scholarly journals Mechanism of anoxic tolerance in backcross lines developed through Jyothi x Swarna-Sub 1 under submergence stress.

2020 ◽  
Vol 80 (04) ◽  
Author(s):  
Deepa John ◽  
K. S. Shylaraj

Rice varieties adapted to flash flood exhibit submergence tolerance by maintaining reduced shoot elongation under submerged conditions. This study focuses on the two main physiological traits leading to flash flood tolerance- high survival percentage with reduced shoot elongation under submergence and increased rate of alcoholic fermentation. Sub1introgressed BC3F2 lines exhibited higher survival percentage with moderate shoot elongation under submergence stress for fourteen days similar to the donor parent Swarna- Sub1. Enzymatic activities of alcohol dehydrogenase and pyruvate decarboxylase were monitored for fourteen days under submergence stress. The developed Sub1 introgressed lines and the donor parent Swarna-Sub1 showed higher rates of alcohol dehydrogenase and pyruvate decarboxylase activities under submergence stress thereby maintaining optimum rates of alcoholic fermentation. The findings of this study confirmed the expression of tolerance mechanism in the Sub1introgressedJyothi Backcross Inbred lines under submergence stress.

HortScience ◽  
1999 ◽  
Vol 34 (3) ◽  
pp. 514A-514
Author(s):  
Yuehe Huang ◽  
David H. Picha ◽  
Anthony W. Kilili

`Beauregard' sweetpotato (Ipomoea batatas L. Lam) roots were maintained under different controlled atmospheres ranging from 0% to 21% O2 at 22 °C in two separate trials for 14 days to study changes in activities of pyruvate decarboxylase (PDC) and alcohol dehydrogenase (ADH). Trial I showed no difference in activities of PDC and ADH between 0% and 1% O2, or among 2%, 5%, and 21% O2. Both PDC and ADH activities were significantly higher at 0% and 1% O2 compared to the 2%, 5%, and 21% O2 atmospheres. In trial II, both enzyme activities were lower at 1.5% O2 than at 0% O2, but higher than at 10% and 21% O2 atmospheres. The combined data of the two trials showed a very strong correlation between PDC and ADH activities (R2 = 0.86). In addition, a strong correlation existed between PDC activity and acetaldehyde concentration (R2 = 0.95). The maximal activities were at pH 6.5 for PDC and at pH 8.5 for ADH in the direction of acetaldehyde-to-ethanol. The results suggest that 1.5% O2 is the critical point for the transition from aerobic to anaerobic metabolism in CA storage of sweetpotato roots, and PDC is the key enzyme in alcoholic fermentation.


Author(s):  
Nikita Kumari ◽  
Rajesh Kumar ◽  
Avinash Kumar

Present investigation was carried out with 240 mutant lines developed from different combination of gamma rays and ethyl methyl sulfonate on three rice varieties i.e FR13A, FR13B and Labella along with three untreated checks (FR13A, FR13B and Labella). These were evaluated for their survival percentage under submerged condition and yield potential along with 9 other morpho-physiological traits using Type 2 modified augmented design during Kharif season of 2017 in the agroclimatic region of north bihar, India. Analysis of variance revealed highly significant differences among the mutant lines for all morpho-physiological characters under study. Higher magnitude of phenotypic coefficient of variation (PCV), genotypic coefficient of variation (GCV), heritability (broad sense) and genetic advance as percentage of mean were observed for number of tillers per plant, number of fertile tillers per plant, relative shoot elongation and survival percentage, indicating that these traits could be used as selection indices for yield improvement and submergence tolerance. Association study revealed that number of tillers per plant and survival percentage had significant positive high to moderate direct association with grain yield per plant under submergence condition. Thus, these traits may be used as selection criteria in further crop improvement programmes for submergence tolerance.


2021 ◽  
Vol 22 (24) ◽  
pp. 13365
Author(s):  
Yong-Pei Wu ◽  
Shu-Mei Wang ◽  
Yu-Chi Chang ◽  
Chi Ho ◽  
Yu-Chia Hsu

Flash flooding is a major environmental stressor affecting rice production worldwide. DT3 is a drought-tolerant, recurrent parent with a good yield, edible quality, and agronomic traits akin to those of an elite Taiwanese variety, Taiken9 (TK9). Progenies carrying Sub1A can enhance submergence stress tolerance and can be selected using the marker-assisted backcross (MAB) breeding method. For foreground selection, Sub1A and SubAB1 were utilized as markers on the BC2F1, BC3F1, and BC3F2 generations to select the submergence-tolerant gene, Sub1A. Background selection was performed in the Sub1A-BC3F2 genotypes, and the percentages of recurrent parent recovery within individuals ranged from 84.7–99.55%. BC3F3 genotypes (N = 100) were evaluated for agronomic traits, yield, and eating quality. Four of the eleven BC3F4 lines showed good yield, yield component, grain, and eating quality. Four BC3F4 lines, SU39, SU40, SU89, and SU92, exhibited desirable agronomic traits, including grain quality and palatability, consistent with those of DT3. These genotypes displayed a high survival rate between 92 and 96%, much better compared with DT3 with 64%, and demonstrated better drought tolerance compared to IR64 and IR96321-345-240. This study provides an efficient and precise MAB strategy for developing climate-resilient rice varieties with good grain quality for flood-prone regions.


2021 ◽  
Vol 8 (3) ◽  
Author(s):  
Pratyasha Samanta ◽  
Abhra Chakrabarti ◽  
Narottam Dey

All the modern high yielding rice varieties precariously respond to flooding, although a number of landraces are tolerant to wide range of flooding with penalty of low yield. Stage-specific flood tolerance experiment was performed at three different conditions for three different growth stages from germination to vegetative stage for five such selected landraces, along with a flood-resistant quiescent variety (FR13A), a sensitive line (IR42), an improved cultivar (Swarna) and one Sub1 loci introgressed improved line (Swarna-Sub1). Different morpho-physiological traits at each stage were observed and genotypes were evaluated by these quantifiable traits to understand their underwater performance. All the studied landraces represented strong seed germination and faster coleoptile elongation than FR13A, Swarna and Swarna-Sub1 under water. At early seedling stage var. Kumrogarh embraced with highest number of seedlings with leaves and extended greater leaf portion above the water. Shoot elongation associated with internodal and petiole/blade elongation and well developed aerenchyma tissue facilitated vegetative tissues to survive. In this stage, Kumrogarh had highest plant height but Bakui had highest internodal length which indicated that kumrogarh might have the greater leaf sheath or blade elongation up to day 21 and also smaller increase (%) in air cavity formation at day 21 which made the stem to be upright devoid of lodging. All these results indicated that the studied landraces are the potential resources for submergence avoiding response for all the stages and should be elaborately investigated for future breeding programme. The rice line kumrogarh may be one of the potent traditional rice which can withstand all sorts of submergence by virtue of all the stage-specific attributes under submergence stress.


Genetics ◽  
1978 ◽  
Vol 90 (1) ◽  
pp. 161-191
Author(s):  
W van Delden ◽  
A C Boerema ◽  
A Kamping

ABSTRACT The allozyme polymorphism at the alcohol dehydrogenase locus in Drosophila melanogaster was studied in order to obtain experimental evidence about the maintenance of this polymorphism. Populations started with different initial allele frequencies from homozygous F and S lines showed a convergence of frequencies on regular food at 25°, leading to values equal to those in the base populations. These results were interpreted as due to some kind of balancing selection. In populations kept at 29.8°, a lower equilibrium F frequency was attained. Addition of ethanol and some other alcohols to the food gave a rapid increase in F frequency, and high humidity decreased the F frequency slightly. Combination or alternation of ethanol and high humidity had variable effects in the populations tested. For a further analysis of the allele-frequency changes, estimates were obtained for egg-to-adult survival under different conditions and for adult survival on ethanol-supplemented food. On ethanol food (both at regular and high humidity), egg-to-adult survival of SS homozygotes was considerably lower than that of the FF and FS genotypes. Under regular conditions of food, temperature and humidity, a tendency to heterozygote superiority was observed, while at high humidity a relative high survival of SS was noticed in some tests. Adult survival of SS was lower than that of FF, but FS was generally intermediate, though the degree of dominance differed between populations. The results are consistent with the hypothesis of the occurrence of selection at the Adh locus.


1997 ◽  
Vol 122 (1) ◽  
pp. 107-111 ◽  
Author(s):  
Hisashi Kato-Noguchi ◽  
Alley E. Watada

Carrot (Daucus carota L.) root shreds were stored under a continuous flow of 0.5% and 2% O2 (balance N2) or in air for 7 days at 5 and 15 °C to study the regulation of ethanolic fermentation metabolism. Low-O2 atmospheres of 0.5% and 2% caused increases in ethanol and acetaldehyde concentrations and the activities of alcohol dehydrogenase (ADH) and pyruvate decarboxylase (PDC) compared to air. By day 3, ethanol increased 38-, 25-, 13-, and 9.5-fold; acetaldehyde increased 20-, 13-, 7.7-, and 5.6-fold; ADH increased 7.6-, 6.3-, 3.8-, and 2.7-fold; and PDC increased 4.2-, 3.9-, 2.3-, and 2.2-fold in samples at 0.5% O2 at 15 or 5 °C and at 2% O2 at 15 or 5 °C, respectively, compared with corresponding samples in air. These results indicate that ethanolic fermentation was accelerated more in the 0.5% than in the 2% O2 atmosphere and more at 15 °C than at 5 °C. The acceleration of ethanolic fermentation may allow production of some ATP, which may permit the carrot tissues to survive.


1992 ◽  
Vol 38 (12) ◽  
pp. 1313-1319 ◽  
Author(s):  
C. S. Tsai ◽  
J.-L. Shi ◽  
B. W. Beehler ◽  
B. Beck

The activities of key enzymes that are members of D-glucose metabolic pathways in Schizosaccharomyces pombe undergoing respirative, respirofermentative, and fermentative metabolisms are monitored. The steady-state activities of glycolytic enzymes, except phosphofructokinase, decrease with a reduced efficiency in D-glucose utilization by yeast continuous culture. On the other hand, the enzymic activities of pentose monophosphate pathway reach the maximum when the cell mass production of the cultures is optimum. Enzymes of tricarboxylate cycle exhibit the maximum activities at approximately the washout rate. The steady-state activity of pyruvate dehydrogenase complex increases rapidly when D-glucose is efficiently utilized. By comparison, the activity of pyruvate decarboxylase begins to increase only when ethanol production occurs. Depletion of dissolved oxygen suppresses the activity of pyruvate dehydrogenase complex but facilitates that of pyruvate decarboxylase. Acetate greatly enhances the acetyl CoA synthetase activity. Similarly, ethanol stimulates alcohol dehydrogenase and aldehyde dehydrogenase activities. Evidence for the existence of alcohol dehydrogenase isozymes in the fission yeast is presented. Key words: yeast, glucose-metabolizing enzymes.


2000 ◽  
Vol 66 (8) ◽  
pp. 3151-3159 ◽  
Author(s):  
Fabienne Remize ◽  
Emilie Andrieu ◽  
Sylvie Dequin

ABSTRACT Acetic acid plays a crucial role in the organoleptic balance of many fermented products. We have investigated the factors controlling the production of acetate by Saccharomyces cerevisiaeduring alcoholic fermentation by metabolic engineering of the enzymatic steps involved in its formation and its utilization. The impact of reduced pyruvate decarboxylase (PDC), limited acetaldehyde dehydrogenase (ACDH), or increased acetoacetyl coenzyme A synthetase (ACS) levels in a strain derived from a wine yeast strain was studied during alcoholic fermentation. In the strain with the PDC1gene deleted exhibiting 25% of the PDC activity of the wild type, no significant differences were observed in the acetate yield or in the amounts of secondary metabolites formed. A strain overexpressingACS2 and displaying a four- to sevenfold increase in ACS activity did not produce reduced acetate levels. In contrast, strains with one or two disrupted copies of ALD6, encoding the cytosolic Mg2+-activated NADP-dependent ACDH and exhibiting 60 and 30% of wild-type ACDH activity, showed a substantial decrease in acetate yield (the acetate production was 75 and 40% of wild-type production, respectively). This decrease was associated with a rerouting of carbon flux towards the formation of glycerol, succinate, and butanediol. The deletion of ALD4, encoding the mitochondrial K+-activated NAD(P)-linked ACDH, had no effect on the amount of acetate formed. In contrast, a strain lacking both Ald6p and Ald4p exhibited a long delay in growth and acetate production, suggesting that Ald4p can partially replace the Ald6p isoform. Moreover, the ald6 ald4 double mutant was still able to ferment large amounts of sugar and to produce acetate, suggesting the contribution of another member(s) of the ALDfamily.


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