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[学术文献 ] The membrane lipid bilayer as a regulated barrier to cope with detrimental ionic conditions: making new tolerant plant lines with altered membrane lipid bilayer 进入全文
Soil Science and Plant Nutrition
Several detrimental ionic conditions can occur in crop fields: soil acidity, salinity, heavy metal toxicity, and/or nutrient deficiency. Crop plants tolerant to these detrimental ionic conditions have excellent strategies that are related to external and/or internal mechanisms. Recently, we proposed a new concept of aluminum (Al) tolerance in plants; specifically, a plasma membrane (PM) lipid bilayer mechanism. This mechanism is defined as the retardation of Al permeation through the PM lipid bilayer based on the specific composition of the lipid molecules in the PM. The molecular basis of a less negatively charged PM lipid bilayer is smaller proportions of phospholipids and greater proportions of galactolipids and sterols. This leads to reduced adsorbability of detrimental ions onto the PM lipid bilayer, resulting in less permeabilization. Phenolics and carotenoids have two moieties; a hydrophilic moiety and a hydrophobic moiety. The hydrophobic moieties of these compounds can occlude the permeabilized spaces in the PM lipid bilayer, thereby reinforcing it. Another strategy to retard the permeability of the PM to detrimental ions is to decrease the proportion of stigmasterol, which has been shown to have no ability to reduce water permeability. The beneficial or harmful effects of various organic materials (organic fertilizers, soil organic matter, agrochemicals, or organic pollutants) on the productivity or quality of crop plants in relation to changes in the PM lipid bilayer are discussed. Modulation of the PM lipid bilayer is a promising strategy to produce new crop lines tolerant to detrimental ionic conditions.
[学术文献 ] PHYTOREMEDIATION OF HEPTACHLOR AND HEPTACHLOR EPOXIDE IN SOIL BY CUCURBITACEAE 进入全文
International Journal of Phytoremediation
Plants in the family of Cucurbitaceae family are known to up take organochlorines. This study was designed to screen seven cultivars of the Lagenaria siceraria species of the Cucurbitaceae family to determine their capacity to remediate heptachlor- and heptachlor epoxide-contaminated soil. The seven Lagenaria cultivars were grown in contaminated and uncontaminated Molokai soil for 13 weeks. The results showed that all the plants tolerated heptachlor and heptachlor epoxide at levels of 0.169 and 0.376 μg/g, respectively, in the soil and were able to bear a limited number of immature fruits during the short study period. All seven Lagenaria cultivars showed some ability to up take heptachlor epoxide into their vines with bioaccumulation factors varying from 1.0 to 5.2. The two contaminants were not detected in the fruits and heptachlor itself was not detected in the vines. The mean concentrations of heptachlor in the soil of all the pots including the no-plant control were not significantly different from that in the initial soil, which might be due to the gradual release of the soil soil-bound heptachlor residues. In the soil, all pots showed a significant decrease for heptachlor epoxide as compared to the initial level, but there was no significant difference between the no-plant control pots and the planted pots of six of the seven cultivars. The local Hyotan cultivar showed the largest decrease, from 0.376 down to 0.050 μg/g dry soil, and was the only cultivar showing a significant difference in the soil heptachlor epoxide concentration with the no-plant control.
[学术文献 ] Generation of male-sterile soybean lines with the CRISPR/Cas9 system 进入全文
The Crop Journal
Soybean [Glycine max (L.) Merr.] provides a rich source of plant protein and oil worldwide. The commercial use of transgenic technology in soybean has become a classical example of the application of biotechnology to crop improvement. Although genetically modified soybeans have achieved commercial success, hybrid soybean breeding is also a potential way to increase soybean yield. Soybean cytoplasmic male-sterile (CMS) lines have been used in three-line hybrid breeding systems, but their application to exploiting soybean heterosis has been limited by rare germplasm resource of sterile lines. The generation of various genetic diversity male-sterile soybean lines will help to overcome the shortcoming. In this study, we used targeted editing of AMS homologs in soybean by CRISPR/Cas9 technology for the first time to generate stable male-sterile lines. Targeted editing of GmAMS1 resulted in a male-sterile phenotype, while editing of GmAMS2 failed to produce male-sterile lines. GmAMS1 functions not only in the formation of the pollen wall but also in the controlling the degradation of the soybean tapetum. CRISPR/Cas9 technology could be used to rapidly produce stable male-sterile lines, providing new sterile-line materials for soybean hybrid breeding systems.
[学术文献 ] Identification of novel source of salt tolerance in local bread wheat germplasm using morpho-physiological and biochemical attributes 进入全文
Scientific Reports
Salt tolerant wheat cultivars may be used as genetic resource for wheat breeding to ensure yield stability in future. The study was aimed to select salt tolerant cultivar(s) to identify novel source of salt tolerance in local wheat germplasm. Initially, 40 local wheat cultivars were screened at 150 mM NaCl stress at seedling stage. Selected salt-tolerant (three; S-24, LU-26S and Pasban-90) and salt-sensitive (four; MH-97, Kohistan-97, Inqilab-91 and Iqbal-2000) wheat cultivars were further evaluated using growth, yield, biochemical and physiological attributes. Growth and yield of selected cultivars were reduced under salt stress due to decline in plant water status, limited uptake of macronutrients (N, P and K), reduced K+/Na+ ratio, photosynthetic pigments and quantum yield of PSII. Wheat plants tried to acclimate salt stress by osmotic adjustment (accumulation of total soluble sugars, proline and free amino acids). Degree of salinity tolerance in cvs. S-24 and LU-26S found to be associated with maintenance of K+/Na+ ratio, osmo-protectant and photosynthetic activity and can be used as donor for salt tolerance in wheat breeding program at least in Pakistan. These cultivars can be further characterized using molecular techniques to identify QTLs/genes for salt exclusion, osmo-protectant and photosynthetic activity for molecular breeding.
[学术文献 ] Brassinosteroids mediate the effect of high temperature during anthesis on the pistil activity of photo-thermosensitive genetic male-sterile rice lines 进入全文
The Crop Journal
Brassinosteroids (BRs) play critical roles in a wide range of plant developmental processes. However, it is unknown whether and how BRs mediate the effect of high temperature (HT) stress during anthesis on the pistil activity of photo-thermosensitive genetic male-sterile (PTSGMS) rice (Oryza sativa L.) lines. This study investigated the question. Three pot-grown PTSGMS rice lines were subjected to HT stress during anthesis. The contents of 24-epibrassinolide (24-EBL) and 28-homobrassinolide (28-HBL), the major forms of BR in rice plants, and levels of reactive oxygen species (ROS) or antioxidants (AOS), hydrogen peroxide (H2O2), 1-aminocylopropane-1-carboxylic acid (ACC), ascorbic acid (AsA), and catalase activity in pistils, were determined. HT stress significantly reduced the contents of both 24-EBL and 28-EBL relative to those under normal temperatures, but the reduction varied by PTSGMS line. A line with higher BR contents under HT stress showed lower contents of ACC and H2O2, higher catalase activity and AsA content in pistils, and higher fertilization rate, seed-setting rate, and seed yield when the line was crossed with a restorer line, indicating that higher levels of BRs increase HT stress resistance. Applying 24-EBL, 28-HBL or an inhibitor of BR biosynthesis confirmed the roles of BRs in response to HT stress. The results suggest that BRs mediate the effect of HT stress on pistil activity during anthesis and alleviate the harm of HT stress by increasing AOS and suppressing ROS generation.
[学术文献 ] Growth, ionic homeostasis, and physiological responses of cotton under different salt and alkali stresses 进入全文
nature
To better understand the mechanism of salt tolerance, we analyzed cotton growth and the ionomes in different tissues under different types of salt–alkali stress. Cotton was exposed to the soil salt and alkali stresses, NaCl, Na2SO4, and Na2CO3?+?NaHCO3, in a pot study. Salt and alkali stress significantly inhibited cotton growth, significantly reduced root length, surface area, and volume, and significantly increased relative electrical conductivity (REC) and malondialdehyde (MDA) content but also significantly increased antioxidant enzyme activities, and proline (Pro) content. The REC in leaves was higher under salt stress than under alkali stress, but the effects on Pro were in the order Na2CO3?+?NaHCO3?>?NaCl?>?Na2SO4. Principal component analysis showed a significant difference in ion composition under the different types of salt–alkali stress. Under the three types of salt–alkali stress, concentrations of Na and Mo increased significantly in different organs of cotton plants. Under NaCl stress, the absorption of Ca was inhibited, the transport capacity of P, Mg, and Cu was reduced, and the ion balance was maintained by promoting the uptake and transport of Zn, Mn, Al, and Mo. Under Na2SO4 stress, the absorption of P and Ca was inhibited, the transport capacity of Mg, B, and Cu was reduced, and the ion balance was maintained by promoting the uptake and transport of S, Zn, Fe, Mo, Al, and Co. Under Na2CO3?+?NaHCO3 stress, the absorption of P and S was inhibited, the transport capacity of Mg and B was reduced, but that of Al and Fe increased, and the ion balance was maintained by promoting the uptake and transport of Mn, Mo, Ni, and Co. The relative expression of GhSOS1 and GhNHX1 in leaves increased significantly under salt stress but decreased under alkali stress. These results suggest that cotton is well-adapted to salt–alkali stress via the antioxidant enzyme system, adjustment of osmotic substances, and reconstruction of ionic equilibrium; neutral salt stress primarily disrupts the ion balance, whereas alkali stress decreases the ability to regulate Na and inhibits the absorption of mineral elements, as well as disrupts the ion balance; and the changes in the expression of salt tolerance-related genes may partially explain the accumulation of Na ions in cotton under salt–alkali stress.
