Choline-Mediated Lipid Reprogramming as a Dominant Salt Tolerance Mechanism in Grass Species Lacking Glycine Betaine

Author(s):  
Kun Zhang ◽  
Weiting Lyu ◽  
Yanli Gao ◽  
Xiaxiang Zhang ◽  
Yan Sun ◽  
...  

Abstract Choline, as a precursor of glycine betaine (GB) and phospholipids, is known to play roles in plant tolerance to salt stress, but the downstream metabolic pathways regulated by choline conferring salt tolerance are still unclear for non-GB-accumulating species. The objectives were to examine how choline affects salt tolerance in a non-GB-accumulating grass species and to determine major metabolic pathways of choline regulating salt tolerance involving GB or lipid metabolism. Kentucky bluegrass (Poa pratensis) plants were subjected to salt stress (100 mM NaCl) with or without foliar application of choline chloride (1 mM) in a growth chamber. Choline or GB alone and the combined application increased leaf photochemical efficiency, relative water content and osmotic adjustment and reduced leaf electrolyte leakage. Choline application had no effects on the endogenous GB content and GB synthesis genes did not show responses to choline under nonstress and salt stress conditions. GB was not detected in Kentucky bluegrass leaves. Lipidomic analysis revealed an increase in the content of monogalactosyl diacylglycerol, phosphatidylcholine and phosphatidylethanolamine and a decrease in the phosphatidic acid content by choline application in plants exposed to salt stress. Choline-mediated lipid reprogramming could function as a dominant salt tolerance mechanism in non-GB-accumulating grass species.

2012 ◽  
Vol 137 (2) ◽  
pp. 96-106 ◽  
Author(s):  
Zhimin Yang ◽  
Jingjin Yu ◽  
Emily Merewitz ◽  
Bingru Huang

Abscisic acid (ABA) and glycine betaine (GB) may regulate plant responses to drought or salinity stress. The objectives of this controlled-environment study were to determine whether foliar application of ABA or GB improves turf quality under drought or salinity and whether improved stress responses were associated changes in antioxidant metabolism in two C3 turfgrass species, creeping bentgrass (Agrostis stolonifera) and kentucky bluegrass (Poa pratensis). Physiological parameters evaluated included turf quality, leaf relative water content, membrane electrolyte leakage (EL), membrane lipid peroxidation [expressed as malondialdehyde (MDA) content], and activity of superoxide dismutase (SOD), peroxidase (POD), and ascorbate peroxidase (APX). Abscisic acid and GB were both effective in mitigating physiological damage resulting from drought or salinity for both grass species, but effects were more pronounced on kentucky bluegrass. The most notable effects of ABA or GB application were the suppression of EL and MDA accumulation and an increase in APX, POD, and SOD activities after prolonged periods of drought (21 days) or salinity stress (35 days). These results suggest foliar application of ABA or GB may alleviate physiological damage by drought or salinity stress in turfgrass and the maintenance of membrane stability and active antioxidant metabolism could contribute to the positive effects in the stress mitigation effects.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Huanyong Li ◽  
Xiaoqian Tang ◽  
Xiuyan Yang ◽  
Huaxin Zhang

AbstractNitraria sibirica Pall., a typical halophyte that can survive under extreme drought conditions and in saline-alkali environments, exhibits strong salt tolerance and environmental adaptability. Understanding the mechanism of molecular and physiological metabolic response to salt stress of plant will better promote the cultivation and use of halophytes. To explore the mechanism of molecular and physiological metabolic of N. sibirica response to salt stress, two-month-old seedlings were treated with 0, 100, and 400 mM NaCl. The results showed that the differentially expressed genes between 100 and 400 mmol L−1 NaCl and unsalted treatment showed significant enrichment in GO terms such as binding, cell wall, extemal encapsulating structure, extracellular region and nucleotide binding. KEGG enrichment analysis found that NaCl treatment had a significant effect on the metabolic pathways in N. sibirica leaves, which mainly including plant-pathogen interaction, amino acid metabolism of the beta alanine, arginine, proline and glycine metabolism, carbon metabolism of glycolysis, gluconeogenesis, galactose, starch and sucrose metabolism, plant hormone signal transduction and spliceosome. Metabolomics analysis found that the differential metabolites between the unsalted treatment and the NaCl treatment are mainly amino acids (proline, aspartic acid, methionine, etc.), organic acids (oxaloacetic acid, fumaric acid, nicotinic acid, etc.) and polyhydric alcohols (inositol, ribitol, etc.), etc. KEGG annotation and enrichment analysis showed that 100 mmol L−1 NaCl treatment had a greater effect on the sulfur metabolism, cysteine and methionine metabolism in N. sibirica leaves, while various amino acid metabolism, TCA cycle, photosynthetic carbon fixation and sulfur metabolism and other metabolic pathways have been significantly affected by 400 mmol L−1 NaCl treatment. Correlation analysis of differential genes in transcriptome and differential metabolites in metabolome have found that the genes of AMY2, BAM1, GPAT3, ASP1, CML38 and RPL4 and the metabolites of L-cysteine, proline, 4-aminobutyric acid and oxaloacetate played an important role in N. sibirica salt tolerance control. This is a further improvement of the salt tolerance mechanism of N. sibirica, and it will provide a theoretical basis and technical support for treatment of saline-alkali soil and the cultivation of halophytes.


2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Dan Jiang ◽  
Bin Lu ◽  
Liantao Liu ◽  
Wenjing Duan ◽  
Yanjun Meng ◽  
...  

Abstract Background As damage to the ecological environment continues to increase amid unreasonable amounts of irrigation, soil salinization has become a major challenge to agricultural development. Melatonin (MT) is a pleiotropic signal molecule and indole hormone, which alleviates the damage of abiotic stress to plants. MT has been confirmed to eliminate reactive oxygen species (ROS) by improving the antioxidant system and reducing oxidative damage under adversity. However, the mechanism by which exogenous MT mediates salt tolerance by regulating the photosynthetic capacity and ion balance of cotton seedlings still remains unknown. In this study, the regulatory effects of MT on the photosynthetic system, osmotic modulators, chloroplast, and anatomical structure of cotton seedlings were determined under 0–500 μM MT treatments with salt stress induced by treatment with 150 mM NaCl. Results Salt stress reduces the chlorophyll content, net photosynthetic rate, stomatal conductance, intercellular CO2 concentration, transpiration rate, PSII photochemical efficiency, PSII actual photochemical quantum yield, the apparent electron transfer efficiency, stomata opening, and biomass. In addition, it increases non-photochemical quenching. All of these responses were effectively alleviated by exogenous treatment with MT. Exogenous MT reduces oxidative damage and lipid peroxidation by reducing salt-induced ROS and protects the plasma membrane from oxidative toxicity. MT also reduces the osmotic pressure by reducing the salt-induced accumulation of Na+ and increasing the contents of K+ and proline. Exogenous MT can facilitate stomatal opening and protect the integrity of cotton chloroplast grana lamella structure and mitochondria under salt stress, protect the photosynthetic system of plants, and improve their biomass. An anatomical analysis of leaves and stems showed that MT can improve xylem and phloem and other properties and aides in the transportation of water, inorganic salts, and organic substances. Therefore, the application of MT attenuates salt-induced stress damage to plants. Treatment with exogenous MT positively increased the salt tolerance of cotton seedlings by improving their photosynthetic capacity, stomatal characteristics, ion balance, osmotic substance biosynthetic pathways, and chloroplast and anatomical structures (xylem vessels and phloem vessels). Conclusions Our study attributes help to protect the structural stability of photosynthetic organs and increase the amount of material accumulation, thereby reducing salt-induced secondary stress. The mechanisms of MT-induced plant tolerance to salt stress provide a theoretical basis for the use of MT to alleviate salt stress caused by unreasonable irrigation, fertilization, and climate change.


1990 ◽  
Vol 115 (4) ◽  
pp. 608-611 ◽  
Author(s):  
Jennifer M. Johnson-Cicalese ◽  
C.R. Funk

Studies were conducted on the host plants of four billbug species (Coleoptera:Curculionidae: Sphenophorus parvulus Gyllenhal, S. venatus Chitt., S. inaequalis Say, and S. minimus Hart) found on New Jersey turfgrasses. A collection of 4803 adults from pure stands of various turfgrasses revealed all four billbugs on Kentucky bluegrass (Poa pratensis L.), tall fescue (Festuca arundinacea Schreb.), and perennial ryegrass (Lolium perenne L.), and S. parvulus, S. venatus, and S. minimus on Chewings fescue (F. rubra L. ssp. commutata Gaud.). Since the presence of larvae, pupae, or teneral adults more accurately indicates the host status of a grass species, immature billbugs were collected from plugs of the various grass species and reared to adults for identification. All four species were reared from immature billbugs found in Kentucky bluegrass turf; immatures of S. venatus, S. inaequalis, and S. minimus were found in tall fescue; S. venatus and S. minimus in perennial ryegrass; and S. inaequalis in strong creeping red fescue (F. rubra L. ssp. rubra). A laboratory experiment was also conducted in which billbug adults were confined in petri dishes with either Kentucky bluegrass, perennial ryegrass, tall fescue, or bermudagrass (Cynodon dactylon Pers.). Only minor differences were found between the four grasses in billbug survival, number of eggs laid, and amount of feeding. In general, bermudagrass was the least favored host and the other grasses were equally adequate hosts. The results of this study indicate a need for updating host-plant lists of these four billbug species.


HortScience ◽  
2018 ◽  
Vol 53 (1) ◽  
pp. 97-101 ◽  
Author(s):  
Xunzhong Zhang ◽  
Wenli Wu ◽  
Erik H. Ervin ◽  
Chao Shang ◽  
Kim Harich

Plant hormones play an important role in plant adaptation to abiotic stress, but hormonal responses of cool-season turfgrass species to salt stress are not well documented. This study was carried out to investigate the responses of hormones to salt stress and examine if salt stress-induced injury was associated with hormonal alteration in kentucky bluegrass (KBG, Poa pratensis L.). The grass was grown in a growth chamber for 6 weeks and then subjected to salt stress (170 mm NaCl) for 28 days. Salt stress caused cell membrane damage, resulting in photosynthetic rate (Pn), chlorophyll (Chl), and turf quality decline in KBG. Salt stress increased leaf abscisic acid (ABA) and ABA/cytokinin (CK) ratio; reduced trans-zeatin riboside (ZR), isopentenyl adenosine (iPA), and indole-3-acetic acid (IAA), but did not affect gibberellin A4 (GA4). On average, salt stress reduced ZR by 67.4% and IAA by 58.6%, whereas it increased ABA by 398.5%. At the end of the experiment (day 28), turf quality, Pn, and stomatal conductance (gs) were negatively correlated with ABA and ABA/CK ratio, but positively correlated with ZR, iPA, and IAA. Electrolyte leakage (EL) was positively correlated with ABA and ABA/CK and negatively correlated with ZR, iPA, IAA, and GA4. GA4 was also positively correlated with turf quality and gs. The results of this study suggest that salt stress-induced injury of the cell membrane and photosynthetic function may be associated with hormonal alteration and imbalance in KBG.


2019 ◽  
Vol 12 (02) ◽  
pp. 133-141
Author(s):  
Chika Egawa ◽  
Atsushi Shoji ◽  
Hiroyuki Shibaike

AbstractAlthough introduced pasture grasses are essential for forage production in current livestock farming, some species cause serious impacts on native biodiversity when naturalized. Information on the seed dispersal of invasive forage grasses from cultivated settings to surrounding environments can inform management efforts to prevent their naturalization. In this case study, we quantified the wind-mediated seed dispersal distance and amount of dispersed seed of invasive forage grasses from agricultural grasslands in Hokkaido, northern Japan. In total, 200 funnel seed traps were installed around three regularly mown grasslands and one unmown grassland where various forage grass species were grown in mixture. Seeds of each species dispersed outside the grasslands were captured from May to October 2017. Based on the trapped distances of seeds, the 99th percentile dispersal distance from the grasslands was estimated for six species, including timothy (Phleum pratense L.), orchardgrass (Dactylis glomerata L.), and Kentucky bluegrass (Poa pratensis L.). For two dominant species, P. pratense and D. glomerata, the numbers of seeds dispersed outside the field under mown and unmown conditions were determined under various plant cover situations. The estimated dispersal distances ranged from 2.3 m (P. pratense) to 31.5 m (P. pratensis), suggesting that areas within approximately 32 m of the grasslands are exposed to the invasion risk of some forage grass species. For both P. pratense and D. glomerata, the number of seeds dispersed outside the unmown grassland exceeded 100 seeds m−2 under high plant cover situations, while the number of seeds dispersed from the mown grasslands at the same plant cover level was less than one-third of that number. The results suggest that local land managers focus their efforts on frequent mowing of grasslands and monitoring of the areas within approximately 32 m of the grasslands to substantially reduce the naturalization of invasive forage grasses.


Weed Science ◽  
2016 ◽  
Vol 64 (3) ◽  
pp. 409-420 ◽  
Author(s):  
Lauren A. Dennhardt ◽  
Edward S. DeKeyser ◽  
Sarah A. Tennefos ◽  
Steven E. Travers

The study of colonizing and of dominant grass species is essential for prairie conservation efforts. We sought to answer how naturalized Kentucky bluegrass in the northern Great Plains has become successful in the last 20 yr despite its long history in the northern Great Plains. We tested for evidence of geographical differentiation using flow cytometry and microsatellite markers to ascertain the population genetics of Kentucky bluegrass. Across all tested wild populations, high levels of genetic diversity were detected along with moderate levels of structure. Mantel tests of geographical patterns were not significant. Using clonal assignment, we found two major clones that made up the majority of the tested wild populations. When we compared the wild individuals to pedigree cultivars, we found virtually no genetic overlap across all tests, which did not support our hypothesis of developed cultivars contributing to high genetic diversity in natural populations. Furthermore, DNA content tests indicated a narrow range in ploidy in wild populations compared with lawn cultivars, further supporting a hypothesis of divergence between wild and pedigree cultivars. These results indicate the recent invasion of Kentucky bluegrass in the northern Great Plains is not because of adaptation or propagule pressure, but rather likely an environmental or land use shift.


2014 ◽  
Vol 1 (1) ◽  
pp. 38-45
Author(s):  
Marzieh Negahban ◽  
◽  
Sajedeh Saeedfar ◽  
Darioush Ramezan ◽  
Moazzam Hassanpour Asil ◽  
...  

2016 ◽  
Vol 141 (5) ◽  
pp. 449-456 ◽  
Author(s):  
B. Shaun Bushman ◽  
Lijun Wang ◽  
Xin Dai ◽  
Alpana Joshi ◽  
Joseph G. Robins ◽  
...  

Much of semiarid western North America is salt affected, and using turfgrasses in salty areas can be challenging. Kentucky bluegrass (Poa pratensis L.) is relatively susceptible to salt stress, showing reduced growth, osmotic and ionic stress, and eventual death at moderate or high salt concentrations. Considerable variation exists for salt tolerance among kentucky bluegrass germplasm, but gaining consistency among studies and entries has been a challenge. In this study, two novel kentucky bluegrass accessions recently reported as salt tolerant (PI 371768 and PI 440603) and two cultivars commonly used as references (Baron and Midnight) were compared for their turf quality (TQ), stomatal conductance (gS), leaf water potential (ψLEAF), electrolyte leakage (EL), and accumulation of inorganic ions under salt stress. TQ, ψLEAF, and EL were highly correlated with each other while only moderately correlated with gS. The tolerant accessions showed higher ψLEAF and lower EL than the cultivars Midnight and Baron at increasing salt concentrations and over 28 days of treatment. The accumulation of sodium (Na) and calcium (Ca) in the leaves was highly correlated and did not vary significantly among the four entries. Genes involved in ion transport across membranes, and in antioxidant activities, were significantly induced on salt stress in the tolerant accessions relative to the susceptible. These data indicate the ability of tolerant accessions to ameliorate oxidative stress and prevent EL, and confirmed the tolerance of germplasm previously reported on while indicating mechanisms by which they tolerate the salt stress.


2015 ◽  
Vol 79 (3) ◽  
pp. 367-375 ◽  
Author(s):  
Sang-Hyun Park ◽  
Bok-Rye Lee ◽  
Jeong-Hyun Lee ◽  
Tae-Hwan Kim

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