Cold Tolerance at Germination and Seedling Stages of Rice:  Methods of Evaluation and Characterization of Thirty Rice  Genotypes under Stress Conditions

Rice cold tolerance at the germination stage is important in Rio Grande do Sul (RS) where temperatures below 15°C prevent or reduce germination and plant establishment in early sowings. The present study aimed at identifying an adequate method for cold tolerance evaluation of the rice germination stage and at verifying the variability among 24 rice genotypes of different origins. Cold tolerance was evaluated in experiment I, germination under two conditions: 13°C for 28 days and 28°C for seven days, and in experiment II, germination under 28°C for 72 hours, 13°C for 96 hours and again 28°C for 72 hours. In experiment I measured characteristics were germination index, percentage of seeds with coleoptile length superior to 5 mm and percentage of reduction in coleoptile length due to cold. In experiment II the measured characteristic was coleoptile regrowth after the cold period. Cold tolerance varied among genotypes studied in both experiments, but only the percentage of reduction in coleoptile length and coleoptile regrowth allowed a better distinction between the tolerant checks and the susceptible one. In general, genotypes belonging to the Japonica subspecies presented higher cold tolerance than Indica, but there was variability within subspecies. The most adequate method of evaluation of cold tolerance is through percentage of reduction in coleoptile length and coleoptile regrowth. Among Japonica genotypes, Quilla 64117 and Diamante presented the highest cold tolerance, and among Indica, cultivars BR-IRGA 410 and IRGA 416 were the most cold tolerant at the germination stage.

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Experimental Characterization of the Reliability of 3-Terminal Dual-Damascene Copper Interconnect Trees

MRS Proceedings ◽

10.1557/proc-716-b8.13 ◽

2002 ◽

Vol 716 ◽

Cited By ~ 4

Author(s):

C. L. Gan ◽

C. V. Thompson ◽

K. L. Pey ◽

W. K. Choi ◽

F. Wei ◽

...

Keyword(s):

Stress Conditions ◽

Experimental Characterization ◽

Contact Lines ◽

Tree Structures ◽

Similar Test ◽

Dual Damascene ◽

Copper Interconnect ◽

Test Conditions

AbstractElectromigration experiments have been carried out on simple Cu dual-damascene interconnect tree structures consisting of straight via-to-via (or contact-to-contact) lines with an extra via in the middle of the line. As with Al-based interconnects, the reliability of a segment in this tree strongly depends on the stress conditions of the connected segment. Beyond this, there are important differences in the results obtained under similar test conditions for Al-based and Cu-based interconnect trees. These differences are thought to be associated with variations in the architectural schemes of the two metallizations. The absence of a conducting electromigrationresistant overlayer in Cu technology, and the possibility of liner rupture at stressed vias lead to significant differences in tree reliabilities in Cu compared to Al.

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Genetic Diversity of Selected Rice Genotypes under Water Stress Conditions

Plants ◽

10.3390/plants10010027 ◽

2020 ◽

Vol 10 (1) ◽

pp. 27

Author(s):

Mahmoud M. Gaballah ◽

Azza M. Metwally ◽

Milan Skalicky ◽

Mohamed M. Hassan ◽

Marian Brestic ◽

...

Keyword(s):

Genetic Diversity ◽

Water Stress ◽

Drought Stress ◽

Drought Tolerance ◽

Ssr Markers ◽

Similarity Index ◽

Stress Conditions ◽

Yield Potential ◽

Drought Tolerant ◽

Rice Genotypes

Drought is the most challenging abiotic stress for rice production in the world. Thus, developing new rice genotype tolerance to water scarcity is one of the best strategies to achieve and maximize high yield potential with water savings. The study aims to characterize 16 rice genotypes for grain and agronomic parameters under normal and drought stress conditions, and genetic differentiation, by determining specific DNA markers related to drought tolerance using Simple Sequence Repeats (SSR) markers and grouping cultivars, establishing their genetic relationship for different traits. The experiment was conducted under irrigated (normal) and water stress conditions. Mean squares due to genotype × environment interactions were highly significant for major traits. For the number of panicles/plants, the genotypes Giza179, IET1444, Hybrid1, and Hybrid2 showed the maximum mean values. The required sterility percentage values were produced by genotypes IET1444, Giza178, Hybrid2, and Giza179, while, Sakha101, Giza179, Hybrid1, and Hybrid2 achieved the highest values of grain yield/plant. The genotypes Giza178, Giza179, Hybrid1, and Hybrid2, produced maximum values for water use efficiency. The effective number of alleles per locus ranged from 1.20 alleles to 3.0 alleles with an average of 1.28 alleles, and the He values for all SSR markers used varied from 0.94 to 1.00 with an average of 0.98. The polymorphic information content (PIC) values for the SSR were varied from 0.83 to 0.99, with an average of 0.95 along with a highly significant correlation between PIC values and the number of amplified alleles detected per locus. The highest similarity coefficient between Giza181 and Giza182 (Indica type) was observed and are susceptible to drought stress. High similarity percentage between the genotypes (japonica type; Sakha104 with Sakha102 and Sakha106 (0.45), Sakha101 with Sakha102 and Sakha106 (0.40), Sakha105 with Hybrid1 (0.40), Hybrid1 with Giza178 (0.40) and GZ1368-S-5-4 with Giza181 (0.40)) was also observed, which are also susceptible to drought stress. All genotypes are grouped into two major clusters in the dendrogram at 66% similarity based on Jaccard’s similarity index. The first cluster (A) was divided into two minor groups A1 and A2, in which A1 had two groups A1-1 and A1-2, containing drought-tolerant genotypes like IET1444, GZ1386-S-5-4 and Hybrid1. On the other hand, the A1-2 cluster divided into A1-2-1 containing Hybrid2 genotype and A1-2-2 containing Giza179 and Giza178 at coefficient 0.91, showing moderate tolerance to drought stress. The genotypes GZ1368-S-5-4, IET1444, Giza 178, and Giza179, could be included as appropriate materials for developing a drought-tolerant variety breeding program. Genetic diversity to grow new rice cultivars that combine drought tolerance with high grain yields is essential to maintaining food security.

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Functional Characterization of DEAD-Box RNA Helicases in Arabidopsis thaliana under Abiotic Stress Conditions

Plant and Cell Physiology ◽

10.1093/pcp/pcn125 ◽

2008 ◽

Vol 49 (10) ◽

pp. 1563-1571 ◽

Cited By ~ 57

Author(s):

Jin Sun Kim ◽

Kyung Ae Kim ◽

Tae Rin Oh ◽

Chul Min Park ◽

Hunseung Kang

Keyword(s):

Arabidopsis Thaliana ◽

Abiotic Stress ◽

Functional Characterization ◽

Stress Conditions ◽

Rna Helicases ◽

Dead Box

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Characterization of glycine-rich RNA-binding proteins inBrassica napusunder stress conditions

Physiologia Plantarum ◽

10.1111/j.1399-3054.2012.01628.x ◽

2012 ◽

Vol 146 (3) ◽

pp. 297-307 ◽

Cited By ~ 12

Author(s):

Min Kyung Kim ◽

Hyun Ju Jung ◽

Dong Hyun Kim ◽

Hunseung Kang

Keyword(s):

Binding Proteins ◽

Rna Binding ◽

Rna Binding Proteins ◽

Stress Conditions

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Rice cold tolerance at the reproductive stage in a controlled environment

Scientia Agricola ◽

10.1590/s0103-90162006000300007 ◽

2006 ◽

Vol 63 (3) ◽

pp. 255-261 ◽

Cited By ~ 21

Author(s):

Renata Pereira da Cruz ◽

Sandra Cristina Kothe Milach ◽

Luiz Carlos Federizzi

Keyword(s):

Cold Tolerance ◽

Oryza Sativa L ◽

Variable Temperature ◽

Reproductive Stage ◽

Spikelet Fertility ◽

High Yield ◽

Cold Temperatures ◽

Cold Tolerant ◽

Rice Genotypes ◽

Highly Correlated

Cold tolerance of rice (Oryza sativa L.) during the reproductive stage is important to guarantee high yield under low temperature environments. Field selection, however, does not allow identification of adequate tolerance sources and limits selection of segregating lines due to variable temperature. The objective of this study was to devise methods for distinguishing rice genotypes as to their cold tolerance at the reproductive stage when evaluated under controlled temperature. The effect of cold temperatures was investigated in six rice genotypes at 17°C for varying length of time (three, five, seven and ten days) at two reproductive stages (microsporogenesis and anthesis). Cold tolerance was measured as the percentage of reduction in panicle exsertion and in spikelet fertility. Evaluating cold tolerance through the reduction in panicle exsertion did not allow for the distinction between cold tolerant from cold sensitive genotypes and, when the reduction in spikelet fertility was considered, a minimum of seven days was required to differentiate the genotypes for cold tolerance. Genotypes were more sensitive to cold at anthesis than at microsporogenesis and, as these stages were highly correlated, cold screening could be performed at anthesis only, since it is easier to determine. Rice cold tolerance at the reproductive stage may be characterized by the reduction in spikelet fertility due to cold temperature (17°C) applied for seven days at anthesis.

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Biochemical and functional characterization of Mycobacterium tuberculosis ketol-acid reductoisomerase

Microbiology ◽

10.1099/mic.0.001087 ◽

2021 ◽

Vol 167 (9) ◽

Author(s):

Nirbhay Singh ◽

Anu Chauhan ◽

Ram Kumar ◽

Sudheer Kumar Singh

Keyword(s):

Amino Acids ◽

Mycobacterium Tuberculosis ◽

Type Species ◽

Low Ph ◽

Stress Conditions ◽

Starvation Stress ◽

Content Type ◽

E Coli ◽

Link Type

Branched-chain amino acids (BCAAs) are essential amino acids, but their biosynthetic pathway is absent in mammals. Ketol-acid reductoisomerase (IlvC) is a BCAA biosynthetic enzyme that is coded by Rv3001c in Mycobacterium tuberculosis H37Rv (Mtb-Rv) and MRA_3031 in M. tuberculosis H37Ra (Mtb-Ra). IlvCs are essential in Mtb-Rv as well as in Escherichia coli . Compared to wild-type and IlvC-complemented Mtb-Ra strains, IlvC knockdown strain showed reduced survival at low pH and under low pH+starvation stress conditions. Further, increased expression of IlvC was observed under low pH and starvation stress conditions. Confirmation of a role for IlvC in pH and starvation stress was achieved by developing E. coli BL21(DE3) IlvC knockout, which was defective for growth in M9 minimal medium, but growth could be rescued by isoleucine and valine supplementation. Growth was also restored by complementing with over-expressing constructs of Mtb-Ra and E. coli IlvCs. The E. coli knockout also had a survival deficit at pH=5.5 and 4.5 and was more susceptible to killing at pH=3.0. The biochemical characterization of Mtb-Ra and E. coli IlvCs confirmed that both have NADPH-dependent activity. In conclusion, this study demonstrates the functional complementation of E. coli IlvC by Mtb-Ra IlvC and also suggests that IlvC has a role in tolerance to low pH and starvation stress.

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