Metabolite-level carbon-flow analysis reveals that starch synthesis from hexose is a limiting factor in a high-yielding rice cultivar

2021 ◽  
Author(s):  
Masaki Okamura ◽  
Masami Yokota Hirai ◽  
Yuji Sawada ◽  
Mami Okamoto ◽  
Akira Oikawa ◽  
...  
Keyword(s):  
Oryza Sativa L ◽  
Flow Analysis ◽  
Starch Synthesis ◽  
Grain Filling ◽  
Rice Cultivar ◽  
Limiting Factors ◽  
Limiting Factor ◽  
Metabolite Level ◽  
Sink Activity ◽  
Adp Glucose Pyrophosphorylase

Abstract Understanding the limiting factors of grain filling is essential for the further improvement of rice (Oryza sativa L.) grain yields. The slower grain growth of Momiroman, a high-yielding rice cultivar, is not improved by increasing the carbon supply. Thus, a low sink activity, which is the metabolic activity of assimilate consumption/storage in sink organs, may be a limiting factor of grain filling. However, there is no metabolic evidence corroborating this hypothesis, partly because there is no consensus on how to define and quantify sink activity. In this study, we investigated the carbon flows, at a metabolite level, from photosynthesis in leaves to starch synthesis in grains of three high-yielding cultivars using a stable isotope of carbon, 13C. The large amount of newly fixed carbon assimilates in Momiroman was stored as hexose instead of being converted to starch. Additionally, the activity of ADP-glucose pyrophosphorylase and the expression of AGPS2b, encoding an ADP-glucose pyrophosphorylase protein, in the superior grains of Momiroman were lower than in the other two rice cultivars. Thus, the slower starch synthesis from hexose, which is partly explained by the low expression level of AGPS2b, may be the primarily metabolic reason for the lower sink activity in Momiroman. (199/200 words)

scholarly journals GC-MS-based metabolite profiling of key differential metabolites between superior and inferior spikelets of rice during the grain filling stage

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Xiumei Min ◽  
Hailong Xu ◽  
Fenglian Huang ◽  
Yidong Wei ◽  
Wenxiong Lin ◽  
...  
Keyword(s):  
Soluble Sugars ◽  
Starch Synthesis ◽  
Grain Filling ◽  
Absolute Quantification ◽  
Metabolite Level ◽  
Inferior Spikelets ◽  
Expression Of Genes ◽  
Grain Filling Rate ◽  
Proteome Level ◽  
The Difference

Abstract Background The asynchronous filling between superior spikelets (SS) and inferior spikelets (IS) in rice has become a research hotspot. The stagnant development and poor grain filling of IS limit yields and the formation of good quality rice. A large number of studies on this phenomenon have been carried out from the genome, transcriptome and proteome level, indicating that asynchronous filling of SS and IS filling is a complex, but orderly physiological and biochemical process involving changes of a large number of genes, protein expression and modification. However, the analysis of metabolomics differences between SS and IS is rarely reported currently. Results This study utilized untargeted metabolomics and identified 162 metabolites in rice spikelets. Among them, 17 differential metabolites associated with unsynchronized grain filling between SS and IS, 27 metabolites were related to the stagnant development of IS and 35 metabolites related to the lower maximum grain-filling rate of IS compared with the SS. We found that soluble sugars were an important metabolite during grain filling for SS and IS. Absolute quantification was used to further analyze the dynamic changes of 4 types of soluble sugars (sucrose, fructose, glucose, and trehalose) between SS and IS. The results showed that sucrose and trehalose were closely associated with the dynamic characteristics of grain filling between SS and IS. The application of exogenous sugar showed that trehalose functioned as a key sugar signal during grain filling of IS. Trehalose regulated the expression of genes related to sucrose conversion and starch synthesis, thereby promoting the conversion of sucrose to starch. The difference in the spatiotemporal expression of TPS-2 and TPP-1 between SS and IS was an important reason that led to the asynchronous change in the trehalose content between SS and IS. Conclusions The results from this study are helpful for understanding the difference in grain filling between SS and IS at the metabolite level. In addition, the present results can also provide a theoretical basis for the next step of using metabolites to regulate the filling of IS.

Ethylene inhibitors enhanced sucrose synthase activity and promoted grain filling of basal rice kernels

2000 ◽  
Vol 27 (11) ◽  
pp. 997 ◽  
Author(s):  
Pradeep K. Naik ◽  
Pravat K. Mohapatra
Keyword(s):  
Sucrose Synthase ◽  
Grain Quality ◽  
Oryza Sativa L ◽  
Starch Synthesis ◽  
Grain Filling ◽  
Soluble Carbohydrates ◽  
Ethylene Inhibitors ◽  
Stage Of Development ◽  
Ethylene Action

At the booting stage of development, rice (Oryza sativa L.) plants were treated with chemicals that either inhibited the action or synthesis of ethylene, or produced ethylene. Inhibitors of ethylene action (AgNO3) and synthesis [uniconazole, paclobutrazol, Co(NO3)2] promoted grain filling and quality of the kernels of the basal spikelets of the panicle, while the ethylene-releasing substance CEPA (2-chloroethylphosphonic acid) depressed these characteristics further. The inhibitors depressed the concentration of ethylene of the basal primary branches, but CEPA increased it above the control during the period of grain filling. The treatments were not effective on the superior apical spikelets of the panicle. The ethylene inhibitors improved starch synthesis in the kernels of the basal spikelets, but CEPA reduced it significantly, resulting in accumulation of soluble carbohydrates in the kernels. During the period of grain filling, sucrose synthase activity was higher than that of invertase in the kernels. Activities of sucrose synthase and invertase were higher in the apical than in the basal kernel. The ethylene inhibitors increased activities of both enzymes only in the basal kernel, whereas CEPA reduced activities significantly. Together, the results indicate that starch filling and grain quality of the basally positioned under-developed rice kernels can be affected by ethylene, and that key enzymes of sucrose metabolism are also affected in the process.

Biochemical and molecular characterisation of salt-induced poor grain filling in a rice cultivar

2016 ◽  
Vol 43 (3) ◽  
pp. 266 ◽  
Author(s):  
Binay B. Panda ◽  
Alok K. Badoghar ◽  
Sudhanshu Sekhar ◽  
Ekamber Kariali ◽  
Pravat K. Mohapatra ◽  
...  
Keyword(s):  
Gene Expression ◽  
Oryza Sativa L ◽  
Grain Filling ◽  
Rice Cultivar ◽  
Inhibitory Effect ◽  
Protective Role ◽  
Ethylene Receptors ◽  
Transcript Levels ◽  
Spikelets Per Panicle ◽  
Gene Expression Studies

Despite the prevalence of poor grain filling in rice (Oryza sativa L.) under abiotic stress, the reason for this is largely unexplored. Application of 0.75% NaCl to a salt-sensitive rice cultivar at late booting resulted in a >20% yield loss. Spikelets per panicle and the percentage of filled grain decreased significantly in response to NaCl application. The inhibitory effect of NaCl on grain filling was greater in basal than in apical spikelets. Sucrose synthase (SUS) activity was positively correlated with grain weight. The transcript levels of the SUS isoforms differed greatly: the levels of SUS2 increased significantly in response to salt; those of SUS4 decreased drastically. Gene expression studies of starch synthase and ADP-glucose pyrophosphorylase showed that the decreased transcript levels of one isoform was compensated by an increase in those of the other. Salt application also significantly increased the gene expression of the ethylene receptors and the ethylene signalling proteins. The increase in their transcript levels was comparatively greater in basal than in apical spikelets. Significant enhancement in the transcript levels of the ethylene receptors and the increase in the production of ethylene indicated that the salt-induced inhibition of grain filling might be mediated by ethylene. Additionally, the inhibition of chromosomal endoreduplication mediated by decreased transcript levels of B-type cyclin could explain poor grain filling under salt stress. A significant increase in the transcript levels of the ethylene-responsive factors in the spikelets during grain filling in response to salt indicated their possible protective role in grain filling under stress.

Partitioning of 13C-labelled photosynthate varies with growth stage andpanicle size in high-yielding rice

2004 ◽  
Vol 31 (2) ◽  
pp. 131 ◽  
Author(s):  
Pravat K. Mohapatra ◽  
Yasuyuki Masamoto ◽  
Satoshi Morita ◽  
Junichi Takanashi ◽  
Tsuneo Kato ◽  
...  
Keyword(s):  
Oryza Sativa L ◽  
Flag Leaf ◽  
Source Area ◽  
Grain Filling ◽  
Rice Cultivar ◽  
Japonica Rice ◽  
Heavy Carbon ◽  
Heavy Carbon Isotope ◽  
Source Sink ◽  
Developing Grains

A super-high-yielding rice (Oryza sativa L.) cultivar, Takanari, and a traditional japonica rice cultivar, Nakateshinsenbon, were grown under field conditions to compare partitioning of 13C-labelled photosynthate to different plant organs during the period of reproductive development. The flag leaf and the two leaves immediately below it on the main culm were exposed individually to 13CO2 and the movement of the heavy carbon isotope to grains, hull, panicle branches and vegetative parts of plant was assessed. Also, the effect of a reduction of sink size on the partitioning of 13C to different organs was studied by removing some of the primary branches of the panicle. 13C taken up by the three leaves in the post-heading period, moved mostly to the grains and hull of the panicle. At this stage, the uppermost three leaves and the panicle consisted of a single source–sink unit. Partitioning of 13C to the rest of the vegetative structures of the plant was minimal. In the case of Nakateshinsenbon, the flag leaf supplied most of the carbon assimilates for the grains and contributions from the other two leaves were much smaller. However, in Takanari, the contribution of 13C to grains from the second leaf was equivalent to that of the flag leaf. In Takanari, removal of more than one third of the primary branches of the panicle significantly reduced partitioning from the third leaf of the culm, but partitioning from the flag leaf was not significantly changed. In contrast, branch removal treatment significantly depressed transport of carbon assimilates from the flag leaf in Nakateshinsenbon. The obligatory nature of the source–sink relationship in rice is discussed. It is concluded that in lower-yielding traditional rice, photosynthesis in the flag leaf supplies carbon assimilates to the developing grains. But in the super-yielding rice Takanari, the main source area is extended to include the two leaves below the flag leaf so as to sustain an extra large panicle. Even greater grain-filling is possible in super-yielding rice, if the source area is increased further.

scholarly journals GC-MS-Based Metabolite Profiling of Key Differential Metabolites Between Superior and Inferior Spikelets of Rice During the Grain Filling Stage

2021 ◽  
Author(s):  
Xiumei Min ◽  
Hailong Xu ◽  
Fenglian Huang ◽  
Yidong Wei ◽  
Wenxiong Lin ◽  
...  
Keyword(s):  
Soluble Sugars ◽  
Starch Synthesis ◽  
Grain Filling ◽  
Absolute Quantification ◽  
Metabolite Level ◽  
Inferior Spikelets ◽  
Expression Of Genes ◽  
Proteome Level ◽  
Superior Spikelets ◽  
The Difference

Abstract Background:The asynchronous filling between superior spikelets (SS) and inferior spikelets (IS) in rice has become a research hotspot. The stagnant development and poor grain filling of IS limit yields and the formation of good quality rice. A large number of studies on this phenomenon have been carried out from the genome, transcriptome and proteome level, indicating that asynchronous filling of SS and IS filling is a complex, but orderly physiological and biochemical process involving changes of a large number of genes, protein expression and modification. However, the analysis of metabolomics differences between SS and IS is rarely reported currently.Results:This study utilized untargeted metabolomics and identified 162 metabolites in rice spikelets. Among them, 17 differential metabolites associated with unsynchronized grain filling between superior spikelets (SS) and IS, 27 metabolites were related to the stagnant development of IS and 35 metabolites related to the lower maximum grain-filling rate of IS compared with the SS. We found that soluble sugars were an important metabolite during grain filling for SS and IS. Absolute quantification was used to further analyze the dynamic changes of 4 types of soluble sugars (sucrose, fructose, glucose, and trehalose) between SS and IS. The results showed that sucrose and trehalose were closely associated with the dynamic characteristics of grain filling between SS and IS. The application of exogenous sugar showed that trehalose functioned as a key sugar signal during grain filling. Trehalose regulated the expression of genes related to sucrose conversion and starch synthesis, thereby promoting the conversion of sucrose to starch. The difference in the spatiotemporal expression of TPS-2 and TPP-1 between SS and IS was an important reason that led to the difference in trehalose contents between SS and IS.Conclusions:The results from this study are helpful for understanding the difference in grain filling between SS and IS at the metabolite level. In addition, the present results can also provide a theoretical basis for the next step of using metabolites to regulate the filling of IS.

scholarly journals Evaluation of soybean (Glycine max L.) adaptation to northern European regions under different agro-climatic scenarios

2021 ◽  
Author(s):  
Guénolé Boulch ◽  
Chloé Elmerich ◽  
Amina Djemel ◽  
Bastien Lange
Keyword(s):  
Negative Impact ◽  
Precipitation Amount ◽  
Genetic Material ◽  
Grain Filling ◽  
Limiting Factors ◽  
Yield Potential ◽  
Limiting Factor ◽  
European Regions ◽  
Area Index ◽  
Northern European

Abstract Soybean is a candidate crop to increase the independency of Europe in leguminous protein crops. However, its adaptation to northern European regions is not yet well defined due to lack of long-term references. Herein, we simulated soybean yield potential in northern France and identified the main yield limiting factors under rainfed vs irrigated conditions. Two cultivars representing maturity groups 000 and 00 were planted within three different trials. Leaf area index, shoot and pod biomass, main phenological stages and yield were recorded to evaluate CROPGRO-soybean model predictability. Adjustment of genetic coefficients was performed prior to simulate yield on 21-years weather database (1999-2018) at Beauvais (France, N 49.46°, E 2.07°) and Estrées-Mons (France, N 49.88°, E 3.01°) under different water regimes and planting dates. Predictions showed that adding irrigation at grain filling period would increase yield potential to the level of non-water limited scenarios. Although simulated yield variability is reduced with irrigation, the remaining variability suggests that water is not the only yield-limiting factor. A tentative explanation is proposed by deriving environmental covariates from the model. The analysis confirmed the importance of precipitation amount (optimum around 200 mm) and duration (optimum around 60 days) of the flowering to physiological maturity period under rainfed conditions. Under irrigated conditions, increasing evapotranspiration and average minimum temperature affected simulated yield positively while increasing the number of days below 10°C had a negative impact. These results give insights for soybean crop management and bring indications to breeders for adapting the existing genetic material to northern Europe.

Identification of the ADP-glucose pyrophosphorylase isoforms essential for starch synthesis in the leaf and seed endosperm of rice (Oryza sativa L.)

2007 ◽  
Vol 65 (4) ◽  
pp. 531-546 ◽  
Author(s):  
Sang-Kyu Lee ◽  
Seon-Kap Hwang ◽  
Muho Han ◽  
Joon-Seob Eom ◽  
Hong-Gyu Kang ◽  
...  
Keyword(s):  
Oryza Sativa ◽  
Oryza Sativa L ◽  
Starch Synthesis ◽  
Adp Glucose Pyrophosphorylase

scholarly journals Multivariate Analysis in Rice (Oryza sativa L.) Mutant Families from Anna (R) 4 Cultivar

2020 ◽  
Author(s):  
P. Arunachalam ◽  
D. V. Sushmitharaj ◽  
C. Vanniarajan ◽  
J. Souframanien ◽  
E. Subramanian
Keyword(s):  
Principal Component Analysis ◽  
Genetic Relatedness ◽  
Oryza Sativa L ◽  
Principal Component ◽  
Component Analysis ◽  
Rice Cultivar ◽  
Rice Production ◽  
Limiting Factors ◽  
Severe Drought ◽  
Market Preference

Background: The drought is one of the major limiting factors in rice production especially in rainfed environment. The rice production loss in rainfed has ranged from 17 to 40 percent during severe drought seasons. The rice cultivar Anna (R) 4 is having best adoptive characteristics to suits direct seeded rice under rainfed cultivation. But it has less market preference due its undesirable grain characters at consumer level. Hence, induced mutagenesis approach resorted to correct the undesirable traits and improve this variety to suits present needs. The mutant lines are having desirable changes and shows more similarity with Anna (R) 4 were identified by multivariate analyses. Methods: The present investigation was carried out during rabi 2018-19 to access the genetic relatedness of the 32 mutant families derived from Anna (R) 4 rice cultivar through electron beam, gamma rays and recurrent EMS mutagenesis. Data on twelve morphological traits were analysed for genetic divergence, principal component analysis and UPGMA clustering. Result: The mutant families were grouped in eight clusters with maximum and minimum diversity (D2) values of 457.21 and 10.90 respectively. The principal component analysis revealed that 75.32 per cent of total variability was explained by first five PCs and traits contributed to the divergence among the mutant families was discussed. The cluster tree obtained from UPGMA clustering based on the dissimilarity among the mutants was narrated.

Marker-assisted identification of potential fertility restorers for the development of three-line hybrids in rice (Oryza sativa L.)

2020 ◽  
Vol 57 (3) ◽  
pp. 181-189
Author(s):  
Asma Majid ◽  
GA Parray ◽  
NR Sofi ◽  
Gazala H Khan ◽  
Showkat A Waza ◽  
...  
Keyword(s):  
Oryza Sativa L ◽  
Chromosome 1 ◽  
Limiting Factor ◽  
Kashmir Valley ◽  
Fertility Restorer ◽  
Yield And Quality ◽  
Restorer Genes ◽  
Increase Productivity ◽  
Fertility Restorers ◽  
Selection Of

Rice being a staple food crop of Kashmir valley, the focus is on enhancement of yield in order to meet the needs of ever-growing population.Identification of new parental lines is crucial for developing ecology-specific hybrids with ideal agronomic performance. Exploitation of heterosis in the form of hybrid rice technology can be one of the approaches to increase productivity in this crop, especially exploiting diversity among japonica lines can serve as an excellent route.A number of CMS lines suitable formountainous areas of Kashmir have been developed, however, the availability of promising restorer lines remains to be the major limitation for utilization of these lines.Identification of potential restorers acts as the main limiting factor for hybrid development in the Kashmir valley. Marker based screening for Rf3 and Rf4 fertility restorer genes can be helpful in rapid selection of restorer lines while dealing with the large quantity of genetic materials. In the present study, 100 rice germplasm were screened with the help of SSR markers, RM3148 and RM6100linked to Rf3 and Rf4 genes on chromosome 1 and 10, respectively. In total, 19 lines revealed the presence of both Rf3 and Rf4 genes. These lines amplified fertility restorer specific alleles for both the genes and may serve as potential restorers for obtaining heterotic rice hybrids. Further the germplasm lines were also evaluated for yield and quality traits.The present results would help in selection of suitable restorers along with preferred grain shape/size.

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