scholarly journals Expression of a novel DREB 5-A subgroup transcription factor gene from Ricinus communis (RcDREB1) enhanced growth, drought tolerance and pollen viability in tobacco

2021 ◽  
Author(s):  
Francisco Lima Aragão ◽  
Tomas Felipe Costa do Rego ◽  
Mirella Pupo Santos ◽  
Glaucia Barbosa Cabral ◽  
Thaís de Moura Cipriano ◽  
...  
Keyword(s):  
Transcription Factor ◽  
Water Stress ◽  
Transgenic Plants ◽  
Drought Tolerance ◽  
Ricinus Communis ◽  
Pollen Viability ◽  
Pollen Grains ◽  
Leaf Water ◽  
Economic Losses ◽  
Transgenic Lines

Abstract Climate change has increased the frequency of long periods of drought, affecting crop cultivation worldwide. Losses due to water stress exceed ten percent of world production of major crops, reaching three-quarters of production areas, with severe economic losses. Therefore, the generation of environmental stress-tolerant genotypes that are more efficient in water use is extremely important. We have previously isolated and characterized a DREB transcription factor coding gene, named RcDREB1, from castor bean (Ricinus communis L.), which probably belongs to the CBF/DREB subfamily subgroup A-5. Aiming to develop drought-tolerant lines, we have stably introduced and expressed the RcDREB1 transgene into tobacco. Transgenic lines have revealed an enhanced drought tolerance. Genetically modified lines cultivated under water deficit presented a higher photosynthetic rate, stomatal conductance, leaf water potential and leaf water content when compared to the control. Transgenic lines revealed lower transpiration rates. In addition, biometric analyses showed that transgenic lines cultivated under water stress presented higher biomass, higher fresh and dry weight and higher plant height than the non-transgenic lines. After re-watering, transgenic lines recovered faster than non-transgenic plants. Moreover, pollen grains from transgenic plants revealed a remarkable increase in viability after exposure to heat (38 ºC) and desiccation stresses. The results presented here will be the foundation for production of commercial crops that are more tolerant to environmental stresses and long-life pollen grains, increasing pollination and in consequence, productivity.

scholarly journals RabA2b Overexpression Alters the Plasma-Membrane Proteome and Improves Drought Tolerance in Arabidopsis

2021 ◽  
Vol 12 ◽  
Author(s):  
Vivek Ambastha ◽  
Ifat Matityahu ◽  
Dafna Tidhar ◽  
Yehoram Leshem
Keyword(s):  
Plasma Membrane ◽  
Transgenic Plants ◽  
Drought Tolerance ◽  
Small Gtpases ◽  
Plant Responses ◽  
Rab Proteins ◽  
Strong Activity ◽  
Native Promoter ◽  
Transgenic Lines ◽  
Drought Resistant

Rab proteins are small GTPases that are important in the regulation of vesicle trafficking. Through data mining, we identified RabA2b to be stress responsive, though little is known about the involvement of RabA in plant responses to abiotic stresses. Analysis of the RabA2b native promoter showed strong activity during osmotic stress, which required the stress hormone Abscisic acid (ABA) and was restricted to the vasculature. Sequence analysis of the promoter region identified predicted binding motifs for several ABA-responsive transcription factors. We cloned RabA2b and overexpressed it in Arabidopsis. The resulting transgenic plants were strikingly drought resistant. The reduced water loss observed in detached leaves of the transgenic plants could not be explained by stomatal aperture or density, which was similar in all the genotypes. Subcellular localization studies detected strong colocalization between RabA2b and the plasma membrane (PM) marker PIP2. Further studies of the PM showed, for the first time, a distinguished alteration in the PM proteome as a result of RabA2b overexpression. Proteomic analysis of isolated PM fractions showed enrichment of stress-coping proteins as well as cell wall/cuticle modifiers in the transgenic lines. Finally, the cuticle permeability of transgenic leaves was significantly reduced compared to the wild type, suggesting that it plays a role in its drought resistant properties. Overall, these data provide new insights into the roles and modes of action of RabA2b during water stresses, and indicate that increased RabA2b mediated PM trafficking can affect the PM proteome and increase drought tolerance.

scholarly journals 276 Effects of Water Stress on Super Oxide Dismutase (SOD) and Water Content of Tomato Cultivars at Different Plant Ages

HortScience ◽  
1999 ◽  
Vol 34 (3) ◽  
pp. 490A-490
Author(s):  
S.M. Lutfor Rahman ◽  
Eiji Nawata ◽  
Tetsuo Sakuratani
Keyword(s):  
Water Stress ◽  
Drought Tolerance ◽  
Water Potential ◽  
Water Content ◽  
Leaf Water Potential ◽  
Control Level ◽  
Leaf Water ◽  
Stress Treatment ◽  
Relative Water ◽  
Tomato Cultivars

Effects of water stress at different plant ages on SOD activities were studied in two tomato cultivars. Water stress treatment decreased the leaf water potential in all stages, but reduction of leaf water potential was more rapid and pronounced in KF than TM at all DSLs (days of seedlings). After withdrawal of water stress treatment, stressed plants of TM increased leaf water potential to the values of control level in all DSLs, but in KF, leaf water potential of stressed plants were much lower than that of control plants. Effects of water stress on relative water content (RWC) of leaves at 20 DSL showed a similar tendency to that on leaf water potential. The SOD activities in both cultivars showed significant increase by water stress treatment at all DSLs, but the increase of SOD by water stress was larger in TM than in KF. This tendency was observed at all DSLs. The results may indicate that SOD activities play an important role in drought tolerance of tomato at various plant ages and suggest a possible use of SOD activities as a criterion for tomato drought tolerance.

scholarly journals Overexpression of OsHox-6 Gene Enhanced Tiller Number in Rice But Induced Yield Penalty

2019 ◽  
Vol 23 (1) ◽  
pp. 30
Author(s):  
Syamsidah Rahmawati ◽  
Chairunnisa Chairunnisa ◽  
Eva Erdayani ◽  
Satya Nugroho ◽  
Amy Estiati
Keyword(s):  
Water Stress ◽  
Transgenic Plants ◽  
Leucine Zipper ◽  
Extra Copy ◽  
Real Time Quantitative Pcr ◽  
Phenotypic Alteration ◽  
Relative Water ◽  
Transgenic Lines ◽  
Response To Water ◽  
Yield Penalty

OsHox-6, belongs to the transcription factor homeodomain leucine zipper (HD-Zip) protein sub-family I, has unknown function. This study was aimed to characterize the phenotypes of two homozygous transgenic rice lines (S29-62-2 and S.40.4-158-1) containing an extra copy of OsHox-6 gene under the control of a rice constitutive promoter, OsLEA3, and to evaluate their tolerance to water stress. A real-time quantitative PCR (qRT-PCR) showed that the transcript expression of OsHox-6 gene in the transgenic lines increased 5-10 folds under a normal irrigation and 10-20 folds after exposure to water stress conditions as compared to its wild type control. Transgenic plants overexpressing OsHox-6 exhibited phenotypic alteration at the normal irrigation by inducing tiller formation, suggesting a decrease in the apical dominance. Transgenic plants also showed significant enhancement in the total grain number, however, the number of empty grains  also increased significantly (~16-22%).  After imposed to the water stress, the number of empty grains in the transgenic lines was even higher (up to 83% in average). Furthermore, observations on the water loss rates, relative water contents and drought resistance indices (DRI) suggested that the overexpression of OsHox-6 did not significantly increase tolerance to water stress.  Further research is required to reveal the detailed mechanisms of OsHox-6 in response to water and other abiotic stresses.

scholarly journals A WRKY Transcription Factor, EjWRKY17, from Eriobotrya japonica Enhances Drought Tolerance in Transgenic Arabidopsis

2021 ◽  
Vol 22 (11) ◽  
pp. 5593
Author(s):  
Dan Wang ◽  
Qiyang Chen ◽  
Weiwei Chen ◽  
Xinya Liu ◽  
Yan Xia ◽  
...  
Keyword(s):  
Transcription Factor ◽  
Drought Stress ◽  
Drought Tolerance ◽  
Gene Family ◽  
Stress Responses ◽  
Transgenic Arabidopsis ◽  
Stomatal Closure ◽  
Eriobotrya Japonica ◽  
Wrky Gene ◽  
Transgenic Lines

The WRKY gene family, which is one of the largest transcription factor (TF) families, plays an important role in numerous aspects of plant growth and development, especially in various stress responses. However, the functional roles of the WRKY gene family in loquat are relatively unknown. In this study, a novel WRKY gene, EjWRKY17, was characterized from Eriobotrya japonica, which was significantly upregulated in leaves by melatonin treatment during drought stress. The EjWRKY17 protein, belonging to group II of the WRKY family, was localized in the nucleus. The results indicated that overexpression of EjWRKY17 increased cotyledon greening and root elongation in transgenic Arabidopsis lines under abscisic acid (ABA) treatment. Meanwhile, overexpression of EjWRKY17 led to enhanced drought tolerance in transgenic lines, which was supported by the lower water loss, limited electrolyte leakage, and lower levels of reactive oxygen species (ROS) and malondialdehyde (MDA). Further investigations showed that overexpression of EjWRKY17 promoted ABA-mediated stomatal closure and remarkably up-regulated ABA biosynthesis and stress-related gene expression in transgenic lines under drought stress. Overall, our findings reveal that EjWRKY17 possibly acts as a positive regulator in ABA-regulated drought tolerance.

In-Vitro Effects of Ricinus Communis Seed Kernel Extract On Some Antioxidant And Hydrolytic Enzymes In Nymph And Adult Zonocerus Variegatus (Grasshopper)

2019 ◽  
Vol 3 (1) ◽  
pp. 129-137
Author(s):  
Gbadebo E . Adeleke ◽  
Olaniyi T. Adedosu ◽  
Rachael O. Adeyi ◽  
John O. Fatoki
Keyword(s):  
Ricinus Communis ◽  
Hydrolytic Enzymes ◽  
Crude Enzyme ◽  
Economic Losses ◽  
Seed Kernel ◽  
Zonocerus Variegatus ◽  
Sod Activity ◽  
Enzyme Preparations ◽  
In Vitro Effects

Background: Many plants have been identified for their insecticidal properties as alternatives to synthetic ones, which are toxic to untargeted organisms and environment. Ricinus communis (Castor) has been re-ported to exhibit insecticidal properties against insect pests. Zonocerus variegatus (Grasshopper) is a notable pest of several crops, and has been linked with great economic losses to farmers. The present study investigates the in-vitro toxicity of R. communis seed kernel extract (RCSKE) on the activities of selected antioxidant and hydrolytic enzymes in nymph and adult Zonocerus variegatus (Grasshopper), using cypermethrin (CYPER-M) and chlorpyrifos (CPF) as standard conventional pesticides. Methods: Seed kernel of Ricinus communis (Castor) was subjected to acidified aqueous extraction to obtain the extract (RCSKE). Crude enzyme preparations were obtained from nymph and adult Z. variegatus grass-hoppers. The in-vitro effects of different concentrations (15, 30, 45, 60, 75, 90 and 105μg/ml) each of RCSKE, CYPER-M and CPF on the activities of superoxide dismutase (SOD), catalase (CAT), acetylcholinesterase (AChE) and carboxylesterase (CES) in crude enzyme preparations were estimated spectrophotometrically. The level of statistical significance was 0.05. Results: The RCSKE significantly reduced the in-vitro SOD activity (p < 0.05) in nymph Z. variegatus at all the concentrations, whereas both CYPER-M and CPF significantly reduced the activity only at certain concentrations. The CAT activity in the nymph was significantly decreased by RCSKE and CPF at all the concentrations, but CYPER-M decreased it only at certain concentrations. In adult Z. variegatus, SOD activity was not significantly affected (p > 0.05), while CAT activity was significantly increased (p < 0.05) by the three agents at all the concentrations. The AChE and CES activities in the nymph were significantly reduced by RCSKE, CYPER-M and CPF at all the concentrations. The RCSKE and CPF significantly increased the CES activity, while CYPER-M caused a significant decrease in the activity in adult Z. variegatus. Conclusion: The seed kernel extract of Ricinus communis is an effective pesticidal agent and hence, it could be a source of biopesticide alternative with greater potential than cypermethrin and chlorpyrifos. In addition, the antioxidant, acetylcholinesterase and carboxylesterase enzymes in the nymphs of Z. variegatus grasshoppers are more susceptible to the effect of the extract than in the adult grasshoppers.

Sensitivity to water stress drives differential decline and mortality dynamics of three co-occurring conifers with different drought tolerance

2021 ◽  
Vol 486 ◽  
pp. 118964
Author(s):  
Macarena Férriz ◽  
Dario Martin-Benito ◽  
Isabel Cañellas ◽  
Guillermo Gea-Izquierdo
Keyword(s):  
Water Stress ◽  
Drought Tolerance
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