Compact panicle architecture is detrimental for growth as well as sucrose synthase activity of developing rice kernels

2015 ◽  
Vol 42 (9) ◽  
pp. 875 ◽  
Author(s):  
B. B. Panda ◽  
A. K. Badoghar ◽  
K. Das ◽  
R. Panigrahi ◽  
E. Kariali ◽  
...  
Keyword(s):  
Sucrose Synthase ◽  
Recombinant Inbred Lines ◽  
Grain Filling ◽  
Active Period ◽  
Rt Pcr ◽  
Spikelet Number ◽  
Genetic Expression ◽  
Starch Concentration ◽  
Carbohydrate Concentration ◽  
Quantitative Appraisal

The increase of spikelet number in the panicles of modern super rice has made the architecture compact, as the extra spikelets are accommodated mostly on secondary branches than on primary branches. However, the grain yield did not improve because of poor grain filling, which was more visible in the basal spikelets than apical spikelets. The objective of this study was to examine the effect of the compactness and positional difference of spikelets in the panicle on grain filling by comparing the activity and genetic expression of starch synthesising enzymes in the developing kernels of lax-(Upahar and CR3856–45–11–2-7–2-5 (CR-45)) and compact-(Mahalaxmi and CR3856–29–14–2-1–1-1 (CR-29)) panicle cultivars. Upahar and Mahalaxmi are genetically related, whereas CR-45 and CR-29 are recombinant inbred lines. The grain carbohydrate concentration and activity of sucrose synthase (SUS) enzyme were estimated during the active period of grain filling. Further, expression of isoforms of SUS, ADP glucose pyrophosphorylase (APL and APS for large and small units respectively) and starch synthase (SS and GBSS for soluble and granule bound starch synthases respectively) were also assayed through PCR studies. The genotype approach used revealed grain SUS activity and starch concentration high and sugar concentration low in the lax- compared with compact-panicle cultivars and in the apical spikelets compared with basal ones. The margin of variation between apical and basal spikelets was higher in the compact- than the lax-panicle cultivars. Genetic expression of most of the isoforms of the enzymes was higher in the lax- than the compact-panicle cultivars as seen in RT–PCR studies. A quantitative appraisal of transcript levels of isoforms in the qRT–PCR identified greater expression of SUS3 in the basal spikelets of Upahar than that in Mahalaxmi and in CR-45 over CR-29, most prominently during the active period of grain filling. We conclude that proximal location as well as increased density of spikelets on panicles affected SUS3 expression in the basal spikelets. The metabolic dominance of a spikelet in rice panicle is dependent on the expression of the genes for different isoforms of starch synthesising enzymes, but the expression of SUS3 could be more specific than the others. SUS3 expression is most active during grain filling of the lax-panicle cultivars, but its dominance is reduced significantly in the kernels of the compact-panicle cultivars.

Identification of Novel QTLs for Spikelet Fertility, Panicle Compactness and Phytohormone Ethylene to Decipher Poor Grain Filling of Basal Spikelets in Dense Panicle Rice

2021 ◽  
Author(s):  
Sudhanshu Sekhar ◽  
Jitendra Kumar ◽  
Soumya Mohanty ◽  
Niharika Mohanty ◽  
Rudraksh Shovan Panda ◽  
...  
Keyword(s):  
Candidate Genes ◽  
Ethylene Production ◽  
Recombinant Inbred Lines ◽  
Grain Filling ◽  
Spikelet Fertility ◽  
Rice Cultivars ◽  
Spikelet Number ◽  
Spikelet Sterility ◽  
Ubiquitin Protein Ligase ◽  
Comparative Expression Analysis

Abstract High grain number is positively correlated with grain yield in rice, but it is compromised because of poor filling of basal spikelets in dense panicle bearing numerous spikelets. The phenomenon that turns the basal spikelets of compact panicle sterile in rice is largely unknown. In order to understand the factor(s) that possibly determines such spikelet sterility in compact panicle cultivars, QTLs and candidate genes were identified for spikelet fertility percentage, panicle compactness and ethylene production that significantly influence the grain filling using recombinant inbred lines developed from a cross between indica rice cultivars, PDK Shriram (compact, high spikelet number) and Heera (lax, low spikelet number). Novel QTLs, qSFP1.1, qSFP3.1 and qSFP6.1 for spikelet fertility percentage; qIGS3.2 and qIGS4.1 for panicle compactness; and qETH1.2, qETH3.1 and qETH4.1 for ethylene production were consistently identified in both kharif seasons of 2017 and 2018. The comparative expression analysis of candidate genes like ERF3, AP2-like ethylene-responsive transcription factor, EREBP, GBSS1, E3 ubiquitin-protein ligase GW2, and LRR receptor-like serine/threonine-protein kinase ERL1 associated with identified QTLs revealed their role in poor grain filling of basal spikelets in dense panicle. These candidate genes thus could be important for improving grain filling in compact-panicle rice cultivars through biotechnological interventions.

scholarly journals Identification of novel QTLs for grain fertility and associated traits to decipher poor grain filling of basal spikelets in dense panicle rice

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Sudhanshu Sekhar ◽  
Jitendra Kumar ◽  
Soumya Mohanty ◽  
Niharika Mohanty ◽  
Rudraksh Shovan Panda ◽  
...  
Keyword(s):  
Candidate Genes ◽  
Ethylene Production ◽  
Recombinant Inbred Lines ◽  
Grain Filling ◽  
Spikelet Fertility ◽  
Rice Cultivars ◽  
Spikelet Number ◽  
Spikelet Sterility ◽  
Ubiquitin Protein Ligase ◽  
Comparative Expression Analysis

AbstractHigh grain number is positively correlated with grain yield in rice, but it is compromised because of poor filling of basal spikelets in dense panicle bearing numerous spikelets. The phenomenon that turns the basal spikelets of compact panicle sterile in rice is largely unknown. In order to understand the factor(s) that possibly determines such spikelet sterility in compact panicle cultivars, QTLs and candidate genes were identified for spikelet fertility and associated traits like panicle compactness, and ethylene production that significantly influences the grain filling using recombinant inbred lines developed from a cross between indica rice cultivars, PDK Shriram (compact, high spikelet number) and Heera (lax, low spikelet number). Novel QTLs, qSFP1.1, qSFP3.1, and qSFP6.1 for spikelet fertility percentage; qIGS3.2 and qIGS4.1 for panicle compactness; and qETH1.2, qETH3.1, and qETH4.1 for ethylene production were consistently identified in both kharif seasons of 2017 and 2018. The comparative expression analysis of candidate genes like ERF3, AP2-like ethylene-responsive transcription factor, EREBP, GBSS1, E3 ubiquitin-protein ligase GW2, and LRR receptor-like serine/threonine-protein kinase ERL1 associated with identified QTLs revealed their role in poor grain filling of basal spikelets in a dense panicle. These candidate genes thus could be important for improving grain filling in compact-panicle rice cultivars through biotechnological interventions.

Effects of Exposure of Wheat Ears to High Temperature on Dry Matter Accumulation and Carbohydrate Metabolism in the Grain of Two Cultivars. I. Immediate Responses

1991 ◽  
Vol 18 (2) ◽  
pp. 165 ◽  
Author(s):  
CF Jenner
Keyword(s):  
High Temperature ◽  
Sucrose Synthase ◽  
Dry Matter ◽  
Starch Synthesis ◽  
Grain Filling ◽  
Mass Action ◽  
Dry Matter Accumulation ◽  
Partial Explanation ◽  
Calculated Mass ◽  
Percentage Basis

Ears of wheat were exposed for up to 7 days during the grain-filling stage to high temperature (35�C day/25�C night) and metabolic responses in the grain were compared to those in ears maintained at lower temperatures (21�C day/16�C night). Two cultivars of wheat known to differ in their post-anthesis tolerance of high temperature were compared. Raising the temperature resulted in a small increase in the rate of dry matter accumulation: both cultivars responded similarly. Sucrose content of the endosperm was either not affected or increased by raising the temperature. Raising the temperature had differential effects on glucose and fructose content: fructose was substantially reduced while glucose was either unaffected or slightly increased. After raising the temperature the concentrations of all three hexose phosphates measured, glucose-6-phosphate (G-6-P), glucose-1-phosphate (G-1-P) and fructose-6-phosphate (F-6-P), were reduced similarly on a percentage basis and to about the same extent as fructose. The concentration of the sugar nucleotide (UDP-glucose) resulting from the breakdown of sucrose by sucrose synthase was also reduced at high temperature. Judging from calculated mass-action ratios, all three catalytic steps involved in the interconversion of the metabolites mentioned above were close to equilibrium, and only one mass action ratio (for sucrose synthase) was affected by heating: it was doubled. Although temperature clearly resulted in changes in the reaction catalysed by sucrose synthase, it was not clear how temperature had acted. Concentration of the precursor for starch synthesis (ADP-glucose) was slightly lower in both cultivars at the higher temperature. Taken together the responses could provide at least a partial explanation for the smallness of the increase in starch deposition with increase in temperature, but do not explain the different responses of these two cultivars to high temperature.

scholarly journals Growth and Carbon Partitioning in Cranberry Uprights as Influenced by Nitrogen Supply

HortScience ◽  
2006 ◽  
Vol 41 (7) ◽  
pp. 1552-1558 ◽  
Author(s):  
Justine E. Vanden Heuvel ◽  
Joan R. Davenport
Keyword(s):  
Chlorophyll Concentration ◽  
Carbon Partitioning ◽  
Nitrogen Supply ◽  
Soil N ◽  
N Application ◽  
Current Season ◽  
Starch Concentration ◽  
Carbohydrate Concentration ◽  
Nonstructural Carbohydrate ◽  
Net Carbon Exchange

Information on growth and carbon partitioning of cranberry uprights in response to soil N application is lacking. Therefore, two experiments were initiated on `Stevens' uprights to determine the effect of soil-applied N on tissue N, growth, net carbon exchange (NCER), and nonstructural carbohydrate production of uprights of `Stevens' cranberry. Tissue N concentration increased linearly with increasing soil N but was greater in vegetative uprights than in fruiting uprights. Current season growth on vegetative uprights was more responsive to tissue N than on fruiting uprights. Although chlorophyll concentration and NCER increased with increased soil N, upright starch concentration and often total nonstructural carbohydrate concentration decreased with increased soil N at midfruit development and preharvest, especially in vegetative uprights.

scholarly journals Correlation and path analysis in recombinant inbred lines (RILs) of wheat (Trticum aestivum L.)

2016 ◽  
Vol 8 (2) ◽  
pp. 826-832
Author(s):  
Ramesh Ramesh ◽  
Shailesh Marker ◽  
S. Muniswamy ◽  
Yamanura Yamanura
Keyword(s):  
Grain Yield ◽  
Recombinant Inbred ◽  
Recombinant Inbred Lines ◽  
Flag Leaf ◽  
Correlation Coefficients ◽  
Grain Filling ◽  
Inbred Lines ◽  
Spike Length ◽  
Grain Filling Period ◽  
Selection Of

Correlation and path coefficient analysis were studied in 22 heat tolerant Recombinant Inbred Lines (RILs) of wheat. Analysis of variance revealed the significant difference among genotypes for all the characters. Suggested that there was ample scope for selection of promising RILs for yield improvement. A wide range of variability was exhibited by most of the traits. The results of correlation studies indicated that genotypic correlation coefficients were higher in magnitude than their corresponding phenotypic correlation coefficients for all the traits which indicated that association among these characters was under genetic control and indicating the preponderance of genetic variance in expression of characters. Grain yield per plant had high, significant and positive association with number of grains per spike, spike weight, spike length, canopy temperature depression, tillers per plant, grain filling period and chlorophyll content both at genotypic and phenotypic levels indicating that these traits were main yield attributing traits. Path analysis revealed that grains per spike, tillers per plant, spike length, had the highest positive direct effect on grain yield followed by flag leaf length, flag leaf width, days 50% heading, plant height, grain filling period, membrane stability and days to maturity at genotypic level. The selection of characters such as grains per spike, tillers per plant, spike length and spike weight would be helpful for further improvement in RILs of wheat.

Assimilate Partitioning Within Floret Components of Contrasting Rice Spikelets Producing Qualitatively Different Types of Grains

1996 ◽  
Vol 23 (1) ◽  
pp. 85 ◽  
Author(s):  
R Patel ◽  
PK Mohapatra
Keyword(s):  
Sucrose Synthase ◽  
Grain Quality ◽  
Starch Synthesis ◽  
Grain Filling ◽  
Poor Quality ◽  
Primary Branch ◽  
Assimilate Partitioning ◽  
Different Types ◽  
Carbohydrate Contents ◽  
Rice Panicles

Grain quality, soluble and insoluble carbohydrate contents, and activities of two key enzymes (sucrose synthase and invertase) involved in starch synthesis in the endosperm were measured in the components of the fertile florets of spikelets located at the tip of the uppermost primary branch (top spikelet), and the penultimate position of the lowermost primary branch (basal spikelet) of rice panicles during the period begining some days before anthesis to maturity. The basal spikelet, which reached anthesis a week after the top spikelet, produced a partially filled poor quality grain in contrast to the good quality high density grain produced by the latter. Sucrose was the major translocatable sugar in the organs of the fertile florets of both top and basal spikelets, and poor grain filling of the latter was not caused by deficiency of this material due to any resistance in supply in the external protective organs. The activities of the sucrose synthase and invertase were higher and lower respectively, in the endosperm cells of the top spikelet compared with the basal spikelet. We conclude that poor synthesis of the starch leading to partial grain filling in the basal spikelet is due to a lower activity of sucrose synthase.

scholarly journals Sucrose transport and Sucrose Synthase activity control the source-sink relationship for biomass and grain yield in rice

2020 ◽  
Author(s):  
Jyotirmaya Mathan ◽  
Anuradha Singh ◽  
Aashish Ranjan
Keyword(s):  
Grain Yield ◽  
Wild Rice ◽  
Sucrose Synthase ◽  
Grain Filling ◽  
Cultivated Rice ◽  
Sucrose Transport ◽  
Cleavage Activity ◽  
In The Wild ◽  
Source Sink ◽  
Grain Filling Stage

AbstractThe source-sink relationship is key to overall crop performance. Detailed understanding of the factors that determine source-sink dynamics is imperative for the balance of biomass and grain yield in a crop plant. We investigated the differences in the source-sink relationship between a cultivated rice Oryza sativa cv. Nipponbare and a wild rice Oryza australiensis that show striking differences in biomass and grain yield. The wild rice, accumulating higher biomass, was not only photosynthetically efficient but also had efficient sucrose export from leaves. However, sucrose mobilization to the grains was limited due to impaired vasculature and sucrose transporter functions at the reproductive tissues of the wild rice. High cleavage activity of Sucrose Synthase followed by higher expression of Cellulose Synthase genes in the wild rice stem efficiently utilized photosynthates for the synthesis of structural carbohydrates, resulting in high biomass. In contrast, the source-sink relationship favored high grain yield in Nipponbare via accumulation of transitory starch in the stem, due to higher expression of starch biosynthetic genes, which is mobilized to panicles at the grain filling stage. Thus, sucrose transport along with functions of key sugar metabolic enzymes explained the differences in the source-sink relationship between the selected cultivated and wild rice.

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.

Ethylene inhibitors improve dry matter partitioning and development of late flowering spikelets on rice panicles

2000 ◽  
Vol 27 (4) ◽  
pp. 311 ◽  
Author(s):  
Pravat Kumar Mohapatra ◽  
Pradeep Kumar Naik ◽  
Rajesh Patel
Keyword(s):  
Growth And Development ◽  
Grain Filling ◽  
Soluble Carbohydrate ◽  
Ethylene Synthesis ◽  
Ethylene Inhibitors ◽  
Synthesis Inhibitor ◽  
Dry Matter Partitioning ◽  
Carbohydrate Concentration ◽  
Branch Development ◽  
Rice Panicles

Primary branch development of the rice panicle was in the order of a basipetal sequence from the top to the bottom at the time of anthesis. Delayed development of spikelets on the proximal branches of the panicle resulted in reduced grain filling. Two experiments were carried out to manipulate growth and development of the proximal spikelets with exogenous application of chemicals regulating formation or action of ethylene. In the first experiment, inhibitors of ethylene synthesis (cobalt) and action (silver) improved grain biomass and specific gravity of the basal spikelets, while 2-chloroethylphosphonic acid (CEPA) depressed these parameters significantly. In the second experiment, the ethylene synthesis inhibitor 1-aminoethoxyvinylglycine (AVG) promoted spikelet development on the basal primary branches and improved their survival and grain biomass. On the contrary, the ethylene precursor 1-aminocyclopropane-1- carboxylic acid (ACC) inhibited growth and development of these spikelets. The action of AVG was reversed when ACC was applied in combination with AVG. In both experiments, the chemicals did not influence growth and development of the superior spikelets on the apical primary branches of the panicle. Depression of growth and development by CEPA or ACC coincided with a concomitant rise in soluble carbohydrate concentration of the spikelets, whereas treatments with ethylene inhibitors decreased the concentration of the materials. The role of ethylene in metabolic dominance of the apical spikelets and its impact on grain yield of rice panicles is discussed.

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