Evolution of the WRKY Family in Angiosperms and Functional Diversity under Environmental Stress.

The transcription factor is an essential factor for regulating the responses of plants to external stimuli. The WRKY protein is a superfamily of plant transcription factors involved in response to various stresses (e.g., cold, heat, salt, drought, ions, pathogens, and insects). During angiosperm evolution, the number and function of WRKY transcription factors constantly change. After suffering from long-term environmental battering, plants of different evolutionary statuses ultimately retained different numbers of WRKY family members. The WRKY family of proteins is generally divided into three large categories of angiosperms, owing to their conserved domain and three-dimensional structures. The WRKY transcription factors mediate plant adaptation to various environments via participating in various biological pathways, such as ROS (reactive oxygen species) and hormone signaling pathways, further regulating plant enzyme systems, stomatal closure, and leaf shrinkage physiological responses. This article analyzed the evolution of the WRKY family in angiosperms and its functions in responding to various external environments, especially the function and evolution in Magnoliaceae plants. It helps to gain a deeper understanding of the evolution and functional diversity of the WRKY family and provides theoretical and experimental references for studying the molecular mechanisms of environmental stress.

Fine mapping and candidate gene analysis of qSRC3 controlling the silk color in maize (Zea mays L.).

KEY MESSAGE: Fine mapping of the maize QTL qSRC3, responsible for red silk, uncovered the candidate gene ZmMYB20, which encodes an R2R3-MYB transcription factor, has light-sensitive expression, and putatively regulates genes expression associated with anthocyanin biosynthesis. Colorless silk is a key characteristic contributing to the visual quality of fresh corn intended for market distribution. Nonetheless, the identification of Mendelian trait loci and associated genes that control silk color has been scarce. In this study, a F2 population arising from the hybridization of the single-segment substitution line qSRC3MT1 with red silk, carrying an introgressed allele from teosinte (Zea mays ssp. mexicana), and the recurrent maize inbred line Mo17, characterized by light green silk, was utilized for fine mapping. We found that the red silk trait is controlled by a semi-dominant genetic locus known as qSRC3, and its expression is susceptible to light-mediated inhibition. Moreover, qSRC3 explained 68.78% of the phenotypic variance and was delimited to a 133.2 kb region, which includes three genes. Subsequent expression analyses revealed that ZmMYB20 (Zm00001d039700), which encodes an R2R3-MYB transcription factor, was the key candidate gene within qSRC3. Yeast one-hybrid and dual-luciferase reporter assays provided evidence that ZmMYB20 suppresses the expression of two crucial anthocyanin biosynthesis genes, namely ZmF3H and ZmUFGT, by directly binding to their respective promoter regions. Our findings underscore the significance of light-inhibited ZmMYB20 in orchestrating the spatial and temporal regulation of anthocyanin biosynthesis. These results advance the production of colorless silk in fresh corn, responding to the misconception that fresh corn with withered colored silk is not fresh and providing valuable genetic resources for the improvement of sweet and waxy maize.

Deploying QTL-seq rapid identification and separation of the major QTLs of tassel branch number for fine-mapping in advanced maize populations.

The tassel competes with the ear for nutrients and shields the upper leaves, thereby reducing the yield of grain. The tassel branch number (TBN) is a pivotal determinant of tassel size, wherein the reduced TBN has the potential to enhance the transmission of light and reduce the consumption of nutrients, which should ultimately result in increased yield. Consequently, the TBN has emerged as a vital target trait in contemporary breeding programs that focus on compact maize varieties. In this study, QTL-seq technology and advanced population mapping were used to rapidly identify and dissect the major effects of the TBN on QTL. Advanced mapping populations (BC4F2 and BC4F3) were derived from the inbred lines 18-599 (8-11 TBN) and 3237 (0-1 TBN) through phenotypic recurrent selection. First, 13 genomic regions associated with the TBN were detected using quantitative trait locus (QTL)-seq and were located on chromosomes 2 and 5. Subsequently, validated loci within these regions were identified by QTL-seq. Three QTLs for TBN were identified in the BC4F2 populations by traditional QTL mapping, with each QTL explaining the phenotypic variation of 6.13-18.17%. In addition, for the major QTL (qTBN2-2 and qTBN5-1), residual heterozygous lines (RHLs) were developed from the BC4F2 population. These two major QTLs were verified in the RHLs by QTL mapping, with the phenotypic variation explained (PVE) of 21.57% and 30.75%, respectively. Near-isogenic lines (NILs) of qTBN2-2 and qTBN5-1 were constructed. There were significant differences between the NILs in TBN. These results will enhance our understanding of the genetic basis of TBN and provide a solid foundation for the fine-mapping of TBN. Supplementary Information: The online version contains supplementary material available at 10.1007/s11032-023-01431-y.

Antifungal mechanisms of the antagonistic bacterium Bacillus mojavensis UTF-33 and its potential as a new biopesticide.

Biological control has gradually become the dominant means of controlling fungal disease over recent years. In this study, an endophytic strain of UTF-33 was isolated from acid mold (Rumex acetosa L.) leaves. Based on 16S rDNA gene sequence comparison, and biochemical and physiological characteristics, this strain was formally identified as Bacillus mojavensis. Bacillus mojavensis UTF-33 was sensitive to most of the antibiotics tested except neomycin. Moreover, the filtrate fermentation solution of Bacillus mojavensis UTF-33 had a significant inhibitory effect on the growth of rice blast and was used in field evaluation tests, which reduced the infestation of rice blast effectively. Rice treated with filtrate fermentation broth exhibited multiple defense mechanisms in response, including the enhanced expression of disease process-related genes and transcription factor genes, and significantly upregulated the gene expression of titin, salicylic acid pathway-related genes, and H2O2 accumulation, in plants; this may directly or indirectly act as an antagonist to pathogenic infestation. Further analysis revealed that the n-butanol crude extract of Bacillus mojavensis UTF-33 could retard or even inhibit conidial germination and prevent the formation of adherent cells both in vitro and in vivo. In addition, the amplification of functional genes for biocontrol using specific primers showed that Bacillus mojavensis UTF-33 expresses genes that can direct the synthesis of bioA, bmyB, fenB, ituD, srfAA and other substances; this information can help us to determine the extraction direction and purification method for inhibitory substances at a later stage. In conclusion, this is the first study to identify Bacillus mojavensis as a potential agent for the control of rice diseases; this strain, and its bioactive substances, have the potential to be developed as biopesticides.

Isolation of Bacillus siamensis B-612, a Strain That Is Resistant to Rice Blast Disease and an Investigation of the Mechanisms Responsible for Suppressing Rice Blast Fungus.

Rice yield can be significantly impacted by rice blast disease. In this investigation, an endophytic strain of Bacillus siamensis that exhibited a potent inhibitory effect on the growth of rice blast was isolated from healthy cauliflower leaves. 16S rDNA gene sequence analysis showed that it belongs to the genus Bacillus siamensis. Using the rice OsActin gene as an internal control, we analyzed the expression levels of genes related to the defense response of rice. Analysis showed that the expression levels of genes related to the defense response in rice were significantly upregulated 48 h after treatment. In addition, peroxidase (POD) activity gradually increased after treatment with B-612 fermentation solution and peaked 48 h after inoculation. These findings clearly demonstrated that the 1-butanol crude extract of B-612 retarded and inhibited conidial germination as well as the development of appressorium. The results of field experiments showed that treatment with B-612 fermentation solution and B-612 bacterial solution significantly reduced the severity of the disease before the seedling stage of Lijiangxintuan (LTH) was infected with rice blast. Future studies will focus on exploring whether Bacillus siamensis B-612 produces new lipopeptides and will apply proteomic and transcriptomic approaches to investigate the signaling pathways involved in its antimicrobial effects.

Age-dependent modulation of oleoresin production in the stem of Sindora glabra.

Plants produce specialized metabolites in various organs which serve important functions in defense and development. However, the molecular regulatory mechanisms of oleoresin production in stems from broadleaved tree species are not fully understood. To determine whether endogenous developmental cues play a role in the regulation of oleoresin biosynthesis in tree stems, anatomy, multi-omics and molecular experiments were utilized to investigate the change of secretory structures, chemical profiles and gene expression in different ontogenetic stages of Sindora glabra tree, which accumulates copious amount of sesquiterpene-rich oleoresin in stems. The size of secretory canals and the concentration of five sesquiterpenes in Sindora stems exhibited obvious increase with plant age, from 0.5- to 20-year-old plants. Moreover, α-copaene and ß-copaene were found to be stem-specific sesquiterpenes. Metabolomic analysis revealed that salicylic acid highly accumulated in mature stems, but the content of triterpenes was greatly decreased. The expression of three repressors AUX/IAA, DELLA and JAZ involved in hormone signaling transduction pathways was significantly downregulated in stems of 10- and 20-year-old plants. Two key genes SgTPS3 and SgTPS5 were identified, whose expression was highly correlated with the accumulation patterns of specific sesquiterpenes and their enzymatic products were consistent with the chemical profiles in the stem. The promoters of three SgTPSs exhibiting high activity were isolated. Furthermore, we demonstrated that SgSPL15 directly interacts with SgTPS3 and SgTPS5 promoters and activates SgTPS5 expression but SgSPL15 inhibits SgTPS3 expression. In addition, SgSPL15 enhanced sesquiterpene levels by upregulating AtTPSs expression in Arabidopsis. These results suggested that sesquiterpene biosynthesis in S. glabra stem was dependent on the regulation of endogenous hormones as well as plant age, and SgSPL15 might act as a buffering factor to regulate sesquiterpene biosynthesis by targeting SgTPS genes.

Integrated transcriptomic and metabolomic analyses reveal regulation of terpene biosynthesis in the stems of Sindora glabra.

Sesquiterpenes are important defensive secondary metabolites that are synthesized in various plant organs. Methyl jasmonate (MeJA) plays a key role in plant defense responses and secondary metabolism. Sindora glabra Merr. ex de Wit produces abundant sesquiterpenes in its trunks, and was subjected to investigation after MeJA treatment in order to characterize the molecular mechanisms underlying the regulation of sesquiterpene biosynthesis in plant stems and further our understanding of oleoresin production in trees. A total of 14 types of sesquiterpenes in the stems of mature S. glabra trees were identified. The levels of two sesquiterpenes, α-copaene and ß-caryophyllene, significantly increased after MeJA treatment. Differentially expressed genes involved in terpenoid backbone biosynthesis were significantly enriched over time, while the expression of JAZ genes involved in the jasmonic acid signaling pathway and TGA genes involved in the salicylic acid signaling pathway was significantly enriched at later time points after treatment. Two new terpene synthase genes, SgSTPS4 and SgSTPS5, were also identified. Following MeJA treatment, the expression levels of SgSTPS1, SgSTPS2 and SgSTPS4 decreased, while SgSTPS5 expression increased. The major enzymatic products of SgSTPS4 were identified as ß-elemene and cyperene, while SgSTPS5 was identified as a bifunctional mono/sesquiterpene synthase that could catalyze farnesyl pyrophosphate to produce nine types of sesquiterpenes, including α-copaene and ß-caryophyllene, while SgSTPS5 could also use geranyl pyrophosphate to produce geraniol. Dramatic changes in the amounts of α-copaene and ß-caryophyllene in response to MeJA were correlated with transcriptional expression changes of SgSTPS5 in the wood tissues. In addition, the transcription factors MYB, NAC, ARF, WRKY, MYC, ERF and GRAS were co-expressed with terpene biosynthesis genes and might potentially regulate terpene biosynthesis. Metabolite changes were further investigated with UPLC-TOF/MS following MeJA treatment. These results contribute to the elucidation of the molecular mechanisms of terpene biosynthesis and regulation as well as to the identification of candidate genes involved in these processes.

The Diesel Tree Sindora glabra Genome Provides Insights Into the Evolution of Oleoresin Biosynthesis.

Sindora glabra is an economically important tree that produces abundant oleoresin in the trunk. Here, we present a high-quality chromosome-scale assembly of S. glabra genome by combining Illumina HiSeq, Pacific Biosciences sequencing, and Hi-C technologies. The size of S. glabra genome was 1.11 Gb, with a contig N50 of 1.27 Mb and 31,944 predicted genes. This is the first sequenced genome of the subfamily Caesalpinioideae. As a sister taxon to Papilionoideae, S. glabra underwent an ancient genome triplication shared by core eudicots and further whole-genome duplication shared by early-legume in the last 73.3 million years. S. glabra harbors specific genes and expanded genes largely involved in stress responses and biosynthesis of secondary metabolites. Moreover, 59 terpene backbone biosynthesis genes and 64 terpene synthase genes were identified, which together with co-expressed transcription factors could contribute to the diversity and specificity of terpene compounds and high terpene content in S. glabra stem. In addition, 63 disease resistance NBS-LRR genes were found to be unique in S. glabra genome and their expression levels were correlated with the accumulation of terpene profiles, suggesting potential defense function of terpenes in S. glabra. These together provide new resources for understanding genome evolution and oleoresin production.

Relationship of Mental Stress of Middle School Students and Campus Safety Atmosphere with Psychosocial Safety Behaviors.

BACKGROUND: Incidents of violence, such as school bullying, are mainly caused by excessive mental stress of students, which will also lead to all kinds of psychologically unsafe behaviors. The emotion regulation ability of students and the safety atmosphere level of campus will be considerably conducive to relieving the mental stress of students. This study aims to analyze the relationships of mental stress and regulatory emotional self-efficacy (RES) among students and campus safety atmosphere with their psychosocial safety behaviors (PSB). METHODS: A total of 120 class teachers and 365 students from three junior high schools in Henan Province, China were selected as the study objects in 2019. Then, middle school students and RES, campus safety atmosphere, and PSB scales were assessed through a mental stress scale. RESULTS: Mental stress (r=-0.8) of middle school students and campus safety atmosphere (r=0.86) had a significant negative and positive influence on their PSB, respectively. RES played a mediating role in the negative correlation between the mental stress of middle school students and their PSB (r=-0.57). Campus safety atmosphere could moderate the relationship between mental stress and RES (r=0.12). Campus safety atmosphere could moderate the mediating effect on the relationship between mental stress of middle school students and their PSB. CONCLUSION: Mental stress of middle school students will give rise to the occurrence of their psychologically unsafe behaviors. The improvement of the campus safety atmosphere level can effectively mitigate the mental stress of students to reduce the occurrence of unsafe behaviors.

Genome-wide characterization of the SPL gene family involved in the age development of Jatropha curcas.

BACKGROUND: SPL (SQUAMOSA-promoter binding protein-like) proteins form a large family of plant-specific transcription factors that play essential roles in various aspects of plant growth and development. They are potentially important candidates for genetic improvement of agronomic traits. However, there were limited information about the SPL genes in Jatropha curcas, an important biofuel plant. RESULTS: In Jatropha, 15 JcSPL genes were identified. Phylogenetic analysis revealed that most of the JcSPLs were closely related to SPLs from woody plant rather than herbaceous plant and distantly related to monocotyledon SPLs. Gene structure, conserved motif and repetitive sequence analysis indicated diverse and specific functions of some JcSPL genes. By combination of target prediction and degradome sequencing analysis, 10 of the 15 JcSPLs were shown to be targets of JcmiR156. Quantitative PCR analysis showed diversified spatial-temporal expression patterns of JcSPLs. It is interesting that the expression levels of JcSPL3 were the highest in all tissues examined in 7- or 10-year-old plants and exhibited increasing trend with plant age, suggesting its important role in the regulation of age development in Jatropha. Overexpression of JcSPL3 in Arabidopsis resulted in earlier flowering time, shorter silique length and reduced biomass of roots. CONCLUSIONS: Through comprehensive and systematic analysis of phylogenetic relationships, conserved motifs, gene structures, chromosomal locations, repetitive sequence and expression patterns, 15 JcSPL genes were identified in Jatropha and characterized in great detail. These results provide deep insight into the evolutionary origin and biological significance of plant SPLs and lay the foundation for further functional characterization of JcSPLs with the purpose of genetic improvement in Jatropha.

Growth, photosynthesis, and nutrient uptake in wheat are affected by differences in nitrogen levels and forms and potassium supply.

Nitrogen (N) and potassium (K) are essential macronutrients for plants growth; however, the mechanism by which K mediates negative effects on ammonium-sensitive plants is still poorly understood. We hypothesized that K supplies may enhance antagonistic ammonium stress while improving nitrate nutrition function, which wheat seedlings were grown in sand culture in the presence of two N forms (ammonium; nitrate) supplied at two rates (2, 10 mmol L-1) and three K levels (0.5, 5, 15 mmol L-1). We found that a high N rate increased plant biomass under nitrate nutrition, while it had a negative effect under ammonium nutrition. Compared with nitrate, biomass was depressed by 54% or 85% for low or high N rate under ammonium. This resulted in a reduction in gas exchange parameters and a subsequent decrease in growth variables and nutrient uptake, whereas these parameters increased significantly with increasing K levels. Moreover, in principal components analysis, these variations were highly clustered under nitrate nutrition and highly separated under ammonium nutrition. Our study shows a clear positive interaction between K and N, suggesting that high K supply relieves ammonium stress while improving growth vigor under nitrate nutrition by enhancing nutrient uptake and assimilate production in wheat plants.

Transcriptome Analysis of Oleoresin-Producing Tree Sindora Glabra and Characterization of Sesquiterpene Synthases.

Terpenes serve important physiological and ecological functions in plants. Sindora glabra trees accumulate copious amounts of sesquiterpene-rich oleoresin in the stem. A transcriptome approach was used to determine the unique terpene biosynthesis pathway and to explore the different regulatory mechanisms responsible for the variation of terpene content among individuals. Analysis of de novo-assembled contigs revealed a complete set of genes for terpene biosynthesis. A total of 23,261 differentially expressed unigenes (DEGs) were discovered between high and low oil-yielding plants. DEG enrichment analysis suggested that the terpene biosynthesis process and the plant hormone signal transduction pathway may exert a major role in determining terpene variation in S. glabra. The expression patterns of candidate genes were further verified by quantitative RT-PCR experiments. Key genes involved in the terpene biosynthesis pathway were predominantly expressed in phloem and root tissues. Phylogenetic analysis and subcellular localization implied that S. glabra terpene synthases may evolve from a common ancestor. Furthermore, two sesquiterpene synthase genes, SgSTPS1 and SgSTPS2, were functionally characterized. SgSTPS1 mainly generated ß-caryophyllene from farnesyl pyrophosphate. SgSTPS2 is a versatile enzyme that catalyzes the formation of 12 sequiterpenes from farnesyl pyrophosphate and synthesis of three monoterpenes using geranyl pyrophosphate. Together, these results provide large reservoir for elucidating the molecular mechanism of terpene biosynthesis and for exploring the ecological function of sesquiterpenes in S. glabra.

Identification and characterization of a novel esterase from Thauera sp.

A novel esterase gene TLip was identified from the strain Thauera sp. and expressed at high levels in Escherichia coli. The TLip protein shared the highest identity (48%) to esterase TesA from Pseudomonas aeruginosa when compared to enzymes with reported properties. Phylogenetic analysis showed that TLip belongs to the GDSL family of bacterial lipolytic enzymes. TLip was an alkaline esterase with a broad optimal temperature range 37-50 °C and an optimal pH of 8.0. Substrate specificity assays showed that TLip preferred medium chain p-nitrophenyl esters (C6 -C12 ). Besides, the activity of TLip was strongly inhibited by Cu2+ but greatly enhanced by Triton X-100 and Tween 80. Thermostability assay revealed that TLip was stable without loss of activity at 37 °C and still retained 69% activity at 50 °C after 2 H of incubation. Together, these provided a good candidate for further exploration of TLip as a promising biocatalyst in industry.

Semaphorin-3A and Netrin-1 predict the development of kidney injury in children with congenital hydronephrosis.

Congenital obstructive nephropathy is amongst the main causes of chronic renal failure in children. Early diagnosis and initiation of the treatment will delay progressive renal tubular atrophy and interstitial fibrosis with the loss of nephrons. The aim of this study was to evaluate whether urinary (u) semaphorin-3A (SEMA-3A) and Netrin-1 may be potential biomarkers in children with congenital hydronephrosis due to ureteropelvic junction obstruction (UPJO). The study consisted of 42 children with severe hydronephrosis who needed surgery and two control groups (Control One: 42 children with mild, non-obstructive hydronephrosis; Control Two: 44 healthy children). All children had normal renal function. Urinary semaphorin-3A and Netrin-1 levels were measured in different groups using immunoenzymatic ELISA commercial kits. Compared with Control One and Control Two groups, the preoperative median uSEMA-3A/creatinine (cr.) and uNetrin-1/cr. levels increased significantly in the children with severe hydronephrosis (p < .01). One month after surgery, uSEMA-3A/cr. and uNetrin-1/cr. levels had decreased significantly in the children with severe hydronephrosis (p < .01), but were still higher than those in both control groups (p < .05). Receiver operator characteristic (ROC) analyses revealed a good diagnostic profile for uSEMA-3A and uNetrin-1 in terms of identifying children with a differential renal function of <40% [area under the curve (AUC) 0.825 and 0.745, respectively]. Our results indicate that increased concentrations of uSEMA-3A and uNetrin-1 are found in urine from children with severe hydronephrosis and that their concentrations are related to the degree of obstruction.

Physiological and proteomic analyses of leaves from the halophyte Tangut Nitraria reveals diverse response pathways critical for high salinity tolerance.

Soil salinization poses a serious threat to the environment and agricultural productivity worldwide. Studies on the physiological and molecular mechanisms of salinity tolerance in halophytic plants provide valuable information to enhance their salt tolerance. Tangut Nitraria is a widely distributed halophyte in saline-alkali soil in the northern areas of China. In this study, we used a proteomic approach to investigate the molecular pathways of the high salt tolerance of T. Nitraria. We analyzed the changes in biomass, photosynthesis, and redox-related enzyme activities in T. Nitraria leaves from plant seedlings treated with high salt concentration. Comparative proteomic analysis of the leaves revealed that the expression of 71 proteins was significantly altered after salinity treatments of T. Nitraria. These salinity-responsive proteins were mainly involved in photosynthesis, redox homeostasis, stress/defense, carbohydrate and energy metabolism, protein metabolism, signal transduction, and membrane transport. Results showed that the reduction of photosynthesis under salt stress was attributed to the down-regulation of the enzymes and proteins involved in the light reaction and Calvin cycle. Protein-protein interaction analysis revealed that the proteins involved in redox homeostasis, photosynthesis, and energy metabolism constructed two types of response networks to high salt stress. T. Nitraria plants developed diverse mechanisms for scavenging reactive oxygen species (ROS) in their leaves to cope with stress induced by high salinity. This study provides important information regarding the salt tolerance of the halophyte T. Nitraria.

Elastic intramedullary nail for treatment of extremity fractures in children.

OBJECTIVE: To assess the clinical therapeutic effects of elastic intramedullary nail on extremity fractures in children. METHODS: From June 2005 to March 2008, 40 children with extremity fractures were treated by elastic intramedullary nail, in whom femoral shaft fractures occurred in 26 cases, tibiofibular fractures in 8 cases, radial capitular fractures in 4 cases, ulnoradial fractures in 2 cases. All patients were treated by closed reduction and elastic intramedullary nail fixation. RESULTS: All the fractures gained satisfactory reduction and healing. The average duration needed for fracture healing was 1-2 months. Postoperative follow-up confirmed a sound functional recovery. CONCLUSIONS: The elastic intramedullary nail is a minimally invasive and effective surgical approach for treatment of extremity fractures in children. It allows early functional exercises after operation and secures a satisfactory bone union and functional recovery.