OsSIG2A is required for chloroplast development in rice (Oryza sativa L.) at low temperature by regulating plastid genes expression

2019 ◽  
Vol 46 (8) ◽  
pp. 766 ◽  
Author(s):  
Yang Yu ◽  
Zhenling Zhou ◽  
Hanchun Pu ◽  
Baoxiang Wang ◽  
Yunhui Zhang ◽  
...  
Keyword(s):  
Low Temperature ◽  
Low Temperatures ◽  
Chloroplast Development ◽  
Oryza Sativa L ◽  
Photosynthetic Apparatus ◽  
Development Stage ◽  
Specific Gene ◽  
Genes Expression ◽  
Young Leaves

The chloroplast is an essential photosynthetic apparatus that is more sensitive to low temperatures than other organelles. Sigma factors were revealed regulating specific gene expression for maintaining photosynthetic efficiency and adapting to physiological and environmental conditions. However, the regulatory mechanisms of SIG genes supporting chloroplast development under low temperature in rice have not yet been reported. Here, we uncovered the essential role of OsSIG2A in rice chloroplast development at low temperatures by a newly reported thermo-sensitive chlorophyll deficient 12 (tcd12) mutant, which exhibited albino leaves with decreased chlorophyll content and malformed chloroplasts at seedling stage under low temperature. OsSIG2A is a typical chloroplast-localised RNA polymerase sigma factor, and constitutively expresses in different rice tissues, especially for young leaves and stems. Moreover, the transcription level of both PEP- and NEP- dependent genes, which are necessary for chloroplast development at early leaf development stage, was greatly affected in the tcd12 mutant under low temperature. Taken together, our findings indicate that OsSIG2A is required for early chloroplast differentiation under low temperatures by regulating plastid genes expression.

Low temperature induced spikelet sterility in rice. II. Effects of panicle and root temperatures

2003 ◽  
Vol 54 (10) ◽  
pp. 947 ◽  
Author(s):  
T. A. Gunawardena ◽  
S. Fukai ◽  
F. P. C. Blamey
Keyword(s):  
Low Temperature ◽  
Low Temperatures ◽  
Oryza Sativa L ◽  
Pollen Grains ◽  
Development Stage ◽  
Dominant Factor ◽  
Microspore Development ◽  
Root Temperature ◽  
Spikelet Sterility ◽  
Germinated Pollen

Low temperatures impose restrictions on rice (Oryza sativa L.) production at high latitudes. This study is related to low temperature damage that can arise mid-season during the panicle development phase. The objective of this study was to determine whether low temperature experienced by the root, panicle, or foliage is responsible for increased spikelet sterility. In temperature-controlled glasshouse experiments, water depth, and water and air temperatures, were changed independently to investigate the effects of low temperature in the root, panicle, and foliage during microspore development on spikelet sterility. The total number of pollen and number of engorged pollen grains per anther, and the number of intercepted and germinated pollen grains per stigma, were measured. Spikelet sterility was then analysed in relation to the total number of pollen grains per spikelet and the efficiency with which these pollen grains became engorged, were intercepted by the stigma, germinated, and were involved in fertilisation. There was a significant combined effect of average minimum panicle and root temperatures on spikelet sterility that accounted for 86% of the variation in spikelet sterility. Total number of pollen grains per anther was reduced by low panicle temperature, but not by low root temperature. Whereas engorgement efficiency (the percentage of pollen grains that were engorged) was determined by both root and panicle temperature, germination efficiency (the percentage of germinated pollen grains relative to the number of engorged pollen grains intercepted by the stigma) was determined only by root temperature. Interception efficiency (i.e. percentage of engorged pollen grains intercepted by the stigma), however, was not affected by either root or panicle temperature. Engorgement efficiency was the dominant factor explaining the variation in spikelet sterility. It is concluded that both panicle and root temperature affect spikelet sterility in rice when the plant encounters low temperatures during the microspore development stage.

DISTINGUISHING THE EFFECTS OF GENOTYPE AND SEED PHYSIOLOGICAL AGE ON LOW TEMPERATURE TOLERANCE OF RICE (ORYZA SATIVA L.)

2006 ◽  
Vol 42 (3) ◽  
pp. 337-349 ◽  
Author(s):  
M. G. ALI ◽  
R. E. L. NAYLOR ◽  
S. MATTHEWS
Keyword(s):  
Low Temperature ◽  
Low Temperatures ◽  
Oryza Sativa L ◽  
Ageing Time ◽  
Physiological State ◽  
Thermal Time ◽  
Physiological Age ◽  
Base Temperature ◽  
Seed Moisture Content ◽  
Rice Genotypes

When differences are observed between genotypes in their response to low temperatures at germination, it has been generally assumed these are purely genetic. Laboratory experiments were carried out to evaluate the effects of physiological age on the temperature responses of 13 rice genotypes from Bangladesh in order to clarify whether (a) differences in seed germination at low temperature represented genetic differences or differences in the physiological state of the particular seed lot used and (b) whether genotype performance at higher temperatures was indicative of performance at lower temperatures. A higher initial seed moisture content (mc) was associated with lower initial viability (Ki). The base temperature for germination differed by less than 1 °C between genotypes. Seeds remaining ungerminated at low temperatures usually germinated when transferred to 21 °C. The thermal time requirement to reach t50 (θ) differed widely between genotypes. Lower optimum temperatures for germination were associated with lower thermal time requirements. Ageing seeds for 24 hours at 24 % mc and 45 °C significantly reduced final germination on a thermal gradient table at all temperatures below 20.8 °C in genotype BR29 but only below 16.5 °C in BR11. The rates of germination (seeds d−1) of aged seeds were also lower at all temperatures. Germination of high quality seeds of four genotypes were compared at 21 °C and 11 °C both before and after ageing (at 24 % mc and 45 °C). Ageing consistently reduced the rates of germination at both 21 °C and 11 °C. Increased ageing time progressively reduced the rate of germination of all seed lots at both temperatures. The rates of germination at 11 °C and 21 °C were positively and significantly (p < 0.01) related to final germination at the lower temperature of 11 °C. These results demonstrate that seed physiological quality as well as genotype might influence the final germination and rate of germination of rice genotypes at low temperatures. This information will be useful for breeders involved in selection of lines suitable for growing in cooler seasons.

scholarly journals The Component of the TAC Complex, TCD7, Controls Rice Chloroplast Development at the Early Seedling Stage under Cold Stress

2021 ◽  
Author(s):  
Dongzhi Lin ◽  
Licheng Kang ◽  
Wenhao Zhou ◽  
Yulu Wang ◽  
Yu Chen ◽  
...  
Keyword(s):  
Cold Stress ◽  
Low Temperatures ◽  
Chloroplast Development ◽  
Oryza Sativa L ◽  
Polymerase Activity ◽  
Regulatory Module ◽  
Complex Functions ◽  
In The Wild ◽  
Early Seedling ◽  
Albino Phenotype

Abstract Transcriptionally active chromosome (TAC) is a component of protein-DNA complexes with RNA polymerase activity found in chloroplasts. Although TAC in Arabidopsis thaliana has been extensively investigated, how the rice (Oryza sativa L.) TAC complex functions remains largely unknown. We report the characterization of the mutant thermosensitive chlorophyll-deficient7 (tcd7) and the cloning of TCD7. tcd7 mutant seedlings displayed an albino phenotype specifically at low temperatures and before the four-leaf stage. We identified TCD7 by map-based cloning followed by transgenic rescue and genome editing tests, showing that TCD7 encodes the putative TAC component FRUCTOKINASE-LIKE 2 (OsFLN2). TCD7 transcripts were highly abundant in green tissues, and the protein localized to chloroplasts. In agreement with the albino phenotype, transcript levels of genes controlling chloroplast development and the establishment of photosynthetic capacity were severely reduced in tcd7 seedlings at low temperatures, but were expressed as in the wild type at high temperatures, implying that TCD7 regulates the PEP pathway and chloroplast development. Moreover, TCD7 interacted with the thioredoxin OsTRXz to form an OsTRXz-TCD7 regulatory module, which might regulate plastid transcription under cold stress. Our results demonstrate that the nucleus-encoded TAC protein TCD7 protects chloroplast development from cold stress via a TRXz-FLN regulatory module.

Jojoba: Temperature Adaptation as Expressed in Growth and Leaf Function

1983 ◽  
Vol 10 (3) ◽  
pp. 299 ◽  
Author(s):  
IF Wardlaw ◽  
JE Begg ◽  
D Bagnall ◽  
RL Dunstone
Keyword(s):  
Low Temperature ◽  
Low Temperatures ◽  
Vascular System ◽  
Starch Content ◽  
Dry Weight ◽  
Co2 Exchange ◽  
Temperature Adaptation ◽  
Pulse Labelling ◽  
Wide Range ◽  
Young Leaves

The adaptation of jojoba [Simmondsia chinensis (Link) Schneider] to temperature was studied under controlled conditions. Shoot extension and leaf area development reflected the very low rate of growth of this species, even under favourable conditions, and were stable with an increase in temperature from 20 to 30°C. However growth was markedly reduced at temperatures below 20°C and at 6°C there was no net gain in dry weight over a 42 day period. Root: shoot ratios were near unity and showed a small drop in response to increasing temperature. Leaves adapted to low temperature by an increase in thickness, specific leaf weight and starch content. Chlorophyll formation was retarded in young leaves developing at 15/10°C, but there was no sign of photodestruction of previously formed chlorophyll in mature leaves. Young leaves developing at 30/25°C had a very high chlorophyll a/b ratio of 9.5, but otherwise leaf chlorophyll was apparently normal (2.3-3.4) over a wide range of temperatures. Light saturation of net CO2 exchange (NCE) occurred at about 1000 �E m-2 s-1 for leaves grown over a wide range of temperatures and the maximum NCE of approximately 16 mg CO2 dm-2 h-1 (0.45 mg m-2 s-1) occurred between 19 and 25°C. Pulse labelling with 14CO2 indicated that low temperature (18°C) reduced the rate of transfer of 14C from the primary products of fixation to sucrose. The rate of movement of 14C-labelled photosynthate out of the leaf was negligible at 18°C, and reached only about 3% h-1 at 30°C. In the stems, shortly after 14CO2 uptake by the leaf, 86% of the 14C activity was in sucrose, indicating that this was the preferred form of translocate in the vascular system. However glucose was more abundant in the leaves than sucrose, particularly at low temperatures. Starch accumulated in the leaves at low temperatures, reaching nearly 30% of the dry weight at 18/13°C. Photosynthetic stability rather than active adaptation appears to form the basis of resistance to temperature stress in jojoba. With low rates even under optimal conditions this is essentially one of adaptation for survival rather than adaptation for production.

Stand establishment in processing carrots – Effects of various temperature regimes on germination and the role of salicylates in promoting germination at low temperatures

2002 ◽  
Vol 82 (2) ◽  
pp. 443-450 ◽  
Author(s):  
Lada R. Rajasekaran ◽  
Azure Stiles, Claude ◽  
D. Caldwell
Keyword(s):  
Low Temperature ◽  
Acetylsalicylic Acid ◽  
Low Temperatures ◽  
Seed Treatment ◽  
Germination Percentage ◽  
Threshold Temperature ◽  
Critical Threshold ◽  
Temperature Regimes ◽  
Carrot Seed

The effects of various temperature regimes on carrot seed germination and the possibility of hastening germination at a low temperature using salicylates were studied. Seeds were incubated at various temperatures viz., 25, 20, 15, 10, 5 and 2°C. Salicylates such as, 2,6-dihydoxybenzoic acid (DHBA), acetylsalicylic acid (ASA), salicylic acid (SA) were supplied at 0, 1, 10, 100 and 1000 mg L-1 continually to the seeds incubated at 25 and 5°C until germination. Data on germination percentage were collected, and vigor value was calculated. Incubating seeds at various low temperature regimes significantly and proportionately reduced germination percentage and vigor value. The highest cumulative germination and vigor value was observed at 25°C. Critical threshold temperature for germination (GT50) was 5°C. Seed treatment using salicylates hastened germination at 5°C. 2,6-dihydoxybenzoic acid 1, ASA 100 and SA 1 mg L-1 all were effective in hastening germination at 5°C. Among all the salicylates, ASA 100 mg L-1 was the most effective in advancing germination at 5°C. Salicylates at the highest concentration of 1000 mg L-1 inhibited germination significantly both at 25 and 5°C. Key words: Acetylsalicylic acid, carrot, 2,6-dihydoxybenzoic acid, germination percentage, rate of germination, salicylates, SA, temperature, thermogenesis, vigor value

A Tale of Two Genomes: Role of a Chloroplast Signal in Coordinating Nuclear and Plastid Genome Expression

1992 ◽  
Vol 19 (4) ◽  
pp. 387 ◽  
Author(s):  
RE Susek ◽  
J Chory
Keyword(s):  
Chloroplast Development ◽  
Photosynthetic Apparatus ◽  
Signal Transduction Pathway ◽  
Nuclear Genes ◽  
Signal Molecules ◽  
Chloroplast Gene Expression ◽  
Genome Expression ◽  
Coordinate Control ◽  
Genes Encoding

Plant cells coordinately regulate the expression of nuclear and plastid genes that encode components of the photosynthetic apparatus. Nuclear genes that regulate chloroplast development and chloroplast gene expression provide part of this coordinate control. However, there is compelling evidence that information also flows in the opposite direction, from chloroplasts to the nucleus. This hypothesised, second pathway functions to coordinate the expression of nuclear genes encoding components of the photosynthetic apparatus with the functional state of the chloroplast. Here we review the evidence for the signal transduction pathway from the chloroplasts to the nucleus and suggest possible signal molecules.

scholarly journals GUN1 regulates tetrapyrrole biosynthesis

2019 ◽  
Author(s):  
Takayuki Shimizu ◽  
Nobuyoshi Mochizuki ◽  
Akira Nagatani ◽  
Satoru Watanabe ◽  
Tomohiro Shimada ◽  
...  
Keyword(s):  
Chloroplast Development ◽  
Photosynthetic Apparatus ◽  
Nuclear Gene ◽  
Retrograde Signaling ◽  
Tetrapyrrole Biosynthesis ◽  
Metal Porphyrins ◽  
Nuclear Gene Expression ◽  
Chloroplast Genomes ◽  
Tetrapyrrole Metabolism

The biogenesis of the photosynthetic apparatus in developing chloroplasts requires the assembly of proteins encoded on both nuclear and chloroplast genomes1. To co-ordinate this process there needs to be communication between these organelles, and while we have a good understanding of how the nucleus controls chloroplast development, how the chloroplast communicates with the nucleus at this time is still essentially unknown2. What we do know comes from pioneering work in which a series of genomes uncoupled (gun) mutants were identified that show elevated nuclear gene expression after chloroplast damage3. Of the six reported gun mutations, five are in tetrapyrrole biosynthesis proteins4-6 and this has led to the development of a model for chloroplast-to-nucleus retrograde signaling in which ferrochelatase 1 (FC1)-dependent heme synthesis generates a positive signal promoting expression of photosynthesis-related genes6. However, the molecular consequences of the strongest of the gun mutants, gun17, is unknown, preventing the development of a unifying hypothesis for chloroplast-to-nucleus signaling. Here, we show that GUN1 directly binds to heme and other metal-porphyrins, affects flux through the tetrapyrrole biosynthesis pathway and can increase the chelatase activity of FC1. These results raise the possibility that the signaling role of GUN1 may be manifested through changes in tetrapyrrole metabolism and supports a role for tetrapyrroles as mediators of a single biogenic chloroplast-to-nucleus retrograde signaling pathway.

scholarly journals Effect of low temperature in the first development stage for five red raspberry genotypes

2019 ◽  
Vol 46 (No. 1) ◽  
pp. 9-16
Author(s):  
Elida Contreras ◽  
Javiera Grez ◽  
José A Alcalde ◽  
Davide Neri ◽  
Marina Gardella
Keyword(s):  
Low Temperature ◽  
Low Temperatures ◽  
Development Stage ◽  
Red Raspberry ◽  
Stages Of Development ◽  
Growth Season ◽  
Early Stages ◽  
Exposure To Cold ◽  
Moment Interaction ◽  
Cold Chamber

In raspberry, the expression of the primocane fruiting trait is influenced by the environment. Although there are several factors that influence the expression of this character, it is well known that low temperatures that occur during the growth season of the primocane, are important and affect the flowering. In this study, plants in their early stages of development were exposed to low temperatures (2°C) for one month, in a dark cold chamber. The following genotypes primocane and floricane were used: ‘UC103’, ‘Autumn Bliss’, ‘Heritage’, ‘Meeker’ and ‘Tulameen’. Flowering and growth were recorded until the end of the season and the morphology of the meristem was characterized in this moment. Interaction between cold and genotype was detected in all parameters studied. In ‘Heritage’, a slight primocane, growth and flowering were favoured by exposure to cold. Thereby, low temperature affects flowering, but this effect depends on primocane fruiting degree of each genotype, slight primocane the cold favored flowering and growth. However, strongly primocane the cold had no effect on flowering and growth.

scholarly journals Effect of Low Temperature on Chlorophyll Biosynthesis and Chloroplast Biogenesis of Rice Seedlings during Greening

2020 ◽  
Vol 21 (4) ◽  
pp. 1390 ◽  
Author(s):  
Yuqing Zhao ◽  
Qiaohong Han ◽  
Chunbang Ding ◽  
Yan Huang ◽  
Jinqiu Liao ◽  
...  
Keyword(s):  
Low Temperature ◽  
Low Temperatures ◽  
Aminolevulinic Acid ◽  
Oryza Sativa L ◽  
Chlorophyll Biosynthesis ◽  
Chilling Stress ◽  
Chlorophyll Synthesis ◽  
Rice Seedling ◽  
Rice Seedlings ◽  
Plastid Development

Rice (Oryza sativa L.) frequently suffers in late spring from severe damage due to cold spells, which causes the block of chlorophyll biosynthesis during early rice seedling greening. However, the inhibitory mechanism by which this occurs is still unclear. To explore the responsive mechanism of rice seedlings to low temperatures during greening, the effects of chilling stress on chlorophyll biosynthesis and plastid development were studied in rice seedlings. Chlorophyll biosynthesis was obviously inhibited and chlorophyll accumulation declined under low temperatures during greening. The decrease in chlorophyll synthesis was due to the inhibited synthesis of δ-aminolevulinic acid (ALA) and the suppression of conversion from protochlorophyllide (Pchlide) into chlorophylls (Chls). Meanwhile, the activities of glutamate-1-semialdehyde transaminase (GSA-AT), Mg-chelatase, and protochlorophyllide oxidoreductase (POR) were downregulated under low temperatures. Further investigations showed that chloroplasts at 18 °C had loose granum lamellae, while the thylakoid and lamellar structures of grana could hardly develop at 12 °C after 48 h of greening. Additionally, photosystem II (PSII) and photosystem I (PSI) proteins obviously declined in the stressed seedlings, to the point that the PSII and PSI proteins could hardly be detected after 48 h of greening at 12 °C. Furthermore, the accumulation of reactive oxygen species (ROS) and malondialdehyde (MDA) and cell death were all induced by low temperature. Chilling stress had no effect on the development of epidermis cells, but the stomata were smaller under chilling stress than those at 28 °C. Taken together, our study promotes more comprehensive understanding in that chilling could inhibit chlorophyll biosynthesis and cause oxidative damages during greening.

In situ Tensile Experiments at Low Temperatures on Niobium Single Crystals by H.V.E.M.

1975 ◽  
Vol 33 ◽  
pp. 58-59
Author(s):  
F. H. Louchet ◽  
L. P. Kubin
Keyword(s):  
Electron Microscope ◽  
Transition Temperature ◽  
Low Temperature ◽  
Slip System ◽  
Low Temperatures ◽  
Tensile Axis ◽  
Image Intensifier ◽  
Screw Dislocations ◽  
Source Operation

Experiments have been carried out on the 3 MeV electron microscope in Toulouse. The low temperature straining holder has been previously described Images given by an image intensifier are recorded on magnetic tape.The microtensile niobium samples are cut in a plane with the two operative slip directions [111] and lying in the foil plane. The tensile axis is near [011].Our results concern:- The transition temperature of niobium near 220 K: at this temperature and below an increasing difference appears between the mobilities of the screw and edge portions of dislocations loops. Source operation and interactions between screw dislocations of different slip system have been recorded.

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