Internodes Of Rice Research Articles

Application of soil amendments and paclobutrazol to shorten internode and increase rice yields

This study aims to determine the role of soil amendments, Paclobutrazol (PBZ), and varieties as well as their interactions on the growth and yield of rice. This study used a randomized block design (RBD) factorial split-split plot 3 x 2 x 2 with 3 replicates. The first factor was soil amendments as the main plot which consisted of 3 levels: A1= biochar, A2= compost, A3= mixture of biochar, compost, Mycorrhiza, and Trichoderma. The second factor was the concentration of PBZ in the split plot, which consisted of 2 levels: PBZ1 = 500 ppm, and PBZ2 = 700 ppm. The third factor is the variety as a split-split plot consisting of 2 levels: V1 = Sigupai Abdya, V2 = Tangse. The results showed that soil amendments had a significant effect on grain weight, and yield potential. The best yields are found in 50 g pot−1 of compost. PBZ had a very significant effect on grain weight and yield potential. PBZ at 700 ppm, can shorten rice internodes. Varieties have a very significant effect on grain weight and yield potential. The best growth and yields were found in the treatment of 50 g pot−1 compost with PBZ at a concentration of 700 ppm using the Tangse variety.

Effects of wheat straw returning and potassium application rates on the physicochemical properties and lodging resistance of different stem internodes in direct-seeded rice

1. Bahmaniar M., Ranjbar G., and Ahmadian S., 2007. Effects of N and K applications on agronomic characteristics of two Iranian and landrace rice (Oryza sativa L.) cultivars. Pakistan J. Biol. Sci., 10(6), 880-860. https://doi.org/10.3923/pjbs.2.... CrossRef Google Scholar

Rice DWARF AND LOW-TILLERING and the homeodomain protein OSH15 interact to regulate internode elongation via orchestrating brassinosteroid signaling and metabolism.

Brassinosteroid (BR) phytohormones play crucial roles in regulating internode elongation in rice (Oryza sativa). However, the underlying mechanism remains largely unclear. The dwarf and low-tillering (dlt) mutant is a mild BR-signaling-defective mutant. Here, we identify two dlt enhancers that show more severe shortening of the lower internodes compared to the uppermost internode (IN1). Both mutants carry alleles of ORYZA SATIVA HOMEOBOX 15 (OSH15), the founding gene for dwarf6-type mutants, which have shortened lower internodes but not IN1. Consistent with the mutant phenotype, OSH15 expression is much stronger in lower internodes, particularly in IN2, than IN1. The osh15 single mutants have impaired BR sensitivity accompanied by enhanced BR synthesis in seedlings. DLT physically interacts with OSH15 to co-regulate many genes in seedlings and internodes. OSH15 targets and promotes the expression of the BR receptor gene BR INSENSITIVE1 (OsBRI1), and DLT facilitates this regulation in a dosage-dependent manner. In osh15, dlt, and osh15 dlt, BR levels are higher in seedlings and panicles, but unexpectedly lower in internodes compared with the wild-type. Taken together, our results suggest that DLT interacts with OSH15, which functions in the lower internodes, to modulate rice internode elongation via orchestrating BR signaling and metabolism.

BRITTLE CULM17, a Novel Allele of TAC4, Affects the Mechanical Properties of Rice Plants.

Lodging resistance of rice (Oryza sativa L.) has always been a hot issue in agricultural production. A brittle stem mutant, osbc17, was identified by screening an EMS (Ethylmethane sulfonate) mutant library established in our laboratory. The stem segments and leaves of the mutant were obviously brittle and fragile, with low mechanical strength. Examination of paraffin sections of flag leaf and internode samples indicated that the number of cell layers in mechanical tissue of the mutant was decreased compared with the wild type, Pingtangheinuo, and scanning electron microscopy revealed that the mechanical tissue cell walls of the mutant were thinner. Lignin contents of the internodes of mature-stage rice were significantly lower in the mutant than in the wild type. By the MutMap method, we found candidate gene OsBC17, which was located on rice chromosome 2 and had a 2433 bp long coding sequence encoding a protein sequence of 810 amino acid residues with unknown function. According to LC-MS/MS analysis of intermediate products of the lignin synthesis pathway, the accumulation of caffeyl alcohol in the osbc17 mutant was significantly higher than in Pingtangheinuo. Caffeyl alcohol can be polymerized to the catechyl lignin monomer by laccase ChLAC8; however, ChLAC8 and OsBC17 are not homologous proteins, which suggests that the osbc17 gene is involved in this process by regulating laccase expression.

Chromatin remodeling factors OsYAF9 and OsSWC4 interact to promote internode elongation in rice.

Deposition of H2A.Z and H4 acetylation by SWI2/SNF2-Related 1 Chromatin Remodeling (SWR1) and Nucleosome Acetyltransferase of H4 (NuA4) complexes in specific regulatory regions modulates transcription and development. However, little is known about these complexes in Oryza sativa (rice) development. Here, we reported that OsYAF9 and OsSWC4, two subunits of SWR1 and NuA4 complexes, are involved in rice vegetative and reproductive development. Loss of OsYAF9 resulted in reduced height, fewer tillers, fewer pollen grains, and defects in embryogenesis and seed filling. OsYAF9 directly interacted with OsSWC4 in vitro and in vivo. Loss of OsSWC4 function exhibited defects in pollen germination and failure to generate seeds, whereas knockdown of OsSWC4 resulted in reduced height and fewer tillers. The reduced height caused by OsYAF9 mutation and OsSWC4 knockdown was due to shorter internodes and defects in cell elongation, and this phenotype was rescued with gibberellin (GA) treatment, suggesting that both OsYAF9 and OsSWC4 are involved in the GA biosynthesis pathway. OsSWC4 was directly bound to the AT-rich region of GA biosynthesis genes, which in turn accomplished H2A.Z deposition and H4 acetylation at the GA biosynthesis genes with OsYAF9. Together, our study provides insights into the mechanisms involving OsSWC4 and OsYAF9 forming a protein complex to promote rice internode elongation with H2A.Z deposition and H4 acetylation.

Breaking paths of rice stalks during threshing

During rice threshing, stems are easily broken and usually mixed with the grains, making it difficult for further automatic processing. Thus, in order to improve the efficiency of grain cleaning during harvesting, it is beneficial to reduce the breakages of rice stems. The threshold values of rice stalks in both the transverse and longitudinal directions under tension, compression and bending forces were studied. Based on the real time threshing loads that occur during threshing, the breaking paths of the rice stalks were determined by applying combined loading tests and fracture mechanisms proposed. When subjected to single load, rice stalk is a hard material to break. Tension fracture is the major failure mechanism of the rice internodes that are wrapped with leaf sheath. Combinations of bending & tension or compression & tension can easily break a complete rice stalk or even a cluster of rice straws. Therefore, breaking paths of rice stalks during threshing include the rice stem internodes (with leaf sheath) are easily fractured under the coupling of three-point bending and tension; the stem cores are broken under compression and tension, but the stem nodes are brittle and susceptible to initial damage caused by bending or compression. These findings can help facilitate design of the combine harvesters by assisting with the design of mechanisms that can reduce rice stem breakages during threshing and improve grain stalk separation.

Identification and genetic analysis of qCL1.2, a novel allele of the \u201cgreen revolution\u201d gene SD1 from wild rice (Oryza rufipogon) that enhances plant height

BackgroundThe exploitation of novel alleles from wild rice that were lost during rice cultivation could be very important for rice breeding and evolutionary studies. Plant height (PH) was a target of artificial selection during rice domestication and is still a target of modern breeding. The “green revolution” gene semi-dwarf 1 (SD1) were well documented and used in the past decades, allele from wild rice could provide new insights into the functions and evolution of this gene.ResultsWe identified a PH-related quantitative trait locus, qCL1.2,from wild riceusing a set of chromosome segment substitution lines. qCL1.2encodesa novel allele of SD1 gene. The wild allele of SD1 is a dominant locus that can significantly promote rice internode length by regulating the expression levels of genes involved in gibberellin biosynthesis and signal transduction. Nucleotide diversity and haplotype network analyses of the SD1 gene were performed using 2822 rice landraces. Two previously reported functional nucleotide polymorphisms clearly differentiated japonica and indica rice; however, they were not associated with PH selection. Other new functional nucleotide polymorphisms in the coding, but not promoter, regions were involved in PH selection during rice domestication. Our study increasesunderstanding of the rice SD1 gene and provides additional evidence of this gene’s selection during rice domestication.ConclusionsOur findings provide evidence thatSD1 gene from wild rice enhances plant height and new functional nucleotide polymorphisms of this gene were artificially selected during cultivated rice differentiation.

Diel O2 Dynamics in Partially and Completely Submerged Deepwater Rice: Leaf Gas Films Enhance Internodal O2 Status, Influence Gene Expression and Accelerate Stem Elongation for 'Snorkelling' during Submergence.

Deepwater rice has a remarkable shoot elongation response to partial submergence. Shoot elongation to maintain air-contact enables 'snorkelling' of O2 to submerged organs. Previous research has focused on partial submergence of deepwater rice. We tested the hypothesis that leaf gas films enhance internode O2 status and stem elongation of deepwater rice when completely submerged. Diel patterns of O2 partial pressure (pO2) were measured in internodes of deepwater rice when partially or completely submerged, and with or without gas films on leaves, for the completely submerged plants. We also took measurements for paddy rice. Deepwater rice elongated during complete submergence and the shoot tops emerged. Leaf gas films improved O2 entry during the night, preventing anoxia in stems, which is of importance for elongation of the submerged shoots. Expressions of O2 deprivation inducible genes were upregulated in completely submerged plants during the night, and more so when gas films were removed from the leaves. Diel O2 dynamics showed similar patterns in paddy and deepwater rice. We demonstrated that shoot tops in air enabled 'snorkelling' and increased O2 in internodes of both rice ecotypes; however, 'snorkelling' was achieved only by rapid shoot elongation by deepwater rice, but not by paddy rice.

Ảnh hưởng của quản lý nước và kẽm sulfate lên sinh trưởng, năng suất lúa OM4900 trồng trong chậu

Zinc is an essential element and functions as cofactor for activity of plant enzymes. In this study, water management strategies and zinc supplement were combined to investigate their effects on growth and yield of OM4900 rice in the pot condition. The completely randomized design with 6 treatments and 4 replicates was employed in the experiment. Zinc was supplied at 15th day after sowing with 3 levels equivalent to 0, 15, and 30 kg of ZnSO4 per ha. There were 2 water regimes, continuous flooding and alternate wetting and drying irrigation. The result showed that alternate wetting and drying irrigation saved 671 m3 per ha, less than 36% of water usage in comparison to the continuous flooding. Zinc fertilization enhanced internode thickness, internode diameter, chlorophyll index but showed no effect on rice internode length. Yield components such as panicles per pot, filled spikelets per panicle, filled spikelet ratio were significantly improved when zinc supplemented but caused no change in the rice yield. The interactions between water managements and zinc levels were found on used water quantity, internode thickness, and filled spikelet fraction. Zinc also contributed to the improvement of harvest biomass, increased zinc accumulation in rice grain and endosperm.

Increasing wall thickness is more effective than increasing diameter for improving breaking resistance of rice internode

Increasing wall thickness is more effective than increasing diameter for improving breaking resistance of rice internode

Proteomics Coupled with Metabolite and Cell Wall Profiling Reveal Metabolic Processes of a Developing Rice Stem Internode.

Internodes of grass stems function in mechanical support, transport, and, in some species, are a major sink organ for carbon in the form of cell wall polymers. This study reports cell wall composition, proteomic, and metabolite analyses of the rice elongating internode. Cellulose, lignin, and xylose increase as a percentage of cell wall material along eight segments of the second rice internode (internode II) at booting stage, from the younger to the older internode segments, indicating active cell wall synthesis. Liquid-chromatography tandem mass spectrometry (LC-MS/MS) of trypsin-digested proteins from this internode at booting reveals 2,547 proteins with at least two unique peptides in two biological replicates. The dataset includes many glycosyltransferases, acyltransferases, glycosyl hydrolases, cell wall-localized proteins, and protein kinases that have or may have functions in cell wall biosynthesis or remodeling. Phospho-enrichment of internode II peptides identified 21 unique phosphopeptides belonging to 20 phosphoproteins including a leucine rich repeat-III family receptor like kinase. GO over-representation and KEGG pathway analyses highlight the abundances of proteins involved in biosynthetic processes, especially the synthesis of secondary metabolites such as phenylpropanoids and flavonoids. LC-MS/MS of hot methanol-extracted secondary metabolites from internode II at four stages (booting/elongation, early mature, mature, and post mature) indicates that internode secondary metabolites are distinct from those of roots and leaves, and differ across stem maturation. This work fills a void of in-depth proteomics and metabolomics data for grass stems, specifically for rice, and provides baseline knowledge for more detailed studies of cell wall synthesis and other biological processes characteristic of internode development, toward improving grass agronomic properties.

Suppressive effect of microRNA319 expression on rice plant height.

KEY MESSAGE: miR319 was identified as a dwarf-inducing gene from Shiokari and its dwarf near isogenic line, and its transgenic rice showed a reduced plant height. This finding reveals the potential application of miR319 in future molecular breeding. It is well known that microRNAs (miRNAs) play important roles in plant physiology, especially in development and stress responses. However, little is known about the role of miRNAs in plant height. In this study, the rice cultivar Shiokari and its dwarf near isogenic line Shiokari-d6 were analysed to identify and characterize plant height-associated miRNAs. This anatomic and morphological investigation revealed that the major cause of the shorter height of Shiokari-d6 is the significantly dis-elongated internodes, particularly the second internode and those underneath it. The results of miRNA microarray profiling and real-time RT-PCR indicated that miR319 is expressed at a significantly higher level in Shiokari-d6 than in Shiokari. Transgenic rice overexpressing miR319 in Oryza sativa L. cv. Tainung 67 generated through Agrobacterium-mediated transformation had a stable dwarf phenotype regardless of whether the plants were from the T1 or T2 generation. We also found that the internodes of miR319-overexpressing rice are shortened, particularly the third internode and those underneath it. Furthermore, we identified three putative miR319 target genes that were previously uncharacterized with expression levels that were negatively correlated with the expression of miR319. In conclusion, miR319 is the first miRNA proposed to be involved in plant height regulation, and its function may influence the elongation of internodes, which leads to decreased plant height.

A Gibberellin-Mediated DELLA-NAC Signaling Cascade Regulates Cellulose Synthesis in Rice.

Cellulose, which can be converted into numerous industrial products, has important impacts on the global economy. It has long been known that cellulose synthesis in plants is tightly regulated by various phytohormones. However, the underlying mechanism of cellulose synthesis regulation remains elusive. Here, we show that in rice (Oryza sativa), gibberellin (GA) signals promote cellulose synthesis by relieving the interaction between SLENDER RICE1 (SLR1), a DELLA repressor of GA signaling, and NACs, the top-layer transcription factors for secondary wall formation. Mutations in GA-related genes and physiological treatments altered the transcription of CELLULOSE SYNTHASE genes (CESAs) and the cellulose level. Multiple experiments demonstrated that transcription factors NAC29/31 and MYB61 are CESA regulators in rice; NAC29/31 directly regulates MYB61, which in turn activates CESA expression. This hierarchical regulation pathway is blocked by SLR1-NAC29/31 interactions. Based on the results of anatomical analysis and GA content examination in developing rice internodes, this signaling cascade was found to be modulated by varied endogenous GA levels and to be required for internode development. Genetic and gene expression analyses were further performed in Arabidopsis thaliana GA-related mutants. Altogether, our findings reveal a conserved mechanism by which GA regulates secondary wall cellulose synthesis in land plants and provide a strategy for manipulating cellulose production and plant growth.

Gibberellin biosynthesis and signal transduction is essential for internode elongation in deepwater rice.

Under flooded conditions, the leaves and internodes of deepwater rice can elongate above the water surface to capture oxygen and prevent drowning. Our previous studies showed that three major quantitative trait loci (QTL) regulate deepwater-dependent internode elongation in deepwater rice. In this study, we investigated the age-dependent internode elongation in deepwater rice. We also investigated the relationship between deepwater-dependent internode elongation and the phytohormone gibberellin (GA) by physiological and genetic approach using a QTL pyramiding line (NIL-1 + 3 + 12). Deepwater rice did not show internode elongation before the sixth leaf stage under deepwater condition. Additionally, deepwater-dependent internode elongation occurred on the sixth and seventh internodes during the sixth leaf stage. These results indicate that deepwater rice could not start internode elongation until the sixth leaf stage. Ultra-performance liquid chromatography tandem mass-spectrometry (UPLC-MS/MS) method for the phytohormone contents showed a deepwater-dependent GA1 and GA4 accumulation in deepwater rice. Additionally, a GA inhibitor abolished deepwater-dependent internode elongation in deepwater rice. On the contrary, GA feeding mimicked internode elongation under ordinary growth conditions. However, mutations in GA biosynthesis and signal transduction genes blocked deepwater-dependent internode elongation. These data suggested that GA biosynthesis and signal transduction are essential for deepwater-dependent internode elongation in deepwater rice.Deepwater rice obtained the ability for rapid internode elongation to avoid drowning and adapt to flooded condition. How does it regulate internode elongation? Using both physiological and genetic approach, this paper shows that the plant hormone, gibberellin (GA) regulates internode elongation.

Effects of Nitrogen Application Rate and Ratio on Lodging Resistance of Super Rice with Different Genotypes

The objective of this study was to determine the morphology mechanism of nitrogen (N) fertilizer rates and ratio on lodging resistance through analying its effects among lodging index (LI), lodging-related morphological traits and physical strength in basal internodes by comparing japonica and indica super rice cultivars. Field experiments, with three nitrogen levels (0, 150 and 300 kg ha−1) and two ratios of basal to topdressing (8:2 and 5:5) with two super rice cultivars (Yliangyou 2 and Wuyunjing 23), were conducted in the Baolin Farm, Danyang Country, Jiangsu Province, China, in 2011 and 2012. Effects of N fertilizer rates and ratios on morphology of whole plant, morphology traits in basal internodes and culm's physical strength parameters were investigated at 20 d after full heading stage. LI of Yliangyou 2 was significant greater than that of Wuyunjing 23 due to larger bending moment by whole plant (WP) with higher plant height and gravity center height. With higher volume of N fertilizer, LI of two super rice cultivars was increased conspicuously. However, no significant effect was detected with increase of panicle fertilizer ratio. The size of breaking strength (M) in basal internodes was the key factor determining LI among N fertilizer treatments. Correlation analysis revealed that M value was positively related bending stress (BS) of Wuyunjing 23 and section modulus (Z) of Yliangyou 2, respectively. The higher N fertilizer levels induced reduction of BS of Wuyunjing 23 due to weak culm and leaf sheath plumpness status and reduced Z of Yliangyou 2 owning to small diameter and culm wall thickness, consequently, influencing their M indirectly. These results suggested that breaking strength was the key factor influencing LI with increase of N fertilizer levels. However, the lodging-related morphology mechanism was different with genotypes. Culm wall thickness and diameter in basal internodes of indica super rice and culm and leaf sheath plumpness status of japonica super rice influenced breaking strength, as well as lodging index, respectively.

Evidence of Duck Activity Induced Anatomical Structure Change and Lodging Resistance of Rice Plant

The system of rice cultivation associated with duck raising is known as an integrated rice-duck (RD) farming system and has a long history in China and Asia. However, the roles of duck activities on rice physiological characteristics are unknown. Field and laboratory experiments were conducted to investigate mechanical stimulations of duck activities on rice physiological characteristics, and hence on morphology and anatomy. Here, we found that there were substantial variations in anatomical structure of the rice culm internodes and in lodging resistance of rice plants with and without the duck activities. Anatomical analysis showed a distinct difference between the RD and rice-no-duck (RND) treatments in culm wall thickness of the rice internodes. For internode N4, the culm wall from the RD treatment was more than 35% thicker than that from the RND treatment. In general, the epidermal layer of the rice culm was significantly denser for the internodes and the thickness of the culm walls increased from N1 to N4 under the RD farming system. Additionally, the areas of vascular bundles were larger and were better organized and structured in the RD treatment. Our results further revealed that the breaking-resistant strength increased whereas the lodging index of the rice culm decreased with duck activities.

Quantification of zinc transport via the phloem to the grain in rice plants (Oryza sativa L.) at early grain-filling by a combination of mathematical modeling and 65Zn tracing

Zinc (Zn) is an essential nutrient for human beings, and most Zn intake occurs through vegetables or cereals such as rice (Oryza sativa L.) grains. Recently, we detected Zn as well as cadmium, which may be partitioned to rice grains, in the phloem saps from the uppermost internodes of rice and in the xylem saps from the cut stems at early grain-filling. To quantify Zn transport to the grains via the phloem and xylem, a mathematical model previously developed for cadmium transport to rice grains was applied. We examined the translocation of zinc into the grains of rice plants at early grain-filling by feeding zinc-65 (65Zn) via a root-bathing medium, through culm cuts above and below the flag-leaf nodes, and through the flag leaves. The estimate made using the mathematical model and experimental data for three types of 65Zn transport suggests that the grain Zn may be accumulated predominantly via the phloem through two means of transport, phloem transport of stored Zn from the leaves and, more importantly, xylem-to-phloem transfer at the nodes from Zn as it is being absorbed. The Zn transport via the phloem to the grains is more selective than that of cadmium, a non-nutrient element, as also evidenced by the greater transport of cadmium to the glumes via the xylem.

Transcription profiling identifies candidate genes for secondary cell wall formation and hydroxycinnamoyl-arabinoxylan biosynthesis in the rice internode

Transcription profiling identifies candidate genes for secondary cell wall formation and hydroxycinnamoyl-arabinoxylan biosynthesis in the rice internode

Improving panicle exsertion of rice cytoplasmic male sterile line by combination of artificial microRNA and artificial target mimic

The adoption of hybrid rice caused the second leap in rice yield after the 'green revolution' and contributes substantially to food security of China and the world. However, almost all cytoplasmic male sterile lines (A lines) as females of hybrid rice have a natural deficiency of 'panicle enclosure', which blocks pollination between the A line and the fertility restorer line as the male (R line) of hybrid rice and decreases seed yield. In hybrid rice seed production, exogenous '920' (the active ingredient is gibberellin A3 ) must be applied to eliminate or alleviate panicle enclosure of the A line; however, this not only increases production cost and pollutes the environment, it also decreases seed quality. In this study, we designed a transgenic approach to improve plant height and panicle exsertion of the A line to facilitate hybrid rice production and maintain the semi-dwarf plant type of the hybrid. This approach comprising two components-artificial microRNA (amiRNA) and artificial target mimicry-can manipulate the differential expression of the endogenous Eui1 gene that is associated with rice internode elongation in the A line and the hybrid. amiRNA is a recently developed gene silencing method with high specificity, while target mimicry is a natural mechanism inhibiting the miRNA function that was also recently characterized. This approach provides a paradigm to tune the expression of endogenous genes to achieve the desired phenotype by combining amiRNA and artificial target mimicry technologies.

Overexpression of rice LRK1 restricts internode elongation by down-regulating OsKO2

Rice (Oryza sativa) has the potential to undergo rapid internodal elongation which determines plant height. Gibberellin is involved in internode elongation. Leucine-rich repeat receptor-like kinases (LRR-RLKs) are the largest subfamily of transmembrane receptor-like kinases in plants. LRR-RLKs play important functions in mediating a variety of cellular processes and regulating responses to environmental signals. LRK1, a PSK receptor homolog, is a member of the LRR-RLK family. In the present study, differences in ectopic expression of LRK1 were consistent with extent of rice internode elongation. Analyses of gene expression demonstrated that LRK1 restricts gibberellin biosynthesis during the internode elongation process by down-regulation of the gibberellin biosynthetic gene coding for ent-kaurene oxidase.