Bodipy-Based Metal-Organic Frameworks Transformed in Solid States from 1D Chains to 2D Layer Structures as Efficient Visible Light Heterogeneous Photocatalysts for Forging C-B and C-C Bonds.

Boron dipyrromethene (also known as bodipy), as a class of versatile and robust fluorophores and a structural analogue of porphyrins, has received a great deal of interests in the field of light-harvesting and energy-transfer processes. However, the fabrication of bodipy monomers into metal-organic frameworks (MOFs) and the exploitation of their potential still lags behind the porphyrin MOFs. In this work, two bodipy-based MOFs, BMOF 1D with 1D chain structure and BMOF 2D with 2D layer structure, were assembled by using dicarboxyl-functionalized bodipy ligands. BMOF 1D can also be converted to BMOF 2D by inserting additional ligands into BMOF 1D to cross-link the adjacent chains into the rhombic grid layer. During this process, spontaneous exfoliation occurred simultaneously and resulted in the formation of several hundred nanometer thickness BMOF 2D (nBMOF 2D), which can be further exfoliated into one-layer MOF nanosheets (BMON 2D) by using the ultrasonic liquid exfoliation method in a high yield. Featuring the distinct bodipy scaffolds in the porous frameworks, both BMOF 2D and BMON 2D displayed high reactivity and recyclability in the photocatalytic inverse hydroboration and cross-dehydrogenative coupling reactions to afford α-amino organoborons and α-amino amides in moderate to high yields. This work not only highlights the cascade utilization of ligand installation and ultrasonic liquid exfoliation methods to provide the single-layer MOF sheets in high yields but also advances the bodipy-based MOFs as a new type of heterogeneous photocatalysts in the forging of C-B and C-C bonds driven by visible light.

Identification of C2H2 zinc finger genes through genome-wide association study and functional analyses of LkZFPs in response to stresses in Larix kaempferi.

BACKGROUND: C2H2 zinc finger proteins (C2H2-ZFPs), one of the largest transcription factors, play a variety of roles in plant development and growth as well as stress response. While, the evolutionary history and expression profile of the C2H2-ZFP genes in Larix kaempferi (LkZFPs) have not been reported so far. RESULTS: In this study, the whole genome of the LkZFPs was identified and characterized, including physicochemical properties, phylogenetic relationships, conservative motifs, the promoter cis-elements and Gene Ontology (GO) annotation. We identified 47 LkZFPs and divided them into four subfamilies based on phylogenetic analysis and conserved motifs. Subcellular localization prediction showed that most of the LkZFPs were located in the nucleus. Promoter cis-element analysis suggested that the LkZFPs may be involved in the regulation of stress responses. Moreover, Real-time quantitative PCR (RT-qPCR) results showed that Q-type LkZFP genes were involved in the response to abiotic stress, such as salt, drought and hormone stresses. Subcellular localization results showed that LkZFP7 and LkZFP37 were located in the nucleus, LkZFP32 was located in both cytoplasm and nucleus. CONCLUSION: The identification and functional analysis of LkZFPs suggested that some LkZFP genes might play important roles in coping with both biological and abiotic stresses. These results could further increase understanding of the function of the LkZFPs, and provide some research direction and theoretical support.

Modeling methods for busulfan-induced oligospermia and asthenozoospermia in mice: a systematic review and meta-analysis.

OBJECTIVE: Modeling methods for busulfan-induced oligoasthenozoospermia are controversial. We aimed to systematically review the modeling method of busulfan-induced oligospermia and asthenozoospermia, and analyze changes in various evaluation indicators at different busulfan doses over time. METHODS: We searched the Cochrane Library, PubMed databases, Web of Science, the Chinese National Knowledge Infrastructure, and the Chinese Biomedical Literature Service System until April 9, 2022. Animal experiments of busulfan-induced spermatogenesis dysfunction were included and screened. The model mortality and parameters of the evaluation indicators were subjected to meta-analysis. RESULTS: Twenty-nine animal studies were included (control/model: 669/1829). The mortality of mice increased with busulfan dose. Significant spermatogenesis impairment occurred within 5 weeks, regardless of busulfan dose (10-40 mg/kg). Testicular weight (weighted mean difference [WMD]: - 0.04, 95% CI: - 0.05, - 0.03), testicular index (WMD: - 2.10, 95% CI: - 2.43, - 1.76), and Johnsen score (WMD: - 4.67, 95% CI: - 5.99, - 3.35) were significantly decreased. The pooled sperm counts of the model group were reduced by 32.8 × 106/ml (WMD: - 32.8, 95% CI: - 44.34, - 21.28), and sperm motility decreased by 37% (WMD: - 0.37, 95% CI: - 0.47, - 0.27). Sperm counts decreased slightly (WMD: - 3.03, 95% CI: - 3.42, - 2.64) in an intratesticular injection of low-dose busulfan (4 - 6 mg/kg), and the model almost returned to normal after one seminiferous cycle. CONCLUSION: The model using low-dose busulfan (10 - 20 mg/kg) returned to normal after 10 - 15 weeks. However, in some spermatogenesis cycles, testicular weight reduction and testicular spermatogenic function damage were not proportional to busulfan dose. Sperm counts and motility results in different studies had significant heterogeneity. Standard protocols for sperm assessment in animal models were needed to reduce heterogeneity between studies.

Living alone and cardiovascular outcomes: a meta-analysis of 11 cohort studies.

To explore whether living alone could increase the risk of cardiovascular outcomes. We searched PubMed, EMBASE, and Web of Science from their inception to 5 October 2020. Cohort studies evaluating the relationship between living alone and cardiovascular outcomes were included. Subgroup analyses were conducted to explore which characteristics would affect the relationship. A total of 13 effect sizes obtained from 11 studies were included and spanned from 1993 to 2019, with 424,286 participants. This study found that living alone increased the risk of cardiovascular outcomes (HR = 1.22, 95% CI: 1.10-1.36, I2 = 80.3%, P = 0.000). In subgroup analyses, living alone increased the risk of cardiovascular outcomes in patients from Europe (HR = 1.37, 95% CI: 1.17-1.61, I2 = 76.2%, P = 0.000), but not increased in Asia (HR = 1.17, 95% CI: 0.83-1.66, I2 = 76.2%, P = 0.000) and multiple regions (HR = 1.02, 95% CI: 0.96-1.08, I2 = 0.0%, P = 0.738). For different cardiovascular outcomes, living alone has statistical significance in increasing the risk of cardiovascular mortality (HR = 1.23, 95% CI: 1.05-1.46, I2 = 84.0%, P = 0.000) and myocardial infarction (HR = 1.11, 95% CI: 1.02-1.21, I2 = 29.6%, P = 0.213). The risk of cardiovascular mortality in men was higher than women (HR = 1.52, 95% CI: 1.24-1.86 vs HR = 1.01, 95% CI: 0.85-1.20; P < 0.05 for interaction). Sensitivity analysis suggested that the results of the meta-analysis were robust. In conclusion, living alone could increase the risk of cardiovascular outcomes and men were more prone to cardiovascular mortality and myocardial infarction.

Comprehensive Analysis of the NF-YB Gene Family and Expression under Abiotic Stress and Hormone Treatment in Larix kaempferi.

NF-YB, a subfamily of Nuclear Factor Y (NF-Y) transcription factor, play crucial role in many biological processes of plant growth and development and abiotic stress responses, and they can therefore be good candidate factors for breeding stress-resistant plants. However, the NF-YB proteins have not yet been explored in Larix kaempferi, a tree species with high economic and ecological values in northeast China and other regions, limiting the breeding of anti-stress L. kaempferi. In order to explore the roles of NF-YB transcription factors in L. kaempferi, we identified 20 LkNF-YB family genes from L. kaempferi full-length transcriptome data and carried out preliminary characterization of them through series of analyses on their phylogenetic relationships, conserved motif structure, subcellular localization prediction, GO annotation, promoter cis-acting elements as well as expression profiles under treatment of phytohormones (ABA, SA, MeJA) and abiotic stresses (salt and drought). The LkNF-YB genes were classified into three clades through phylogenetic analysis and belong to non-LEC1 type NF-YB transcription factors. They have 10 conserved motifs; all genes contain a common motif, and their promoters have various phytohormones and abiotic stress related cis-acting elements. Quantitative real time reverse transcription PCR (RT-qPCR) analysis showed that the sensitivity of the LkNF-YB genes to drought and salt stresses was higher in leaves than roots. The sensitivity of LKNF-YB genes to ABA, MeJA, SA stresses was much lower than that to abiotic stress. Among the LkNF-YBs, LkNF-YB3 showed the strongest responses to drought and ABA treatments. Further protein interaction prediction analysis for LkNF-YB3 revealed that LkNF-YB3 interacts with various factors associated with stress responses and epigenetic regulation as well as NF-YA/NF-YC factors. Taken together, these results unveiled novel L. kaempferi NF-YB family genes and their characteristics, providing the basic knowledge for further in-depth studies on their roles in abiotic stress responses of L. kaempferi.

PuHox52 promotes coordinated uptake of nitrate, phosphate, and iron under nitrogen deficiency in Populus ussuriensis.

It is of great importance to better understand how trees regulate nitrogen (N) uptake under N deficiency conditions which severely challenge afforestation practices, yet the underlying molecular mechanisms have not been well elucidated. Here, we functionally characterized PuHox52, a Populus ussuriensis HD-ZIP transcription factor, whose overexpression greatly enhanced nutrient uptake and plant growth under N deficiency. We first conducted an RNA sequencing experiment to obtain root transcriptome using PuHox52-overexpression lines of P. ussuriensis under low N treatment. We then performed multiple genetic and phenotypic analyses to identify key target genes of PuHox52 and validated how they acted against N deficiency under PuHox52 regulation. PuHox52 was specifically induced in roots by N deficiency, and overexpression of PuHox52 promoted N uptake, plant growth, and root development. We demonstrated that several nitrate-responsive genes (PuNRT1.1, PuNRT2.4, PuCLC-b, PuNIA2, PuNIR1, and PuNLP1), phosphate-responsive genes (PuPHL1A and PuPHL1B), and an iron transporter gene (PuIRT1) were substantiated to be direct targets of PuHox52. Among them, PuNRT1.1, PuPHL1A/B, and PuIRT1 were upregulated to relatively higher levels during PuHox52-mediated responses against N deficiency in PuHox52-overexpression lines compared to WT. Our study revealed a novel regulatory mechanism underlying root adaption to N deficiency where PuHox52 modulated a coordinated uptake of nitrate, phosphate, and iron through 'PuHox52-PuNRT1.1', 'PuHox52-PuPHL1A/PuPHL1B', and 'PuHox52-PuIRT1' regulatory relationships in poplar roots.

Sex-specific and dose-response relationships of urinary cobalt and molybdenum levels with glucose levels and insulin resistance in U.S. adults.

Growing studies have linked metal exposure to diabetes risk. However, these studies had inconsistent results. We used a multiple linear regression model to investigate the sex-specific and dose-response associations between urinary metals (cobalt (Co) and molybdenum (Mo)) and diabetes-related indicators (fasting plasma glucose (FPG), hemoglobin A1c (HbA1c), homeostasis model assessment for insulin resistance (HOMA-IR), and insulin) in a cross-sectional study based on the United States National Health and Nutrition Examination Survey. The urinary metal concentrations of 1423 eligible individuals were stratified on the basis of the quartile distribution. Our results showed that the urinary Co level in males at the fourth quartile (Q4) was strongly correlated with increased FPG (ß = 0.61, 95% CI: 0.17-1.04), HbA1c (ß = 0.31, 95% CI: 0.09-0.54), insulin (ß = 8.18, 95% CI: 2.84-13.52), and HOMA-IR (ß = 3.42, 95% CI: 1.40-5.44) when compared with first quartile (Q1). High urinary Mo levels (Q4 vs. Q1) were associated with elevated FPG (ß = 0.46, 95% CI: 0.17-0.75) and HbA1c (ß = 0.27, 95% CI: 0.11-0.42) in the overall population. Positive linear dose-response associations were observed between urinary Co and insulin (Pnonlinear = 0.513) and HOMA-IR (Pnonlinear = 0.736) in males, as well as a positive linear dose-response relationship between urinary Mo and FPG (Pnonlinear = 0.826) and HbA1c (Pnonlinear = 0.376) in the overall population. Significant sex-specific and dose-response relationships were observed between urinary metals (Co and Mo) and diabetes-related indicators, and the potential mechanisms should be further investigated.

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The American Academy of Pediatrics updated the guidelines for the management of hyperbilirubinemia in the newborn infants with a gestational age of ≥35 weeks in September 2022. Based on the evidence over the past 18 years, the guidelines are updated from the aspects of the prevention, risk assessment, intervention, and follow-up of hyperbilirubinemia in the newborn infants with a gestational age of ≥35 weeks. This article gives an interpretation of the key points in the guidelines, so as to safely reduce the risk of bilirubin encephalopathy and unnecessary intervention.

Two high hierarchical regulators, PuMYB40 and PuWRKY75, control the low phosphorus driven adventitious root formation in Populus ussuriensis.

Adventitious rooting is an essential biological process in the vegetative propagation of economically important horticultural and forest tree species. It enables utilization of the elite genotypes in breeding programmes and production. Promotion of adventitious root (AR) formation has been associated with starvation of inorganic phosphate and some factors involved in low phosphorus (LP) signalling. However, the regulatory mechanism underlying LP-mediated AR formation remains largely elusive. We established an efficient experimental system that guaranteed AR formation through short-term LP treatment in Populus ussuriensis. We then generated a time-course RNA-seq data set to recognize key regulatory genes and regulatory cascades positively regulating AR formation through data analysis and gene network construction, which were followed by experimental validation and characterization. We constructed a multilayered hierarchical gene regulatory network, from which PuMYB40, a typical R2R3-type MYB transcription factor (TF), and its interactive partner, PuWRKY75, as well as their direct targets, PuLRP1 and PuERF003, were identified to function upstream of the known adventitious rooting genes. These regulatory genes were functionally characterized and proved their roles in promoting AR formation in P. ussuriensis. In conclusion, our study unveiled a new hierarchical regulatory network that promoted AR formation in P. ussuriensis, which was activated by short-term LP stimulus and primarily governed by PuMYB40 and PuWRKY75.

PuC3H35 confers drought tolerance by enhancing lignin and proanthocyanidin biosynthesis in the roots of Populus ussuriensis.

Since the roots are the very organ where plants first sense and respond drought stress, it is of great importance to better understand root responses to drought. Yet the underlying molecular mechanisms governing root responses to drought stress have been poorly understood. Here, we identified and functionally characterized a CCCH type transcription factor, PuC3H35, and its targets, anthocyanin reductase (PuANR) and early Arabidopsis aluminum induced1 (PuEARLI1), which are involved in mediating proanthocyanidin (PA) and lignin biosynthesis in response to drought stress in Populus ussuriensis root. PuC3H35 was root-specifically induced upon drought stress. Overexpressing PuC3H35 promoted PA and lignin biosynthesis and vascular tissue development, resulting in enhanced tolerance to drought stress by the means of anti-oxidation and mechanical supporting. We further demonstrated that PuC3H35 directly bound to the promoters of PuANR and PuEARLI1 and overexpressing PuANR or PuEARLI1 increased root PA or lignin levels, respectively, under drought stress. Taken together, these results revealed a novel regulatory pathway for drought tolerance, in which PuC3H35 mediated PA and lignin biosynthesis by collaboratively regulating 'PuC3H35-PuANR-PA' and 'PuC3H35-PuEARLI1-PuCCRs-lignin' modules in poplar roots.

Cohort Profile Update: the China Metal-Exposed workers Cohort Study (Jinchang Cohort).

The Jinchang Cohort was an ongoing 20-year ambispective cohort with unique metal exposures to an occupational population. From January 2014 to December 2019, the Jinchang Cohort has completed three phases of follow-up. The baseline cohort was completed from June 2011 to December 2013, and a total of 48 001 people were included. Three phases of follow-ups included 46 713, 41 888, and 40 530 participants, respectively. The death data were collected from 2001 to 2020. The epidemiological, physical examination, physiological, and biochemical data of the cohort were collected at baseline and during follow-up. Biological specimens were collected on the baseline to establish a biological specimen bank. The concentrations of metals in urine and serum were detected by inductively coupled plasma mass spectrometry (ICP-MS). The new areas of research aim to study the all-cases mortality, the burden of diseases, heavy metals and diseases, and the course of the chain from disease to high-risk outcomes using a combination of macro and micro means, which provided a scientific basis to explore the pathogenesis of multi-etiology and multi-disease and to evaluate the effects of the intervention measures in the population.

Elevated serum bilirubin may significantly reduce coronary heart disease risk in females: A prospective cohort study.

BACKGROUND AND AIMS: There is still inconsistent evidence over the protective effect of total bilirubin on the development of coronary heart disease (CHD). Therefore, we aimed to investigate the association between bilirubin in population subtypes and the risks of CHD between different gender and menstruation subgroups. METHODS AND RESULTS: In this prospective cohort study, 29,750 participants free of CHD with an average age of 47 ± 14 years were recruited at baseline; of these, 720 CHD first-attack cases were collected after 7-years of follow up. The covariate-adjusted Cox proportional hazards models were used to estimate hazard ratios (HRs) of CHD with 95% confidence intervals (CIs). The serum bilirubin concentration was quarterly stratified based on the distribution of healthy population without CHD onset. The HRs of incident CHD decreased with elevated bilirubin in females (ρ trend<0.05), but not males. In postmenopausal females, compared with the lowest quartile of total bilirubin, the adjusted HRs for the third and fourth quartiles were 0.64 (95% CI: 0.45, 0.93) and 0.59 (95% CI: 0.42, 0.86), the adjusted HRs in the third and fourth quartiles of direct bilirubin were 0.56 (0.39, 0.82) and 0.56 (0.38, 0.81), and for indirect bilirubin, corresponding HR in the highest quartile was 0.56 (0.38, 0.83). CONCLUSION: Elevated serum bilirubin was inversely associated with adjusted HRs of CHD in females, especially postmenopausal females. The relationship between elevated direct bilirubin and reduced HRs of CHD may be closer than indirect bilirubin in postmenopausal females.

Sex-specific associations of the urinary fourteen-metal mixture with NAFLD and liver fibrosis among US adults: A nationally representative study.

Although previous studies have examined the hepatotoxicity of single metal exposure, the associations between metal mixture and non-alcoholic fatty liver disease (NAFLD) or fibrosis remain unclear. This study investigated the associations of urinary metal mixture with the risks of NAFLD and liver fibrosis in US adults using data from the National Health and Nutrition Examination Survey (NHANES) from 2017.01 to 2020.03. Vibration-controlled transient elastography was used to detect the controlled attenuation parameter (CAP) and liver stiffness measurement (LSM), which are indicators of NAFLD and liver fibrosis respectively. Three novel mixture modeling approaches including the Bayesian kernel machine regression (BKMR), weighted quantile sum (WQS) regression and quantile g-computation (qgcomp) were used to estimate the associations of the urinary fourteen-metal mixture with Ln CAP and Ln LSM. There were 2283 adults aged over 18 years (1209 women and 1074 men) were included. Among women, urinary metal mixture was positively associated with Ln CAP in the BKMR and qgcomp models (both P < 0.05). However, no significantly associations of urinary metal mixture with Ln CAP were observed among men in all models (all P > 0.05). The metal mixture was not associated with Ln LSM in the three models regardless of genders (all P > 0.05). In conclusion, we observed sex-specific associations between urinary metal mixture and the prevalence of NAFLD in US adults. These findings emphasize the role of environmental heavy metal exposure in the development of NAFLD, and confirm the need for more prospective cohort studies on sex-specific manner.

Root GS and NADH-GDH Play Important Roles in Enhancing the Ammonium Tolerance in Three Bedding Plants.

Ammonium is a paradoxical nutrient because it is more metabolically efficient than nitrate, but also causes plant stresses in excess, i.e., ammonium toxicity. Current knowledge indicates that ammonium tolerance is species-specific and related to the ammonium assimilation enzyme activities. However, the mechanisms underlying the ammonium tolerance in bedding plants remain to be elucidated. The study described herein explores the primary traits contributing to the ammonium tolerance in three bedding plants. Three NH4+:NO3- ratios (0:100, 50:50, 100:0) were supplied to salvia, petunia, and ageratum. We determined that they possessed distinct ammonium tolerances: salvia and petunia were, respectively, extremely sensitive and moderately sensitive to high NH4+ concentrations, whereas ageratum was tolerant to NH4+, as characterized by the responses of the shoot and root growth, photosynthetic capacity, and nitrogen (amino acid and soluble protein)-carbohydrate (starch) distributions. An analysis of the major nitrogen assimilation enzymes showed that the root GS (glutamine synthetase) and NADH-GDH (glutamate dehydrogenase) activities in ageratum exhibited a dose-response relationship (reinforced by 25.24% and 6.64%, respectively) as the NH4+ level was raised from 50% to 100%; but both enzyme activities were significantly diminished in salvia. Besides, negligible changes of GS activities monitored in leaves revealed that only the root GS and NADH-GDH underpin the ammonium tolerances of the three bedding plants.

Lighting from Top and Side Enhances Photosynthesis and Plant Performance by Improving Light Usage Efficiency.

Light is a critical environmental factor that influences plant growth and development, ranging from seed germination to flowering and fruiting. This study was carried out to explore how the optimal combination of various lighting directions increases the light usage efficiency and influences the plant morphophysiology, by investigating the plant growth parameters, leaf anatomy, epidermal morphology, stomatal properties, chlorophyll content, key physiological changes, and correlated gene expressions. In closed-type plant growth chambers, rooted cuttings of two chrysanthemum (Chrysanthemum morifolium Ramat.) cultivars, "Pearl Egg" and "Gaya Glory", were subjected to a 10-h photoperiod with 600 µmol∙m-2·s-1 photosynthetic photon flux density (PPFD) provided by light-emitting diodes (LEDs) in each light-direction combination (top (1/1) (T), top (1/2) + side (1/2) (TS), top (1/2) + bottom (1/2) (TB), side (1/2) + bottom (1/2) (SB), and top (1/3) + side (1/3) + bottom (1/3) (TSB)). The TS lighting significantly enhanced the morphophysiological performance, compared to the other lighting direction combinations. Notably, the excellent branch formation and earlier flowering were induced by the TS lighting in both "Pearl Egg" and "Gaya Glory" plants.

Drenched Silicon Suppresses Disease and Insect Pests in Coffee Plant Grown in Controlled Environment by Improving Physiology and Upregulating Defense Genes.

Plant disease and insect pests are major limiting factors that reduce crop production worldwide. The ornamental indoor cultivation cash crop dwarf coffee Punica arabica 'Pacas' is also troubled by these issues. Silicon (Si) is one of the most abundant elements in the lithosphere and positively impacts plant health by effectively mitigating biotic and abiotic stresses. Several studies have shown that Si activates plant defense systems, although the specific nature of the involvement of Si in biochemical processes that lead to resistance is unclear. In our study, Si significantly promoted the growth and development of dwarf coffee seedlings grown in plant growth chambers. More than that, through natural infection, Si suppressed disease and insect pests by improving physiology (e.g., the strong development of the internal structures of roots, stems, and leaves; higher photosynthetic efficiency; more abundant organic matter accumulation; the promotion of root activity; the efficient absorption and transfer of mineral elements; and various activated enzymes) and up-regulating defense genes (CaERFTF11 and CaERF13). Overall, in agriculture, Si may potentially contribute to global food security and safety by assisting in the creation of enhanced crop types with optimal production as well by mitigating plant disease and insect pests. In this sense, Si is a sustainable alternative in agricultural production.

Synergistic Effects of Silicon and Preservative on Promoting Postharvest Performance of Cut Flowers of Peony (Paeonia lactiflora Pall.).

As a commercial high-grade cut flower, the marketability of herbaceous peony (Paeonia lactiflora Pall.) is limited by its short vase life in water. Si (silicon) is an alternative to improve the postharvest life of cut flowers. However, the effects of the combined application of Si and preservatives on the postharvest performance of cut peony flowers are unknown. In this study, the effects of a Si application and a preservative alone and collegial on the longevity of the vase life, water loss, antioxidant defense system, and stock carbohydrates level of cut flowers of three peony cultivars were investigated. It was observed that Si effectively prolonged the vase life, while the preservative alone, to a lesser extent, but markedly induced an early flowering and a greater flower diameter (flower open degree). The simultaneous use of Si and the preservatives not only showed larger flowers, but also improved the postharvest performance as characterized by an extended vase life and delayed the water loss. In addition, the Si supplementation dramatically intensified the antioxidant defense system (ameliorated antioxidant enzymes and alleviated ROS accumulation) in petals but did not increase the stock carbohydrates (starch and soluble sugars) levels, as compared to the treatment with the preservative alone. We show that a Si supplementation to a preservative is highly recommended for a large-scale use to promote the postharvest performance and competitiveness of marketed cut flowers.

Characterization of the Gene Expression Profile Response to Drought Stress in Populus ussuriensis Using PacBio SMRT and Illumina Sequencing.

In this study, we characterized the gene expression profile in the roots of Populus ussuriensis at 0, 6, 12, 24, 48 and 120 h after the start of polyethylene glycol (PEG)-induced drought stress using PacBio single-molecule real-time sequencing (SMRT-seq) and Illumina RNA sequencing. Compared to the control, 2244 differentially expressed genes (DEGs) were identified, and many of these DEGs were associated with the signal transduction, antioxidant system, ion accumulation and drought-inducing proteins. Changes in certain physiological and biochemical indexes, such as antioxidant activity and the contents of Ca2+, proline, and total soluble sugars, were further confirmed in P. ussuriensis roots. Furthermore, most of the differentially expressed transcription factors were members of the AP2/ERF, C2H2, MYB, NAC, C2C2 and WRKY families. Additionally, based on PacBio SMRT-seq results, 5955 long non-coding RNAs and 700 alternative splicing events were identified. Our results provide a global view of the gene expression profile that contributes to drought resistance in P. ussuriensis and meaningful information for genetic engineering research in the future.

Characterization and analysis of the transcriptome response to drought in Larix kaempferi using PacBio full-length cDNA sequencing integrated with de novo RNA-seq reads.

MAIN CONCLUSION: A hypothetical model of drought tolerance mechanism of Larix kaempferi was established through SMRT-seq and Illumina HiSeq. Larix kaempferi is an important economic and ecological species and a major afforestation species in north-eastern China. To date, no information has been reliably derived regarding full-length cDNA sequencing information on L. kaempferi. By single-molecule long-read isoform sequencing (SMRT-seq), here we report a total of 26,153,342 subreads (21.24 Gb) and 330,371 circular consensus sequence (CCS) reads after the modification of site mismatch, and 35,414 unigenes were successfully collected. To gain deeper insights into the molecular mechanisms of L. kaempferi response to drought stress, we combined Illumina HiSeq with SMRT-seq to decode full-length transcripts. In this study, we report 27 differentially expressed genes (DEGs) involved in the perception and transmission of drought stress signals in L. kaempferi. A large number of DEGs responding to drought stress were detected in L. kaempferi, especially DEGs involved in the reactive oxygen species (ROS) scavenging, lignin biosynthesis, and sugar metabolism, and DEGs encoding drought stress proteins. We detected 73 transcription factors (TFs) under drought stress, including AP2/ERF, bZIP, TCP, and MYB. This study provides basic full sequence resources for L. kaempferi research and will help us to better understand the functions of drought-resistance genes in L. kaempferi.

Pu-miR172d regulates stomatal density and water-use efficiency via targeting PuGTL1 in poplar.

miRNAs play essential regulatory roles in many aspects of plant development and in responses to abiotic and biotic stresses. Here, we characterize Pu-miR172d, which acts as a negative regulator of stomatal density by directly repressing the expression of PuGTL1 in Populus ussuriensis. Quantitative real-time PCR and GUS reporter analyses showed that Pu-miR172d was strongly expressed in the guard cells of young leaves. Overexpression of Pu-miR172d significantly decreased stomatal density, resulting in increases in water use efficiency (WUE) and drought tolerance by reducing net photosynthetic rate, stomatal conductance, and transpiration. Molecular analysis showed that PuGTL1 was a major target of Pu-miR172d cleavage. Moreover, PuGTL1-SRDX plants, in which PuGTL1 is suppressed, phenocopied Pu-miR172d-overexpression lines with reduced stomatal density and enhanced WUE. The expression of PuSDD1, a negative regulator of stomatal development, was significantly increased in young leaves of both Pu-miR172d-overexpression and PuGTL1-SRDX plants. RNA-seq analysis of mature leaves indicated that overexpression of Pu-miR172d decreased the expression of many genes related to photosynthesis. Our findings show that the Pu-miR172d/PuGTL1/PuSDD1 module plays an important role in stomatal differentiation, and hence it is a potential target for engineering improved drought tolerance in poplar.