Infochemical-mediated preference behavior of the maize weevil, Sitophilus zeamais Motschulsky, when searching for its hosts

Behavioral responses of S. zeamais to odours from pulverized wheat, brown rice, sorghum, buckwheat, peanut and cork were compared in a Y-tube-olfactometerbioassay. Results showed that both sexes responded to host volatiles and males were more sensitive than females. The strongest responses to grains of wheat and brown rice were found, and insects reared on these were dramatically heavier than on other tested materials (grain sorghum, buckwheat, peanut and cork). Multiple-choices tests, in which volatiles from males that were removed from the wheat within different minutes were simultaneously presented in the chamber, were used to study whether males can release aggregation pheromone if not on the grain. The pheromone was released by males within about 13 minutes after removal from the grains. Responses to pheromones produced by males were skewed toward females although both sexes were attracted. Both sexes responded most strongly to the odour source comprising pheromone with host volatiles

Chinese Discourse Markers in Oral Speech of Mainland Mandarin Speakers

The present paper investigates the frequency and functions of Chinese discourse markers in oral speech of native Chinese speakers from mainland China. Most of the previous studies on Chinese discourse markers examine the speech of Mandarin speakers from Taiwan. Data for the study were gathered using individual sociolinguistic interviews. The native Chinese speakers were ten graduate students at an American university originally from mainland China. Fourteen discourse markers are identified in my data. Each marker is described when it is used as a DM in the data, and its textual and/or interpersonal functions are further analyzed. All the discourse markers used by the participants are ranked by the order of their frequency as well. 1

Characterization and mapping of a spotted leaf mutant in rice (Oryza sativa)

Spotted leaf mutant belongs to a class of mutants that can produce necrotic lesions spontaneously in plants without any attack by pathogens. These mutants have no beneficial effect on plant productivity but provide a unique opportunity to study programmed cell death in plant defense responses. A novel rice spotted leaf mutant (spl30) was isolated through low-energy heavy ion irradiation. Lesion expression was sensitive to light and humidity. The spl30 mutant caused a decrease in chlorophyll and soluble protein content, with marked accumulation of reactive oxygen species (ROS) around the lesions. In addition, the spl30 mutant significantly enhanced resistance to rice bacterial blight (X. oryzae pv. oryzae) from China (C1-C7). The use of SSR markers showed that the spl30 gene was located between markers XSN2 and XSN4. The genetic distance between the spl30 gene and XSN2 and between spl30 and XSN4 was 1.7 cM and 0.2 cM, respectively. The spl30 gene is a new gene involved in lesion production and may be related to programmed cell death in rice. The ability of this mutant to confer broad resistance to bacterial blight provides a model for studying the interaction between plants and pathogenic bacteria

OsSND2, a NAC family transcription factor, is involved in secondary cell wall biosynthesis through regulating MYBs expression in rice

Abstract Background As one of the most important staple food crops, rice produces huge agronomic biomass residues that contain lots of secondary cell walls (SCWs) comprising cellulose, hemicelluloses and lignin. The transcriptional regulation mechanism underlying SCWs biosynthesis remains elusive. Results In this study, we isolated a NAC family transcription factor (TF), OsSND2 through yeast one-hybrid screening using the secondary wall NAC-binding element (SNBE) on the promoter region of OsMYB61 which is known transcription factor for regulation of SCWs biosynthesis as bait. We used an electrophoretic mobility shift assay (EMSA) and chromatin immunoprecipitation analysis (ChIP) to further confirm that OsSND2 can directly bind to the promoter of OsMYB61 both in vitro and in vivo. OsSND2, a close homolog of AtSND2, is localized in the nucleus and has transcriptional activation activity. Expression pattern analysis indicated that OsSND2 was mainly expressed in internodes and panicles. Overexpression of OsSND2 resulted in rolled leaf, increased cellulose content and up-regulated expression of SCWs related genes. The knockout of OsSND2 using CRISPR/Cas9 system decreased cellulose content and down-regulated the expression of SCWs related genes. Furthermore, OsSND2 can also directly bind to the promoters of other MYB family TFs by transactivation analysis in yeast cells and rice protoplasts. Altogether, our findings suggest that OsSND2 may function as a master regulator to mediate SCWs biosynthesis. Conclusion OsSND2 was identified as a positive regulator of cellulose biosynthesis in rice. An increase in the expression level of this gene can improve the SCWs cellulose content. Therefore, the study of the function of OsSND2 can provide a strategy for manipulating plant biomass production

Behavior, Characteristics and Sources of Microplastics in Tea

Microplastics have become a widespread environmental concern because they are found in most tested places, including the air we breathe and the food and beverages we consume. To explore the current status of microplastic pollution and future research trends in tea, we reviewed the distribution, abundance, shape, size and sources of microplastics in tea. Microplastics are plastic particles that are 5 mm in diameter or less. Those found in tea and tea gardens originate from agricultural plastic films, plastic packaging of products and tools used in tea production, organic fertilizers, even atmospheric deposition. The microplastics in tea gardens are typically fragments and fibers, mainly composed of polyethylene, polypropylene and polyethylene terephthalate. The prevention and control of microplastics in tea planting, tea processing and packaging should be strengthened, and reduce the input of products containing microplastics. Future research on microplastic detection methods in tea and determination of safety thresholds should be prioritized to provide a reference for microplastic contamination risk, control, and management in tea

The Physiology of Postharvest Tea (Camellia sinensis) Leaves, According to Metabolic Phenotypes and Gene Expression Analysis

Proper postharvest storage preserves horticultural products, including tea, until they can be processed. However, few studies have focused on the physiology of ripening and senescence during postharvest storage, which affects the flavor and quality of tea. In this study, physiological and biochemical indexes of the leaves of tea cultivar ‘Yinghong 9′ preserved at a low temperature and high relative humidity (15–18 °C and 85–95%, PTL) were compared to those of leaves stored at ambient conditions (24 ± 2 °C and relative humidity of 65% ± 5%, UTL). Water content, chromatism, chlorophyll fluorescence, and key metabolites (caffeine, theanine, and catechins) were analyzed over a period of 24 h, and volatilized compounds were determined after 24 h. In addition, the expression of key biosynthesis genes for catechin, caffeine, theanine, and terpene were quantified. The results showed that water content, chromatism, and chlorophyll fluorescence of preserved leaves were more similar to fresh tea leaves than unpreserved tea leaves. After 24 h, the content of aroma volatiles and caffeine significantly increased, while theanine decreased in both groups. Multiple catechin monomers showed distinct changes within 24 h, and EGCG was significantly higher in preserved tea. The expression levels of CsFAS and CsTSI were consistent with the content of farnesene and theanine, respectively, but TCS1 and TCS2 expression did not correlate with caffeine content. Principal component analysis considered results from multiple indexes and suggested that the freshness of PTL was superior to that of UTL. Taken together, preservation conditions in postharvest storage caused a series of physiological and metabolic variations of tea leaves, which were different from those of unpreserved tea leaves. Comprehensive evaluation showed that the preservation conditions used in this study were effective at maintaining the freshness of tea leaves for 2–6 h. This study illustrates the metabolic changes that occur in postharvest tea leaves, which will provide a foundation for improvements to postharvest practices for tea leaves

Behavior, Characteristics and Sources of Microplastics in Tea

Microplastics have become a widespread environmental concern because they are found in most tested places, including the air we breathe and the food and beverages we consume. To explore the current status of microplastic pollution and future research trends in tea, we reviewed the distribution, abundance, shape, size and sources of microplastics in tea. Microplastics are plastic particles that are 5 mm in diameter or less. Those found in tea and tea gardens originate from agricultural plastic films, plastic packaging of products and tools used in tea production, organic fertilizers, even atmospheric deposition. The microplastics in tea gardens are typically fragments and fibers, mainly composed of polyethylene, polypropylene and polyethylene terephthalate. The prevention and control of microplastics in tea planting, tea processing and packaging should be strengthened, and reduce the input of products containing microplastics. Future research on microplastic detection methods in tea and determination of safety thresholds should be prioritized to provide a reference for microplastic contamination risk, control, and management in tea

Non-Destructive Discrimination of Sunflower Seeds with Different Internal Mildew Grades by Fusion of Near-Infrared Diffuse Reflectance and Transmittance Spectra Combined with 1D-CNN

Internally mildewed sunflower seeds, which cannot be recognized and discarded based on their appearance, pose a serious risk to human health. Thus, there is a need for a rapid non-destructive mildew grade discrimination method. Currently, few reports are available regarding this process. In this study, a method based on the combination of the near-infrared diffuse reflectance and near-infrared diffuse transmission (NIRr-NIRt) fusion spectra and a one-dimension convolutional neural network (1D-CNN) is proposed. The NIRr-NIRt fusion spectra can provide more complementary and comprehensive information, and therefore better discrimination accuracy, than a single spectrum. The first derivative (FD) preprocessing method could further improve the discrimination effect. By comparison against three conventional machine learning algorithms (artificial neural network (ANN), support vector machine (SVM), and K-nearest neighbor (KNN)), the 1D-CNN model based on the fusion spectra was found to perform the best. The mean prediction accuracy was 2.01%, 5.97%, and 10.55% higher than that of the ANN, SVM, and KNN models, respectively. These results indicate that the CNN model was able to precisely classify the mildew grades with a prediction accuracy of 97.60% and 94.04% for the training and test set, respectively. Thus, this study provides a non-destructive and rapid method for classifying the mildew grade of sunflower seeds with the potential to be applied in the quality control of sunflower seeds

Deletion of the <i>OsLA1</i> Gene Leads to Multi-Tillering and Lazy Phenotypes in Rice

Plant architecture, one of the key factors that determine grain yield in rice, is mainly affected by components such as plant height, tiller number, and panicle morphology. For this paper, we obtained a multi-tillering and lazy mutant from a japonica rice cultivar, Wuyunjing 7 (WYJ7), via treatment with a heavy ion beam. Compared to WYJ7, the mutant showed a significant increase in tiller angle, tiller number, number of primary and secondary branches, and number of grains; however, the plant height and grain thickness of the mutant was significantly decreased. Phenotypic analysis of the F1 hybrids revealed that the multi-tillering and lazy mutant phenotypes were regulated by a recessive gene. The segregation ratio of 1׃3 of the mutant phenotype and the wild-type plant in the F2 population indicated that the former was controlled by a single gene named Multi-Tillering and Lazy 1 (MTL1). Bulked segregant analysis was performed using the individual plants with extremely typical tiller angles in the F2 population. The MTL1 gene was initially mapped within a region of 5.58–17.64 Mb on chromosome 11. By using the F2 segregated population for fine mapping, the MTL1 gene was ultimately fine mapped within the range of 66.67 kb on chromosome 11. The analysis of genes in this region revealed the presence of the previously identified LAZY1 (LA1) gene. Genomic PCR amplification and semi-quantitative RT-PCR assays showed that the LA1 gene could not be amplified and was not expressed, thus indicating that the MTL1 gene might be identical to the LA1 gene. This study suggests that the multi-tillering and lazy mutant phenotypes might be caused by the deletion of LA1 function. This finding can guide further investigations on the functional mechanisms of the LA1 gene, thus enriching the theoretical knowledge of plant architecture in relation to rice