional applications, and are of growing interest to scientists due to their wide range of pharmacological and biological activities. Artemisia cultivars are commonly used as raw materials for medicine, food, and moxibustion in China. However, most of the metabolites produced by Artemisia species have not been identified, and few studies have addressed differences in active compounds between species and cultivars. RESULTS: We here investigated two Artemisia cultivars, 'Nanyangshiyong' (NYSY) and 'Nanyangyaoyong' (NYYY), which are commonly used in foods and moxibustion, respectively. NYSY and NYYY were confirmed to be Artemisia argyi cultivars. Total flavonoids contents and antioxidant activities were higher in NYYY than in NYSY. A total of 882 metabolites were identified in the samples; most of the potentially medicinally active compounds, especially flavonoids (e.g., flavone, flavonol, isoflavone, and anthocyanin), were up-regulated in NYYY compared to NYSY. Furthermore, most of the genes related to flavonoids biosynthesis were up-regulated in NYYY. Correlation analysis was used to identify putative members of transcription factor families that may regulate genes encoding key flavonoids biosynthesis enzymes. CONCLUSIONS: We found that the antioxidant activities and flavonoids contents significantly varied between two Artemisia cultivars of the same species. We also uncovered metabolomic and transcriptomic evidence of the molecular phenomena underlying those differences in flavonoids contents between the two Artemisia cultivars. This study provides a wealth of data for future utilization and improvements of Artemisia cultivars, and highlights a need to study the specific metabolite profiles of plants that are used in foods and medicines.

Quantitative fingerprint and antioxidative properties of Artemisia argyi leaves combined with chemometrics.

Quantitative fingerprint and differences of Artemisia argyi from different varieties, picking time, aging year, and origins were analyzed combing with chemometrics. The antioxidant activity was determined and antioxidant markers of Artemisia argyi were screened. Variety WA3 was significantly different from that of the other varieties. Fingerprint peak response and antioxidant activity of A. argyi picked in December were lower than samples collected in May and August. Fresh A. argyi leaves were significantly superior to withered leaves and stems. Artemisia argyi aging 1-5 years presented a classification trend. Antioxidant activity of A. argyi produced in Nanyang was generally superior to others origins. Peak 9, isochlorogenic acid A, and 6-methoxyluteolin contributed greatly for classification of A. argyi from different variety, picking time, aging year, and origin. Isochlorogenic acid A, isochlorogenic acid C, 6-methoxyluteolin, and chlorogenic acid were selected as antioxidant marker of A. argyi. The method based on quantitative fingerprint, antioxidant activity evaluation, and chemometrics was reliable to analyze the differences of A. argyi samples from different sources.

Arabidopsis phytochromes A and B synergistically repress SPA1 under blue light.

In Arabidopsis, although studies have demonstrated that phytochrome A (phyA) and phyB are involved in blue light signaling, how blue light-activated phytochromes modulate the activity of the CONSTITUTIVELY PHOTOMORPHOGENIC1 (COP1)-SUPPRESSOR OF PHYA-105 (SPA1) E3 complex remains largely unknown. Here, we show that phyA responds to early and weak blue light, whereas phyB responds to sustainable and strong blue light. Activation of both phyA and phyB by blue light inhibits SPA1 activity. Specifically, blue light irradiation promoted the nuclear import of both phytochromes to stimulate their binding to SPA1, abolishing SPA1's interaction with LONG HYPOCOTYL 5 (HY5) to release HY5, which promoted seedling photomorphogenesis.

HFR1, a bHLH Transcriptional Regulator from Arabidopsis thaliana, Improves Grain Yield, Shade and Osmotic Stress Tolerances in Common Wheat.

Common wheat, Triticum aestivum, is the most widely grown staple crop worldwide. To catch up with the increasing global population and cope with the changing climate, it is valuable to breed wheat cultivars that are tolerant to abiotic or shade stresses for density farming. Arabidopsis LONG HYPOCOTYL IN FAR-RED 1 (AtHFR1), a photomorphogenesis-promoting factor, is involved in multiple light-related signaling pathways and inhibits seedling etiolation and shade avoidance. We report that overexpression of AtHFR1 in wheat inhibits etiolation phenotypes under various light and shade conditions, leading to shortened plant height and increased spike number relative to non-transgenic plants in the field. Ectopic expression of AtHFR1 in wheat increases the transcript levels of TaCAB and TaCHS as observed previously in Arabidopsis, indicating that the AtHFR1 transgene can activate the light signal transduction pathway in wheat. AtHFR1 transgenic seedlings significantly exhibit tolerance to osmotic stress during seed germination compared to non-transgenic wheat. The AtHFR1 transgene represses transcription of TaFT1, TaCO1, and TaCO2, delaying development of the shoot apex and heading in wheat. Furthermore, the AtHFR1 transgene in wheat inhibits transcript levels of PHYTOCHROME-INTERACTING FACTOR 3-LIKEs (TaPIL13, TaPIL15-1B, and TaPIL15-1D), downregulating the target gene STAYGREEN (TaSGR), and thus delaying dark-induced leaf senescence. In the field, grain yields of three AtHFR1 transgenic lines were 18.2-48.1% higher than those of non-transgenic wheat. In summary, genetic modification of light signaling pathways using a photomorphogenesis-promoting factor has positive effects on grain yield due to changes in plant architecture and resource allocation and enhances tolerances to osmotic stress and shade avoidance response.

Genetic Diversity Assessment of a Chinese Medicinal Endemic Species, Aspidopterys obcordata var. obcordata, by Combined Molecular Marker Methods (ISSR & SRAP).

Aspidopterys obcordata var. obcordata, a medicinal plant endemic to China, is a narrowly distributed species and wild resources are extremely limited. To evaluate the genetic variability and degree of genetic divergence of A. obcordata var. obcordata, and to make rational scientific decisions on its harvest and germplasm conservation, we collected 122 samples from across nearly all of its distribution area and studied genetic diversity using inter-simple sequence repeats (ISSRs), sequence-related amplified polymorphisms (SRAPs), and a method combining the two techniques. The results revealed the high genetic diversity of A. obcordata var. obcordata, mainly due to its intra-population diversity, and the top two populations with the highest levels of intra-population diversity were ML and DH, individuals of which can serve as excellent germplasm candidates during the processing of germplasm screening and conservation. In general, the combining method was prior to the ISSR analyses and SRAP analyses results, except for a slight difference in the genetic structure of individual populations. Therefore, we suggest that a combination analysis of the two marker methods is ideal for evaluating the genetic diversity and genetic relationships of A. obcordata var. obcordata.

[DNA barcoding identification of original plants of a rare medicinal material Resina Draconis and related Dracaena species].

Resina Draconis, a rare and precious traditional medicine in China, is known as the "holy medicine for promoting blood circulation". According to the national drug standard, it's derived from the resin extracted from the wood of Dracaena cochinchinensis, a Liliaceae plant. In addition, a variety of Dracaena species all over the world can form red resins, and there is currently no molecular identification method that can efficiently identify the origin of Dracaena medicinal materials. In this study, seven species of Dracaena distributed in China were selected as the research objects. Four commonly used DNA barcodes(ITS2, matK, rbcL and psbA-trnH), and four highly variable regions(trnP-psaJ, psbK-psbI, trnT-trnL, clpP) in chloroplast genome were used to evaluate the identification efficiency of Dracaena species. The results showed that clpP sequence fragment could accurately identify seven species of Dracaena plants. However, due to the long sequence of clpP fragment, there were potential problems in the practical application process. We found that the combined fragment "psbK-psbI+ trnP-psaJ" can also be used for accurate molecular identification of the Resina Draconis origin plants and relative species of Dracaena, which were both relatively short sequences in the combined fragment, showing high success rates of amplification and sequencing. Therefore, the "psbK-psbI+ trnP-psaJ" combined fragment can be used as the DNA barcode fragments for molecular identification of Resina Dracon's origin plants and relative species of Dracaena. Research on the identification of Dracaena species, the results of this study can be used to accurately identify the original material of Resina Draconis, and providing effective means for identification, rational development and application of Resina Draconis base source.

ER-localized adenine nucleotide transporter ER-ANT1: an integrator of energy and stress signaling in rice.

Most environmental perturbations have a direct or indirect deleterious impact on photosynthesis, and, in consequence, the overall energy status of the cell. Despite our increased understanding of convergent energy and stress signals, the connections between photosynthesis, energy and stress signals through putative common nodes are still unclear. Here we identified an endoplasmic reticulum (ER)-localized adenine nucleotide transporter1 (ER-ANT1), whose deficiency causes seedling lethality in air but viable under high CO2, exhibiting the typical photorespiratory phenotype. Metabolic analysis suggested that depletion of ER-ANT1 resulted in circadian rhythm disorders in sucrose synthesis and induced sucrose signaling pathways, indicating that the ER is involved in the regulation of vital energy metabolism in plants. In addition, the defect of ER-ANT1 triggers ER stress and activates the unfolded protein response in plant cells, suggesting ER stress and photorespiration are closely linked. These findings provide an important evidence for a key role of ER-localized ER-ANT1 in convergent energy and stress signals in rice. Our findings support the idea that ATP is a central signal involved in the plant response to a variety of stresses.

Arabidopsis phytochrome B promotes SPA1 nuclear accumulation to repress photomorphogenesis under far-red light.

Phytochrome A (phyA) is the primary photoreceptor mediating deetiolation under far-red (FR) light, whereas phyB predominantly regulates light responses in red light. SUPPRESSOR OF PHYA-105 (SPA1) forms an E3 ubiquitin ligase complex with CONSTITUTIVE PHOTOMORPHOGENIC1 (COP1), which is responsible for the degradation of various photomorphogenesis-promoting factors, resulting in desensitization to light signaling. However, the role of phyB in FR light signaling and the regulatory pathway from light-activated phytochromes to the COP1-SPA1 complex are largely unknown. Here, we confirm that PHYB overexpression causes an etiolation response with reduced ELONGATED HYPOCOTYL5 (HY5) accumulation under FR light. Notably, phyB exerts its nuclear activities and promotes seedling etiolation in both the presence and absence of phyA in response to FR light. PhyB acts upstream of SPA1 and is functionally dependent on it in FR light signaling. PhyB interacts and forms a protein complex with SPA1, enhancing its nuclear accumulation under FR light. During the dark-to-FR transition, phyB is rapidly imported into the nucleus and facilitates nuclear SPA1 accumulation. These findings support the notion that phyB plays a role in repressing FR light signaling. Activity modulation of the COP1-SPA E3 complex by light-activated phytochromes is an effective and pivotal regulatory step in light signaling.

[Acute toxicity study of Aspidopterys obcordata aqueous extract in Sprague-Dawley rats].

OBJECTIVE: To examine the acute toxicity of an aqueous extract of Aspidopterys obcordata (A. obcordata) in Sprague Dawley rats. METHODS: The rats were orally administered a dose of 5000 mg/kg body weight and observed continuously for 6 h and then daily for 14 days. Control rats were administered distilled water. The effect of the extract on general behavior, body weight, and food and water intake were measured. After 14 days, the rats were sacrificed and their organs (liver, heart, spleen, lungs, kidney, adrenal glands, ovaries, and testes) were removed for macroscopic examination. The body and organ weights in addition to hematology (e.g., hemoglobin and white blood cell counts) and clinical blood biochemistry (e.g., albumin and bilirubin) were also examined. RESULTS: There were no deaths recorded, and the rats treated with A. obcordata showed no signs of toxicity. All measured parameters in rats treated with A. obcordata were unaffected when compared with those in control rats. The acute toxicity (LD50) was estimated to be > 5000 mg/kg body weight. CONCLUSION: Our results demonstrate the safety of an acute oral administration of an aqueous extract of A. obcordata in rats and indicate that future subacute and long-term toxicity testing of A. obcordata is warranted.

Ectopic expression of a phytochrome B gene from Chinese cabbage (Brassica rapa L. ssp. pekinensis) in Arabidopsis thaliana promotes seedling de-etiolation, dwarfing in mature plants, and delayed flowering.

Phytochrome B (phyB) is an essential red light receptor that predominantly mediates seedling de-etiolation, shade-avoidance response, and flowering time. In this study, we isolate a full-length cDNA of PHYB, designated BrPHYB, from Chinese cabbage (Brassica rapa L. ssp. pekinensis), and we find that BrphyB protein has high amino acid sequence similarity and the closest evolutionary relationship to Arabidopsis thaliana phyB (i.e., AtphyB). Quantitative reverse transcription (RT)-PCR results indicate that the BrPHYB gene is ubiquitously expressed in different tissues under all light conditions. Constitutive expression of the BrPHYB gene in A. thaliana significantly enhances seedling de-etiolation under red- and white-light conditions, and causes dwarf stature in mature plants. Unexpectedly, overexpression of BrPHYB in transgenic A. thaliana resulted in reduced expression of gibberellins biosynthesis genes and delayed flowering under short-day conditions, whereas AtPHYB overexpression caused enhanced expression of FLOWERING LOCUS T and earlier flowering. Our results suggest that BrphyB might play an important role in regulating the development of Chinese cabbage. BrphyB and AtphyB have conserved functions during de-etiolation and vegetative plant growth and divergent functions in the regulation of flowering time.

Both PHYTOCHROME RAPIDLY REGULATED1 (PAR1) and PAR2 promote seedling photomorphogenesis in multiple light signaling pathways.

Arabidopsis (Arabidopsis thaliana) seedlings undergo photomorphogenesis in the light and etiolation in the dark. Light-activated photoreceptors transduce the light signals through a series of photomorphogenesis promoting or repressing factors to modulate many developmental processes in plants, such as photomorphogenesis and shade avoidance. CONSTITUTIVE PHOTOMORPHOGENIC1 (COP1) is a conserved RING finger E3 ubiquitin ligase, which mediates degradation of several photomorphogenesis promoting factors, including ELONGATED HYPOCOTYL5 (HY5) and LONG HYPOCOTYL IN FAR-RED1 (HFR1), through a 26S proteasome-dependent pathway. PHYTOCHROME RAPIDLY REGULATED1 (PAR1) was first detected as an early repressed gene in both phytochrome A (phyA)-mediated far-red and phyB-mediated red signaling pathways, and subsequent studies showed that both PAR1 and PAR2 are negative factors of shade avoidance in Arabidopsis. However, the role of PAR1 and PAR2 in seedling deetiolation, and their relationships with other photomorphogenesis promoting and repressing factors are largely unknown. Here, we confirmed that both PAR1 and PAR2 redundantly enhance seedling deetiolation in multiple photoreceptor signaling pathways. Their transcript abundances are repressed by phyA, phyB, and cryptochrome1 under far-red, red, and blue light conditions, respectively. Both PAR1 and PAR2 act downstream of COP1, and COP1 mediates the degradation of PAR1 and PAR2 through the 26S proteasome pathway. Both PAR1 and PAR2 act in a separate pathway from HY5 and HFR1 under different light conditions, except for sharing in the same pathway with HFR1 under far-red light. Together, our results substantiate that PAR1 and PAR2 are positive factors functioning in multiple photoreceptor signaling pathways during seedling deetiolation.

Synergistic and Antagonistic Action of Phytochrome (Phy) A and PhyB during Seedling De-Etiolation in Arabidopsis thaliana.

It has been reported that Arabidopsis phytochrome (phy) A and phyB are crucial photoreceptors that display synergistic and antagonistic action during seedling de-etiolation in multiple light signaling pathways. However, the functional relationship between phyA and phyB is not fully understood under different kinds of light and in response to different intensities of such light. In this work, we compared hypocotyl elongation of the phyA-211 phyB-9 double mutant with the wild type, the phyA-211 and phyB-9 single mutants under different intensities of far-red (FR), red (R), blue (B) and white (W) light. We confirmed that phyA and phyB synergistically promote seedling de-etiolation in B-, B plus R-, W- and high R-light conditions. The correlation of endogenous ELONGATED HYPOCOTYL 5 (HY5) protein levels with the trend of hypocotyl elongation of all lines indicate that both phyA and phyB promote seedling photomorphogenesis in a synergistic manner in high-irradiance white light. Gene expression analyses of RBCS members and HY5 suggest that phyB and phyA act antagonistically on seedling development under FR light.

[Fungal composition in massa medicata fermentata based on culture dependent method and independent PCR-SSCP technique].

OBJECTIVE: To analyze the fungal composition in Massa Medicata Fermentata based on culture dependent method and independent PCR-SSCP technique. METHOD: Fungi were directly isolated from Massa Medicata Fermentata samples. The obtained strains were identified according to morphology and DNA sequence. Meanwhile the total fungal DNA was extracted from Massa Medicata Fermentata samples, the cultural independent PCR-SSCP technique based on ß-tubulin gene were used to identify the mycobiota. RESULT: According to cultural method, Aspergillus flavus and Rhizopus oryzae were present in Massa Medicata Fermentata samples, while A. flavus and A. niger were present in fried Massa Medicata Fermentata samples. In contrast, 5 species were obtained by PCR-SSCP technique, A. flavus was overlapped with fungal taxa derived from culture dependent method; A. ambiguu and A. s ivoriensis were dominant with relative abundance of 57% and 35% respectively, while the relative abundance of A. flavus was as low as 4%. None species was obtained from fried Massa Medicata Fermentata samples. CONCLUSION: PCR-SSCP based on ß-tubulin gene could distinguish fungi into species, culture dependent method combined with culture independent method could better understand the fungal composition associated with Massa Medicata Fermentata fermentation.

Assessment of hepatic fatty infiltration using spectral computed tomography imaging: a pilot study.

OBJECTIVE: The objective of this study was to investigate the feasibility of using monochromatic spectral computed tomography (CT) imaging to assess fatty infiltration in liver. MATERIALS: With spectral CT imaging, phantoms with known fat concentrations were studied for scanning parameter optimization, then 52 patients enrolled into 4 groups (healthy, mild, moderate, and severe fatty infiltration) received abdominal scanning. Based on reconstructed monochromatic images, hepatic attenuation was analyzed, and dual-energy subtraction imaging (DESI) was created for quantifying fat infiltration. RESULTS: Corresponding to various hepatic fat infiltrations, 4 characteristic CT attenuation curve patterns were described. In DESI images, only fat and fatty components appeared bright. For livers without abnormal fat deposition, isolated bright pixels were visualized (% area = 0.5% ± 0.3%). With hepatic fat accumulation increasing, more bright pixels appeared in subtraction images with percentages of total liver area involved in 2.5%, 6.7%, and 13.4% of mild, moderate, and severe fat infiltration cases, respectively (P < 0.05). The corresponding CT values were as follows: 1.33, 2.53, 8.69, and 16.4 Hounsfield units (P < 0.01), which correlated with the % DESI area values (r = 0.9811). CONCLUSIONS: Spectral CT imaging is a promising method to quantitatively assess hepatic fat content and fatty infiltration with advantages compared with conventional CT imaging.

FGD5-AS1/miR-5590-3p/PINK1 induces Lenvatinib resistance in hepatocellular carcinoma.

BACKGROUND: Lenvatinib is a common systemic treatment for advanced hepatocellular carcinoma (HCC), the resistance to which presents a great challenge. However, the mechanism of lenvatinib resistance in HCC remains unclear. Therefore, elucidating the underlying and key regulatory molecular mechanisms of lenvatinib resistance is urgently needed. METHODS: Bioinformatic enrichment analysis was used to investigate the gene associated with lenvatinib resistance. RT-PCR, Western blot, immunohistochemistry, and luciferase assays were used to explore the mechanisms of lenvatinib resistance. The effects of the FGD5-AS1/miR-5590-3p/PINK1 axis on lenvatinib resistance were evaluated by colony formation assay, cell viability, apoptosis, mitochondrial homeostasis, and morphology analyses. RESULTS: Higher expression of PINK1 was observed in lenvatinib-resistant cells and tissues. PINK1 could be activated by increased FGD5-AS1 expression, thereby maintaining the mitochondrial structure and function and promoting the antioxidative stress response. FGD5-AS1/miR-5590-3p showed competitive regulation of PINK1, which affected lenvatinib sensitivity through regulation of mitochondrial structure and antioxidative stress. CONCLUSIONS: PINK1 was identified as a key gene leading to lenvatinib resistance by maintaining the mitochondrial structure and function. The FGD5-AS1/miR-5590-3p/PINK1 axis may be a promising strategy to overcome lenvatinib resistance in treatment-negative patients.

[Genetic relationship on several medicinal plants in Marsdenia from Yunnan in ISSR marker].

OBJECTIVE: To analyze the genetic relationship of 9 Marsdenia species from Yunnan, especially the traditional Dai medicine "Dai Bai Jie" (M. auricularis). METHOD: Applying the inter-simple sequence repeats (ISSR) markers technology. RESULT: Twenty-five primers were screened out of 60 ISSR random primers and produced 391 bands totally, every primer produce 8-21 bands and the mean number was 15.6. The range of the GS (genetic similarity) value was 0.6675-0.8210. In 9 Marsdenia species, M. auricularis is a relative of M. tenacissima. M. balansae and M. officinalis have the closest genetic relationship. CONCLUSION: It is supported by ISSR that the M. auricularis which is sib species of M. tenacissima, and the folk medicine of Marsdenia are worthy deep investigation and study.

[Primary investigation of contaminating fungi on Panax notoginseng and Amomum tsaoko in Yunnan].

OBJECTIVE: To analyze the potential risks of fungal contaminants on Panax notoginseng and Amomum tsaoko. METHOD: The primary investigation was conducted in the P. notoginseng and A. tsaoko major production areas in Yunnan. Samples of P. notoginseng and A. tsaoko were collected from drugstores and markets in 3 cities of Yunnan. Dilution-plate method was applied for the isolation of fungi, the obtained species were identified according to morphological and molecular approaches. RESULT: Paecilomyces lilacinus and Penicillium citrinum were dominant on samples of Panax notoginseng. P. lilacinus and Aspergillus flavus were dominant on samples of Amomum tsaoko. CONCLUSION: In Yunnan province, the major fungal contaminants on P. notoginseng are P. lilacinus and P. citrinum and the major fungal contaminants on A. tsaoko are P. lilacinus and Aspergillus flavus. There exists a potential contamination risk of citrinin on P. notoginseng and aflatoxin on A. tsaoko.

Arabidopsis SPA2 represses seedling de-etiolation under multiple light conditions.

In Arabidopsis, phytochrome (phy) A, phyB, and cryptochrome 1 (cry1) are representative far-red, red, and blue light photoreceptors, respectively. Members of the SUPPRESSOR OF PHYA-105 (SPA) protein family (SPA1-SPA4) form E3 ubiquitin ligase complexes with CONSTITUTIVE PHOTOMORPHOGENIC1 (COP1), which mediates the degradation of photomorphogenesis-promoting factors to desensitize light signaling. SPA2 has been reported to promote seedling etiolation in the dark. However, the unique roles of SPA2 and its three functional domains in suppressing photomorphogenesis under different light conditions are largely unknown. Here, we demonstrate that overexpression of the full-length or the central coiled-coil and C-terminal WD-repeat domains of SPA2 cause hyper-etiolation phenotypes under several light conditions. The SPA2 central coiled-coil and C-terminal WD-repeat domains are necessary and sufficient for repressing seedling de-etiolation, cotyledon unfolding, and promoting hypocotyl negative gravitropism under several light conditions. Furthermore, phyA, phyB, cry1, and COP1 repress protein accumulation or nuclear translocation of SPA2 through direct interactions with its kinase-like and coiled-coil domains located in the N-terminus in response to far-red, red, and blue light treatments, respectively. Taken together, our results demonstrate that SPA2 functions under multiple light conditions; moreover, light-activated photoreceptors rapidly suppress SPA2 activity via direct interactions in response to different light treatments.