Correlation between expression and activity of ADP glucose pyrophosphorylase and starch synthase and their role in starch accumulation during grain filling under drought stress in rice

2020 ◽  
Vol 157 ◽  
pp. 239-243 ◽  
Author(s):  
Prathap V ◽  
Aruna Tyagi
Keyword(s):  
Drought Stress ◽  
Grain Filling ◽  
Starch Synthase ◽  
Starch Accumulation ◽  
Adp Glucose Pyrophosphorylase ◽  
Expression And Activity

scholarly journals Effect of Foliar Application of Various Nitrogen Forms on Starch Accumulation and Grain Filling of Wheat (Triticum aestivum L.) Under Drought Stress

2021 ◽  
Vol 12 ◽  
Author(s):  
Xiaokang Lv ◽  
Yunpeng Ding ◽  
Mei Long ◽  
Wenxin Liang ◽  
Xiaoyan Gu ◽  
...  
Keyword(s):  
Triticum Aestivum ◽  
Drought Stress ◽  
Foliar Application ◽  
Grain Filling ◽  
Triticum Aestivum L ◽  
Starch Accumulation ◽  
Nitrogen Forms ◽  
Stress Injury ◽  
N Application ◽  
Foliar Nitrogen

Foliar nitrogen (N) fertilizer application at later stages of wheat (Triticum aestivum L.) growth is an effective method of attenuating drought stress and improving grain filling. The influences or modes of action of foliar application of various nitrogen forms on wheat growth and grain filling need further research. The objective of this study was to examine the regulatory effects of various forms of foliar nitrogen [NO3–, NH4+, and CO(NH2)2] on wheat grain filling under drought stress and to elucidate their underlying mechanisms. The relative effects of each nitrogen source differed in promoting grain filling. Foliar NH4+-N application notably prolonged the grain filling period. In contrast, foliar application of CO(NH2)2 and NO3–-N accelerated the grain filling rate and regulated levels of abscisic acid (ABA), z-riboside (ZR), and ethylene (ETH) in wheat grains. Analysis of gene expression revealed that CO(NH2)2 and NO3–-N upregulated the genes involved in the sucrose–starch conversion pathway, promoting the remobilization of carbohydrates and starch synthesis in the grains. Besides, activities of superoxide dismutase (SOD), peroxidase (POD), and catalase (CAT) were increased, whereas the content of malondialdehyde (MDA) declined under foliar nitrogen application (especially NH4+-N). Under drought stress, enhancement of carbohydrate remobilization and sink strength became key factors in grain filling, and the relative differences in the effects of three N forms became more evident. In conclusion, NH4+-N application improved the antioxidant enzyme system and delayed photoassimilate transportation. On the other hand, foliar applications of NO3–-N and CO(NH2)2 enhanced sink capacity and alleviated drought stress injury in wheat.

scholarly journals Genotype-dependent and heat-induced grain chalkiness in rice correlates with the expression patterns of starch biosynthesis genes

2020 ◽  
Author(s):  
Peter James Gann ◽  
Manuel Esguerra ◽  
Paul Allen Counce ◽  
Vibha Srivastava
Keyword(s):  
Expression Pattern ◽  
Large Subunit ◽  
Expression Patterns ◽  
Grain Filling ◽  
Starch Biosynthesis ◽  
Starch Synthase ◽  
Starch Accumulation ◽  
Air Pockets ◽  
Granular Morphology ◽  
Grain Chalkiness

ABSTRACTTo understand the molecular basis of environment-induced and genotype-dependent chalkiness, six rice genotypes showing variable chalk levels were subjected to gene expression analysis during reproductive stages. In the high chalk genotypes, the peak expressions of ADP-Glucose Pyrophosphorylase (AGPase) Large Subunit 4 (AGPL4) occurred in the stages before grain filling commenced, creating a temporal gap with the upregulation of Granule Bound Starch Synthase I (GBSSI) and Starch Synthase IIA (SSIIA). Whereas, in the low chalk genotypes, AGPL4 expression generally occurred in later stages, close to the upregulation of GBSSI and SSIIA. However, heat treatment altered the expression pattern and created a gap between the expression peaks of AGPL4, and GBSS1 and SSIIA. This change was accompanied by transformed granular morphology, increased protein content, and chalkiness in the grains. AGPL4 expression pattern may partially explain chalkiness as it contributes to the pool of ADP-Glucose for producing amylose and amylopectin, the major components of the starch. Down-regulation of AGPase during grain filling stages could result in a limited pool of ADP-Glucose leading to inefficient grain filling and air pockets that contribute to chalkiness. The study suggests a mechanism of grain chalkiness based on the coordination of the three starch biosynthesis genes in rice.Significance statementGenotype-dependent and heat-induced grain chalkiness in rice is partially based on the increased gap between the upregulation AGPase and that of GBSSI and SSIIA through reproductive stages. This temporal gap could limit starch accumulation and alter granular morphology, eventually leading to grain chalkiness.

scholarly journals Heritability and mode of gene action determination for grain filling rate and relative water content in hexaploid wheat

Genetika ◽  
2012 ◽  
Vol 44 (1) ◽  
pp. 25-32 ◽  
Author(s):  
Ahmad Golparvar
Keyword(s):  
Drought Stress ◽  
Water Content ◽  
Relative Water Content ◽  
Stress Condition ◽  
Gene Action ◽  
Grain Filling ◽  
Stress Conditions ◽  
Filling Rate ◽  
Grain Filling Rate ◽  
Relative Water

Mode of gene action, heritability and determination of the effective breeding strategy for improvement of physiological and traits specifically in drought stress conditions is very important. Therefore, this study was conducted by using two drought susceptible and tolerant wheat cultivars. Cultivars Sakha8 (tolerant) and Pishtaz (susceptible) as parents along with F1, F2, BC1 and BC2 generations were sown in a randomized complete block design with three replications in drought stress conditions. Results of analysis of variance indicated significant difference between generations as well as degree of dominance revealed over-dominance for the both traits. Fitting simple additive-dominance model designated that this model was not able to account for changes of traits relative water content and mean of grain filling rate. It was revealed that m-d-h-i-j model for relative water content and m-d-h-i model for mean of grain filling rate are the best models. Estimation of heritability and mode of gene action indicated that selection for improvement of traits studied in stress condition and specifically in early generations have medium genetic gain. In conclusion, grain filling rate is better than relative water content as indirect selection criteria to improve plant grain yield in drought stress condition.

scholarly journals Carbohydrate Dynamics in Maize Leaves and Developing Ears in Response to Nitrogen Application

Agronomy ◽  
2018 ◽  
Vol 8 (12) ◽  
pp. 302 ◽  
Author(s):  
Peng Ning ◽  
Yunfeng Peng ◽  
Felix Fritschi
Keyword(s):  
Grain Yield ◽  
Grain Filling ◽  
N Fertilization ◽  
Starch Accumulation ◽  
N Availability ◽  
Maize Grain Yield ◽  
Filling Phase ◽  
Maize Grain ◽  
Carbohydrate Dynamics ◽  
Maize Ear

Maize grain yield is considered to be highly associated with ear and leaf carbohydrate dynamics during the critical period bracketing silking and during the fast grain filling phase. However, a full understanding of how differences in N availability/plant N status influence carbohydrate dynamics and processes underlying yield formation remains elusive. Two field experiments were conducted to examine maize ear development, grain yield and the dynamics of carbohydrates in maize ear leaves and developing ears in response to differences in N availability. Increasing N availability stimulated ear growth during the critical two weeks bracketing silking and during the fast grain-filling phase, consequently resulting in greater maize grain yield. In ear leaves, sucrose and starch concentrations exhibited an obvious diurnal pattern at both silking and 20 days after silking, and N fertilization led to more carbon flux to sucrose biosynthesis than to starch accumulation. The elevated transcript abundance of key genes involved in starch biosynthesis and maltose export, as well as the sugar transporters (SWEETs) important for phloem loading, indicated greater starch turnover and sucrose export from leaves under N-fertilized conditions. In developing ears, N fertilization likely enhanced the cleavage of sucrose to glucose and fructose in the cob prior to and at silking and the synthesis from glucose and fructose to sucrose in the kernels after silking, and thus increasing kernel setting and filling. At the end, we propose a source-sink carbon partitioning framework to illustrates how N application influences carbon assimilation in leaves, transport, and conversions in developing reproductive tissues, ultimately leading to greater yield.

scholarly journals Effects of Drought Stress on Some Agronomic and Morpho-Physiological Traits in Durum Wheat Genotypes

2020 ◽  
Vol 12 (14) ◽  
pp. 5610
Author(s):  
Alireza Pour-Aboughadareh ◽  
Reza Mohammadi ◽  
Alireza Etminan ◽  
Lia Shooshtari ◽  
Neda Maleki-Tabrizi ◽  
...  
Keyword(s):  
Drought Stress ◽  
Grain Yield ◽  
Durum Wheat ◽  
Harvest Index ◽  
Plant Biomass ◽  
Geometric Mean ◽  
Grain Filling ◽  
Tolerance Index ◽  
Wheat Genotypes ◽  
Grain Filling Period

Durum wheat performance in the Mediterranean climate is limited when water scarcity occurs before and during anthesis. The present research was performed to determine the effect of drought stress on several physiological and agro-morphological traits in 17 durum wheat genotypes under two conditions (control and drought) over two years. The results of analysis of variance indicated that the various durum wheat genotypes responded differently to drought stress. Drought stress significantly reduced the grain filling period, plant height, peduncle length, number of spikes per plot, number of grains per spike, thousand grains weight, grain yield, biomass, and harvest index in all genotypes compared to the control condition. The heatmap-based correlation analysis indicated that grain yield was positively and significantly associated with phenological characters (days to heading, days to physiological maturity, and grain filling period), as well as number of spikes per plant, biomass, and harvest index under drought conditions. The yield-based drought and susceptible indices revealed that stress tolerance index (STI), geometric mean productivity (GMP), mean productivity (MP), and harmonic mean (HM) were positively and significantly correlated with grain yields in both conditions. Based on the average of the sum of ranks across all indices and a three-dimensional plot, two genotypes (G9 and G12) along with the control variety (G1) were identified as the most tolerant genotypes. Among the investigated genotypes, the new breeding genotype G12 showed a high drought tolerance and yield performance under both conditions. Hence, this genotype can be a candidate for further multi-years and locations test as recommended for cultivation under rainfed conditions in arid and semi-arid regions.

Heat Stress During Grain Filling in Maize: Effects on Carbohydrate Storage and Metabolism

1994 ◽  
Vol 21 (6) ◽  
pp. 829 ◽  
Author(s):  
GW Singletary ◽  
R Banisadr ◽  
PL Keeling
Keyword(s):  
Heat Stress ◽  
Seed Size ◽  
Starch Synthesis ◽  
Dry Weight ◽  
Grain Filling ◽  
Soluble Starch ◽  
Effect Of Temperature ◽  
Starch Accumulation ◽  
Maize Kernels

Heat stress during maize seed development can interfere with endosperm starch biosynthesis and reduce seed size, an important component of yield. Our objectives were to evaluate the direct influence of temperature during grain filling on kernel growth, carbohydrate accumulation, and corresponding endosperm metabolism. Kernels of maize were grown in vitro at 25�C until 15 or 16 days after pollination and then subjected to various temperatures for the remainder of their development. Mature kernel dry weight declined 45% in a linear fashion between 22 and 36�C. The rate of starch accumulation reached a maximum at approximately 32�C, and when measured at frequent intervals, declined only slightly with further temperature increase to 35�C. Reduced seed size resulted from an abbreviated duration of starch-related metabolism, which did not appear to be limited by endogenous sugars. Instead, a survey of 12 enzymes of sugar and starch metabolism indicated that ADP glucose pyrophosphorylase and soluble starch synthase were unique in displaying developmental peaks of activity which were compressed both in amount and time, similar to the effect of temperature on starch accumulation. We conclude that decreased starch synthesis in heat-stressed maize kernels results from a premature decline in the activity of these enzymes.

Reduced Starch Content and Sucrose Synthase Activity in Developing Endosperm of Barley Plants Grown at Elevated Temperatures

1988 ◽  
Vol 15 (3) ◽  
pp. 367 ◽  
Author(s):  
LC MacLeod ◽  
CM Duffus
Keyword(s):  
Elevated Temperatures ◽  
Starch Content ◽  
Grain Filling ◽  
Starch Accumulation ◽  
Grain Development ◽  
Irreversible Reduction ◽  
Short Period ◽  
Cleavage Enzyme ◽  
Grain Filling Period ◽  
Sucrose Cleavage

Starch accumulation is reduced when endosperms develop at elevated temperatures. Reduced starch deposition does not appear to be due to limiting assimilate levels during the grain filling period; on the contrary, endosperm sucrose may even be increased at the elevated temperature. Results indicate that elevated temperatures significantly reduce the activity of the sucrose cleavage enzyme UDPsucrose synthase (EC 2.4.1.13), found in the endosperm during grain development, and that these effects may be initiated by a relatively short period of thermal stress applied close to anthesis. It would appear that, when developing barley ears are exposed to elevated temperatures, there is an irreversible reduction in the capacity of the endosperm to convert sucrose to starch, caused by a decrease in the activity of at least one of the enzymes involved in this conversion pathway.

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