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TRANS-ACTING SIRNA3-derived short interfering RNAs confer cleavage of mRNAs in rice.
Luo, L, Yang, X, Guo, M, Lan, T, Yu, Y, Mo, B, Chen, X, Gao, L, Liu, L
Plant physiology. 2022;(1):347-362
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Abstract
Plant TRANS-ACTING SIRNA3 (TAS3)-derived short interfering RNAs (siRNAs) include tasiR-AUXIN RESPONSE FACTORs (ARFs), which are functionally conserved in targeting ARF genes, and a set of non-tasiR-ARF siRNAs, which have rarely been studied. In this study, TAS3 siRNAs were systematically characterized in rice (Oryza sativa). Small RNA sequencing results showed that an overwhelming majority of TAS3 siRNAs belong to the non-tasiR-ARF group, while tasiR-ARFs occupy a diminutive fraction. Phylogenetic analysis of TAS3 genes across dicot and monocot plants revealed that the siRNA-generating regions were highly conserved in grass species, especially in the Oryzoideae. Target genes were identified for not only tasiR-ARFs but also non-tasiR-ARF siRNAs by analyzing rice Parallel Analysis of RNA Ends datasets, and some of these siRNA-target interactions were experimentally confirmed using tas3 mutants generated by genome editing. Consistent with the de-repression of target genes, phenotypic alterations were observed for mutants in three TAS3 loci in comparison to wild-type rice. The regulatory role of ribosomes in the TAS3 siRNA-target interactions was further revealed by the fact that TAS3 siRNA-mediated target cleavage, in particular tasiR-ARFs targeting ARF2/3/14/15, occurred extensively in rice polysome samples. Altogether, our study sheds light into TAS3 genes in plants and expands our knowledge about rice TAS3 siRNA-target interactions.
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Analysis of four toxic metals in a single rice seed by matrix solid phase dispersion -inductively coupled plasma mass spectrometry.
He, X, Chen, L, Chen, X, Yu, H, Peng, L, Han, B
Scientific reports. 2016;:38472
Abstract
Toxic metals in rice pose great risks to human health. Metal bioaccumulation in rice grains is a criterion of breeding. Rice breeding requires a sensitive method to determine metal content in single rice grains to assist the variety selection. In the present study, four toxic metals of arsenic (As), cadmium (Cd), chromium (Cr) and lead (Pb) in a single rice grain were determined by a simple and rapid method. The developed method is based on matrix solid phase dispersion using multi-wall carbon nanotubes (MWCNTs) as dispersing agent and analyzed by inductively coupled plasma mass spectrometry. The experimental parameters were systematically investigated. The limits of detection (LOD) were 5.0, 0.6, 10 and 2.1 ng g-1 for As, Cd, Cr, and Pb, respectively, with relative standard deviations (n = 6) of <7.7%, demonstrating the good sensitivity and precision of the method. The results of 30 real world rice samples analyzed by this method agreed well with those obtained by the standard microwave digestion. The amount of sample required was reduced approximately 100 fold in comparison with the microwave digestion. The method has a high application potential for other sample matrices and elements with high sensitivity and sample throughput.
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Association of arsenic with nutrient elements in rice plants.
Duan, G, Liu, W, Chen, X, Hu, Y, Zhu, Y
Metallomics : integrated biometal science. 2013;(7):784-92
Abstract
Rice is the main cereal crop that feeds half of the world's population, and two thirds of the Chinese population. Arsenic (As) contamination in paddy soil and irrigation water elevates As concentration in rice grains, thus rice consumption is an important As intake route for populations in south and south-east Asia, where rice is the staple food. In addition to direct toxicity of As to human, As may limit the accumulation of micro-nutrients in rice grains, such as selenium (Se) and zinc (Zn). These micro-nutrients are essential for humans, while mineral deficiencies, especially iron (Fe) and Zn, are prevalent in China. Therefore, it is important to understand the interactions between As and micro-nutrients in rice plants, which is the principal source of these nutrients for people on rice diets. In addition, during the processes of As uptake, translocation and transformation, the status of macro-nutrients (e.g. silicon (Si), phosphors (P), sulfur (S)) are important factors affecting As dynamics in soil-plant systems and As accumulation in rice grains. Recently, synchrotron-based spectroscopic techniques have been applied to map the distribution of As and nutrient elements in rice plants, which will aid to understand how As are accumulated, complexed and transported within plants. This paper reviews the interactions between As and macro-nutrients, as well as micro-nutrients in rice plants.
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Substituting white rice with brown rice for 16 weeks does not substantially affect metabolic risk factors in middle-aged Chinese men and women with diabetes or a high risk for diabetes.
Zhang, G, Pan, A, Zong, G, Yu, Z, Wu, H, Chen, X, Tang, L, Feng, Y, Zhou, H, Chen, X, et al
The Journal of nutrition. 2011;(9):1685-90
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Abstract
Epidemiologic studies have suggested that higher consumption of white rice (WR) is associated with increased risk for type 2 diabetes mellitus. However, it is unclear whether substituting brown rice (BR) for WR can improve metabolic risk factors. A total of 202 middle-aged adults with diabetes or a high risk for diabetes were randomly assigned to a WR (n = 101) or BR group (n = 101) and consumed the rice ad libitum for 16 wk. Metabolic risk markers, including BMI, waist circumference, blood pressure, glycated hemoglobin, and serum lipid, glucose, and insulin concentrations were measured before and after the intervention. Over the course of the intervention, no between-group differences were found for any markers except the serum LDL cholesterol concentration, which decreased more in the WR group compared to the BR group (P = 0.02). However, this effect was observed only among participants with diabetes (n = 47). The reversion rate of reduced serum HDL cholesterol was marginally higher in the BR group (14.9%) than in the WR group (6.9%) (P = 0.07). Among participants with diabetes, a greater reduction in diastolic blood pressure was observed in the BR group compared to the WR group (P = 0.02). Our study suggests that incorporating BR into the daily diet for 16 wk did not substantially improve metabolic risk factors. Further studies with larger sample sizes, longer durations of follow-up, and different varieties of rice are needed to carefully examine the role of BR in the prevention and management of diabetes.
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Study of rice pollen grains by multispectral imaging microscopy.
Hu, Y, Wu, Q, Liu, S, Wei, L, Chen, X, Yan, Z, Yu, J, Zeng, L, Ding, Y
Microscopy research and technique. 2005;(6):335-46
Abstract
Cellular images obtained by light microscopy have been analyzed qualitatively, but there is still a lack of quantitative information about the variations in cellular metabolism of selective substances. A new approach using the multispectral imaging microscope (MIM) to observe rice (Oryza sativa L.) pollen grains is reported. A liquid crystal tunable filter device was used for wavelength selection from 400 to 720 nm and a cooled two-dimensional monochrome charge coupled device for image detection. Rice pollen were stained respectively by acetocarmine, Coomassie blue, or iodine potassium-iodine, and then imaged by MIM. The images were processed by the WuDa Image Analysis System 2003 (computer software), and the transmittance spectra for pollen grain images were obtained. The statistical analysis of the transmittance data showed that the macromolecular amount (nucleic acid, protein, starch) of male-sterile line (MSL) pollen grains was less than those of the fertility-maintaining line (FML). For instance there was a significantly lower nucleic acid content in the MSL than in the FML pollen. The results revealed that pollen abortion was directly related to the diminution of intracellular substances for metabolism. Consequently, we have established a quantitative criterion to determine pollen sterility. Comparing the spectra features of the FML with the MSL, we found that certain spectra features can be used to identify various types of abortion pollens and the deficient cytoplasm of male-sterile rice. Our experimental results offer the first quantitative understanding for evaluating cell morphological structure correlated with cellular physiological status.