scholarly journals Cyclin-Dependent Kinase Inhibitors KRP1 and KRP2 Are Involved in Grain Filling and Seed Germination in Rice (Oryza sativa L.)

2019 ◽  
Vol 21 (1) ◽  
pp. 245 ◽  
Author(s):  
Abolore Adijat Ajadi ◽  
Xiaohong Tong ◽  
Huimei Wang ◽  
Juan Zhao ◽  
Liqun Tang ◽  
...  
Keyword(s):  
Seed Germination ◽  
Cellular Localization ◽  
Kinase Inhibitors ◽  
Oryza Sativa L ◽  
Grain Filling ◽  
Rice Seed ◽  
Cyclin Dependent Kinase ◽  
Cell Cycles ◽  
Transgenic Lines ◽  
Dependent Protein

Cyclin-dependent kinase inhibitors known as KRPs (kip-related proteins) control the progression of plant cell cycles and modulate various plant developmental processes. However, the function of KRPs in rice remains largely unknown. In this study, two rice KRPs members, KRP1 and KRP2, were found to be predominantly expressed in developing seeds and were significantly induced by exogenous abscisic acid (ABA) and Brassinosteroid (BR) applications. Sub-cellular localization experiments showed that KRP1 was mainly localized in the nucleus of rice protoplasts. KRP1 overexpression transgenic lines (OxKRP1), krp2 single mutant (crkrp2), and krp1/krp2 double mutant (crkrp1/krp2) all exhibited significantly smaller seed width, seed length, and reduced grain weight, with impaired seed germination and retarded early seedling growth, suggesting that disturbing the normal steady state of KRP1 or KRP2 blocks seed development partly through inhibiting cell proliferation and enlargement during grain filling and seed germination. Furthermore, two cyclin-dependent protein kinases, CDKC;2 and CDKF;3, could interact with KRP1 in a yeast-two-hybrid system, indicating that KRP1 might regulate the mitosis cell cycle and endoreduplication through the two targets. In a word, this study shed novel insights into the regulatory roles of KRPs in rice seed maturation and germination.

scholarly journals Mechanism of delayed seed germination caused by high temperature during grain filling in rice (Oryza sativa L.)

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Chetphilin Suriyasak ◽  
Yui Oyama ◽  
Toshiaki Ishida ◽  
Kiyoshi Mashiguchi ◽  
Shinjiro Yamaguchi ◽  
...  
Keyword(s):  
Oryza Sativa ◽  
High Temperature ◽  
Seed Germination ◽  
Oryza Sativa L ◽  
Grain Filling ◽  
Aleurone Layer ◽  
Gene Promoters ◽  
Aba Catabolism ◽  
Amylase Genes ◽  
Transcriptional Changes

Abstract High temperature during grain filling considerably reduces yield and quality in rice (Oryza sativa L.); however, how high temperature affects seed germination of the next generation is not yet well understood. Here, we report that seeds from plants exposed to high temperature during the grain filling stage germinated significantly later than seeds from unstressed plants. This delay remained even after dormancy release treatments, suggesting that it was not due to primary seed dormancy determined during grain filling. In imbibed embryos of heat-stressed seeds, expression of abscisic acid (ABA) biosynthesis genes (OsNCEDs) was higher than in those of control seeds, whereas that of ABA catabolism genes (OsABA8′OHs) was lower. In the aleurone layer, despite no change in GA signaling as evidenced by no effect of heat stress on OsGAMYB gene expression, the transcripts of α-amylase genes OsAmy1C, OsAmy3B, and OsAmy3E were significantly down-regulated in heat-stressed seeds in comparison with controls. Changes in promoter methylation levels were consistent with transcriptional changes of ABA catabolism-related and α-amylase genes. These data suggest that high temperature during grain filling results in DNA methylation of ABA catabolism-related and α-amylase gene promoters, delaying germination of heat-stressed seeds.

scholarly journals Senescence-Specific Expression of RAmy1A Accelerates Non-structural Carbohydrate Remobilization and Grain Filling in Rice (Oryza sativa L.)

2021 ◽  
Vol 12 ◽  
Author(s):  
Ning Ouyang ◽  
Xuewu Sun ◽  
Yanning Tan ◽  
Zhizhong Sun ◽  
Dong Yu ◽  
...  
Keyword(s):  
Oryza Sativa ◽  
Transgenic Rice ◽  
Oryza Sativa L ◽  
Sugar Content ◽  
Soluble Sugar ◽  
Grain Filling ◽  
Leaf Sheath ◽  
Specific Expression ◽  
Total Soluble Sugar ◽  
Transgenic Lines

Remobilization of pre-anthesis NSCs (non-structural carbohydrates) is significant for effective grain filling in rice (Oryza sativa L.). However, abundant starch particles as an important component of NSCs are still present in the leaf sheath and stem at the late stage of grain filling. There are no studies on how bioengineering techniques can be used to improve the efficiency of NSC remobilization. In this study, RAmy1A was expressed under the senescence-specific promoter of SAG12, which was designed to degrade starch in the leaf sheath and stem during grain filling. RAmy1A mRNA successfully accumulated in the leaf, stem, and sheath of transgenic plants after anthesis. At the same time, the starch and total soluble sugar content in the leaf, stem, and leaf sheath were obviously decreased during the grain-filling period. The photosynthetic rate of transgenic lines was higher than that of the wild types by an average of 4.0 and 9.9%, at 5 and 10 days after flowering, respectively. In addition, the grain-filling rate of transgenic lines was faster than that of the wild types by an average of 26.09%. These results indicate an enhanced transport efficiency of NSCs from source tissues in transgenic rice. Transgenic rice also displayed accelerated leaf senescence, which was hypothesized to contribute to decreased grain weight.

scholarly journals GABA-Alleviated Oxidative Injury Induced by Salinity, Osmotic Stress and their Combination by Regulating Cellular and Molecular Signals in Rice

2019 ◽  
Vol 20 (22) ◽  
pp. 5709 ◽  
Author(s):  
Mohamed S. Sheteiwy ◽  
Hongbo Shao ◽  
Weicong Qi ◽  
Yousef Alhaj Hamoud ◽  
Hiba Shaghaleh ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Antioxidant Enzymes ◽  
Seed Germination ◽  
Osmotic Stress ◽  
Salinity Stress ◽  
Cell Cycle Progression ◽  
Molecular Mechanisms ◽  
Oryza Sativa L ◽  
Water Relation ◽  
Rice Seed

This study was conducted in order to determine the effect of priming with γ-aminobutyric acid (GABA) at 0.5 mM on rice (Oryza sativa L.) seed germination under osmotic stress (OS) induced by polyethylene glycol (30 g/L PEG 6000); and salinity stress (S, 150 mM NaCl) and their combination (OS+S). Priming with GABA significantly alleviated the detrimental effects of OS, S and OS+S on seed germination and seedling growth. The photosynthetic system and water relation parameters were improved by GABA under stress. Priming treatment significantly increased the GABA content, sugars, protein, starch and glutathione reductase. GABA priming significantly reduced Na+ concentrations, proline, free radical and malonaldehyde and also significantly increased K+ concentration under the stress condition. Additionally, the activities of antioxidant enzymes, phenolic metabolism-related enzymes, detoxification-related enzymes and their transcription levels were improved by GABA priming under stress. In the GABA primed-plants, salinity stress alone resulted in an obvious increase in the expression level of Calcineurin B-like Protein-interacting protein Kinases (CIPKs) genes such as OsCIPK01, OsCIPK03, OsCIPK08 and OsCIPK15, and osmotic stress alone resulted in obvious increase in the expression of OsCIPK02, OsCIPK07 and OsCIPK09; and OS+S resulted in a significant up-regulation of OsCIPK12 and OsCIPK17. The results showed that salinity, osmotic stresses and their combination induced changes in cell ultra-morphology and cell cycle progression resulting in prolonged cell cycle development duration and inhibitory effects on rice seedlings growth. Hence, our findings suggested that the high tolerance to OS+S is closely associated with the capability of GABA priming to control the reactive oxygen species (ROS) level by inducing antioxidant enzymes, secondary metabolism and their transcription level. This knowledge provides new evidence for better understanding molecular mechanisms of GABA-regulating salinity and osmotic-combined stress tolerance during rice seed germination and development.

scholarly journals Germination and seedling growth of rice (Oryza sativa L.) as affected by varying concentrations of loom-dye effluent

2019 ◽  
Vol 17 (2) ◽  
pp. 153-160 ◽  
Author(s):  
Md. Arifur Rahman ◽  
Md. Sohanur Rahman ◽  
K.M. Mohiuddin ◽  
Md. Akhter Hossain Chowdhury ◽  
Md. Abul Khair Chowdhury
Keyword(s):  
Oryza Sativa ◽  
Seed Germination ◽  
Seedling Growth ◽  
Oryza Sativa L ◽  
Industrial Effluent ◽  
Rice Seed ◽  
Early Seedling Growth ◽  
Significant Difference ◽  
Early Seedling ◽  
Radical Length

Indiscriminate discharge of industrial effluent has become a serious problem for the agro-ecological environment in most of the areas of Bangladesh. The effects of loom-dye effluents on seed germination and early seedling growth of rice (Oryza sativa L.) were investigated by conducting an experiment in the laboratory of the Department of Agricultural Chemistry of Bangladesh Agricultural University, Mymensingh. Three types of loom-dye effluents were applied in sterilized petridishes at different loading ratios. Seven treatments (i.e., T0, T1, T2, T3, T4, T5 and T6 with 0, 5, 10, 25, 50, 75 and 100% effluent, respectively) of each effluent were used following completely randomized design (CRD) and replicated three times. Subsequently, Pb, Fe, Zn, Mn and Cr accumulation were also investigated in the harvested rice seedlings. Rice seed showed a significant difference in germination percentage with varying levels of effluent application at different days after setting of germination. The decreased seed germination rate and seedling growth of rice were observed with increased concentration of loom-dye effluents. The highest germination speed (97.8%) was obtained from control whereas the lowest germination speeds were obtained from T5 of black, and T6 of both black and violet effluents. Phytotoxic effects of loom-dye effluents on germination and radical length were extreme at 100% effluent concentration having the order of black > violet > pink. The maximum radical length (6.4 cm) and plumule length (7.5 cm) were observed with T1 of pink dye effluent whereas the minimum length of radical and plumule were obtained from T6 treatment of the effluents. The highest fresh weight (39.8 mg petridish–1), dry weight (5.7 mg petridish–1) and seedling vigor index (746.7%) were also observed from T1 of pink dye effluent. The maximum uptake of Pb, Fe, Mn and Zn was 0.48, 3.81, 0.79 and 0.13 μg g−1, respectively. The uptake of Cr was below the detectable limit. Total heavy metal accumulation in rice was in the following order: Fe>Mn>Pb>Zn>Cr. Results showed that the higher concentration of loom-dye effluent showed the higher toxic effects on different parameters of germination and early seedling growth compared with the lower effluent concentrations. J. Bangladesh Agril. Univ. 17(2): 153–160, June 2019

scholarly journals Allelopathic effect of Sphenoclea zeylanica Gaertn. on rice (Oryza sativa L.) germination and seedling growth

2020 ◽  
pp. 1450-1455
Author(s):  
Ramida Krumsri ◽  
Hisashi Kato Noguchi ◽  
Thanatsan Poonpaiboonpipat
Keyword(s):  
Seed Germination ◽  
Seedling Growth ◽  
Oryza Sativa L ◽  
Inhibitory Effect ◽  
Growth And Yield ◽  
Plant Residue ◽  
Plant Residues ◽  
Allelopathic Effect ◽  
Rice Seed ◽  
Equal Concentration

The allelopathic effect of Sphenoclea zeylanica Gaertn., a broadleaf paddy weed that hinders rice production in Thailand, was investigated. Different parts of S. zeylanica were used to determine their inhibitory effect on seed germination, and shoot and root length of rice in a laboratory. Aqueous extracts of leaves and stems had an inhibitory effect on rice germination and seedling growth more than 50% that of control at concentrations higher than 50 g L-1, whereas all concentrations of root extracts had no effect on rice seeds. At the concentration of 100 g L-1, leaf and stem extracts completely (100%) inhibited rice seed germination. The inhibitory effect was increased with increasing concentrations. Additionally, leaf extracts contained higher total phenolics (7.36 mg GE g-1 DW) and total flavonoids (254.19 µg QE g-1 DW) than extracts of other parts. In glasshouse conditions, soil incorporation with dried whole plant residue had a significant inhibitory effect on rice emergence, seedling height, and dry weight when compared with extracted residue at an equal concentration. The decomposition of S. zeylanica in the soil was also evaluated regarding rice seedling growth. The maximum inhibition was achieved 1-3 days after the application of plant residues. At the 30th day, the inhibition disappeared, suggesting that residue decomposition in the soil has been finished. These results support that S. zeylanica has an allelopathic effect on paddy fields, which may cause a reduction in rice growth and yield.

Endosperm-specific OsPYL8 and OsPYL9 act as positive regulators of the ABA signaling pathway in rice seed germination

2017 ◽  
Vol 44 (6) ◽  
pp. 635 ◽  
Author(s):  
Ziqiang Chen ◽  
Lan Kong ◽  
Yun Zhou ◽  
Zaijie Chen ◽  
Dagang Tian ◽  
...  
Keyword(s):  
Seed Germination ◽  
Plant Hormone ◽  
Oryza Sativa L ◽  
Expression Patterns ◽  
Biochemical Properties ◽  
Rice Seed ◽  
Biological Functions ◽  
Specific Expression ◽  
Future Studies ◽  
Positive Regulators

Pyrabactin resistance-like (PYL) proteins were identified as receptors of the plant hormone ABA. The PYL family consists of multiple members that are differently expressed in various tissues, exhibit distinct biochemical properties and have diverse biological functions. In the present study, we explored the expression patterns of the rice (Oryza sativa L.) OsPYL family genes and determined that OsPYL8 and OsPYL9 are specifically expressed in the endosperms. Sequence analysis and deletion experiments revealed that the OsPYL8 and OsPYL9 promoters contain multiple motifs involved in endosperm-specific expression. Transgenic rice plants overexpressing OsPYL8 or OsPYL9 showed hypersensitivity to ABA during seed germination, suggesting that both OsPYL8 and OsPYL9 act as positive regulators of the ABA signalling pathway in the seed. OsPYL8 and OsPYL9 interact with OsPP2C51 and OsPP2C68, whose expression is induced in the endosperms by ABA. Our results provided a foundation for future studies on OsPYL8- and OsPYL9-mediated ABA signalling in the rice endosperms.

Acquisition of desiccation tolerance during seed development is associated with oxidative processes in rice

Botany ◽  
2016 ◽  
Vol 94 (2) ◽  
pp. 91-101 ◽  
Author(s):  
Yongqi He ◽  
Jinping Cheng ◽  
Xiaodan Li ◽  
Peng Zeng ◽  
Bin Yang ◽  
...  
Keyword(s):  
Seed Germination ◽  
Seed Development ◽  
Desiccation Tolerance ◽  
Seed Quality ◽  
Developmental Stages ◽  
Oryza Sativa L ◽  
Rice Seed ◽  
Sod Activity ◽  
Oxidative Processes ◽  
Germination Traits

Desiccation tolerance is an important characteristic of rice seed quality during seed drying. In this study, two varieties of Oryza sativa L. subsp. japonica (Jiucaiqing and Wuyunjing 7) were used to investigate the dynamic changes in rice seeds that are associated with desiccation tolerance (germination traits produced by dried seeds), grain mass (GW), moisture content (MC), and electrical conductivity (EC) during seed development (18 to 42 days after heading (DAH)). Changes in the levels of malondialdehyde (MDA) and hydrogen peroxide (H2O2) in fresh, dry, and imbibed states, and antioxidant enzyme activity (superoxide dismutase (SOD); catalase (CAT); and glutathione reductase (GR)) in fresh and imbibed seeds were also evaluated during seed development. The results showed that seeds started to acquire desiccation tolerance at 26 DAH and reached the highest levels at 38 DAH. The increase in GW and decline in MC coincided with the acquisition of desiccation tolerance. MDA and H2O2 levels, and SOD, CAT, and GR activities in fresh and imbibed seeds rapidly decreased during the early developmental stages (18–30 DAH), and then their levels gradually stabilized (30–42 DAH). Regression analyses indicated that H2O2 levels in fresh seeds was negatively correlated with seed germination, whereas SOD activity in imbibed seeds was positively correlated with seed germination. H2O2 and SOD are, therefore, good parameters for assessing desiccation tolerance during rice seed development.

scholarly journals Serine carboxypeptidase 46 Regulates Grain Filling and Seed Germination in Rice (Oryza sativa L.)

PLoS ONE ◽  
2016 ◽  
Vol 11 (7) ◽  
pp. e0159737 ◽  
Author(s):  
Zhiyong Li ◽  
Liqun Tang ◽  
Jiehua Qiu ◽  
Wen Zhang ◽  
Yifeng Wang ◽  
...  
Keyword(s):  
Oryza Sativa ◽  
Seed Germination ◽  
Oryza Sativa L ◽  
Grain Filling ◽  
Serine Carboxypeptidase

Allelopathic Potential of Rice Seed (Oryza sativa L.) on Seed Germination of Monochoria vaginalis var. plantaginea.

1997 ◽  
Vol 42 (3) ◽  
pp. 262-267 ◽  
Author(s):  
Shun Kawaguchi ◽  
Yasutomo Takeuchi ◽  
Masaru Ogasawara ◽  
Koichi Yoneyama ◽  
Makoto Konnai
Keyword(s):  
Oryza Sativa ◽  
Seed Germination ◽  
Oryza Sativa L ◽  
Rice Seed ◽  
Allelopathic Potential
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