Xuezhikang alleviates lipid accumulation via AMPK activation in hepatocellular steatosis model

Abstract Xuezhikang (XZK) is an extract of Chinese red yeast rice. It has multiple protective effects in cardiovascular systems. However, the underlying mechanism by which XZK affects free fatty acid (FFA)-induced lipogenesis in hepatocellular steatosis model is still unknown. Herein, we investigated this mechanism in HepG2 cells. The HepG2 cells were treated with palmitate acid (PA) to induce lipogenesis. Then the PA-induced HepG2 cells were subsequently treated with XZK. After 24 h of treatment, we determined the intracellular triglyceride (TG) contents and average areas of lipid droplets. To study the involvement of AMPK signaling pathway, we pre-treated the PA-induced HepG2 cells with Compound C, an AMPK inhibitor, before XZK treatment. Expressions of p-AMPK and AMPK were determined by Western blot. The results showed that XZK decreased TG content and lipid accumulation in hepatocellular steatosis model. Compound C abolished the effects of XZK. These results demonstrated for the first time that XZK protects hepatocytes against lipid accumulation induced by free fatty acids. Its effects may be mediated by the activation of AMPK pathway.

Microstructure investigation of plant architecture with X-ray microscopy.

In recent years, the plant morphology has been well studied by multiple approaches at cellular and subcellular levels. Two-dimensional (2D) microscopy techniques offer imaging of plant structures on a wide range of magnifications for researchers. However, subcellular imaging is still challenging in plant tissues like roots and seeds. Here we use a three-dimensional (3D) imaging technology based on the X-ray microscope (XRM) and analyze several plant tissues from different plant species. The XRM provides new insights into plant structures using non-destructive imaging at high-resolution and high contrast. We also utilized a workflow aiming to acquire accurate and high-quality images in the context of the whole specimen. Multiple plant samples including rice, tobacco, Arabidopsis and maize were used to display the differences of phenotypes. Our work indicates that the XRM is a powerful tool to investigate plant microstructure in high-resolution scale. Our work also provides evidence that evaluate and quantify tissue specific differences for a range of plant species. We also characterize novel plant tissue phenotypes by the XRM, such as seeds in Arabidopsis, and utilize them for novel observation measurement. Our work represents an evaluated spatial and temporal resolution solution on seed observation and screening.

ABC transporter OsABCG18 controls the shootward transport of cytokinins and grain yield in rice.

Cytokinins are one of the most important phytohormones and play essential roles in multiple life processes in planta. Root-derived cytokinins are transported to the shoots via long-distance transport. The mechanisms of long-distance transport of root-derived cytokinins remain to be demonstrated. In this study, we report that OsABCG18, a half-size ATP-binding cassette transporter from rice (Oryza sativa L.), is essential for the long-distance transport of root-derived cytokinins. OsABCG18 encodes a plasma membrane protein and is primarily expressed in the vascular tissues of the root, stem, and leaf midribs. Cytokinin profiling, as well as [14C]trans-zeatin tracer, and xylem sap assays, demonstrated that the shootward transport of root-derived cytokinins was significantly suppressed in the osabcg18 mutants. Transport assays in tobacco (Nicotiana benthamiana) indicated that OsABCG18 exhibited efflux transport activities for various substrates of cytokinins. While the mutation reduced root-derived cytokinins in the shoot and grain yield, overexpression of OsABCG18 significantly increased cytokinins in the shoot and improved grain yield. The findings for OsABCG18 as a transporter for long-distance transport of cytokinin provide new insights into the cytokinin transport mechanism and a novel strategy to increase cytokinins in the shoot and promote grain yield.

Selenium downregulates auxin and ethylene biosynthesis in rice seedlings to modify primary metabolism and root architecture.

MAIN CONCLUSION: Selenium modulates the formation of primary and lateral roots through alterations in auxin and ethylene, leading to new patterns of root architecture in rice seedlings. Selenium (Se) at low concentrations can control root growth through interaction with hormone biosynthesis. Auxin and ethylene have been shown to control the root architecture, with most of the information obtained from the eudicots such Arabidopsis and Nicotiana tabacum. Here, we presented the effects of Se on auxin and ethylene pathways and examined their impact on primary metabolism and root system architecture in rice (Oryza sativa L.) seedlings. Se treatment increased elongation of primary root, but decreased the number and length of lateral roots. Se led to decreased expression of genes associated with the biosynthesis of auxin and ethylene, concomitantly with reduced production of these hormones by the roots. Moreover, Se decreased the abundance of transcripts encoding auxin transport proteins. Indole-3-acetic acid (IAA) treatment overrode the repressive effect of Se on lateral root growth. The ethylene synthesis inhibitor L-α-(2-aminoethoxyvinyl)-glycine (AVG) increased elongation of primary root, whereas the ethylene precursor 1-aminocyclopropane-1-carboxylic acid (ACC) resulted in the opposite effect. Soluble sugars accumulate in roots of rice seedlings under Se treatment. Thus, Se modulates the formation of primary and lateral roots through alterations in auxin and ethylene, leading to new patterns of root architecture in rice seedlings.

Effect of exogenous abscisic acid on morphology, growth and nutrient uptake of rice (Oryza sativa) roots under simulated acid rain stress.

MAIN CONCLUSION: Application of proper ABA can improve acid tolerance of rice roots by balancing endogenous hormones and promoting nutrient uptake. Abscisic acid (ABA) has an important signaling role in enhancing plant tolerance to environmental stress. To alleviate the inhibition on plant growth and productivity caused by acid rain, it is crucial to clarify the regulating mechanism of ABA on adaptation of plants to acid rain. Here, we studied the effects of exogenously applied ABA on nutrients uptake of rice roots under simulated acid rain (SAR) stress from physiological, biochemical and molecular aspects. Compared to the single SAR treatment (pH 4.5 or 3.5), exogenous 10 µM ABA alleviated the SAR-induced inhibition of root growth by balancing endogenous hormones (abscisic acid, indole-3-acetic acid, gibberellic acid and zeatin), promoting nutrient uptake (nitrate, P, K and Mg) in rice roots, and increasing the activity of the plasma membrane H+-ATPase by up-regulating expression levels of genes (OSA2, OSA4, OSA9 and OSA10). However, exogenous 100 µM ABA exacerbated the SAR-caused inhibition of root growth by disrupting the balance of endogenous hormones, and inhibiting nutrient uptake (nitrate, P, K, Ca and Mg) through decreasing the activity of the plasma membrane H+-ATPase. These results indicate that proper concentration of exogenous ABA could enhance tolerance of rice roots to SAR stress by promoting nutrients uptake and balancing endogenous hormones.

Mechanistic understanding of iron toxicity tolerance in contrasting rice varieties from Africa: 1. Morpho-physiological and biochemical responses.

Iron (Fe) is a fundamental element involved in various plant metabolic processes. However, when Fe uptake is excessive, it becomes toxic to the plant and disrupts cellular homeostasis. The aim of this study was to determine the physiological and biochemical mechanisms underlying tolerance to Fe toxicity in contrasting rice varieties adapted to African environments. Four varieties (CK801 and Suakoko 8 (tolerant), Supa and IR64 (sensitive)) selected from our previous work were analysed in more detail, and the first part of this study reports morphological, physiological and biochemical responses induced by Fe toxicity in these four varieties. Morphological (shoot length, root length, number of lateral roots), physiological (photosynthesis rate, stomatal conductance, transpiration rate, fluorescence, relative water content and cell membrane stability) and biochemical (tissue Fe, chlorophyll pigments, soluble sugars, protein and starch) traits were measured, as appropriate, on both shoot and root tissues and at different time points during the stress period. Fe toxicity significantly (P≤0.05) reduced growth and metabolism of all the four varieties. Tolerant varieties showed more lateral roots than the sensitive ones, under Fe toxic conditions as well as higher photosynthesis rate, chlorophyll content and cell membrane stability. Strong dilution of Fe concentration in cells was identified, as one of the additional tolerance mechanisms used by CK801, whereas Suakoko 8 mainly used strong mobilisation of carbohydrates at the early stage of the stress period to anticipate metabolite shortage. Traits associated with Fe toxicity tolerance in this study could be specifically targeted in trait-based breeding programs of superior lowland rice varieties tolerant of Fe toxicity.

Non-canonical regulation of SPL transcription factors by a human OTUB1-like deubiquitinase defines a new plant type rice associated with higher grain yield.

Achieving increased grain productivity has long been the overriding focus of cereal breeding programs. The ideotype approach has been used to improve rice yield potential at the International Rice Research Institute and in China. However, the genetic basis of yield-related traits in rice remains unclear. Here, we show that a major quantitative trait locus, qNPT1, acts through the determination of a 'new plant type' (NPT) architecture characterized by fewer tillers, sturdier culms and larger panicles, and it encodes a deubiquitinating enzyme with homology to human OTUB1. Downregulation of OsOTUB1 enhances meristematic activity, resulting in reduced tiller number, increased grain number, enhanced grain weight and a consequent increase in grain yield in rice. Unlike human OTUB1, OsOTUB1 can cleave both K48- and K63-linked polyubiquitin. OsOTUB1 interacts with the E2 ubiquitin-conjugating protein OsUBC13 and the squamosa promoter-binding protein-like transcription factor OsSPL14. OsOTUB1 and OsSPL14 share common target genes, and their physical interaction limits K63-linked ubiquitination (K63Ub) of OsSPL14, which in turn promotes K48Ub-dependent proteasomal degradation of OsSPL14. Conversely, loss-of-function of OsOTUB1 is correlated with the accumulation of high levels of OsSPL14, resulting in the NPT architecture. We also demonstrated that pyramiding of high-yielding npt1 and dep1-1 alleles provides a new strategy for increasing rice yield potential above what is currently achievable.

Comparative proteomics of the superior and inferior spikelets at the early grain filling stage in rice cultivars contrast for panicle compactness and ethylene evolution.

The breeding programmes in rice aimed at increasing the number of spikelets per panicle have been accompanied by poor grain filling in the inferior spikelets of large panicle rice, leading to yield disadvantage. The present study attempted to understand the reason for differential grain filling in the inferior and superior spikelets by comparative proteomics considering a compact-panicle rice cultivar Mahalaxmi and a lax-panicle rice cultivar Upahar, which show poor and good grain filling, respectively. An initial study of two rice cultivars for panicle compactness and grain filling revealed an inverse correlation between the two parameters. It was further observed that the panicle compactness in Mahalaxmi was associated with a higher evolution of ethylene by the spikelets, both superior and inferior, compared with the lax-panicle Upahar. The proteomic studies revealed that the superior and inferior spikelets of Mahalaxmi differentially expressed 21 proteins that were also expressed in Upahar. However, in Upahar, only two of these proteins were differentially expressed between the superior and inferior spikelets, indicating that the metabolic activities of the spikelets occupying the superior and inferior positions on the panicle were very different in Mahalaxmi compared with those in Upahar. Among the proteins that were downregulated in the inferior spikelets compared with the superior ones in Mahalaxmi were importin-α, elongation factor 1-ß and cell division control protein 48, which are essential for cell cycle progression and cell division. Low expression of these proteins might inhibit endosperm cell division in the inferior spikelets, limiting their sink capacity and leading to poor grain filling compared to that in the superior spikelets. The poor grain filling in Mahalaxmi may also be a result of the high evolution of ethylene in the inferior spikelets, which is reflected from the observation that these spikelets showed significantly higher expression of S-adenosylmethionine synthase and the gene encoding the enzyme than the superior spikelets in this cultivar, but not in Upahar; S-adenosynlmethionine synthase catalyses the synthesis of S-adenosylmethionine, the precursor of ethylene biosynthesis.

Ethylene-dependent aerenchyma formation in adventitious roots is regulated differently in rice and maize.

In roots of gramineous plants, lysigenous aerenchyma is created by the death and lysis of cortical cells. Rice (Oryza sativa) constitutively forms aerenchyma under aerobic conditions, and its formation is further induced under oxygen-deficient conditions. However, maize (Zea mays) develops aerenchyma only under oxygen-deficient conditions. Ethylene is involved in lysigenous aerenchyma formation. Here, we investigated how ethylene-dependent aerenchyma formation is differently regulated between rice and maize. For this purpose, in rice, we used the reduced culm number1 (rcn1) mutant, in which ethylene biosynthesis is suppressed. Ethylene is converted from 1-aminocyclopropane-1-carboxylic acid (ACC) by the action of ACC oxidase (ACO). We found that OsACO5 was highly expressed in the wild type, but not in rcn1, under aerobic conditions, suggesting that OsACO5 contributes to aerenchyma formation in aerated rice roots. By contrast, the ACO genes in maize roots were weakly expressed under aerobic conditions, and thus ACC treatment did not effectively induce ethylene production or aerenchyma formation, unlike in rice. Aerenchyma formation in rice roots after the initiation of oxygen-deficient conditions was faster and greater than that in maize. These results suggest that the difference in aerenchyma formation in rice and maize is due to their different mechanisms for regulating ethylene biosynthesis.

Biochemical and molecular responses underlying differential arsenic tolerance in rice (Oryza sativa L.).

The arsenic (As) is a toxic element causing major health concern worldwide. Arsenate stress caused no significant reduction in growth parameters and shoot electrolyte leakage but showed increased root arsenate reductase activity along with relatively lower root As content and shoot translocation rate in As-tolerant BRRI 33 than in As-sensitive BRRI 51. It indicates that As inhibition and tolerance mechanisms are driven by root responses. Interestingly, As stress showed consistent decrease in phosphate content and expression of phosphate transporters (OsPT8, OsPT4, OsPHO1;2) under both high and low phosphate conditions in roots of BRRI 33, suggesting that limiting phosphate transport mainly mediated by OsPHO1;2 directs less As accumulation in BRRI 33. Further, BRRI 33 showed simultaneous increase in OsPCS1 (phytochelatin synthase) expression and phytochelatins (PCs) content in roots under As exposure supporting the hypothesis that root As sequestration acts as 'firewall system' in limiting As translocation in shoots. Furthermore, increased CAT, POD, SOD, GR, along with elevated glutathione, methionine, cysteine and proline suggests that strong antioxidant defense plays integral part to As tolerance in BRRI 33. Again, BRRI 33 self-grafts and plants having BRRI 33 rootstock combined with BRRI 51 scion had no adverse effect on morphological parameters but showed reduced As translocation rate, increased root arsenate reductase activity, shoot PC synthesis and root OsPHO1;2 expression due to As stress. It confirms that signal driving As tolerance mechanisms is generated in the roots. These findings can be implemented for As detoxification and As-free transgenic rice production for health safety.

Spikelet-specific variation in ethylene production and constitutive expression of ethylene receptors and signal transducers during grain filling of compact- and lax-panicle rice (Oryza sativa) cultivars.

Grain yields in modern super rice cultivars do not always meet the expectations because many spikelets are located on secondary branches in closely packed homogeneous distribution in these plants, and they do not fill properly. The factors limiting grain filling of such spikelets, especially in the lower panicle branches, are elusive. Two long-duration rice cultivars differing in panicle density, Mahalaxmi (compact) and Upahar (lax), were cultivated in an open field plot. Grain filling, ethylene production and constitutive expression of ethylene receptors and ethylene signal transducers in apical and basal spikelets of the panicle were compared during the early post-anthesis stage, which is the most critical period for grain development. In another experiment, a similar assessment was made for the medium-duration cultivars compact-panicle OR-1918 and lax-panicle Lalat. Grain weight of the apical spikelets was always higher than that of the basal spikelets. This gradient of grain weight was wide in the compact-panicle cultivars and narrow in the lax-panicle cultivars. Compared to apical spikelets, the basal spikelets produced more ethylene at anthesis and retained the capacity for post-anthesis expression of ethylene receptors and ethylene signal transducers longer. High ethylene production enhanced the expression of the RSR1 gene, but reduced expression of the GBSS1 gene. Ethylene inhibited the partitioning of assimilates of developing grains resulting in low starch biosynthesis and high accumulation of soluble carbohydrates. It is concluded that an increase in grain/spikelet density in rice panicles reduces apical dominance to the detriment of grain filling by production of ethylene and/or enhanced perception of the ethylene signal. Ethylene could be a second messenger for apical dominance in grain filling. The manipulation of the ethylene signal would possibly improve rice grain yield.

Iron- and manganese-assisted cadmium tolerance in Oryza sativa L.: lowering of rhizotoxicity next to functional photosynthesis.

MAIN CONCLUSION: Cadmium toxicity is alleviated by iron and manganese supplements because of reduction in cadmium accumulation and upholding of redox regulation that prevent cadmium-inducible damage to root growth and photosynthesis. Cadmium toxicity in Oryza sativa L. MTU 7029 was investigated in the presence of different concentrations of the micronutrients Fe and Mn. It had been observed that these micronutrients reduce Cd uptake and minimize Cd-inducible rhizotoxicity. The photosynthetic electron transport chain, which is the hub of Fe containing metalloproteins, was severely affected by Cd and resulted in reduced bioproductivity under Cd stress. However, exogenous Fe restored the photosynthetic electron transport. Thus, due to the maintenance of the photosynthetic electron transport, the Cd tolerance was improved during Fe supplement. Both antioxidant enzymes and non-enzymatic antioxidant metabolites were found to play important roles in the alleviation of Cd stress under Fe or Mn supplement. It is concluded that the presence of excess Fe and Mn protects rice plants from Cd stress.

Differential expression of GS5 regulates grain size in rice.

Grain weight is a major determinant of grain yield. GS5 is a positive regulator of grain size such that grain width, filling, and weight are correlated with its expression level. Previous work suggested that polymorphisms of GS5 in the promoter region might be responsible for the variation in grain size. In this study, two single nucleotide polymorphisms (SNPs) between the wide-grain allele GS5-1 and the narrow-grain allele GS5-2 in the upstream region of the gene that were responsible for the differential expression in developing young panicles were identified. These two polymorphs altered the responses of the GS5 alleles to abscisic acid (ABA) treatments, resulting in higher expression of GS5-1 than of GS5-2 in developing young panicles. It was also shown that SNPs in light-responsive elements of the promoter altered the response to light induction, leading to higher expression of GS5-2 than GS5-1 in leaves. Enhanced expression of GS5 competitively inhibits the interaction between OsBAK1-7 and OsMSBP1 by occupying the extracellular leucine-rich repeat (LRR) domain of OsBAK1-7, thus preventing OsBAK1-7 from endocytosis caused by interacting with OsMSBP1, providing an explanation for the positive association between grain size and GS5 expression. These results advanced our understanding of the molecular mechanism by which GS5 controls grain size.

Operative photo assimilation associated proteome modulations are critical for iron-dependent cadmium tolerance in Oryza sativa L.

Iron-dependent Cd tolerance in Oryza sativa L. cv 7029 had been explored. Photo assimilatory process such as photosynthesis and nitrogen fixation found to be functional in the presence of excess Fe during Cd stress. Cd-inducible Fe deficiency demonstrated with upregulation of iron uptake gene families such as OsIRT and OsYSL was attributed as foremost reason for retardation of photo assimilation in the course of Cd treatment. Upholding of photo assimilation during Fe supplement was associated with proteome modulations. Monitoring of proteome responses in leaf and root revealed proteins imperative for alleviation of Cd stress. Specifically, proteins that take part in photosynthesis, glucose metabolism, nitrogen fixation, and abiotic stress tolerance played key role in Fe-dependent Cd detoxification. It is concluded that Fe supply help to operate photo assimilation which enable favorable proteome responses of Cd stress tolerance.

Transcriptional profile of genes involved in ascorbate glutathione cycle in senescing leaves for an early senescence leaf (esl) rice mutant.

To clarify the complex relationship between ascorbate-glutathione (AsA-GSH) cycle and H2O2-induced leaf senescence, the genotype-dependent difference in some senescence-related physiological parameters and the transcript levels and the temporal patterns of genes involved in the AsA-GSH cycle during leaf senescence were investigated using two rice genotypes, namely, the early senescence leaf (esl) mutant and its wild type. Meanwhile, the triggering effect of exogenous H2O2 on the expression of OsAPX genes was examined using detached leaves. The results showed that the esl mutant had higher H2O2 level than its wild type at the initial stage of leaf senescence. At transcriptional level, the association of expression of various genes involved in the AsA-GSH cycle with leaf senescence was isoform dependent. For OsAPXs, the transcripts of two cytosolic OsAPX genes (OsAPX1 and OsAPX2), thylakoid-bound OsAPX8, chloroplastic OsAPX7 and peroxisomal OsAPX4 exhibited remarkable genotype-dependent variation in their expression levels and temporal patterns during leaf senescence, there were significantly increasing transcripts of OsAXP1 and OsAPX7, severely repressed transcripts of OsAPX4 and OsAPX8 for the esl rice at the initial leaf senescence. In contrast, the repressing transcript of OsAPX8 was highly sensitive to the increasing H2O2 level in the senescing rice leaves, while higher H2O2 concentration resulted in the enhancing transcripts of two cytosolic OsAPX genes, OsAPX7 transcript was greatly variable with different H2O2 concentrations and incubating duration, suggesting that the different OsAPXs isoforms played a complementary role in perceiving and scavenging H2O2 accumulation at various H2O2 concentrations during leaf senescence. Higher H2O2 level, increased AsA level, higher activities of APX and glutathione reductase (GR), and relatively stable GSH content during the entire sampling period in the leaves of esl mutant implied that a close interrelationship existed between AsA level and APX activity in the ongoing senescence of rice leaves. The GSH supply in rice leaves was not the limiting factor for the efficient maintenance of AsA-GSH cycle, despite the senescence-related change in GR activity between the two rice genotypes.

Cadmium accumulation retard activity of functional components of photo assimilation and growth of rice cultivars amended with vermicompost.

Cadmium (Cd) uptake mediated alterations in functional components of photo assimilation during conversion of cow dung and poultry cast to vermicompost were studied in two Indian rice cultivars; MO 16 and MTU 7029. It was found that higher amount of Cd accumulate in plants grown in soil amended with vermicompost which in turn damaged functional components in photo assimilation. Enhancement of root growth was recognized as reason for Cd accumulation. Metabolic alterations noticed among plants were not taken place during application of raw materials used for vermicomposting such as cow dung and poultry cast amendment. Rice varieties accumulated Cd differentially where MTU 7029 accumulated more Cd compare to MO 16. It was also noticed that existence of negative correlation between zinc status of the plant and Cd accumulation.

Spatio-temporal regulation of the OsHFP gene promoter establishes the involvement of this protein in rice anther development.

Anther development leading to pollen maturation, anther dehiscence and pollen dispersal depends upon the precise timing of programmed cell death (PCD) in specified anther tissues. The PCD necessitates a properly tuned transcriptional regulation of some crucial genes. However, the detailed genetic regulation of this PCD in rice anther is yet to be deciphered. Recently, we have established that the OsHFP, a structurally novel hemopexin fold protein of rice is a flower-specific heme binding protein, and plays a role in chlorophyll degradation. Here, we report the spatio-temporal transcriptional regulation of the OsHFP gene, which is proposed to be involved in anther PCD. The OsHFP was immunodetected in rice anthers, and OsHFP-related proteins were also found to be present in anthers of other monocot (lily) and dicot (tobacco) plant species. Unique cis-acting elements, possibly involved in the activation and anther-specificity of the OsHFP promoter were identified based upon in silico prediction and in planta expression profiling of the reporter gene driven by the OsHFP promoter (2051 bp) and its two deleted versions (1057 bp and 437 bp). The temporal regulation of the OsHFP promoter in different developmental stages of tobacco anther implies the physiological function of this protein in anther PCD.

Concordancia entre analistas de laboratorios de latinoamérica para la determinación de la apariencia de grano de arroz pulido mediante el uso de imágenes digitales

La determinación de la apariencia del grano de arroz es un aspecto clave para evaluar su calidad. Generalmente, este análisis es realizado de manera visual empleando analistas expertos, sin embargo debido a la naturaleza subjetiva de su determinación, los resultados pueden ser divergentes. Con el objetivo de evaluar la concordancia entre analistas de laboratorios latinoamericanos de calidad de arroz en la determinación de la apariencia del grano de arroz pulido con ayuda de imágenes digitalizadas, se realizó un ensayo interlaboratorio con diez analistas e imágenes de 90 granos, capturadas mediante scanner de alta resolución. Los granos fueron clasificados en cuatro categorías incluyendo grano traslúcido, grano yesoso, grano panza blanca y granos dañados. La categorización fue analizada mediante la moda, frecuencia, concordancia relativa y coeficiente de concordancia Kappa. Adicionalmente, se elaboró una galería referencial de imágenes de granos típicos de cada categoría, basada en la frecuencia de modas. Los resultados revelaron un valor de Kappa de 0,49 que corresponde a una reproducibilidad moderada, atribuida a la subjetividad del análisis visual de las imágenes. Los resultados evidencian la necesidad de uniformizar criterios de evaluación entre analistas para mejorar la confiabilidad en la determinación de la apariencia de granos de arroz.

Concordance among analysts from Latin-american laboratories for rice grain appearance determination using a gallery of digital images. The appearance of rice grain is a key aspect in quality determination. Mainly, this analysis is performed by expert analysts through visual observation; however, due to the subjective nature of the analysis, the results may vary among analysts. In order to evaluate the concordance between analysts from Latin-American rice quality laboratories for rice grain appearance through digital images, an inter-laboratory test was performed with ten analysts and images of 90 grains captured with a high resolution scanner. Rice grains were classified in four categories including translucent, chalky, white belly, and damaged grain. Data was categorized using statistic parameters like mode and its frequency, the relative concordance, and the reproducibility parameter kappa. Additionally, a referential image gallery of typical grain for each category was constructed based on mode frequency. Results showed a Kappa value of 0.49, corresponding to a moderate reproducibility, attributable to subjectivity in the visual analysis of grain images. These results reveal the need for standardize the evaluation criteria among analysts to improve the confidence of the determination of rice grain appearance.

Ectopic expression of foxtail millet zip-like gene, SiPf40, in transgenic rice plants causes a pleiotropic phenotype affecting tillering, vascular distribution and root development.

Plant architecture determines grain production in rice (Oryza sativa) and is affected by important agronomic traits such as tillering, plant height, and panicle morphology. Many key genes involved in controlling the initiation and outgrowth of axillary buds, the elongation of stems, and the architecture of inflorescences have been isolated and analyzed. Previous studies have shown that SiPf40, which was identified from a foxtail millet (Setaria italica) immature seed cDNA library, causes extra branches and tillers in SiPf40-transgenic tobacco and foxtail millet, respectively. To reconfirm its function, we generated transgenic rice plants overexpressing SiPf40 under the control of the ubiquitin promoter. SiPf40-overexpressing transgenic plants have a greater tillering number and a wider tiller angle than wild-type plants. Their root architecture is modified by the promotion of lateral root development, and the distribution of xylem and phloem in the vascular bundle is affected. Analysis of hormone levels showed that the ratios of indole-3-acetic acid/zeatin (IAA/ZR) and IAA/gibberellic acid (IAA/GA) decreased in SiPf40-transgenic plants compared with wild-type plants. These findings strongly suggest that SiPf40 plays an important role in plant architecture.

Inhibition of degranulation and cytokine production in bone marrow-derived mast cells by hydrolyzed rice bran.

OBJECTIVE: We investigated the effects of hydrolyzed rice bran (HRB), an arabinoxylan extracted from rice bran, on mast cell degranulation and cytokine production. MATERIALS AND METHODS: HRB was obtained by treating rice bran with an extract obtained from shiitake mushrooms. Bone marrow-derived mast cells (BMMCs) were prepared by culturing bone marrow cells from BALB/c mice in the presence of interleukin-3 and stem cell factor for 4 weeks. BMMCs were pretreated with HRB (0-3 mg/ml) for 30 min and were then antigen activated. RESULTS: Pretreatment of BMMCs with HRB significantly inhibited antigen-induced degranulation and cytokine production (tumor necrosis factor-alpha and interleukin-4) in a dose-dependent manner. HRB also diminished membrane fusion between liposomes in which soluble N-ethyl maleimide-sensitive factor attachment protein receptors were reconstituted. Phosphorylation of RelA and mitogen-activated kinases after antigen stimulation was suppressed by pretreatment of BMMCs with HRB. CONCLUSIONS: These findings suggest that HRB may have an anti-inflammatory effect by inhibiting mast cell degranulation and cytokine production.