Chromosome-level assembly of the Neolamarckia cadamba genome provides insights into the evolution of cadambine biosynthesis.

Neolamarckia cadamba (Roxb.), a close relative of Coffea canephora and Ophiorrhiza pumila, is an important traditional medicine in Southeast Asia. Three major glycosidic monoterpenoid indole alkaloids (MIAs), cadambine and its derivatives 3ß-isodihydrocadambine and 3ß-dihydrocadambine, accumulate in the bark and leaves, and exhibit antimalarial, antiproliferative, antioxidant, anticancer and anti-inflammatory activities. Here, we report a chromosome-scale N. cadamba genome, with 744.5 Mb assembled into 22 pseudochromosomes with contig N50 and scaffold N50 of 824.14 Kb and 29.20 Mb, respectively. Comparative genomic analysis of N. cadamba with Co. canephora revealed that N. cadamba underwent a relatively recent whole-genome duplication (WGD) event after diverging from Co. canephora, which contributed to the evolution of the MIA biosynthetic pathway. We determined the key intermediates of the cadambine biosynthetic pathway and further showed that NcSTR1 catalyzed the synthesis of strictosidine in N. cadamba. A new component, epoxystrictosidine (C27H34N2O10, m/z 547.2285), was identified in the cadambine biosynthetic pathway. Combining genome-wide association study (GWAS), population analysis, multi-omics analysis and metabolic gene cluster prediction, this study will shed light on the evolution of MIA biosynthetic pathway genes. This N. cadamba reference sequence will accelerate the understanding of the evolutionary history of specific metabolic pathways and facilitate the development of tools for enhancing bioactive productivity by metabolic engineering in microbes or by molecular breeding in plants.

Identification of the CONSTANS-like family in Cymbidium sinense, and their functional characterization.

BACKGROUND: Cymbidium sinense is an orchid that is typically used as a potted plant, given its high-grade ornamental characteristics, and is most frequently distributed in China and SE Asia. The inability to strictly regulate flowering in this economically important potted and cut-flower orchid is a bottleneck that limits its industrial development. Studies on C. sinense flowering time genes would help to elucidate the mechanism regulating flowering. There are very few studies on the genetic regulation of flowering pathways in C. sinense. Photoperiod significantly affects the flowering of C. sinense, but it was unknown how the CONSTANS gene family is involved in regulating flowering. RESULTS: In this study, eight CONSTANS-like genes were identified and cloned. They were divided into three groups based on a phylogenetic analysis. Five representative CsCOL genes (CsCOL3/4/6/8/9) were selected from the three groups to perform expression characterization and functional study. CsCOL3/4/6/8/9 are nucleus-localized proteins, and all five CsCOL genes were expressed in all organs, mainly in leaves followed by sepals. The expression levels of CsCOL3/4 (group I) were higher in all organs than other CsCOL genes. Developmental stage specific expression revealed that the expression of CsCOL3/4/9 peaked at the initial flowering stage. In contrast, the transcript level of CsCOL6/8 was highest at the pedicel development stage. Photoperiodic experiments demonstrated that the transcripts of the five CsCOL genes exhibited distinct diurnal rhythms. Under LD conditions, the overexpression of CsCOL3/4 promoted early flowering, and CsCOL6 had little effect on flowering time, whereas CsCOL8 delayed flowering of Arabidopsis thaliana. However, under SD conditions, overexpression of CsCOL4/6/8 promoted early flowering and the rosette leaves growth, and CsCOL3 induced flower bud formation in transgenic Arabidopsis. CONCLUSION: The phylogenetic analysis, temporal and spatial expression patterns, photoperiodic rhythms and functional study indicate that CsCOL family members in C. sinense were involved in growth, development and flowering regulation through different photoperiodic pathway. The results will be useful for future research on mechanisms pertaining to photoperiod-dependent flowering, and will also facilitate genetic engineering-based research that uses Cymbidium flowering time genes.

Discovery of ß-cyclocitral-derived mono-carbonyl curcumin analogs as anti-hepatocellular carcinoma agents via suppression of MAPK signaling pathway.

Hepatocellular carcinoma (HCC) is one of the most common malignant tumors with a high recurrence and mortality rate. In this study, a series of ß-cyclocitral-derived mono-carbonyl curcumin analogs were synthesized and their anticancer properties were evaluated. Among the series, A19 exhibited the strongest cytotoxic activity by inhibiting cell viability and colony formation, inducing cell cycle G2/M phase arrest and cell apoptosis of HCC HepG2 and Huh-7 cells, while having almost no cytotoxicity on normal liver MIHA cells. Mechanistically, our results demonstrated that A19 triggered intense DNA damage via suppression of the ERK/JNK/p38 MAPK signaling pathway. Additionally, a combination of A19 with sorafenib significantly induced synergistic cytotoxicity in HCC cells. Overall, our results indicate the potential of A19 as a novel chemotherapeutic drug administered either separately or in combined therapy for HCC treatment.

VyUSPA3, a universal stress protein from the Chinese wild grape Vitis yeshanensis, confers drought tolerance to transgenic V. vinifera.

KEY MESSAGE: VyUSPA3 from the Chinese wild grape Vitis yeshanensis interacts with ERF105, PUB24 and NF-YB3, and overexpression of the VyUSPA3 gene in V. vinifera cv. 'Thompson Seedless' confers drought tolerance. Drought is a major abiotic stress factor that seriously affects the growth and yield of grapevine. Although many drought-related genes have been identified in Arabidopsis and other plants, the functions of only a few of their counterparts have been revealed in grape. Here, a universal stress protein (USP) A from the Chinese wild grape Vitis yeshanensis, VyUSPA3, was identified and its function was subsequently characterized by overexpressing or silencing the VyUSPA3 gene in V. vinifera cv. 'Thompson Seedless' via Agrobacterium-mediated genetic transformation. After 21 d of the drought treatment, most leaves of the untransformed (UT) 'Thompson Seedless' lines wilted, yet UT lines were less damaged compared to the RNAi-VyUSPA3 lines, nonetheless, the OE-VyUSPA3 lines were mostly unaffected. Meanwhile, OE-VyUSPA3 lines showed smaller stomatal aperture, more developed roots, higher leaf relative water content, proline content, and antioxidant enzyme activities, as well as lower malondialdehyde, H2O2 and O2•- accumulation than UT lines, but this response pattern was reversed in the RNAi-VyUSPA3 lines. Besides, the transcript levels of four drought-related genes (RD22, RD29B, DREB2A, and NCED1) in OE-VyUSPA3 lines were greater than those in the RNAi-VyUSPA3 and UT lines. In addition, a yeast two-hybrid assay and a bimolecular fluorescence complementation assay confirmed that VyUSPA3 interacted with ERF105, PUB24, and NF-YB3, respectively. This study revealed that VyUSPA3 improved drought tolerance in transgenic grapevines possibly through interaction with the hormone signaling, ubiquitination system, ethylene-responsive element binding factor and nuclear factors.

Genome-Wide Identification and Expression Analysis of WRKY Gene Family in Neolamarckia cadamba.

The WRKY transcription factor family plays important regulatory roles in multiple biological processes in higher plants. They have been identified and functionally characterized in a number of plant species, but very little is known in Neolamarckia cadamba, a 'miracle tree' for its fast growth and potential medicinal resource in Southeast Asia. In this study, a total of 85 WRKY genes were identified in the genome of N. cadamba. They were divided into three groups according to their phylogenetic features, with the support of the characteristics of gene structures and conserved motifs of protein. The NcWRKY genes were unevenly distributed on 22 chromosomes, and there were two pairs of segmentally duplicated events. In addition, a number of putative cis-elements were identified in the promoter regions, of which hormone- and stress-related elements were shared in many NcWRKYs. The transcript levels of NcWRKY were analyzed using the RNA-seq data, revealing distinct expression patterns in various tissues and at different stages of vascular development. Furthermore, 16 and 12 NcWRKY genes were confirmed to respond to various hormone treatments and two different abiotic stress treatments, respectively. Moreover, the content of cadambine, the active metabolite used for the various pharmacological activities found in N. cadamba, significantly increased after Methyl jasmonate treatment. In addition, expression of NcWRKY64/74 was obviously upregulated, suggesting that they may have a potential function of regulating the biosynthesis of cadambine in response to MeJA. Taken together, this study provides clues into the regulatory roles of the WRKY gene family in N. cadamba.

Incidence of and risk factors for post-intensive care syndrome among Chinese respiratory intensive care unit patients: A cross-sectional, prospective study.

BACKGROUND: Patients transferred from the respiratory intensive care unit (ICU) can experience post-intensive care syndrome (PICS), which comprises cognitive, psychological, and physical disorders that seriously affect the quality of life. Therefore, it was necessary to explore the incidence of and the risk factors for PICS among respiratory ICU patients. OBJECTIVES: This study evaluated PICS among respiratory ICU patients and explored the risk factors for PICS. METHODS: This cross-sectional, prospective study was performed at one hospital in China. Using convenience sampling, 125 respiratory ICU patients from August 2018 to June 2019 were recruited for the study. The Mini-Mental State Examination, Confusion Assessment Method for the Intensive Care Unit, Hospital Anxiety and Depression Scale, Medical Research Council Scale, activities of daily living scale, Pittsburgh Sleep Quality Index, and the 14-item fatigue scale were used to comprehensively assess the patients' cognitive status, psychological status, and physiological status when entering the ICU and 2 weeks after leaving the ICU. Factors affecting PICS were measured using researcher-created questionnaires of patients' general information and disease-related information. RESULTS: Fifteen patients were lost to follow-up. Fifty-nine patients had PICS (incidence rate, 53.6%). Logistic regression showed that risk factors for PICS were age, invasive mechanical ventilation, noninvasive ventilator-assisted ventilation, and coronary heart disease (P < 0.05). CONCLUSION: The PICS incidence was high. Older age, longer invasive mechanical ventilation times, longer noninvasive ventilator times, and coronary heart disease were risk factors for PICS. ICU medical workers in China should pay more attention on PICS, know the risk factors, and implement preventive measures.

VaMYB44 transcription factor from Chinese wild Vitis amurensis negatively regulates cold tolerance in transgenic Arabidopsis thaliana and V. vinifera.

KEY MESSAGE: Heterologous expression of VaMYB44 gene in Arabidopsis and V. vinifera cv. 'Thompson Seedless' increases cold sensitivity, which is mediated by the interaction of VaMYC2 and VaTIFY5A with VaMYB44 MYB transcription factors play critical roles in plant stress response. However, the function of MYB44 under low temperature stress is largely unknown in grapes. Here, we isolated a VaMYB44 gene from Chinese wild Vitis amurensis acc. 'Shuangyou' (cold-resistant). The VaMYB44 is expressed in various organs and has lower expression levels in stems and young leaves. Exposure of the cold-sensitive V. vinifera cv. 'Thompson Seedless' and cold-resistant 'Shuangyou' grapevines to cold stress (-1 °C) resulted in differential expression of MYB44 in leaves with the former reaching 14 folds of the latter after 3 h of cold stress. Moreover, the expression of VaMYB44 was induced by exogenous ethylene, abscisic acid, and methyl jasmonate in the leaves of 'Shuangyou'. Notably, the subcellular localization assay identified VaMYB44 in the nucleus. Interestingly, heterologous expression of VaMYB44 in Arabidopsis and 'Thompson Seedless' grape increased freezing-induced damage compared to their wild-type counterparts. Accordingly, the transgenic lines had higher malondialdehyde content and electrolyte permeability, and lower activities of superoxide dismutase, peroxidase, and catalase. Moreover, the expression levels of some cold resistance-related genes decreased in transgenic lines. Protein interaction assays identified VaMYC2 and VaTIFY5A as VaMYB44 interacting proteins, and VaMYC2 could bind to the VaMYB44 promoter and promote its transcription. In conclusion, the study reveals VaMYB44 as the negative regulator of cold tolerance in transgenic Arabidopsis and transgenic grapes, and VaMYC2 and VaTIFY5A are involved in the cold sensitivity of plants by interacting with VaMYB44.

The co-expression of genes involved in seed coat and endosperm development promotes seed abortion in grapevine.

MAIN CONCLUSION: The seed coat gene VviAGL11 coordinates with endosperm development genes FIS2, PHERESE1 and IKU2 and functions as the key regulator in seed development and abortion processes in grapevine. Seed development is essential for the reproduction of flowering plants. Seed abortion is a specific characteristic that produces seedless berries and is often observed in cultivated grapevines. Although seedlessness is an important trait for table and dried grapevine production, the mechanism of seed abortion remains poorly understood. This research aimed to analyze the co-expression of the seed coat development gene VviAGL11 and the endosperm development genes FERTILIZATION INDEPENDENT SEED2 (FIS2), PHERESE1 and HAIKU2 (IKU2) that regulate seedless fruit development in grapevine. The transcript levels of VviAGL11, FIS2, PHERESE1 and IKU2 all decreased during seed abortion in the seedless grape 'Thompson Seedless' plants, compared to those of the seeded grape 'Pinot Noir'. The transcript levels of the salicylic acid (SA)-dependent defense response genes EDS1, NPR1, NDR1 and SID2 were higher in 'Thompson Seedless' than 'Pinot Noir' during seed development. Also, WRKY3, WRKY6 and WRKY52, which participate in the SA pathway, were higher expressed in 'Thompson Seedless' than in 'Pinot Noir', indicating that SA-dependent defense responses may regulate seed abortion. The genes related to synthesis and metabolism of gibberellic acid (GA) and abscisic acid (ABA) also showed differential expression between 'Thompson Seedless' and 'Pinot Noir'. Exogenous applications of plant growth regulators (PGRs) to inflorescences of three stenospermocarpy grapevines before flowering showed that GA3 was critical prominently in seed development. Therefore, the co-expression of seed coat and endosperm development-related genes, SA pathway genes, and genes for the synthesis and metabolism of GA3 together enhance seed abortion in seedless grapes.

VpSTS29/STS2 enhances fungal tolerance in grapevine through a positive feedback loop.

Accumulation of stilbene phytoalexins stimulates resistance mechanisms against the grapevine fungus Uncinula necator. However, the defensive mechanisms triggered by stilbene synthase (STS) genes, remain largely unknown. Here, we report the function and molecular mechanism of the stilbene synthase gene VpSTS29/STS2 from Vitis pseudoreticulata in the regulation of plant responses to powdery mildew. Stilbene synthesis occurred mainly in root tips and mesophyll cells of transgenic grapevines via transport through the vascular bundles. Overexpression of VpSTS29/STS2 in Vitis vinifera increased the abundance of STSs in mesophyll tissue and resulted in the accumulation of biologically active resveratrol derivatives at the invasion site. Similarly, expression of VpSTS29/STS2 in Arabidopsis increased resistance to Golovinomyces cichoracearum. The VpSTS29/STS2-expressing Arabidopsis lines showed increased piceid accumulation together with more local hypersensitive reactions, inhibition of mycelial growth, and a reduced incidence of pathogens. Transcriptome profiling analyses demonstrated that VpSTS29/STS2-induced defences led to reprograming of global gene expression and activation of salicylic acid (SA) signalling, thus increasing expression of WRKY-MYB transcription factors and other defence response genes. We propose a model for resveratrol-mediated coordination of defence responses in which SA participates in a positive feedback loop.

VpPUB24, a novel gene from Chinese grapevine, Vitis pseudoreticulata, targets VpICE1 to enhance cold tolerance.

The ubiquitination system plays important roles in the degradation and modification of substrate proteins. In this study, we characterize a putative U-box type E3 ubiquitin ligase gene, VpPUB24 (plant U-box protein 24), from Chinese wild grapevine, Vitis pseudoreticulata accession Baihe-35-1. We show that VpPUB24 is induced by a number of stresses, especially cold treatment. Real-time PCR analysis indicated that the PUB24 transcripts were increased after cold stress in different grapevine species, although the relative expression level was different. In grapevine protoplasts, we found that VpPUB24 was expressed at a low level at 22 °C but accumulated rapidly following cold treatment. A yeast two-hybrid assay revealed that VpPUB24 interacted physically with VpICE1. Further experiments indicated that VpICE1 is targeted for degradation via the 26S proteasome and that the degradation is accelerated by VpHOS1, and not by VpPUB24. Immunoblot analyses indicated that VpPUB24 promotes the accumulation of VpICE1 and suppresses the expression of VpHOS1 to regulate the abundance of VpICE1. Furthermore, VpICE1 promotes transcription of VpPUB24 at low temperatures. We also found that VpPUB24 interacts with VpHOS1 in a yeast two-hybrid assay. Additionally, over-expression of VpPUB24 in Arabidopsis thaliana enhanced cold tolerance. Collectively, our results suggest that VpPUB24 interacts with VpICE1 to play a role in cold stress.

RING-H2-type E3 gene VpRH2 from Vitis pseudoreticulata improves resistance to powdery mildew by interacting with VpGRP2A.

Grapevine is one of the world's most important fruit crops. European cultivated grape species have the best fruit quality but show almost no resistance to powdery mildew (PM). PM caused by Uncinula necator is a harmful disease that has a significant impact on the economic value of the grape crop. In this study, we examined a RING-H2-type ubiquitin ligase gene VpRH2 that is associated with significant PM-resistance of Chinese wild-growing grape Vitis pseudoreticulata accession Baihe-35-1. The expression of VpRH2 was clearly induced by U. necator inoculation compared with its homologous gene VvRH2 in a PM-susceptible grapevine V. vinifera cv. Thompson Seedless. Using a yeast two-hybrid assay we confirmed that VpRH2 interacted with VpGRP2A, a glycine-rich RNA-binding protein. The degradation of VpGRP2A was inhibited by treatment with the proteasome inhibitor MG132 while VpRH2 did not promote the degradation of VpGRP2A. Instead, the transcripts of VpRH2 were increased by over-expressing VpGRP2A while VpRH2 suppressed the expression of VpGRP2A. Furthermore, VpGRP2A was down-regulated in both Baihe-35-1 and Thompson Seedless after U. necator inoculation. Specifically, we generated VpRH2 overexpression transgenic lines in Thompson Seedless and found that the transgenic plants showed enhanced resistance to powdery mildew compared with the wild-type. In summary, our results indicate that VpRH2 interacts with VpGRP2A and plays a positive role in resistance to powdery mildew.

Involvement of rice histone deacetylase HDA705 in seed germination and in response to ABA and abiotic stresses.

Histone acetylation and deacetylation play crucial roles in the modification of chromatin structure and regulation of gene expression in eukaryotes. Histone acetyltransferases (HATs) and histone deacetylases (HDACs) assist to maintain the balance of chromatin acetylation status. Previous studies showed that plant HDACs are key regulators involved in response to development and stresses. In this study, we examined the expression pattern and function of HDA705, a member of the RPD3/HDA1-type HDAC in rice. Overexpression of HDA705 in rice decreased ABA and salt stress resistance during seed germination. Delayed seed germination of HDA705 overexpression lines was associated with down-regulated expression of GA biosynthetic genes and up-regulation of ABA biosynthetic genes. Moreover, overexpression of HDA705 in rice enhanced osmotic stress resistance during the seedling stage. Our findings demonstrate that HDA705 may play a role in regulating seed germination and the response to abiotic stresses in rice.

Genetic transformation of a fruit-specific, highly expressed stilbene synthase gene from Chinese wild Vitis quinquangularis.

MAIN CONCLUSION: The stilbene synthase gene VqSTS6, from Chinese wild type Vitis quinquangularis accession Danfeng-2, increases the resveratrol content and pathogen resistance of transgenic plants of V. vinifera Thompson Seedless. This study successfully created transgenic plants of V. vinifera Thompson Seedless which overexpressed VqSTS6, cloned from Chinese wild type V. quinquangularis accession Danfeng-2. Western blot and qRT-PCR showed a variable range in transcript levels among transgenic lines. The resistance to powdery mildew (Uncinula necator) was particularly enhanced in lines most highly expressing VqSTS6. Compared with the non-transformed controls, trans-resveratrol and other stilbene compounds were significantly increased in the transgenic lines. The correlation between high resveratrol content and high pathogen resistance in transgenic grapes is discussed. We hypothesize that the fruit-specific, highly expressed gene VqSTS6 from Chinese wild V. quinquangularis accession Danfeng-2, is directly involved in the resveratrol synthesis pathway in grapes, and plays an important role in the plant's defense against pathogens. Genetic transformation of VqSTS6 explored the potential of the wild Chinese grape species for use in breeding, the results of which would raise both the disease resistance and the fruit quality of V. vinifera grapevines.

In vitro propagation of Paphiopedilum orchids.

Paphiopedilum is one of the most popular and rare orchid genera. Members of the genus are sold and exhibited as pot plants and cut flowers. Wild populations of Paphiopedilum are under the threat of extinction due to over-collection and loss of suitable habitats. A reduction in their commercial value through large-scale propagation in vitro is an option to reduce pressure from illegal collection, to attempt to meet commercial needs and to re-establish threatened species back into the wild. Although they are commercially propagated via asymbiotic seed germination, Paphiopedilum are considered to be difficult to propagate in vitro, especially by plant regeneration from tissue culture. This review aims to cover the most important aspects and to provide an up-to-date research progress on in vitro propagation of Paphiopedilum and to emphasize the importance of further improving tissue culture protocols for ex vitro-derived explants.

Identification of genes involved in biosynthesis of mannan polysaccharides in Dendrobium officinale by RNA-seq analysis.

Dendrobium officinale is a traditional Chinese medicinal plant. The stems of D. officinale contain mannan polysaccharides, which are promising bioactive polysaccharides for use as drugs. However, the genes involved in the biosynthesis of mannan polysaccharides in D. officinale have not yet been identified. In this study, four digital gene expression profiling analyses were performed on developing stems of greenhouse-grown D. officinale to identify such genes. Based on the accumulation of mannose and on gene expression levels, eight CELLULOSE SYNTHASE-LIKE A genes (CSLA), which are highly likely to be related to the biosynthesis of bioactive mannan polysaccharides, were identified from the differentially expressed genes database. In order to further analyze these DoCSLA genes, a full-length cDNA of each was obtained by RACE. The eight genes, belonging to the CSLA family of the CesA superfamily, contain conserved domains of the CesA superfamily. Most of the genes, which were highly expressed in the stems of D. officinale, were related to abiotic stress. Our results suggest that the CSLA family genes from D. officinale are involved in the biosynthesis of bioactive mannan polysaccharides.

Deep sequencing-based comparative transcriptional profiles of Cymbidium hybridum roots in response to mycorrhizal and non-mycorrhizal beneficial fungi.

BACKGROUND: The Orchidaceae is one of the largest families in the plant kingdom and orchid mycorrhizae (OM) are indispensable in the life cycle of all orchids under natural conditions. In spite of this, little is known concerning the mechanisms underlying orchid- mycorrhizal fungi interactions. Our previous work demonstrated that the non-mycorrhizal fungus Umbelopsis nana ZH3A-3 could improve the symbiotic effects of orchid mycorrhizal fungus Epulorhiza repens ML01 by co-cultivation with Cymbidium hybridum plantlets. Thus, we investigated the C. hybridum transcript profile associated with different beneficial fungi. RESULTS: More than 54,993,972 clean reads were obtained from un-normalized cDNA library prepared from fungal- and mock- treated Cymbidium roots at four time points using RNA-seq technology. These reads were assembled into 16,798 unique transcripts, with a mean length of 1127 bp. A total of 10,971 (65.31%) sequences were annotated based on BLASTX results and over ninety percent of which were assigned to plant origin. The digital gene expression profiles in Cymbidium root at 15 days post inoculation revealed that 1674, 845 and 1743 genes were sigificantly regulated in response to ML01, ZH3A-3 and ML01+ ZH3A-3 treatments, respectively. Twenty-six genes in different regulation patterns were validated using quantitative RT-PCR. Our analysis showed that general defense responses were co- induced by three treatments, including cell wall modification, reactive oxygen species detoxification, secondary biosynthesis and hormone balance. Genes involved in phosphate transport and root morphogenesis were also detected to be up-regulated collectively. Among the OM specifically induced transcripts, genes related to signaling, protein metabolism and processing, defense, transport and auxin response were identifed. Aside from these orchid transcripts, some putative fungal genes were also identified in symbiotic roots related to plant cell wall degradation, remodeling the fungal cell wall and nutrient transport. CONCLUSION: The orchid root transcriptome will facilitate our understanding of orchid-associated biological mechanism. The comparative expression profiling revealed that the transcriptional reprogramming by OM symbiosis generally overlapped that of arbuscular mycorrhizas and ectomycorrhizas. The molecular basis of OM formation and function will improve our knowledge of plant-mycorrhzial fungi interactions, and their effects on plant and fungal growth, development and differentiation.

Seed biology and in vitro seed germination of Cypripedium.

Cypripedium orchids have high horticultural value. The populations of most species are very geographically restricted and they are becoming increasingly rare due to the destruction of native habitats and illegal collection. Reduction of the commercial value through large-scale propagation in vitro is a preferable option to reduce pressure from illegal collection. Cypripedium species are commercially propagated via seed germination in vitro. This review focuses on in vitro seed germination and provides an in-depth analysis of the seed biology of this genus.

Bacillus-derived consortium enhances Ginkgo biloba's health and resistance to Alternaria tenuissima.

BACKGROUND: Bacillus, as a plant-growth-promoting rhizobacteria, can enhance the resistance of plants to phytopathogens. In our study, Bacillus strains showing excellent biocontrol were screened and used to control ginkgo leaf blight (Alternaria tenuissima). RESULTS: Four biocontrol Bacillus strains-Bsa537, Bam337, Bso544, and Bsu503-were selected from 286 isolates based on their capacity to inhibit pathogens and promote plant growth. The four Bacillus strains significantly improved the resistance of ginkgo to leaf blight. This was especially the case when the four strains were used as a mixture, which contributed to a decrease in lesion area of >40%. Hence, a mixture of Bacillus strains was used to control ginkgo leaf blight in the field. Treatment efficiency varied from 30% to 100% (average 81.5%) and was higher than that of the control (-2% to -18%, average - 8.5%); the antioxidant capacity of the treated ginkgo was also stronger. In addition, ginkgo biomass increased as a result of treatment with the Bacillus mixture, including leaf weight, area, thickness, number of lateral roots and root weight. Furthermore, the Bacillus mixture improved the ginkgo rhizosphere soil by boosting the number of beneficial microorganisms, lowering the number of pathogens and hastening soil catabolism. CONCLUSION: The Bacillus mixture improved the health status of ginkgo by protecting it from pathogen attack, promoting its growth and improving the microorganism community in the rhizosphere. This work closes a technological gap in the biological control of ginkgo leaf blight, investigates application methods for compound Bacillus biofertilizers and establishes a framework for the popularity and commercialization of these products. © 2024 Society of Chemical Industry.

Transcriptome analysis of Cymbidium sinense and its application to the identification of genes associated with floral development.

BACKGROUND: Cymbidium sinense belongs to the Orchidaceae, which is one of the most abundant angiosperm families. C. sinense, a high-grade traditional potted flower, is most prevalent in China and some Southeast Asian countries. The control of flowering time is a major bottleneck in the industrialized development of C. sinense. Little is known about the mechanisms responsible for floral development in this orchid. Moreover, genome references for entire transcriptome sequences do not currently exist for C. sinense. Thus, transcriptome and expression profiling data for this species are needed as an important resource to identify genes and to better understand the biological mechanisms of floral development in C. sinense. RESULTS: In this study, de novo transcriptome assembly and gene expression analysis using Illumina sequencing technology were performed. Transcriptome analysis assembles gene-related information related to vegetative and reproductive growth of C. sinense. Illumina sequencing generated 54,248,006 high quality reads that were assembled into 83,580 unigenes with an average sequence length of 612 base pairs, including 13,315 clusters and 70,265 singletons. A total of 41,687 (49.88%) unique sequences were annotated, 23,092 of which were assigned to specific metabolic pathways by the Kyoto Encyclopedia of Genes and Genomes (KEGG). Gene Ontology (GO) analysis of the annotated unigenes revealed that the majority of sequenced genes were associated with metabolic and cellular processes, cell and cell parts, catalytic activity and binding. Furthermore, 120 flowering-associated unigenes, 73 MADS-box unigenes and 28 CONSTANS-LIKE (COL) unigenes were identified from our collection. In addition, three digital gene expression (DGE) libraries were constructed for the vegetative phase (VP), floral differentiation phase (FDP) and reproductive phase (RP). The specific expression of many genes in the three development phases was also identified. 32 genes among three sub-libraries with high differential expression were selected as candidates connected with flower development. CONCLUSION: RNA-seq and DGE profiling data provided comprehensive gene expression information at the transcriptional level that could facilitate our understanding of the molecular mechanisms of floral development at three development phases of C. sinense. This data could be used as an important resource for investigating the genetics of the flowering pathway and various biological mechanisms in this orchid.

Purification of contaminated paddy fields by clean water irrigation over two decades.

Paddy fields near a mining site in north part of Guangdong Province, PR China, were severely contaminated by heavy metals as a result of wastewater irrigation from the tailing pond. The following clean water irrigation for 2 decades produced marked rinsing effect, especially on Pb and Zn. Paddy fields continuously irrigated with wastewater ever since mining started (50 years) had 1,050.0 mg kg−1 of Pb and 810.3 mg kg−1 of Zn for upper 20 cm soil, in comparison with 215.9 mg kg−1 of Pb and 525.4 mg kg−1 of Zn, respectively, with clean water irrigation for 20 years. Rinsing effect mainly occurred to a depth of upper 40 cm, of which the soil contained highest metals. Copper and Cd in the farmlands were also reduced due to clean water irrigation. Higher availability of Pb might partly account for more Pb transferred from the tailing pond to the farmland and also more Pb removal from the farmland as a result of clean water irrigation. Neither rice in the paddy field nor dense weeds in the uncultivated field largely took up the metals. However, they might contribute to activate metals differently, leading to a different purification extent. Rotation of rice and weed reduced metal retention in the farmland soil, in comparison with sole rice growth. Harvesting of rice grain (and partially rice stalk) only contributed small fraction of total amount of removed metal. In summary, heavy metal in paddy field resulting from irrigation of mining wastewater could be largely removed by clean water irrigation for sufficient time.