Influence of surface water and groundwater on functional traits and trade-off strategies of oasis communities at the end of the Keriya River, China.

Plant functional traits reflect the capacity of plants to adapt to their environment and the underlying optimization mechanisms. However, few studies have investigated trade-off strategies for functional traits in desert-wetland ecosystems, the mechanisms by which surface water disturbance and groundwater depth drive functional trait variation at the community scale, and the roles of intraspecific and interspecific variation. Therefore, this study analyzed specific differences in community-weighted mean traits among habitat types and obtained the relative contribution of intraspecific and interspecific variation by decomposing community-weighted mean traits, focusing on the Daliyabuyi Oasis in the hinterland of the Taklamakan Desert. We also explored the mechanisms by which surface water and groundwater influence different sources of variability specifically. The results showed that plant height, relative chlorophyll content, leaf thickness, leaf nitrogen content, and nitrogen-phosphorus ratio were the key traits reflecting habitat differences. As the groundwater depth becomes shallower and surface water disturbance intensifies, plant communities tend to have higher leaf nitrogen content, nitrogen-phosphorus ratio, and relative chlorophyll content and lower height. Surface water, groundwater, soil water content, and total soil nitrogen can influence interspecific and intraspecific variation in these traits through direct and indirect effects. As arid to wet habitats change, plant trade-off strategies for resources will shift from conservative to acquisitive. The study concluded that community functional traits are mainly contributed by interspecific variation, but consideration of intraspecific variation and the covariation effects that exist between it and interspecific variation can help to further enhance the understanding of the response of community traits in desert-wetland ecosystems to environmental change. Surface water disturbance has a non-negligible contribution to this adaptation process and plays a higher role than groundwater depth.

Incidence and Risk Factors for Radiotherapy-Induced Oral Mucositis Among Patients With Nasopharyngeal Carcinoma: A Meta-Analysis.

PURPOSE: To evaluate the incidence and identify the risk factors for radiotherapy-induced oral mucositis among patients with nasopharyngeal carcinoma. METHODS: A meta-analysis was conducted. Eight electronic databases (Medline, Embase, Cochrane Library, CINAHL Plus with Full Text, Web of Science, China National Knowledge Infrastructure, Wanfang Database, and Chinese Scientific Journals Database) were systematically searched from inception to 4 March 2023 for relevant studies. Study selection and data extraction were conducted by two independent authors. The Newcastle‒Ottawa scale was used for quality assessment among the included studies. Data synthesis and analyses were performed in R software package version 4.1.3 and Review Manager Software 5.4. The pooled incidence was calculated using proportions with 95% confidence intervals (CIs), and the risk factors were evaluated using the odds ratio (OR) with 95% CIs. Sensitivity analysis and predesigned subgroup analyses were also conducted. RESULTS: A total of 22 studies published from 2005 to 2023 were included. The results of the meta-analysis showed that the incidence of radiotherapy-induced oral mucositis was 99.0% among nasopharyngeal carcinoma patients, and the incidence of severe radiotherapy-induced oral mucositis was 52.0%. Poor oral hygiene, overweight before radiotherapy, oral pH < 7.0, the use of oral mucosal protective agents, smoking, drinking, combined chemotherapy, and the use of antibiotics at early treatment stage are risk factors for severe radiotherapy-induced oral mucositis. Sensitivity analysis and subgroup analyses also revealed that our results are stable and reliable. CONCLUSIONS: Almost all patients with nasopharyngeal carcinoma have suffered from radiotherapy-induced oral mucositis, and more than half of patients have experienced severe oral mucositis. Facilitating oral health might be the key focus of reducing the incidence and severity of radiotherapy-induced oral mucositis among nasopharyngeal carcinoma patients. REGISTRATION NUMBER: CRD42022322035.

Mediating effect of resilience on the relationship between perceived social support and burnout among Chinese palliative nurses.

AIMS AND OBJECTIVES: To detect the mediating effect of resilience on the relationship between perceived social support and burnout in Chinese palliative nurses. BACKGROUND: Palliative nurses are a group that is vulnerable to burnout. Perceived social support may contribute to decreasing palliative nurses' burnout and facilitating their personal resilience, and resilience may be associated with lower levels of burnout. However, these relationships were unclear in the Chinese context. DESIGN: A cross-sectional design. METHODS: The STROBE guideline was performed to report this study. A mixed sampling method including convenience sampling and stratified sampling was used to recruit participants, and a total of 319 palliative nurses completed the Nursing Burnout Scale, the Perceived Social Support Scale and the Connor-Davidson Resilience Scale from May 2021 to September 2021. Influencing factors were primarily identified using independent-sample t tests and one-way ANOVA. Bootstrap method was used to detect the mediating effect of resilience. RESULTS: The level of burnout in palliative nurses (23.4 ± 7.68) was higher than that of general nurses in China. Education level, health condition and monthly income were influencing factors of burnout. Resilience was detected as a mediator in the relationships between perceived social support and dimensions of burnout. CONCLUSIONS: Chinese palliative nurses experience a relatively high level of burnout, which may be influenced by several sociodemographic variables. Resilience could mediate the effect of perceived social support on the dimensions of burnout. Problem-oriented and palliative-tailored strategies should be developed to further address burnout in Chinese palliative nurses. RELEVANCE TO CLINICAL PRACTICE: Nurse managers and policy makers should support nurse ongoing education, adopt health-promoting interventions and optimise salary systems. In addition, perceived social support resources and resilience training programmes are also warranted. PATIENT OR PUBLIC CONTRIBUTION: All participants were invited to complete the informed consent form and paper questionnaires. Human resource managers helped us collect some subjective data through the personnel management system. Nurse managers of palliative units conducted regular staff meetings to promote the data collection process.

Status and related factors of burnout among palliative nurses in China: a cross-sectional study.

BACKGROUND: Burnout occurs frequently in nurses and seems more common in nurses providing palliative care. However, to our knowledge, there is a lack of understanding regarding the factors influencing burnout among palliative nurses in China. METHODS: A cross-sectional design was conducted. A total of 331 palliative nurses from 25 hospitals participated in this study. Anonymous data were collected through a self-designed social-demographic questionnaire, the Nursing Burnout Scale, the Perceived Social Support Scale, the General Self-Efficacy Scale, the Connor-Davidson Resilience Scale, and the Simplified Coping Style Questionnaire. Independent sample t tests, one-way ANOVA, Pearson correlations, and multiple linear regressions were performed to identify the related factors of the three dimensions of burnout. RESULTS: In the results of multiple linear regression, resilience, health condition, coping style, and pessimistic personality were common related factors; in addition, end-of-life care training, social support, and income satisfaction were statistically significantly associated with burnout. These factors could explain 38.6%, 27.8%, and 34.5% of the total variance in emotional exhaustion, depersonalization, and reduced personal accomplishment, respectively. CONCLUSIONS: The findings of this study help policy makers and nurse managers better understand burnout among palliative nurses in China. The results highlighted the importance of implementing culture-oriented training programs, providing perceived organizational support, and building a reasonable salary system to decrease burnout among palliative nurses, increase the quality of nursing and promote the development of Chinese palliative care.

Exercise in cancer prevention and anticancer therapy: Efficacy, molecular mechanisms and clinical information.

Modifiable lifestyle factors are the strongest determinants and major preventable causes of most type of cancer. Exercise has shown many beneficial effects in cancer prevention and anticancer treatment. However, the underlying mechanisms remain unclear. To contribute to our understanding of the role of exercise regulation in cancer and provide recommendations for future preclinical and clinical exercise oncology research, we examine the functions of exercise in cancer and its underlying mechanisms. In addition to reducing the incidence of cancer, exercise can enhance the efficacy of certain types of approved anticancer treatments (e.g., targeted therapy, immunotherapy, and radiotherapy) and reduce the symptoms/side effects of cancer and its treatment (e.g., fatigue, cancer cachexia, cognitive impairment, and depression). The mechanisms mediating these effects include the regulation of intratumoral angiogenesis, myokines, adipokines and their associated pathways, cancer metabolism, and anticancer immunity. Cancer rehabilitation guidelines advise cancer survivors to perform exercises. Many ongoing clinical trials have investigated the effects and mechanisms of exercise in cancer. This review supports the prescription of exercise for cancer prevention to sensitize cancer to anticancer therapy and manage associated symptoms and side effects after cancer diagnosis.

Exploring the potential of UAV hyperspectral image for estimating soil salinity: Effects of optimal band combination algorithm and random forest.

Hyperspectral remote sensing by unmanned aerial vehicle (UAV) is an important technical tool for rapid, accurate, and real-time monitoring of soil salinity in arid zone agroecosystems. However, the key to effective soil salinity (electrical conductivity, EC) prediction by UAV visible and near-infrared (Vis-NIR) spectroscopy depends on the selection of effective features selection techniques and robust prediction characteristics algorithms. Therefore, in this study, two advanced feature selection methods and two commonly used modeling methods were applied to predict and characterize the spatial patterns of soil salinity (EC). The aim of this study was to explore the predictive performance of different feature band selection methods and to identify a robust soil salinity mapping strategy. The results demonstrated that standard normal variate (SNV) pre-processing broadened the absorption characteristics of the spectrum. Compared with competitive adaptive reweighted sampling (CARS), the optimal band combination algorithm (OBCA) strengthened the correlation with soil salinity and had a higher variable importance in the modeling. Random forest (RF) was more stable in mapping the spatial pattern of surface soil salinity compared to the partial least squares regression model (PLSR). Our results confirm the effectiveness of OBCA and RF in the developing UAV remote sensing models for surface soil salinity estimation and mapping.

Pleiotropic and nonredundant effects of an auxin importer in Setaria and maize.

Directional transport of auxin is critical for inflorescence and floral development in flowering plants, but the role of auxin influx carriers (AUX1 proteins) has been largely overlooked. Taking advantage of available AUX1 mutants in green millet (Setaria viridis) and maize (Zea mays), we uncover previously unreported aspects of plant development that are affected by auxin influx, including higher order branches in the inflorescence, stigma branch number, glume (floral bract) development, and plant fertility. However, disruption of auxin flux does not affect all parts of the plant, with little obvious effect on inflorescence meristem size, time to flowering, and anther morphology. In double mutant studies in maize, disruptions of ZmAUX1 also affect vegetative development. A green fluorescent protein (GFP)-tagged construct of the Setaria AUX1 protein Sparse Panicle1 (SPP1) under its native promoter showed that SPP1 localizes to the plasma membrane of outer tissue layers in both roots and inflorescences, and accumulates specifically in inflorescence branch meristems, consistent with the mutant phenotype and expected auxin maxima. RNA-seq analysis indicated that most gene expression modules are conserved between mutant and wild-type plants, with only a few hundred genes differentially expressed in spp1 inflorescences. Using clustered regularly interspaced short palindromic repeats (CRISPR)-Cas9 technology, we disrupted SPP1 and the other four AUX1 homologs in S. viridis. SPP1 has a larger effect on inflorescence development than the others, although all contribute to plant height, tiller formation, and leaf and root development. The AUX1 importers are thus not fully redundant in S. viridis. Our detailed phenotypic characterization plus a stable GFP-tagged line offer tools for future dissection of the function of auxin influx proteins.

Effectiveness of eHealth interventions for cancer-related pain, fatigue, and sleep disorders in cancer survivors: A systematic review and meta-analysis of randomized controlled trials.

PURPOSE: To systematically evaluate the effects of Electronic health (eHealth) interventions on fatigue, pain, and sleep disorders in cancer survivors. DESIGN: A systematic review and meta-analysis was conducted. METHODS: Relevant studies were searched from five databases (MEDLINE, Embase, the Cochrane Central Register of Controlled trials, CINAHL, and PsycINFO). The comprehensive literature search was done in December 2020. Only randomized controlled trials (RCTs) that examined the effects of eHealth interventions among cancer survivors were included. FINDINGS: Twenty-five RCTs were included. The meta-analysis showed that eHealth interventions had a positive impact on pain interference (SMD = -0.37, 95% CI: -0.54 to -0.20, p = 0.0001) and sleep disorders (SMD = -0.43, 95% CI: -0.77 to -0.08, p = 0.02) but not on pain severity or fatigue in cancer survivors. The sensitivity and subgroup analyses indicated that the pooled results were robust and reliable. CONCLUSION: eHealth interventions are effective in improving pain interference and sleep disorders in cancer survivors. Additional high-quality RCTs are needed to test the effectiveness of eHealth interventions on fatigue, pain, and sleep disorders in cancer survivors. CLINICAL RELEVANCE: This systematic review and meta-analysis provides evidence to offer effective and sustainable eHealth care for symptom management among cancer survivors.

The CLV3 Homolog in Setaria viridis Selectively Controls Inflorescence Meristem Size.

The CLAVATA pathway controls meristem size during inflorescence development in both eudicots and grasses, and is initiated by peptide ligands encoded by CLV3/ESR-related (CLE) genes. While CLV3 controls all shoot meristems in Arabidopsis, evidence from cereal grasses indicates that different meristem types are regulated by different CLE peptides. The rice peptide FON2 primarily controls the size of the floral meristem, whereas the orthologous peptides CLE7 and CLE14 in maize have their most dramatic effects on inflorescence and branch meristems, hinting at diversification among CLE responses in the grasses. Setaria viridis is more closely related to maize than to rice, so can be used to test whether the maize CLE network can be generalized to all members of subfamily Panicoideae. We used CRISPR-Cas9 in S. viridis to knock out the SvFON2 gene, the closest homolog to CLV3 and FON2. Svfon2 mutants developed larger inflorescence meristems, as in maize, but had normal floral meristems, unlike Osfon2, suggesting a panicoid-specific CLE network. Vegetative traits such as plant height, tiller number and leaf number were not significantly different between mutant and wild type plants, but time to heading was shorter in the mutants. In situ hybridization showed strong expression of Svfon2 in the inflorescence and branch meristems, consistent with the mutant phenotype. Using bioinformatic analysis, we predicted the co-expression network of SvFON2 and its signaling components, which included genes known to control inflorescence architecture in maize as well as genes of unknown function. The similarity between SvFON2 function in Setaria and maize suggests that its developmental specialization in inflorescence meristem control may be shared among panicoid grasses.

FRA1 Kinesin Modulates the Lateral Stability of Cortical Microtubules through Cellulose Synthase-Microtubule Uncoupling Proteins.

Cell wall assembly requires harmonized deposition of cellulose and matrix polysaccharides. Cortical microtubules orient the deposition of cellulose by guiding the trajectory of cellulose synthase complexes. Vesicles containing matrix polysaccharides are thought to be transported by the FRAGILE FIBER1 (FRA1) kinesin to facilitate their secretion along cortical microtubules. The cortical microtubule cytoskeleton thus may provide a platform to coordinate the delivery of cellulose and matrix polysaccharides, but the underlying molecular mechanisms remain unknown. Here, we show that the tail region of the Arabidopsis (Arabidopsis thaliana) FRA1 kinesin physically interacts with cellulose synthase-microtubule uncoupling (CMU) proteins that are important for the microtubule-dependent guidance of cellulose synthase complexes. Interaction with CMUs did not affect microtubule binding or motility of the FRA1 kinesin but differentially affected the protein levels and microtubule localization of CMU1 and CMU2, thus regulating the lateral stability of cortical microtubules. Phosphorylation of the FRA1 tail region inhibited binding to CMUs and consequently reversed the extent of cortical microtubule decoration by CMU1 and CMU2. Genetic experiments demonstrated the significance of this interaction to the growth and reproduction of Arabidopsis plants. We propose that modulation of CMU protein levels and microtubule localization by FRA1 provides a mechanism that stabilizes the sites of deposition of both cellulose and matrix polysaccharides.

Combination of efficient signal pre-processing and optimal band combination algorithm to predict soil organic matter through visible and near-infrared spectra.

Visible and near-infrared (Vis-NIR) spectroscopy is a promising alternative to replace soil physicochemical Analysis to quickly and effectively determine the content of soil organic matter (SOM). However, choosing appropriate pre-processing methods and effective data mining techniques is the essential step in Vis-NIR to improve the quality of spectral data and the accuracy of the model prediction. In this study, nine spectral pre-processing methods and optimal band combination algorithms were introduced to process the spectra and select sensitive spectral parameters. The purpose of this study is to determine the effective pre-processing method and explore the prediction potential of the optimal band combination algorithm. Two hundred thirty-three soil samples were gathered from northwestern Xinjiang, China, and the soil properties and reflectance spectra were measured in the laboratory. The spectra were subjected to nine pre-processing methods, e.g., Savitzky-Golay (SG) smoothing, discrete wavelet transformation (DWT), First (FD) and second (SD) derivatives, multiplicative scatter correction (MSC), standard normal variate and detrend (SNV-DT), continuum removal (CR), correction by the maximum reflectance (CMR) and pseudo-absorbance values and detrend (Abs-DT). The results indicate, the SG proved to be the most effective pre-processing method for SOM in saline soil. The Abs-DT, FD, SD, SNV-DT, MSC, CR, DWT, and CMR led to degrading the prediction performance. Furthermore, the use of SG before further processing can improve the prediction effect, although it is not obvious. The optimal band combination algorithm can derive spectral parameters that have a good correlation with SOM content. Prediction accuracy (RPIQ was 3.058 and 3.045 in independent and cross-validation respectively) and model complexity (latent variables were both 4) from spectral parameter combination were both better than that from full-spectrum data. In summary, the combination of SG and the optimal band combination algorithm can improve the prediction accuracy of SOM in saline soil.

Assessing Soil Organic Matter Content in a Coal Mining Area through Spectral Variables of Different Numbers of Dimensions.

Soil organic matter (SOM) is a crucial indicator for evaluating soil quality and an important component of soil carbon pools, which play a vital role in terrestrial ecosystems. Rapid, non-destructive and accurate monitoring of SOM content is of great significance for the environmental management and ecological restoration of mining areas. Visible-near-infrared (Vis-NIR) spectroscopy has proven its applicability in estimating SOM over the years. In this study, 168 soil samples were collected from the Zhundong coal field of Xinjiang Province, Northwest China. The SOM content (g kg-1) was determined by the potassium dichromate external heating method and the soil reflectance spectra were measured by the spectrometer. Two spectral feature extraction strategies, namely, principal component analysis (PCA) and the optimal band combination algorithm, were introduced to choose spectral variables. Linear models and random forests (RF) were used for predictive models. The coefficient of determination (R2), root mean square error (RMSE), and the ratio of the performance to the interquartile distance (RPIQ) were used to evaluate the predictive performance of the model. The results indicated that the variables (2DI and 3DI) derived from the optimal band combination algorithm outperformed the PCA variables (1DV) regardless of whether linear or RF models were used. An inherent gap exists between 2DI and 3DI, and the performance of 2DI is significantly poorer than that of 3DI. The accuracy of the prediction model increases with the increasing number of spectral variable dimensions (in the following order: 1DV < 2DI < 3DI). This study proves that the 3DI is the first choice for the optimal band combination algorithm to derive sensitive parameters related to SOM in the coal mining area. Furthermore, the optimal band combination algorithm can be applied to hyperspectral or multispectral images and to convert the spectral response into image pixels, which may be helpful for a soil property spatial distribution map.

A Dynamic Co-expression Map of Early Inflorescence Development in Setaria viridis Provides a Resource for Gene Discovery and Comparative Genomics.

The morphological and functional diversity of plant form is governed by dynamic gene regulatory networks. In cereal crops, grain and/or pollen-bearing inflorescences exhibit vast architectural diversity and developmental complexity, yet the underlying genetic framework is only partly known. Setaria viridis is a small, rapidly growing grass species in the subfamily Panicoideae, a group that includes economically important cereal crops such as maize and sorghum. The S. viridis inflorescence displays complex branching patterns, but its early development is similar to that of other panicoid grasses, and thus is an ideal model for studying inflorescence architecture. Here we report a detailed transcriptional resource that captures dynamic transitions across six sequential stages of S. viridis inflorescence development, from reproductive onset to floral organ differentiation. Co-expression analyses identified stage-specific signatures of development, which include homologs of previously known developmental genes from maize and rice, suites of transcription factors and gene family members, and genes of unknown function. This spatiotemporal co-expression map and associated analyses provide a foundation for gene discovery in S. viridis inflorescence development, and a comparative model for exploring related architectural features in agronomically important cereals.

Importin-ß Directly Regulates the Motor Activity and Turnover of a Kinesin-4.

Spatiotemporal regulation of kinesins is essential for microtubule-dependent intracellular transport. In plants, cell wall deposition depends on the FRA1 kinesin, whose abundance and motility are tightly controlled to match cellular growth rate. Here, we show that an importin-ß, IMB4, regulates FRA1 activity in a developmental manner. IMB4 physically interacts with a PY motif in the FRA1 motor domain and inhibits its motility by preventing microtubule binding, while also protecting FRA1 against proteasome-mediated degradation, thus providing a mechanism to couple the motility and stability of FRA1. This regulatory mechanism is likely to be broadly applicable, based on the conservation of the PY motif in the motor domains of plant and animal kinesins and the direct interaction of multiple plant kinesins with IMB4. Together, our data establish IMB4 as a multi-functional regulator of FRA1 and reveal a mechanism for how plants control the magnitude of cargo transport needed for cell wall assembly.

Setaria Comes of Age: Meeting Report on the Second International Setaria Genetics Conference.

Setaria viridis is an emerging model for cereal and bioenergy grasses because of its short stature, rapid life cycle and expanding genetic and genomic toolkits. Its close phylogenetic relationship with economically important crops such as maize and sorghum positions Setaria as an ideal model system for accelerating discovery and characterization of crop genes that control agronomically important traits. The Second International Setaria Genetics Conference was held on March 6-8, 2017 at the Donald Danforth Plant Science Center, St. Louis, MO, United States to discuss recent technological breakthroughs and research directions in Setaria (presentation abstracts can be downloaded at https://www.brutnelllab.org/setaria). Here, we highlight topics presented in the conference including inflorescence architecture, C4 photosynthesis and abiotic stress. Genetic and genomic toolsets including germplasm, mutant populations, transformation and gene editing technologies are also discussed. Since the last meeting in 2014, the Setaria community has matured greatly in the quality of research being conducted. Outreach and increased communication with maize and other plant communities will allow broader adoption of Setaria as a model system to translate fundamental discovery research to crop improvement.

Sparse panicle1 is required for inflorescence development in Setaria viridis and maize.

Setaria viridis is a rapid-life-cycle model panicoid grass. To identify genes that may contribute to inflorescence architecture and thus have the potential to influence grain yield in related crops such as maize, we conducted an N-nitroso-N-methylurea (NMU) mutagenesis of S. viridis and screened for visible inflorescence mutant phenotypes. Of the approximately 2,700 M2 families screened, we identified four recessive sparse panicle mutants (spp1-spp4) characterized by reduced and uneven branching of the inflorescence. To identify the gene underlying the sparse panicle1 (spp1) phenotype, we performed bulked segregant analysis and deep sequencing to fine map it to an approximately 1 Mb interval. Within this interval, we identified disruptive mutations in two genes. Complementation tests between spp1 and spp3 revealed they were allelic, and deep sequencing of spp3 identified an independent disruptive mutation in SvAUX1 (AUXIN1), one of the two genes in the ∼1 Mb interval and the only gene disruption shared between spp1 and spp3. SvAUX1 was found to affect both inflorescence development and root gravitropism in S. viridis. A search for orthologous mutant alleles in maize confirmed a very similar role of ZmAUX1 in maize, which highlights the utility of S. viridis in accelerating functional genomic studies in maize.

Optimization of Phenotyping Assays for the Model Monocot Setaria viridis.

Setaria viridis (green foxtail) is an important model plant for the study of C4 photosynthesis in panicoid grasses, and is fast emerging as a system of choice for the study of plant development, domestication, abiotic stress responses and evolution. Basic research findings in Setaria are expected to advance research not only in this species and its close relative S. italica (foxtail millet), but also in other panicoid grasses, many of which are important food or bioenergy crops. Here we report on the standardization of multiple growth and development assays for S. viridis under controlled conditions, and in response to several phytohormones and abiotic stresses. We optimized these assays at three different stages of the plant's life: seed germination and post-germination growth using agar plate-based assays, early seedling growth and development using germination pouch-based assays, and adult plant growth and development under environmentally controlled growth chambers and greenhouses. These assays will be useful for the community to perform large scale phenotyping analyses, mutant screens, comparative physiological analysis, and functional characterization of novel genes of Setaria or other related agricultural crops. Precise description of various growth conditions, effective treatment conditions and description of the resultant phenotypes will help expand the use of S. viridis as an effective model system.

Comprehensive identification and clustering of CLV3/ESR-related (CLE) genes in plants finds groups with potentially shared function.

CLV3/ESR (CLE) proteins are important signaling peptides in plants. The short CLE peptide (12-13 amino acids) is cleaved from a larger pre-propeptide and functions as an extracellular ligand. The CLE family is large and has resisted attempts at classification because the CLE domain is too short for reliable phylogenetic analysis and the pre-propeptide is too variable. We used a model-based search for CLE domains from 57 plant genomes and used the entire pre-propeptide for comprehensive clustering analysis. In total, 1628 CLE genes were identified in land plants, with none recognizable from green algae. These CLEs form 12 groups within which CLE domains are largely conserved and pre-propeptides can be aligned. Most clusters contain sequences from monocots, eudicots and Amborella trichopoda, with sequences from Picea abies, Selaginella moellendorffii and Physcomitrella patens scattered in some clusters. We easily identified previously known clusters involved in vascular differentiation and nodulation. In addition, we found a number of discrete groups whose function remains poorly characterized. Available data indicate that CLE proteins within a cluster are likely to share function, whereas those from different clusters play at least partially different roles. Our analysis provides a foundation for future evolutionary and functional studies.

The fragile Fiber1 kinesin contributes to cortical microtubule-mediated trafficking of cell wall components.

The cell wall consists of cellulose microfibrils embedded within a matrix of hemicellulose and pectin. Cellulose microfibrils are synthesized at the plasma membrane, whereas matrix polysaccharides are synthesized in the Golgi apparatus and secreted. The trafficking of vesicles containing cell wall components is thought to depend on actin-myosin. Here, we implicate microtubules in this process through studies of the kinesin-4 family member, Fragile Fiber1 (FRA1). In an fra1-5 knockout mutant, the expansion rate of the inflorescence stem is halved compared with the wild type along with the thickness of both primary and secondary cell walls. Nevertheless, cell walls in fra1-5 have an essentially unaltered composition and ultrastructure. A functional triple green fluorescent protein-tagged FRA1 fusion protein moves processively along cortical microtubules, and its abundance and motile density correlate with growth rate. Motility of FRA1 and cellulose synthase complexes is independent, indicating that FRA1 is not directly involved in cellulose biosynthesis; however, the secretion rate of fucose-alkyne-labeled pectin is greatly decreased in fra1-5, and the mutant has Golgi bodies with fewer cisternae and enlarged vesicles. Based on our results, we propose that FRA1 contributes to cell wall production by transporting Golgi-derived vesicles along cortical microtubules for secretion.

Functions of the Arabidopsis kinesin superfamily of microtubule-based motor proteins.

Plants possess a large number of microtubule-based kinesin motor proteins. While the kinesin-2, 3, 9, and 11 families are absent from land plants, the kinesin-7 and 14 families are greatly expanded. In addition, some kinesins are specifically present only in land plants. The distinctive inventory of plant kinesins suggests that kinesins have evolved to perform specialized functions in plants. Plants assemble unique microtubule arrays during their cell cycle, including the interphase cortical microtubule array, preprophase band, anastral spindle and phragmoplast. In this review, we explore the functions of plant kinesins from a microtubule array viewpoint, focusing mainly on Arabidopsis kinesins. We emphasize the conserved and novel functions of plant kinesins in the organization and function of the different microtubule arrays.