A pair of nuclear factor Y transcription factors act as positive regulators in jasmonate signaling and disease resistance in Arabidopsis.

The plant hormone jasmonate (JA) regulates plant growth and immunity by orchestrating a genome-wide transcriptional reprogramming. In the resting stage, JASMONATE-ZIM DOMAIN (JAZ) proteins act as main repressors to regulate the expression of JA-responsive genes in the JA signaling pathway. However, the mechanisms underlying de-repression of JA-responsive genes in response to JA treatment remain elusive. Here, we report two nuclear factor Y transcription factors NF-YB2 and NF-YB3 (thereafter YB2 and YB3) play key roles in such de-repression in Arabidopsis. YB2 and YB3 function redundantly and positively regulate plant resistance against the necrotrophic pathogen Botrytis cinerea, which are specially required for transcriptional activation of a set of JA-responsive genes following inoculation. Furthermore, YB2 and YB3 modulated their expression through direct occupancy and interaction with histone demethylase Ref6 to remove repressive histone modifications. Moreover, YB2 and YB3 physically interacted with JAZ repressors and negatively modulated their abundance, which in turn attenuated the inhibition of JAZ proteins on the transcription of JA-responsive genes, thereby activating JA response and promoting disease resistance. Overall, our study reveals the positive regulators of YB2 and YB3 in JA signaling by positively regulating transcription of JA-responsive genes and negatively modulating the abundance of JAZ proteins.

Two H3K36 methyltransferases differentially associate with transcriptional activity and enrichment of facultative heterochromatin in rice blast fungus.

Di- and tri-methylation of lysine 36 on histone H3 (H3K36me2/3) is catalysed by histone methyltransferase Set2, which plays an essential role in transcriptional regulation. Although there is a single H3K36 methyltransferase in yeast and higher eukaryotes, two H3K36 methyltransferases, Ash1 and Set2, were present in many filamentous fungi. However, their roles in H3K36 methylation and transcriptional regulation remained unclear. Combined with methods of RNA-seq and ChIP-seq, we revealed that both Ash1 and Set2 are redundantly required for the full H3K36me2/3 activity in Magnaporthe oryzae, which causes the devastating worldwide rice blast disease. Ash1 and Set2 distinguish genomic H3K36me2/3-marked regions and are differentially associated with repressed and activated transcription, respectively. Furthermore, Ash1-catalysed H3K36me2 was co-localized with H3K27me3 at the chromatin, and Ash1 was required for the enrichment and transcriptional silencing of H3K27me3-occupied genes. With the different roles of Ash1 and Set2, in H3K36me2/3 enrichment and transcriptional regulation on the stress-responsive genes, they differentially respond to various stresses in M. oryzae. Overall, we reveal a novel mechanism by which two H3K36 methyltransferases catalyze H3K36me2/3 that differentially associate with transcriptional activities and contribute to enrichment of facultative heterochromatin in eukaryotes. Supplementary Information: The online version contains supplementary material available at 10.1007/s42994-023-00127-3.

Effectors and environment modulating rice blast disease: from understanding to effective control.

Rice blast is a highly destructive crop disease that requires the interplay of three essential factors: the virulent blast fungus, the susceptible rice plant, and favorable environmental conditions. Although previous studies have focused mainly on the pathogen and rice, recent research has shed light on the molecular mechanisms by which the blast fungus and environmental conditions regulate host resistance and contribute to blast disease outbreaks. This review summarizes significant achievements in understanding the sophisticated modulation of blast resistance by Magnaporthe oryzae effectors and the dual regulatory mechanisms by which environmental conditions influence rice resistance and virulence of the blast fungus. Furthermore, it emphasizes potential strategies for developing blast-resistant rice varieties to effectively control blast disease.

Genetic and epigenetic basis of phytohormones control of floral transition in plants.

The timing of the developmental transition from the vegetative to the reproductive stages is critical for angiosperm and fine-tuned by the integration of endogenous factors and external environmental cues to ensure proper and successful reproduction. Plants have evolved sophisticated mechanisms to response to diverse environmental or stress signals, which may be mediated by plant hormones which coordinate their flowering time. Endogenous and exogenous phytohormones such as gibberellin (GA), auxin, cytokinin (CK), jasmonate (JA), abscisic acid (ABA), ethylene (ET), brassinosteroids (BR) and the cross-talk among them are critical for the precise regulating of flowering time. Recent studies on the model flowering plant Arabidopsis thaliana revealed that diverse transcription factors and epigenetic regulators play key roles in the phytohormones that regulate floral transition. This review aims to summarize current knowledge on the genetic and epigenetic mechanisms that underlying the phytohormone control of floral transition in Arabidopsis, offering insights into how these processes are regulated and their implications for plant biology.

Mitigating growth-stress tradeoffs via elevated TOR signaling in rice.

Rice production accounts for approximately half of the freshwater resources utilized in agriculture, resulting in greenhouse gas emissions such as methane (CH4) from flooded paddy fields. To address this challenge, environmentally friendly and cost-effective water-saving techniques have become widely adopted in rice cultivation. However, the implementation of water-saving treatments (WSTs) in paddy-field rice has been associated with a substantial yield loss of up to 50% as well as a reduction in nitrogen use efficiency (NUE). In this study, we discovered that the target of rapamycin (TOR) signaling pathway is compromised in rice under WST. Polysome profiling-coupled transcriptome sequencing (polysome-seq) analysis unveiled a substantial reduction in global translation in response to WST associated with the downregulation of TOR activity. Molecular, biochemical, and genetic analyses revealed new insights into the impact of the positive TOR-S6K-RPS6 and negative TOR-MAF1 modules on translation repression under WST. Intriguingly, ammonium exhibited a greater ability to alleviate growth constraints under WST by enhancing TOR signaling, which simultaneously promoted uptake and utilization of ammonium and nitrogen allocation. We further demonstrated that TOR modulates the ammonium transporter AMT1;1 as well as the amino acid permease APP1 and dipeptide transporter NPF7.3 at the translational level through the 5' untranslated region. Collectively, these findings reveal that enhancing TOR signaling could mitigate rice yield penalty due to WST by regulating the processes involved in protein synthesis and NUE. Our study will contribute to the breeding of new rice varieties with increased water and fertilizer utilization efficiency.

Reversible phosphorylation of a lectin-receptor-like kinase controls xylem immunity.

Pattern-recognition receptors (PRRs) mediate basal resistance to most phytopathogens. However, plant responses can be cell type specific, and the mechanisms governing xylem immunity remain largely unknown. We show that the lectin-receptor-like kinase LORE contributes to xylem basal resistance in Arabidopsis upon infection with Ralstonia solanacearum, a destructive plant pathogen that colonizes the xylem to cause bacterial wilt. Following R. solanacearum infection, LORE is activated by phosphorylation at residue S761, initiating a phosphorelay that activates reactive oxygen species production and cell wall lignification. To prevent prolonged activation of immune signaling, LORE recruits and phosphorylates type 2C protein phosphatase LOPP, which dephosphorylates LORE and attenuates LORE-mediated xylem immunity to maintain immune homeostasis. A LOPP knockout confers resistance against bacterial wilt disease in Arabidopsis and tomatoes without impacting plant growth. Thus, our study reveals a regulatory mechanism in xylem immunity involving the reversible phosphorylation of receptor-like kinases.

Transcriptional Regulation of Autophagy-Related Genes by Sin3 Negatively Modulates Autophagy in Magnaporthe oryzae.

Autophagy is a conserved degradation and recycling pathway in eukaryotes and is important for their normal growth and development. An appropriate status of autophagy is crucial for organisms which is tightly regulated both temporally and continuously. Transcriptional regulation of autophagy-related genes (ATGs) is an important layer in autophagy regulation. However, the transcriptional regulators and their mechanisms are still unclear, especially in fungal pathogens. Here, we identified Sin3, a component of the histone deacetylase complex, as a transcriptional repressor of ATGs and negative regulator of autophagy induction in the rice fungal pathogen Magnaporthe oryzae. A loss of SIN3 resulted in upregulated expression of ATGs and promoted autophagy with an increased number of autophagosomes under normal growth conditions. Furthermore, we found that Sin3 negatively regulated the transcription of ATG1, ATG13, and ATG17 through direct occupancy and changed levels of histone acetylation. Under nutrient-deficient conditions, the transcription of SIN3 was downregulated, and the reduced occupancy of Sin3 from those ATGs resulted in histone hyperacetylation and activated their transcription and in turn promoted autophagy. Thus, our study uncovers a new mechanism of Sin3 in modulating autophagy through transcriptional regulation. IMPORTANCE Autophagy is an evolutionarily conserved metabolic process and is required for the growth and pathogenicity of phytopathogenic fungi. The transcriptional regulators and precise mechanisms of regulating autophagy, as well as whether the induction or repression of ATGs is associated with autophagy level, are still poorly understood in M. oryzae. In this study, we revealed that Sin3 acts as a transcriptional repressor of ATGs to negatively regulate autophagy level in M. oryzae. Under the nutrient-rich conditions, Sin3 inhibits autophagy with a basal level through directly repressing the transcription of ATG1-ATG13-ATG17. Upon nutrient-deficient treatment, the transcriptional level of SIN3 would decrease and dissociation of Sin3 from those ATGs associates with histone hyperacetylation and activates their transcriptional expression and in turn contributes to autophagy induction. Our findings are important as we uncover a new mechanism of Sin3 for the first time to negatively modulate autophagy at the transcriptional level in M. oryzae.

ETHYLENE INSENSITIVE3/EIN3-LIKE1 modulate FLOWERING LOCUS C expression via histone demethylase interaction.

Time to flowering (vegetative to reproductive phase) is tightly regulated by endogenous factors and environmental cues to ensure proper and successful reproduction. How endogenous factors coordinate with environmental signals to regulate flowering time in plants is unclear. Transcription factors ETHYLENE INSENSITIVE 3 (EIN3) and its homolog EIN3 LIKE 1 (EIL1) are the core downstream regulators in ethylene signal transduction, and their null mutants exhibit late flowering in Arabidopsis (Arabidopsis thaliana); however, the precise mechanism of floral transition remains unknown. Here, we reveal that FLOWERING LOCUS D (FLD), encoding a histone demethylase acting in the autonomous pathway of floral transition, physically associates with EIN3 and EIL1. Loss of EIN3 and EIL1 upregulated transcriptional expression of the floral repressor FLOWERING LOCUS C (FLC) and its homologs in Arabidopsis, and ethylene-insensitive mutants displayed inhibited flowering in an FLC-dependent manner. We further demonstrated that EIN3 and EIL1 directly bind to FLC loci, modulating their expression by recruiting FLD and thereafter removing di-methylation of lysine 4 on histone H3 (H3K4me2). In plants treated with 1-aminocyclopropane-1-carboxylic acid, decreased expression of FLD resulted in increased enrichment of H3K4me2 at FLC loci and transcriptional activation of FLC, leading to floral repression. Our study reveals the role of EIN3 and EIL1 in FLC-dependent and ethylene-induced floral repression and elucidates how phytohormone signals are transduced into chromatin-based transcriptional regulation.

An animal research on the application of drag-and-bond anastomosis in the anastomosis between bladder and intestine / 中华泌尿外科杂志

Objective:To explore the feasibility of anastomosis between bladder and intestine of experimental rabbit by drag anastomosis.Methods:In this study 40 Japanese big-eared rabbits were randomly divided into two groups through random number table, the experimental group and the control group, each group with 20 rabbits. In the experimental group, the bladder neck was fixed to the catheter and then the catheter was drawn outward. With the traction of the catheter, the bladder neck was anastomosed with the distal intestinal tube by means of suture free. The control group was anastomosed by regular interrupted suture of bladder and intestine. The operation time, anastomosis time, intraoperative blood loss, postoperative urinary leakage rate and postoperative anastomotic healing of rabbits in the two groups were compared.Results:The operation time of the experimental group was shorter than that of the traditional interrupted suture anastomosis group [(33.26±2.79)min vs. (35.25±1.83)min, P=0.014]. The anastomosis time of the experimental group was significantly shorter than that of the traditional interrupted suture anastomosis group[(7.55±1.2)min vs. (8.65±1.03 min), P=0.005]. The intraoperative blood loss in the experimental group was similar to that in the control group[(6.47±2.41) ml vs. (6.75±1.83) ml, P=0.691]. The event of contrast media extravasation occurred in 2 of the 10 experimental rabbits after receiving cystography in the experimental group, and the urinary leakage rate was 20%(2/10). In the control group, contrast media extravasation occurred in 1 of the 9 experimental rabbits after receiving cystography, and the urinary leakage rate was 11.1%(1/9), and the difference of the two groups was not statistically significant ( P=0.348). Anastomotic healing score was (2.0±0.7) in the experimental group, and (2.1±0.74) in the control group ( P=0.767). Conclusions:The bladder-intestine drag-and-bond anastomosis technique, with significantly shorter anastomosis time, was feasible, easy and convenient. Our research provides an experimental and theoretical basis for the clinical application of drag-and-bond anastomosis technique in clinic.

Genome-wide DNA methylation differences between conservation and breeding populations of Shaoxing ducks.

The genome-wide DNA methylation assay was used to analyze the difference in methylation between the breeding and conservation populations of Shaoxing ducks. The methylation level of the breeding population was higher than that of the two conservation populations, and the proportion of CG methylation sites was the largest in the three populations, most of the methylation sites were located in the exon region. There were 1247 different methylation regions in the two populations (group A and B), and 927 different methylation regions in the two groups (group A and group C). The differential methylation regions of the three groups were evenly distributed in the gene and intergene regions. GO and KEGG enrichment analysis showed that the differentially expressed genes in the A and B groups were mainly involved in synaptic and cell connections and the signaling pathways were significantly enriched in cAMP and oxytocin signaling pathways. The results showed that the group C was significantly enriched in eight signaling pathways, including the cAMP signaling pathway and long-term enhancement, compared to the group A. There were thirty-five differentially methylated genes, including CACNA1C, GRIA1, GRIA2, GABBR2, PDE10A, BRAF, GRM5, CPEB3, FMn2, GABRB2, PTK2, and CNTN1. These genes were involved in the development and ovulation of ovaries and follicles and were closely related to the excellent production performance of the breeding population. In addition, ATP2B1, ATP2B2, and other genes related to eggshell quality were identified, which can be used as molecular markers to improve eggshell quality in the future.

The additional PRC2 subunit and Sin3 histone deacetylase complex are required for the normal distribution of H3K27me3 occupancy and transcriptional silencing in Magnaporthe oryzae.

Development in higher organisms requires proper gene silencing, partially achieved through trimethylation of lysine 27 on histone H3 (H3K27me3). However, how the normal distribution of this modification is established and maintained and how it affects gene expression remains unclear, especially in fungi. Polycomb repressive complex 2 (PRC2) catalyses H3K27me3 to assemble transcriptionally repressed facultative heterochromatin and is crucial in animals, plants, and fungi. Here, we report on the critical role of an additional PRC2 subunit in the normal distribution of H3K27me3 occupancy and the stable maintenance of gene repression in the rice fungal pathogen Magnaporthe oryzae. P55, identified as an additional PRC2 subunit, is physically associated with core subunits of PRC2 and is required for a complete level of H3K27me3 modification. Loss of P55 caused severe global defects in the normal distribution of H3K27me3 and transcriptional reprogramming on the H3K27me3-occupied genes. Furthermore, we found that the Sin3 histone deacetylase complex was required to sustain H3K27me3 occupancy and stably maintain gene repression by directly interacting with P55. Our results revealed a novel mechanism by which P55 and Sin3 participate in the normal distribution of facultative heterochromatic modifications and the stable maintenance of gene repression in eukaryotes.

UvKmt2-Mediated H3K4 Trimethylation Is Required for Pathogenicity and Stress Response in Ustilaginoidea virens.

Epigenetic modification is important for cellular functions. Trimethylation of histone H3 lysine 4 (H3K4me3), which associates with transcriptional activation, is one of the important epigenetic modifications. In this study, the biological functions of UvKmt2-mediated H3K4me3 modification were characterized in Ustilaginoidea virens, which is the causal agent of the false smut disease, one of the most destructive diseases in rice. Phenotypic analyses of the ΔUvkmt2 mutant revealed that UvKMT2 is necessary for growth, conidiation, secondary spore formation, and virulence in U. virens. Immunoblotting and chromatin immunoprecipitation assay followed by sequencing (ChIP-seq) showed that UvKMT2 is required for the establishment of H3K4me3, which covers 1729 genes of the genome in U. virens. Further RNA-seq analysis demonstrated that UvKmt2-mediated H3K4me3 acts as an important role in transcriptional activation. In particular, H3K4me3 modification involves in the transcriptional regulation of conidiation-related and pathogenic genes, including two important mitogen-activated protein kinases UvHOG1 and UvPMK1. The down-regulation of UvHOG1 and UvPMK1 genes may be one of the main reasons for the reduced pathogenicity and stresses adaptability of the ∆Uvkmt2 mutant. Overall, H3K4me3, established by histone methyltransferase UvKMT2, contributes to fungal development, secondary spore formation, virulence, and various stress responses through transcriptional regulation in U. virens.

Embryonic reactivation of FLOWERING LOCUS C by ABSCISIC ACID-INSENSITIVE 3 establishes the vernalization requirement in each Arabidopsis generation.

Many over-wintering plants grown in temperate climate acquire competence to flower upon prolonged cold exposure in winter, through vernalization. In Arabidopsis thaliana, prolonged cold exposure induces the silencing of the potent floral repressor FLOWERING LOCUS C (FLC) through repressive chromatin modifications by Polycomb proteins. This repression is maintained to enable flowering after return to warmth, but is reset during seed development. Here, we show that embryonic FLC reactivation occurs in two phases: resetting of cold-induced FLC silencing during embryogenesis and further FLC activation during embryo maturation. We found that the B3 transcription factor (TF) ABSCISIC ACID-INSENSITIVE 3 (ABI3) mediates both FLC resetting in embryogenesis and further activation of FLC expression in embryo maturation. ABI3 binds to the cis-acting cold memory element at FLC and recruits a scaffold protein with active chromatin modifiers to reset FLC chromatin into an active state in late embryogenesis. Moreover, in response to abscisic acid (ABA) accumulation during embryo maturation, ABI3, together with the basic leucine zipper TF ABI5, binds to an ABA-responsive cis-element to further activate FLC expression to high level. Therefore, we have uncovered the molecular circuitries underlying embryonic FLC reactivation following parental vernalization, which ensures that each generation must experience winter cold prior to flowering.

The characteristics of distribution and drug resistance of urinary bacteria in patients with infectious stones / 中华泌尿外科杂志

Objective:To investigate the characteristics of distribution and drug resistance of urinary bacteria in the mid-stream urine of patients with infectious stones.Methods:The retrospective study analyzed the clinical data of 254 patients with infectious stones in the First Affiliated Hospital of Guangzhou Medical University from September 2016 to September 2018. All patients were treated with PCNL. Overall, there were 101 male and 153 female patients, with the mean age of(51.5±12.3) years, and the mean stone burden of 1443.5(660.8, 2837.5) mm2. There were 58 (22.8%) patients with hypertension, 17(6.7%) patients with diabetes and 195(76.8%)with hydronephrosis. The mid-stream urine samples were obtained for bacterial culture and susceptibility test, and the results of urine culture and antimicrobial susceptibility were recorded and analyzed.Results:Of 254 patients involved in this study, 89(35.0%) were positive and 165 (65.0%) were negative for urinary bacterial culture of the mid-stream. The proportion of patients with positive urine bacterial culture of the mid-stream who had positive urine leucocytes, positive urine nitrite and postoperative pyrexia were 86.5%(77/89), 64.0%(57/89), 25.8%(23/89), respectively, which was higher than that of patients with negative urine bacterial culture of the mid-stream [50.3%(83/165), 14.5%(24/165), 14.5%(24/165), P<0.05]. Four teen kinds of bacteria were detected from the mid-stream urine, and the three bacteria with the highest detection rate in turn were Escherichia coli of 38.2%(34/89), Proteus mirabilis of 15.7%(14/89), and Pseudomonas aeruginosa of 11.2%(10/89). The results of this study showed that three common bacteria had high resistance to drug including Cefazolin, Cefuroxime, Cefuroxime ester, Ampicillin and Co-trimoxazole (all resistance rate>40%). The resistance rates of Escherichia coli and Pseudomonas aeruginosa to Ciprofloxacin and Levofloxacin were higher than or equal to 40%. The resistance rates of Escherichia coli and Proteus mirabilis to meropenem, imipenem, ertapenem, piperacillin/tazobactam and amikacin were all lower than 10%. In addition, the resistance rates of Escherichia coli to nitrofurantoin and tigecycline and Proteus mirabilis to tobramycin, aztreonam and cefoxitin were all less than 10%. The resistance rates of Pseudomonas aeruginosa to ceftazidime, cefepime, gentamicin and aztreonam were less than 10%. Conclusions:The highest detection rate of urinary bacteria in culture of the mid-stream with infectious stones are Escherichia coli, Proteus mirabilis and Pseudomonas aeruginosa, all of which showed high resistance to Ampicillin, Cotrimoxazole, and some cephalosporins. Escherichia coli and Pseudomonas aeruginosa showe high resistance to Ciprofloxacin and Levofloxacin, and all of the three bacteria have low resistance rates to some β-Lactamase inhibitor complex and carbapenems, suggesting a reference for clinical empirical medical treatment.

Research progress on the health effects of occupational noise exposure on cardiovascular system of workers / 中国职业医学

@#Noise is a common occupational hazardous factor in the workplace. In addition to the specific damage to the auditory ， system of workers it can also harm the cardiovascular system and cause a serious disease burden. The mechanism of ， occupational noise on the cardiovascular system of workers is mainly oxidative stress inflammation and vascular endothelial ， - - - damage. As a stressor noise mainly leads to the changes of sympathoadrenal medullary system and hypothalamic pituitary ， ， ， - ， adrenal axis. The substances that play an important role include catecholamines cortisol angiotensin Ⅱ endothelin 1 - endothelial nitric oxide synthase and interleukin 6. The population epidemiological studies have shown that occupational noise ， exposure can lead to elevated blood pressure abnormal electrocardiogram and elevated blood lipids in workers. The influencing （ ， ， ） factors include noise characteristics intensity cumulative noise exposure and frequency and noise combined with other （ ， ， ， - ， occupational hazards such as high temperature welding fumes organic solvents hand transmitted vibration and work ） ， ， ， shifts . However due to the influence of research conditions experimental design and other factors some research conclusions still have limitations. More prospective and comprehensive studies are needed to verify the relevant conclusions in the future.

UvKmt6-mediated H3K27 trimethylation is required for development, pathogenicity, and stress response in Ustilaginoidea virens.

Polycomb repressive complex 2 (PRC2) is responsible for the trimethylation of lysine 27 of histone H3 (H3K27me3)-mediated transcriptional silencing. At present, its biological roles in the devastating rice pathogenic fungus Ustilaginoidea virens remain unclear. In this study, we analyzed the function of a putative PRC2 catalytic subunit UvKmt6. The results showed that disruption of UvKMT6 resulted in reduced growth, conidiation and pathogenicity in U. virens. Furthermore, UvKmt6 is essential for establishment of H3K27me3 modification, which covers 321 genes in the genome. Deletion of UvKMT6 led to transcriptional derepression of 629 genes, 140 of which were occupied with H3K27me3 modification. Consistent with RNA-seq and ChIP-seq analysis, UvKmt6 was further confirmed to participate in the transcriptional repression of genes encoding effectors and genes associated with secondary metabolites production, such as PKSs, NRPSs and Cytochrome P450s. Notably, we found that UvKmt6 is involved in transcriptional repression of oxidative, osmotic, cell wall and nutrient starvation stresses response-related genes. From the perspective of gene expression and phenotype, in addition to the relatively conservative role in fungal development, virulence and production of secondary metabolites, we further reported that UvKmt6-mdediated H3K27me3 plays a critical role in the response to various stresses in U. virens.

Improved Functional Expression of Cytochrome P450s in Saccharomyces cerevisiae Through Screening a cDNA Library From Arabidopsis thaliana.

Cytochrome P450 enzymes (P450s) are a superfamily of heme-thiolate proteins widely existing in various organisms and play a key role in the metabolic network and secondary metabolism. However, the low expression levels and activities have become the biggest challenge for P450s studies. To improve the functional expression of P450s in Saccharomyces cerevisiae, an Arabidopsis thaliana cDNA library was expressed in the betaxanthin-producing yeast strain, which functioned as a biosensor for high throughput screening. Three new target genes AtGRP7, AtMSBP1, and AtCOL4 were identified to improve the functional expression of CYP76AD1 in yeast, with accordingly the accumulation of betaxanthin increased for 1.32-, 1.86-, and 1.10-fold, respectively. In addition, these three targets worked synergistically/additively to improve the production of betaxanthin, representing a total of 2.36-fold improvement when compared with the parent strain. More importantly, these genes were also determined to effectively increase the activity of another P450 enzyme (CYP736A167), catalyzing the hydroxylation of α-santalene to produce Z-α-santalol. Simultaneous overexpression of AtGRP7, AtMSBP1, and AtCOL4 increased α-santalene to Z-α-santalol conversion rate for more than 2.97-fold. The present study reported a novel strategy to improve the functional expression of P450s in S. cerevisiae and promises the construction of platform yeast strains for the production of natural products.

Transcriptional memory and response to adverse temperatures in plants.

Temperature is one of the major environmental signals controlling plant development, geographical distribution, and seasonal behavior. Plants perceive adverse temperatures, such as high, low, and freezing temperatures, as stressful signals that can cause physiological defects and even death. As sessile organisms, plants have evolved sophisticated mechanisms to adapt to recurring stressful environments through changing gene expression or transcriptional reprogramming. Transcriptional memory refers to the ability of primed plants to remember previously experienced stress and acquire enhanced tolerance to similar or different stresses. Epigenetic modifications mediate transcriptional memory and play a key role in adapting to adverse temperatures. Understanding the mechanisms of the formation, maintenance, and resetting of stress-induced transcriptional memory will not only enable us to understand why there is a trade-off between plant defense and growth, but also provide a theoretical basis for generating stress-tolerant crops optimized for future climate change. In this review, we summarize recent advances in dissecting the mechanisms of plant transcriptional memory in response to adverse temperatures, based mainly on studies of the model plant Arabidopsis thaliana. We also discuss remaining questions that are important for further understanding the mechanisms of transcriptional memory during the adverse temperature response.

Fusarium BP1 is a reader of H3K27 methylation.

Histone H3 lysine 27 methylation catalyzed by polycomb repressive complex 2 (PRC2) is conserved from fungi to humans and represses gene transcription. However, the mechanism for recognition of methylated H3K27 remains unclear, especially in fungi. Here, we found that the bromo-adjacent homology (BAH)-plant homeodomain (PHD) domain containing protein BAH-PHD protein 1 (BP1) is a reader of H3K27 methylation in the cereal fungal pathogen Fusarium graminearum. BP1 interacts with the core PRC2 component Suz12 and directly binds methylated H3K27. BP1 is distributed in a subset of genomic regions marked by H3K27me3 and co-represses gene transcription. The BP1 deletion mutant shows identical phenotypes on mycelial growth and virulence, as well as similar expression profiles of secondary metabolite genes to the strain lacking the H3K27 methyltransferase Kmt6. More importantly, BP1 can directly bind DNA through its PHD finger, which might increase nucleosome residence and subsequently reinforce transcriptional repression in H3K27me3-marked target regions. A phylogenetic analysis showed that BP1 orthologs are mainly conserved in fungi. Overall, our findings provide novel insights into the mechanism by which PRC2 mediates gene repression in fungi, which is distinct from the PRC1-PRC2 system in plants and mammals.

Nuclear translocation of OsMFT1 that is impeded by OsFTIP1 promotes drought tolerance in rice.

Drought is the leading environmental threat affecting crop productivity, and plants have evolved a series of mechanisms to adapt to drought stress. The FT-interacting proteins (FTIPs) and phosphatidylethanolamine-binding proteins (PEBPs) play key roles in developmental processes, whereas their roles in the regulation of stress response are still largely unknown. Here, we report that OsFTIP1 negatively regulates drought response in rice. We showed that OsFTIP1 interacts with rice MOTHER OF FT AND TFL1 (OsMFT1), a PEBP that promotes rice tolerance to drought treatment. Further studies discovered that OsMFT1 interacts with two key drought-related transcription factors, OsbZIP66 and OsMYB26, regulating their binding capacity on drought-related genes and thereby enhancing drought tolerance in rice. Interestingly, we found that OsFTIP1 impedes the nucleocytoplasmic translocation of OsMFT1, implying that dynamic modulation of drought-responsive genes by the OsMFT1-OsMYB26 and OsMFT1-OsbZIP66 complexes is integral to OsFTIP1-modulated nuclear accumulation of OsMFT1. Our findings also suggest that OsMFT1 might act as a hitherto unknown nucleocytoplasmic trafficking signal that regulates drought tolerance in rice in response to environmental signals.