Stress tolerance mechanisms in Juncus: responses to salinity and drought in three Juncus species adapted to different natural environments

2016 ◽  
Vol 43 (10) ◽  
pp. 949 ◽  
Author(s):  
Mohamad Al Hassan ◽  
María del Pilar López-Gresa ◽  
Monica Boscaiu ◽  
Oscar Vicente

Comparative studies on the responses to salinity and drought were carried out in three Juncus species, two halophytes (Juncus maritimus Lam. and Juncus acutus L.) and one more salt-sensitive (Juncus articulatus L.). Salt tolerance in Juncus depends on the inhibition of transport of toxic ions to the aerial part. In the three taxa studied Na+ and Cl– accumulated to the same extent in the roots of salt treated plants; however, ion contents were lower in the shoots and correlated with the relative salt sensitivity of the species, with the lowest levels measured in the halophytes. Activation of K+ transport at high salt concentration could also contribute to salt tolerance in the halophytes. Maintenance of cellular osmotic balance is mostly based on the accumulation of sucrose in the three species. Yet, neither the relative salt-induced increase in sugar content nor the absolute concentrations reached can explain the observed differences in salt tolerance. In contrast, proline increased significantly in the presence of salt only in the salt-tolerant J. maritimus and J. acutus, but not in J. articulatus. Similar patterns of osmolyte accumulation were observed in response to water stress, supporting a functional role of proline in stress tolerance mechanisms in Juncus.

2020 ◽  
Vol 11 ◽  
Author(s):  
Jianrong Guo ◽  
Lili Liu ◽  
Ming Du ◽  
Huaying Tian ◽  
Baoshan Wang

Salinity inhibits plant growth due to salt ion accumulation in plant cells and reduced absorption of other nutrients such as metal ions; however halophyte plants have evolved mechanisms to survive and thrive in high-salt conditions. The euhalophyte Suaeda salsa generates dimorphic seeds (black and brown), which show marked differences in germination and seedling growth under high-salt conditions. However, it is unclear whether their ionic status differs. Here, to provide insight on the role of ions in salt tolerance, we used inductively coupled plasma mass spectrometry to measure the ion contents in the dimorphic seeds from S. salsa plants treated with or without NaCl. We measured the macroelements Na, K, Mg, and Ca, and the microelements Mn, Fe, Zn, Cu, and Mo. NaCl-treated S. salsa plants produced seeds with significantly reduced metallic element contents and significantly increased Na+ contents. The brown seeds of S. salsa plants treated with 0 and 200 mM NaCl had much higher contents of K+, Ca2+, and Fe2+ compared with the black seeds. However, the S. salsa seeds (both black and brown) from NaCl-treated plants were significantly larger, and had higher germination rate and higher seedling salt tolerance compared with seeds from plants not treated with NaCl. Interestingly, we measured significantly higher Zn2+ contents in the brown seeds from plants treated with NaCl compared with the black seeds. This suggests that the high contents of Zn2+ and other cations affected seed development and salt tolerance during germination under high-salt conditions. These observations provide insight into the mechanisms of salt tolerance in this halophyte and inform efforts to increase salt tolerance in salt-sensitive species.


HortScience ◽  
2000 ◽  
Vol 35 (3) ◽  
pp. 414A-414 ◽  
Author(s):  
Saad Alshammary ◽  
Y.L. Qian ◽  
S.J. Wallner

The need for salinity-tolerant turfgrasses is increasing because of increased use of effluent water for turfgrass irrigation. Greenhouse studies were conducted to determine the relative salt tolerance and salt tolerance mechanisms of `Challenger' Kentucky bluegrass (Poa pratensis), `Arid' tall fescue (Festuca arundinacea), `Fults' alkaligrass (Puccinellia distans.), and a saltgrass (Distichlis spicata) collection. Kentucky bluegrass and tall fescue were irrigated with saline solutions at 0.2,1.7, 4.8, or 9.9 dS/m, whereas alkaligrass and saltgrass were irrigated with saline solutions at 0.2, 28.1, 32.8, or 37.5 dS/m prepared using a mixture of NaCl and CaCl2. The salinity levels that caused 50% shoot growth reduction were 9.0, 10.4, 20.0, and 28.5 dS/m for Kentucky bluegrass, tall fescue, saltgrass, and alkaligrass, respectively. Concentrations of proline, a proposed cytoplasmic compatible solute, were 25.8, 30.4, 68.1, and 17.7 μmol/g shoot fw in Kentucky bluegrass, tall Fescue, alkaligrass, and saltgrass, respectively, at the highest salinity level imposed. Bicellular, salt-secreting glands were only observed by scanning electron microscopy on leaves of saltgrass, indicating salt secretion is one of the important salt tolerance mechanisms adopted by saltgrass. Ion contents (Na, Cl, and Ca) in both shoots and roots of all grasses increased with increasing salinity levels. However, alkaligrass maintained a much lower Na, Ca, and Cl contents in roots and shoots than other grasses, suggesting that ion exclusion is one of the major salt tolerance mechanisms in alkaligrass. Tall fescue did not appear to restrict the uptake and translocation of salt in shoot tissues, but maintained a higher K/Na ratio than all other grasses under saline conditions.


2004 ◽  
Vol 59 (11-12) ◽  
pp. 835-842 ◽  
Author(s):  
Balasubramanian Ramani ◽  
Holger Zorn ◽  
Jutta Papenbrock

This study was aimed at understanding the role of sulfolipids in salt tolerance mechanisms of the halophytes Aster tripolium L., Compositae, and Sesuvium portulacastrum L., Aizoaceae, and of the glycophyte Arabidopsis thaliana (L.) Heynh., Brassicaceae. In Aster and Sesuvium the sulfolipid contents increased significantly under salt stress conditions (517 mᴍ or 864 mᴍ). In Arabidopsis, changes in sulfolipid contents were not observed (NaCl up to 100 mᴍ). The fatty acid profile of sulfoquinovosyldiacylglycerol (SQDG) in Aster was modified with increasing NaCl concentrations. LC-MS analyses of sulfolipids from Aster and Sesuvium revealed the presence of 18:3/18:3 and 16:0/18:3 molecules. Obviously, the function of sulfolipids during salt stress differs between halophytic species and between halophytes and glycophytes where sulfolipid accumulation was not observed.


2018 ◽  
Vol 19 (11) ◽  
pp. 1114-1123 ◽  
Author(s):  
Anjali Khajuria ◽  
Nandni Sharma ◽  
Renu Bhardwaj ◽  
Puja Ohri

2021 ◽  
Author(s):  
Mei Zheng ◽  
Jingchen Lin ◽  
Xingbei Liu ◽  
Wei Chu ◽  
Jinpeng Li ◽  
...  

Abstract Polyploidy occurs prevalently and plays an important role during plant speciation and evolution. This phenomenon suggests polyploidy could develop novel features that enable them to adapt wider range of environmental conditions compared with diploid progenitors. Bread wheat (Triticum aestivum L., BBAADD) is a typical allohexaploid species and generally exhibits greater salt tolerance than its tetraploid wheat progenitor (BBAA). However, little is known about the underlying molecular basis and the regulatory pathway of this trait. Here, we show that the histone acetyltransferase TaHAG1 acts as a crucial regulator to strengthen salt tolerance of hexaploid wheat. Salinity-induced TaHAG1 expression was associated with tolerance variation in polyploidy wheat. Overexpression, silencing and CRISPR-mediated knockout of TaHAG1 validated the role of TaHAG1 in salinity tolerance of wheat. TaHAG1 contributed to salt tolerance by modulating ROS production and signal specificity. Moreover, TaHAG1 directly targeted a subset of genes that are responsible for hydrogen peroxide production, and enrichment of TaHAG1 triggered increased H3 acetylation and transcriptional upregulation of these loci under salt stress. In addition, we found the salinity-induced TaHAG1-mediated ROS production pathway is involved in salt tolerance difference of wheat accessions with varying ploidy. Our findings provide insight into the molecular mechanism of how an epigenetic regulatory factor facilitates adaptability of polyploidy wheat and highlights this epigenetic modulator as a strategy for salt tolerance breeding in bread wheat.


2021 ◽  
Vol 22 (6) ◽  
pp. 2906
Author(s):  
Urszula Talar ◽  
Agnieszka Kiełbowicz-Matuk

B-box proteins represent diverse zinc finger transcription factors and regulators forming large families in various plants. A unique domain structure defines them—besides the highly conserved B-box domains, some B-box (BBX) proteins also possess CCT domain and VP motif. Based on the presence of these specific domains, they are mostly classified into five structural groups. The particular members widely differ in structure and fulfill distinct functions in regulating plant growth and development, including seedling photomorphogenesis, the anthocyanins biosynthesis, photoperiodic regulation of flowering, and hormonal pathways. Several BBX proteins are additionally involved in biotic and abiotic stress response. Overexpression of some BBX genes stimulates various stress-related genes and enhanced tolerance to different stresses. Moreover, there is evidence of interplay between B-box and the circadian clock mechanism. This review highlights the role of BBX proteins as a part of a broad regulatory network in crop plants, considering their participation in development, physiology, defense, and environmental constraints. A description is also provided of how various BBX regulators involved in stress tolerance were applied in genetic engineering to obtain stress tolerance in transgenic crops.


Author(s):  
Debasish B. Krishnatreya ◽  
Niraj Agarwala ◽  
Sarvajeet Singh Gill ◽  
Tirthankar Bandyopadhyay
Keyword(s):  

Sign in / Sign up

Export Citation Format

Share Document