SAFB restricts contact domain boundaries associated with L1 chimeric transcription.

Long interspersed element-1 (LINE-1 or L1) comprises 17% of the human genome, continuously generates genetic variations, and causes disease in certain cases. However, the regulation and function of L1 remain poorly understood. Here, we uncover that L1 can enrich RNA polymerase IIs (RNA Pol IIs), express L1 chimeric transcripts, and create contact domain boundaries in human cells. This impact of L1 is restricted by a nuclear matrix protein scaffold attachment factor B (SAFB) that recognizes transcriptionally active L1s by binding L1 transcripts to inhibit RNA Pol II enrichment. Acute inhibition of RNA Pol II transcription abolishes the domain boundaries associated with L1 chimeric transcripts, indicating a transcription-dependent mechanism. Deleting L1 impairs domain boundary formation, and L1 insertions during evolution have introduced species-specific domain boundaries. Our data show that L1 can create RNA Pol II-enriched regions that alter genome organization and that SAFB regulates L1 and RNA Pol II activity to preserve gene regulation.

WRKY53 negatively regulates rice cold tolerance at the booting stage by fine-tuning anther gibberellin levels.

Cold tolerance at the booting (CTB) stage is a major factor limiting rice (Oryza sativa L.) productivity and geographical distribution. A few cold-tolerance genes have been identified, but they either need to be overexpressed to result in CTB or cause yield penalties, limiting their utility for breeding. Here, we characterize the function of the cold-induced transcription factor WRKY53 in rice. The wrky53 mutant displays increased CTB, as determined by higher seed setting. Low temperature is associated with lower gibberellin (GA) contents in anthers in the wild type but not in the wrky53 mutant, which accumulates slightly more GA in its anthers. WRKY53 directly binds to the promoters of GA biosynthesis genes and transcriptionally represses them in anthers. In addition, we uncover a possible mechanism by which GA regulates male fertility: SLENDER RICE1 (SLR1) interacts with and sequesters two critical transcription factors for tapetum development, UNDEVELOPED TAPETUM1 (UDT1), and TAPETUM DEGENERATION RETARDATION (TDR), and GA alleviates the sequestration by SLR1, thus allowing UDT1 and TDR to activate transcription. Finally, knocking out WRKY53 in diverse varieties increases cold tolerance without a yield penalty, leading to a higher yield in rice subjected to cold stress. Together, these findings provide a target for improving CTB in rice.

Size Scaling of Condensates in Multicomponent Phase Separation.

Constant proportionalities between cells and their intracellular organelles have been widely observed in various types of cells, known as intracellular size scaling. However, the mechanism underlying the size scaling and its modulation by environmental factors in multicomponent systems remain poorly understood. Here, we study the size scaling of membrane-less condensates using microdroplet-encapsulated minimalistic condensates formed by droplet microfluidics and mean-field theory. We demonstrate that the size scaling of condensates is an inherent characteristic of liquid-liquid phase separation. This concept is supported by experiments showing the occurrence of size scaling phenomena in various condensate systems and a generic lever rule acquired from mean-field theory. Moreover, it is found that the condensate-to-microdroplet scaling ratio can be affected by the solute and salt concentrations, with good agreement between experiments and predictions by theory. Notably, we identify a noise buffering mechanism whereby condensates composed of large macromolecules effectively maintain constant volumes and counteract concentration fluctuations of small molecules. This mechanism is achieved through the dynamic rearrangement of small molecules in and out of membrane-free interfaces. Our work provides crucial insights into understanding mechanistic principles that govern the size of cells and intracellular organelles as well as associated biological functions.

Comprehensive analysis of stress-activated protein kinase genes (OsSAPKs) in rice flowering time.

MAIN CONCLUSION: The rice SnRK2 members SAPK4, SAPK5, SAPK7 and SAPK10 are positive regulators involved in the regulation of rice flowering, while other single mutants exhibited no effect on rice flowering. The rice SnRK2 family, comprising 10 members known as SAPK (SnRK2-Associated Protein Kinase), is pivotal in the abscisic acid (ABA) pathway and crucial for various biological processes, such as drought resistance and salt tolerance. Additionally, these members have been implicated in the regulation of rice heading date, a key trait influencing planting area and yield. In this study, we utilized gene editing technology to create mutants in the Songjing 2 (SJ2) background, enabling a comprehensive analyze the role of each SAPK member in rice flowering. We found that SAPK1, SAPK2, and SAPK3 may not directly participate in the regulatory network of rice heading date, while SAPK4, SAPK5, and SAPK7 play positive roles in rice flowering regulation. Notably, polygene deletion resulted in an additive effect on delaying flowering. Our findings corroborate the previous studies indicating the positive regulatory role of SAPK10 in rice flowering, as evidenced by delayed flowering observed in sapk9/10 double mutants. Moving forward, our future research will focus on analyzing the molecular mechanisms underlying SAPKs involvement in rice flowering regulation, aiming to enhance our understanding of the rice heading date relationship network and lay a theoretical foundation for breeding efforts to alter rice ripening dates.

WRKY53 integrates classic brassinosteroid signaling and the mitogen-activated protein kinase pathway to regulate rice architecture and seed size.

In rice (Oryza sativa) and other plants, plant architecture and seed size are closely related to yield. Brassinosteroid (BR) signaling and the mitogen-activated protein kinase (MAPK) pathway (MAPK kinase kinase 10 [MAPKKK10]-MAPK kinase 4 [MAPKK4]-MAPK6) are two major regulatory pathways that control rice architecture and seed size. However, their possible relationship and crosstalk remain elusive. Here, we show that WRKY53 mediated the crosstalk between BR signaling and the MAPK pathway. Biochemical and genetic assays demonstrated that glycogen synthase kinase-2 (GSK2) phosphorylates WRKY53 and lowers its stability, indicating that WRKY53 is a substrate of GSK2 in BR signaling. WRKY53 interacted with BRASSINAZOLE-RESISTANT 1(BZR1); they function synergistically to regulate BR-related developmental processes. We also provide genetic evidence showing that WRKY53 functions in a common pathway with the MAPKKK10-MAPKK4-MAPK6 cascade in leaf angle and seed size control, suggesting that WRKY53 is a direct substrate of this pathway. Moreover, GSK2 phosphorylated MAPKK4 to suppress MAPK6 activity, suggesting that GSK2-mediated BR signaling might also regulated MAPK pathway. Together, our results revealed a critical role for WRKY53 and uncovered sophisticated levels of interplay between BR signaling and the MAPK pathway in regulating rice architecture and seed size.

Simple and complex coacervation in systems involving plant proteins.

Plant-based foods are gaining popularity as alternatives to meat and dairy products due to sustainability and health concerns. As a consequence, there is a renewed interest in the phase behaviour of plant proteins and of mixtures of plant proteins and polysaccharides, in particular in the cases where coacervation is found to occur, i.e., liquid-liquid phase separation (LLPS) into two phases, one of which is rich in biopolymers and one of which is poor in biopolymer. Here we review recent research into both simple and complex coacervation in systems involving plant proteins, and their applications in food- as well as other technologies, such as microencapsulation, microgel production, adhesives, biopolymer films, and more.

A novel functional allele of Ehd3 controls flowering time in rice.

Rice flowering time determines its geographical distribution and yield traits. As a short-day plant, rice can grow in the northern long-day conditions due to the functional mutations of many photosensitive genes. In this study, to identify novel genes or alleles that regulate flowering time in high latitude region, two cultivar, Dongnong 413 (DN413) and Yukimochi (XN) showing extreme early flowering were used for investigation. DN413 is around 4.0 days earlier than XN, and both cultivars can be grown in II (2500 â„ƒ-2700 â„ƒ) to III (2300 â„ƒ-2500 â„ƒ) accumulated temperature zones. We found that the two cultivars shared the same genotype of heading date genes, including Hd1/2/4/5/6/16/17/18, Ehd2, DTH2, SE5, Hd3a. Importantly, a novel Ehd3 allele characterized by a A1146C substitution was identified, which results in the E382D substitution, hereafter the 382 position E is defined as Hap_E and the 382 position D is defined as Hap_D. Association analysis showed that Hap_E is earlier flowering than Hap_D. Subsequently, we construct DN413 Hap_D line by three times back-crossing DN413 with XN, and found the heading date of DN413 Hap_D was 1.7-3.5 days later than DN413. Moreover, Hap_E and Hap_D of Ehd3 were transformed into ehd3 mutant, respectively, and the Ehd3pro:Ehd3D/ehd3 flowered later than that Ehd3pro:Ehd3E/ehd3 by around 4.3 days. Furthermore, we showed Ehd3 functions as a transcriptional suppressor and the substitution of Asp-382 lost the inhibition activity in protoplasts. Finally, a CAPS marker was developed and used for genotyping and marker assistant breeding. Collectively, we discovered a novel functional allele of Ehd3, which can used as a valuable breeding target. Supplementary Information: The online version contains supplementary material available at 10.1007/s11032-024-01472-x.

OsPGL3A encodes a DYW-type pentatricopeptide repeat protein involved in chloroplast RNA processing and regulated chloroplast development.

The chloroplast serves as the primary site of photosynthesis, and its development plays a crucial role in regulating plant growth and morphogenesis. The Pentatricopeptide Repeat Sequence (PPR) proteins constitute a vast protein family that function in the post-transcriptional modification of RNA within plant organelles. In this study, we characterized mutant of rice with pale green leaves (pgl3a). The chlorophyll content of pgl3a at the seedling stage was significantly reduced compared to the wild type (WT). Transmission electron microscopy (TEM) and quantitative PCR analysis revealed that pgl3a exhibited aberrant chloroplast development compared to the wild type (WT), accompanied by significant alterations in gene expression levels associated with chloroplast development and photosynthesis. The Mutmap analysis revealed that a single base deletionin the coding region of Os03g0136700 in pgl3a. By employing CRISPR/Cas9 mediated gene editing, two homozygous cr-pgl3a mutants were generated and exhibited a similar phenotype to pgl3a, thereby confirming that Os03g0136700 was responsible for pgl3a. Consequently, it was designated as OsPGL3A. OsPGL3A belongs to the DYW-type PPR protein family and is localized in chloroplasts. Furthermore, we demonstrated that the RNA editing efficiency of rps8-182 and rpoC2-4106, and the splicing efficiency of ycf3-1 were significantly decreased in pgl3a mutants compared to WT. Collectively, these results indicate that OsPGL3A plays a crucial role in chloroplast development by regulating the editing and splicing of chloroplast genes in rice. Supplementary Information: The online version contains supplementary material available at 10.1007/s11032-024-01468-7.

OsWRKY78 regulates panicle exsertion via gibberellin signaling pathway in rice.

Panicle exsertion is one of the crucial agronomic traits in rice (Oryza sativa). Shortening of panicle exsertion often leads to panicle enclosure and severely reduces seed production. Gibberellin (GA) plays important roles in regulating panicle exsertion. However, the underlying mechanism and the relative regulatory network remain elusive. Here, we characterized the oswrky78 mutant showing severe panicle enclosure, and found that the defect of oswrky78 is caused by decreased bioactive GA contents. Biochemical analysis demonstrates that OsWRKY78 can directly activate GA biosynthesis and indirectly suppress GA metabolism. Moreover, we found OsWRKY78 can interact with and be phosphorylated by mitogen-activated protein kinase (MAPK) kinase OsMAPK6, and this phosphorylation can enhance OsWRKY78 stability and is necessary for its biological function. Taken together, these results not only reveal the critical function of OsWRKY78, but also reveal its mechanism via mediating crosstalk between MAPK and the GA signaling pathway in regulating panicle exsertion.

Tuning Material States and Functionalities of G-Quadruplex-Modulated RNA-Peptide Condensates.

RNA encodes sequence- and structure-dependent interactions to modulate the assembly and properties of biomolecular condensates. RNA G-quadruplexes (rG4s) formed by guanine-rich sequences can trigger the formation of liquid- or solid-like condensates that are involved in many aberrant phase transitions. However, exactly how rG4 motifs modulate different phase transitions and impart distinct material properties to condensates is unclear. Here, using RNA oligonucleotides and cationic peptides as model systems, we show that RNA-peptide condensates exhibit tunability in material properties over a wide spectrum via interactions arising from rG4 folding/unfolding kinetics. rG4-containing oligonucleotides formed strong pairwise attraction with peptides and tended to form solid-like condensates, while their less-structured non-G4 mutants formed liquid-like droplets. We find that the coupling between rG4 dissociation and RNA-peptide complex coacervation triggers solid-to-liquid transition of condensates prior to the complete unfolding of rG4s. This coupling points to a mechanism that material states of rG4-modulated condensates can be finely tuned from solid-like to liquid-like by the addition of less-structured RNA oligonucleotides, which have weak but dominant binding with peptides. We further show that the tunable material states of condensates can enhance RNA aptamer compartmentalization and RNA cleavage reactions. Our results suggest that condensates with complex properties can emerge from subtle changes in RNA oligonucleotides, contributing ways to treat dysfunctional condensates in diseases and insights into prebiotic compartmentalization.

OsMAPK6 positively regulates rice cold tolerance at seedling stage via phosphorylating and stabilizing OsICE1 and OsIPA1.

Rice is a chilling-sensitive plant, and extremely low temperatures seriously decrease rice production. Several genes involved in chilling stress have been reported in rice; however, the chilling signaling in rice remains largely unknown. Here, we investigated the chilling tolerance phenotype of overexpression of constitutive active OsMAPK6 (CAMAPK6-OE) and OsMAPK6 mutant dsg1, and demonstrated that OsMAPK6 positively regulated rice chilling tolerance. It was shown that, under cold stress, the survival rate of dsg1 was significantly lower than that of WT, whereas CAMAPK6-OE display higher survival rate than WT. Physiological assays indicate that ion leakage and dead cell in dsg1 was much more severe than those in WT and CAMAPK6-OE. Consistently, expression of chilling responsive genes in dsg1, including OsCBFs and OsTPP1, was significantly lower than that of in WT and CAMAPK6-OE. Biochemical analyses revealed that chilling stress promotes phosphorylation of OsMAPK6. Besides, we found that OsMAPK6 interacts with and phosphorylates two key regulators in rice cold signaling, OsIPA1 and OsICE1, and then enhance their protein stability. Overall, our results revealed a cold-induced OsMAPK6-OsICE1/OsIPA1 signaling cascade by which OsMAPK6 was involved in rice chilling tolerance, which provides novel insights to understand rice cold response at seedling stage.

Advanced Magnetic Resonance Imaging and Molecular Imaging of the Painful Knee.

Chronic knee pain is a common condition. Causes of knee pain include trauma, inflammation, and degeneration, but in many patients the pathophysiology remains unknown. Recent developments in advanced magnetic resonance imaging (MRI) techniques and molecular imaging facilitate more in-depth research focused on the pathophysiology of chronic musculoskeletal pain and more specifically inflammation. The forthcoming new insights can help develop better targeted treatment, and some imaging techniques may even serve as imaging biomarkers for predicting and assessing treatment response in the future. This review highlights the latest developments in perfusion MRI, diffusion MRI, and molecular imaging with positron emission tomography/MRI and their application in the painful knee. The primary focus is synovial inflammation, also known as synovitis. Bone perfusion and bone metabolism are also addressed.

Tailorable and Biocompatible Supramolecular-Based Hydrogels Featuring two Dynamic Covalent Chemistries.

Dynamic covalent chemistry (DCC) has proven to be a valuable tool in creating fascinating molecules, structures, and emergent properties in fully synthetic systems. Here we report a system that uses two dynamic covalent bonds in tandem, namely disulfides and hydrazones, for the formation of hydrogels containing biologically relevant ligands. The reversibility of disulfide bonds allows fiber formation upon oxidation of dithiol-peptide building block, while the reaction between NH-NH2 functionalized C-terminus and aldehyde cross-linkers results in a gel. The same bond-forming reaction was exploited for the "decoration" of the supramolecular assemblies by cell-adhesion-promoting sequences (RGD and LDV). Fast triggered gelation, cytocompatibility and ability to "on-demand" chemically customize fibrillar scaffold offer potential for applying these systems as a bioactive platform for cell culture and tissue engineering.

Transcription factor bZIP65 delays flowering via suppressing Ehd1 expression in rice.

Flowering time is one of the most fundamental factors that determine the distribution and final yield of rice. Ehd1 (Early heading date 1) is a B-type response regulator which functions as a flowering time activator. Although diverse flowering time genes have been reported as regulatory factors of Ehd1 expression, the potential regulators of Ehd1 largely remain to be identified. Here, we identified a basic leucine zipper transcription factor bZIP65, a homolog of bZIP71, as a new negative regulator of Ehd1. The overexpression of bZIP65 delays flowering, while bzip65 mutants have similar flowering time to SJ2 (Songjing2) in both long-day and short-day conditions. Biochemically, bZIP65 associates with Ehd1 promoter and transcriptionally represses the expression of Ehd1. Moreover, we found that bZIP65 enhances H3K27me3 level of Ehd1. Taken together, we cloned a new gene, bZIP65, regulating rice heading date, and uncovered the mechanism of bZIP65 delaying flowering time, where bZIP65 increases the H3K27me3 level of Ehd1 and transcriptionally represses the expression of Ehd1, similar to its homolog bZIP71. Supplementary Information: The online version contains supplementary material available at 10.1007/s11032-022-01334-4.

Enhancing N uptake and reducing N pollution via green, sustainable N fixation-release model.

The overuse of N fertilizers has caused serious environmental problems (e.g., soil acidification, excessive N2O in the air, and groundwater contamination) and poses a serious threat to human health. Improving N fertilizer utilization efficiency and plant uptake is an alternative for N fertilizers overuses. Enterobacter cloacae is an opportunistic pathogen, also used as plant growth-promoting rhizobacteria (PGPR), has been widely presented in the fields of bioremediation and bioprotection. Here we developed a new N fixation-release model by combining biochar with E. cloacae. The efficiency of the model was evaluated using a greenhouse pot experiment with maize (Zea mays L.) as the test crop. The results showed that biochar combined with E. cloacae significantly increased the N content. The application of biochar combined with E. cloacae increased total N in soil by 33% compared with that of N fertilizers application. The N-uptake and utilization efficiency (NUE) in plant was increased 17.03% and 14.18%, respectively. The activities of urease, dehydrogenase and fluorescein diacetate hydrolase (FDA) was improved, the catalase (CAT) activity decreased. Analysis of the microbial community diversity revealed the abundance of Proteobacteria, Actinobacteria, Firmicutes, and Gemmatimonadetes were significantly improved. The mechanism under the model is that E. cloacae acted as N-fixation by capturing N2 from air. Biochar served as carrier, supporting better living environment for E. cloacae, also as adsorbent adsorbing N from fertilizer and from fixed N by E. cloacae, the adsorption in turn slower the N release. Altogether, the model promotes N utilization by plants, improves the soil environment, and reduces N pollution.

Associations of perfluoroalkyl and polyfluoroalkyl substances with gestational hypertension and blood pressure during pregnancy: A cohort study.

Previous studies have reported inconsistent associations between perfluoroalkyl and polyfluoroalkyl substances (PFAS) and gestational hypertension (GH) and blood pressure (BP) during pregnancy. Herein, we aimed to evaluate individual and overall effects of PFAS on GH and longitudinal BP measures during pregnancy. We included 826 pregnant women from the Jiashan Birth Cohort established between 2016 and 2018. Concentrations of thirteen PFAS were quantified using plasma samples collected within 16 weeks of gestation. Longitudinal BP measures were obtained from medical records, and more than nine measurements were available for 85.60% of participants. GH was defined as new-onset hypertension occurring after 20 weeks of gestation. Logistic regression models were used to examine the effect of PFAS on GH, while generalized estimating equation models evaluated the average effect of PFAS on BP in each trimester. The potential effect modification by fetal sex was also examined. Bayesian kernel machine regression (BKMR) and quantile g-computation (QgC) were implemented to explore the overall effect of the PFAS mixture. PFOA, PFOS, and PFHxS presented the highest median concentrations of 11.99, 8.81 and 5.43 ng/mL, respectively. Overall, 5.57% of subjects developed GH. PFOS, PFDA, PFUdA, and PFDoA were significantly associated with lower GH odds, and odds ratios ranged between 0.62 and 0.68. We noted associations between PFAS and lower systolic BP and diastolic BP in the third trimester, with PFDA and PFUdA exhibiting the effect on systolic BP only in pregnant women carrying a female fetus. These associations were further confirmed by BKMR and QgC, showing an inverse overall effect of the PFAS mixture. Higher concentrations of PFAS during early pregnancy were associated with lower GH risk and longitudinal BP measures in the third trimester in a population with relatively high exposure levels. Fetal sex might modify the effects of PFDA and PFUdA on systolic BP in the third trimester.

Association of pre-pregnancy body mass index and gestational weight gain with neonatal anogenital distance in a Chinese birth cohort.

BACKGROUND: This study aimed to investigate the associations of pre-pregnancy body mass index (BMI) and gestational weight gain (GWG) with anogenital distance (AGD) among newborns. METHODS: The study included 556 mother-newborn pairs from the Jiashan birth cohort. AGD was measured as AGDAP (from the center of the anus to the anterior base of the penis, where the penile tissue meets the pubic bone) and AGDAS (from the center of the anus to the posterior base of the scrotum, where the skin changes from rugate to smooth) in males and AGDAC (from the center of the anus to the clitoris) and AGDAF (from the center of the anus to the posterior convergence of the fourchette) in females. Multiple linear regression models were used to estimate the associations of pre-pregnancy BMI and GWG, with AGD. RESULTS: After adjusting for pre-pregnancy BMI and other potential confounders, male newborns whose mothers had excessive GWG had shorter AGDAP than those whose mothers had normal GWG. Male newborns whose mothers had normal pre-pregnancy BMI and inadequate/excessive GWG had shorter AGDAP than the reference group where mothers had normal pre-pregnancy BMI and GWG in stratified analyses. CONCLUSION: Gestational weight gain during pregnancy was associated with AGD in newborns in this birth cohort.

In China, the prevalence of underweight and overweight/obesity remained high among women. Appropriate pre-pregnancy body mass index (BMI) and gestation weight gain (GWG) were critical to reduce the risk of adverse birth outcomes. The anogenital distance (AGD) was measured as an indicator of neonatal reproductive function and was associated with adverse reproductive outcomes in adults. Thus, we investigated the associations of both sub-optimal pre-pregnancy BMI, as well as GWG, with AGD among newborns to draw a picture about their effect on offspring reproductive health.A total of 556 mother-newborns were included in the study from the Jiashan birth cohort in China. We extracted information about maternal lifestyles, social demographic characteristics, diet, and medical history from questionnaires conducted during 8­16 gestational weeks and medical records. AGD among newborns was measured within 3 days of delivery.We found that maternal excessive GWG was associated with shorter AGD in male newborns after adjusting for maternal pre-pregnancy BMI in multiple linear regression models. The study also suggested that maternal inadequate GWG was associated with a shorter AGD in male newborns, which needed to be corroborated in further studies with a larger sample size.In conclusion, health professionals shall implement sufficient intervention to prevent suboptimal GWG during prenatal checkups.

bZIP71 delays flowering by suppressing Ehd1 expression in rice.

Flowering time is a fundamental factor determining the global distribution and final yield of rice (Oryza sativa). Although diverse flowering time genes have been reported in this crop, the transcriptional regulation of its key flowering genes are poorly understood. Here, we report that a basic leucine zipper transcription factor, bZIP71, functions as a flowering repressor. The overexpression of bZIP71 delays flowering, while the bzip71 mutant flowers early in both long-day and short-day conditions. A genetic analysis showed that the regulation of flowering by bZIP71 might be independent of Heading date 2 (Hd2), Hd4, and Hd5. Importantly, bZIP71 directly associates with the Early heading date 1 (Ehd1) promoter and represses its transcription, and genetically the function of bZIP71 is impaired in the ehd1 mutant. Moreover, bZIP71 interacts with major components of polycomb repressive complex 2 (PRC2), SET domain group protein 711 (SDG711), and Fertilization independent endosperm 2 (FIE2), through which bZIP71 regulates the H3K27me3 level of Ehd1. Taken together, we present a transcriptional regulatory mechanism in which bZIP71 enhances the H3K27me3 level of Ehd1 and transcriptionally represses its expression, which not only offers a novel insight into a flowering pathway, but also provides a valuable putative target for the genetic engineering and breeding of elite rice cultivars.

Measuring particle size in ultra-low concentration suspensions by removing the number fluctuation contribution in dynamic light scattering.

In ultra-low concentration suspensions, particle number fluctuations in the scattering volume add a long delay component to the intensity autocorrelation function (ACF) in dynamic light scattering (DLS) measurements. This gives a strong artifact peak in the particle size distribution (PSD) recovered. To improve the accuracy of DLS at ultra-low concentrations, we analyzed the different decay characteristics of particle Brownian motion and particle number fluctuation in the ACF. By differentiating the ACF we were able to identify and separate the number fluctuation term and then analyze the ACF to recover the PSD. The results for simulated DLS data at 151nm and 690nm diameters with average particle numbers of 6, 12, 24 and 48 in the scattering volume at four noise levels show that, compared with the usual DLS data processing method, inversion of the ACF after the separation of the number fluctuation term effectively eliminates the strong artifact peaks, and the relative errors of peak positions and distribution errors are significantly reduced. This was further verified with experimental results from samples of standard polystyrene spheres.

The E3 Ligase DROUGHT HYPERSENSITIVE Negatively Regulates Cuticular Wax Biosynthesis by Promoting the Degradation of Transcription Factor ROC4 in Rice.

Cuticular wax plays crucial roles in protecting plants from environmental stresses, particularly drought stress. Many enzyme-encoding genes and transcription factors involved in wax biosynthesis have been identified, but the underlying posttranslational regulatory mechanisms are poorly understood. Here, we demonstrate that DROUGHT HYPERSENSITIVE (DHS), encoding a Really Interesting New Gene (RING)-type protein, is a critical regulator of wax biosynthesis in rice (Oryza sativa). The cuticular wax contents were significantly reduced in DHS overexpression plants but increased in dhs mutants compared with the wild type, which resulted in a response opposite that of drought stress. DHS exhibited E3 ubiquitin ligase activity and interacted with the homeodomain-leucine zipper IV protein ROC4. Analysis of ROC4 overexpression plants and roc4 mutants indicated that ROC4 positively regulates cuticular wax biosynthesis and the drought stress response. ROC4 is ubiquitinated in vivo and subjected to ubiquitin/26S proteasome-mediated degradation. ROC4 degradation was promoted by DHS but delayed in dhs mutants. ROC4 acts downstream of DHS, and Os-BDG is a direct downstream target of the DHS-ROC4 cascade. These results suggest a mechanism whereby DHS negatively regulates wax biosynthesis by promoting the degradation of ROC4, and they suggest that DHS and ROC4 are valuable targets for the engineering of drought-tolerant rice cultivars.