scholarly journals Inhibition of gibberellin accumulation by water deficiency promotes fast and long‐term ‘drought avoidance’ responses in tomato

2021 ◽  
Author(s):  
Hagai Shohat ◽  
Hadar Cheriker ◽  
Himabindu Vasuki Kilambi ◽  
Natanella Illouz Eliaz ◽  
Shula Blum ◽  
...  
2021 ◽  
Author(s):  
Hagai Shohat ◽  
Hadar Cheriker ◽  
Himabindu Vasuki ◽  
Natanella Illouz-Eliaz ◽  
Shula Blum ◽  
...  

ABSTRACTPlants reduce transpiration to avoid dehydration during drought episodes by stomatal closure and inhibition of canopy growth. While abscisic acid (ABA) has a primary role in ‘drought avoidance’, previous studies suggest that gibberellin (GA), might also be involved. Here we show in tomato (Solanum lycopersicum) that shortage of water inhibited the expression of the GA biosynthesis genes GA20 oxidase1 (GA20ox1) and GA20ox2 and induced the GA-deactivating gene GA2ox7 in leaves and guard cells, resulting in reduced bioactive GA levels. Drought regulation of GA metabolism was mediated by ABA-dependent and independent pathways, and by the transcription factor DEHYDRATION RESPONSIVE ELEMENT BINDING (DREB), TINY1. Mutations in GA20ox1 and GA20ox2 reduced water loss due to the smaller canopy area. On the other hand, loss of GA2ox7 did not affect leaf size, but attenuated stomatal response to water deficiency; during soil dehydration, ga2ox7 plants closed their stomata and reduced transpiration later than WT, suggesting that ga2ox7 stomata are hyposensitive to soil dehydration. Together, the results suggest that drought-induced GA deactivation in guard cells contributes to stomatal closure at the early stages of soil dehydration, whereas inhibition of GA synthesis in leaves promotes mainly the long-term reduction in canopy growth to reduce transpiration area.


2021 ◽  
Vol 1 (1) ◽  
Author(s):  
Hagai Shohat ◽  
Natanella Illouz Eliaz ◽  
David Weiss

AbstractThe growth-promoting hormone gibberellin (GA) regulates numerous developmental processes throughout the plant life cycle. It also affects plant response to biotic and abiotic stresses. GA metabolism and signaling in tomato (Solanum lycopersicum) have been studied in the last three decades and major components of the pathways were characterized. These include major biosynthesis and catabolism enzymes and signaling components, such as the three GA receptors GIBBERELLIN INSENSITIVE DWARF 1 (GID1) and DELLA protein PROCERA (PRO), the central response suppressor. The role of these components in tomato plant development and response to the environment have been investigated. Cultivated tomato, similar to many other crop plants, are susceptible to water deficiency. Numerous studies on tomato response to drought have been conducted, including the possible role of GA in tomato drought resistance. Most studies showed that reduced levels or activity of GA improves drought tolerance and drought avoidance. This review aims to provide an overview on GA biosynthesis and signaling in tomato, how drought affects these pathways and how changes in GA activity affect tomato plant response to water deficiency. It also presents the potential of using the GA pathway to generate drought-tolerant tomato plants with improved performance under both irrigation and water-limited conditions.


1977 ◽  
Vol 40 (3) ◽  
pp. 936-938
Author(s):  
Yoshitaka Tamaki

5-dimethyldithiocarbamylpicolinic acid (YP-279) is a selective inhibitor of peripheral dopamine β-hydroxylase (DβH). After 72 training days in a discriminated Sidman avoidance situation, rats were administered three dosages (25, 50, and 75 mg/kg) of YP-279. YP-279 treatment produced no observable change in avoidance responses. These results indicate that well-learned coping behavior was not influenced by the inhibition of peripheral DβH.


2020 ◽  
Vol 21 (17) ◽  
pp. 6032
Author(s):  
Anna Piasecka ◽  
Aneta Sawikowska ◽  
Anetta Kuczyńska ◽  
Piotr Ogrodowicz ◽  
Krzysztof Mikołajczak ◽  
...  

Eight barley varieties from Europe and Asia were subjected to moisture deficit at various development stages. At the seedling stage and the flag leaf stage combined stress was applied. The experiment was designed for visualization of the correlation between the dynamics of changes in phenolic compound profiles and the external phenome. The most significant increase of compound content in water deficiency was observed for chrysoeriol and apigenin glycoconjugates acylated with methoxylated hydroxycinnamic acids that enhanced the UV-protection effectiveness. Moreover, other good antioxidants such as derivatives of luteolin and hordatines were also induced by moisture deficit. The structural diversity of metabolites of the contents changed in response to water deficiency in barley indicates their multipath activities under stress. Plants exposed to moisture deficit at the seedling stage mobilized twice as many metabolites as plants exposed to this stress at the flag leaf stage. Specific metabolites such as methoxyhydroxycinnamic acids participated in the long-term acclimation. In addition, differences in phenolome mobilization in response to moisture deficit applied at the vegetative and generative phases were correlated with the phenotypical consequences. Observations of plant yield and biomass gave us the possibility to discuss the developmentally related consequences of moisture deficit for plants’ fitness.


2003 ◽  
Vol 95 (6) ◽  
pp. 1566-1576 ◽  
Author(s):  
Larry C. Purcell ◽  
Thomas R. Sinclair ◽  
Ronald W. McNew

2021 ◽  
Author(s):  
Hongkun Yang ◽  
Wenmei Hu ◽  
Jiarong Zhao ◽  
Xiulan Huang ◽  
Ting Zheng ◽  
...  

Abstract Knowledge of short-term physiological adaption of wheat to soil water deficit is well understood, but little is known about seed ethylene priming effect on long-term drought stress memory of dryland winter wheat. The 42 leading and new cultivars released between 1992 to 2017 were subjected to drought (45% Field water-holding capacity), and well-watered (75% Field water-holding capacity) conditions aim to screen cultivars with contrasting drought resistance and grain yield. Seeds primed with ethylene were subjected to both PEG-8000 and pure water to uncover ethylene-induced stress memory at both physiological and organ levels. Results showed that the soil water deficit (45%FC) that occurred at the tillering stage resulted in 3.2% to 67.4% yield loss for 42 cultivars, which was determined mainly by the decrease in the fertile spike. Seed ethylene priming maintained leaf water by reducing root volume and dry weight, which played a crucial role in drought avoidance. Seed ethylene priming decreased malondialdehyde content by regulating auxin and abscisic acid signaling, reactive oxygen species scavenging capability, and osmotic regulation, which plays a crucial role in drought tolerance. Seed ethylene priming improved drought tolerance of the wheat through metabolic modification of carbon metabolism, glutathione metabolism, and phenylpropanoid biosynthesis . The seed ethylene priming induced long-term stress memory that improved tillering capacity and reduced wheat spikelets abortion, which provided extra 0.3 t ha -1 of grain yield. These results suggested that seed ethylene priming allowed the recall of long-lasting stress defensive memory, increasing grain yield by both drought avoidance and drought tolerance.


2002 ◽  
Vol 45 (4) ◽  
pp. 305-311 ◽  
Author(s):  
Mitsuhiro Yoshioka ◽  
Noriyuki Suda ◽  
Kiyoshi Mori ◽  
Ken-ichi Ueno ◽  
Yoshitada Itoh ◽  
...  

2019 ◽  
Vol 42 ◽  
Author(s):  
John P. A. Ioannidis

AbstractNeurobiology-based interventions for mental diseases and searches for useful biomarkers of treatment response have largely failed. Clinical trials should assess interventions related to environmental and social stressors, with long-term follow-up; social rather than biological endpoints; personalized outcomes; and suitable cluster, adaptive, and n-of-1 designs. Labor, education, financial, and other social/political decisions should be evaluated for their impacts on mental disease.


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