共查询到20条相似文献,搜索用时 15 毫秒
1.
Water movement across cellular membranes is regulated largely by a family of water channel proteins called aquaporins (AQPs).
Since several abiotic stresses such as, drought, salinity and freezing, manifest themselves via altering water status of plant
cells and are linked by the fact that they all result in cellular dehydration, we overexpressed an AQP (tonoplast intrinsic
protein) from Panax ginseng, PgTIP1, in transgenic Arabidopsis
thaliana plants to test its role in plant’s response to drought, salinity and cold acclimation (induced freezing tolerance). Under
favorable conditions, PgTIP1 overexpression significantly increased plant growth as determined by the biomass production, and leaf and root morphology.
PgTIP1 overexpression had beneficial effect on salt-stress tolerance as indicated by superior growth status and seed germination
of transgenic plants under salt stress; shoots of salt-stressed transgenic plants also accumulated greater amounts of Na+ compared to wild-type plants. Whereas PgTIP1 overexpression diminished the water-deficit tolerance of plants grown in shallow (10 cm deep) pots, the transgenic plants
were significantly more tolerant to water stress when grown in 45 cm deep pots. The rationale for this contrasting response,
apparently, comes from the differences in the root morphology and leaf water channel activity (speed of dehydration/rehydration)
between the transgenic and wild-type plants. Plants overexpressed with PgTIP1 exhibited lower (relative to wild-type control) cold acclimation ability; however, this response was independent of cold-regulated
gene expression. Our results demonstrate a significant function of PgTIP1 in growth and development of plant cells, and suggest that the water movement across tonoplast (via AQP) represents a rate-limiting
factor for plant vigor under favorable growth conditions and also significantly affect responses of plant to drought, salt
and cold stresses. 相似文献
2.
NADP-malic enzyme (NADP-ME, EC 1.1.1.40) functions in many different pathways in plant and may be involved in plant defense
such as wound and UV-B radiation. Here, expression of the gene encoding cytosolic NADP-ME (cytoNADP-ME, GenBank Accession No. AY444338) in rice (Oryza sativa L.) seedlings was induced by salt stress (NaCl). NADP-ME activities in leaves and roots of rice also increased in response
to NaCl. Transgenic Arabidopsis plants over-expressing rice cytoNADP-ME had a greater salt tolerance at the seedling stage than wild-type plants in MS medium-supplemented with different levels
of NaCl. Cytosolic NADPH/NADP+ concentration ratio of transgenic plants was higher than those of wild-type plants. These results suggest that rice cytoNADP-ME confers salt tolerance in transgenic Arabidopsis seedlings. 相似文献
3.
Guosheng Shao Mingxue Chen Weixia Wang Guoping Zhang 《Journal of Plant Growth Regulation》2008,27(3):205-210
The influence of betaine aldehyde dehydrogenase (BADH) and salinity pretreatment on oxidative stress under cadmium (Cd) toxicity
was investigated in rice cv. Xiushui 11 and its BADH-transgenic line Bxiushui 11. The results showed that plants previously treated with 4.25 and 8.5 mM NaCl, respectively, for
5 days each had higher Cd concentrations in both roots and shoots of the two rice genotypes compared with the controls. Malondialdehyde
(MDA) content in both leaves and roots was increased by salinity pretreatment and was significantly lower in the salinity-pretreatment
plants than in the controls when the plants were consequently exposed to Cd stress. Salinity pretreatment also increased proline
content and the activities of superoxide dismutase (SOD) and peroxidase (POD) in both leaves and roots. It can be assumed
that salinity pretreatment enhances the defensive ability of plants against oxidative stress through increasing activities
of antioxidative enzymes. The BADH-transgenic line (Bxiushui 11) had lower Cd and MDA content, higher SOD and POD activities, and higher proline content than
its wild type (Xiushui 11). The current results suggest that betaine, a product of BADH expression, improves the tolerance of rice plants to Cd stress through increasing the activities of antioxidative enzymes
and osmoprotectant content. 相似文献
4.
Three types of transgenic tobacco plants were acquired by separate transformation or co-transformation of a vacuolar Na+/H+ antiporter gene, SeNHX1, and a betaine synthesis gene, BADH. When exposed to 200 mM NaCl, the dual gene-transformed plants displayed greater accumulation of betaine and Na+ than their wild-type counterparts. Photosynthetic rate and photosystem II activity in the transgenic plants were less affected
by salt stress than wild-type plants. Transgenic plants exhibited a greater increase in osmotic pressure than wild-type plants
when exposed to NaCl. More importantly, the dual gene transformed plants accumulated higher biomass than either of the single
transgenic plants under salt stress. Taken together, these findings indicate that simultaneous transformation of BADH and SeNHX1 genes into tobacco plants can enable plants to accumulate betaine and Na+, thus conferring them more tolerance to salinity than either of the single gene transformed plants or wild-type tobacco plants.
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users. 相似文献
5.
The miR166/165 group and its target genes regulate diverse aspects of plant development, including apical and lateral meristem
formation, leaf polarity, and vascular development. We demonstrate here that MIR166/165 genes are dynamically controlled in regulating shoot apical meristem (SAM) and floral development in parallel to the WUSCHEL (WUS)-CLAVATA (CLV) pathway. Although miR166 and miR165 cleave same target mRNAs, individual MIR166/165 genes exhibit distinct expression domains in different plant tissues. The MIR166/165 expression is also temporarily regulated. Consistent with the dynamic expression patterns, an array of alterations in SAM
activities and floral architectures was observed in the miR166/165-overproducing plants. In addition, when a MIR166a-overexpressing mutant was genetically crossed with mutants defective in the WUS-CLV pathway, the resultant crosses exhibited additive phenotypic effects, suggesting that the miR166/165-mediated signal exerts
its role via a distinct signaling pathway. 相似文献
6.
Leaves of seed plants can be described as simple, where the leaf blade is entire, or dissected, where the blade is divided into distinct leaflets. Both simple and dissected leaves are initiated at the flanks of a pluripotent structure termed the shoot apical meristem (SAM). In simple-leafed species, expression of class I KNOTTED1-like homeobox (KNOX) proteins is confined to the meristem while in many dissected leaf plants, including tomato, KNOX expression persists in leaf primordia. Elevation of KNOX expression in tomato leaves can result in increased leaflet number, indicating that tight regulation of KNOX expression may help define the degree of leaf dissection in this species. To test this hypothesis and understand the mechanisms controlling leaf dissection in tomato, we studied the clausa (clau) and tripinnate (tp) mutants both of which condition increased leaflet number phenotypes. We show that TRIPINNATE and CLAUSA act together, to restrict the expression level and domain of the KNOX genes Tkn1 and LeT6/Tkn2 during tomato leaf development. Because loss of CLAU or TP activity results in increased KNOX expression predominantly on the adaxial (upper) leaf domain, our observations indicate that CLAU and TP may participate in a domain-specific KNOX repressive system that delimits the ability of the tomato leaf to generate leaflets. 相似文献
7.
P. D. Nguyen C.-L. Ho J. A. Harikrishna M. C. V.-L. Wong R. Abdul Rahim 《Trees - Structure and Function》2007,21(5):515-520
Salinity reduces plant growth and crop production globally. The discovery of genes in salinity tolerant plants will provide
the basis for effective genetic engineering strategies, leading to greater stress tolerance in economically important crops.
In this study, we have identified and isolated 107 salinity tolerant candidate genes from a mangrove plant, Acanthus ebracteatus Vahl by using bacterial functional assay. Sequence analysis of these putative salinity tolerant cDNA candidates revealed that 65% of them have not been reported to
be stress related and may have great potential for the elucidation of unique salinity tolerant mechanisms in mangrove. Among
the genes identified were also genes that had previously been linked to stress response including salinity tolerance, verifying
the reliability of this method in isolating salinity tolerant genes by using E. coli as a host. 相似文献
8.
Ting Liu Li Wang Yu-Xi Duan Xue Wang 《World journal of microbiology & biotechnology》2008,24(1):113-118
Culture filtrates of Beauveria bassiana at different concentrations were evaluated for nematicidal activity against the northern root knot nematode (Meloidogyne hapla); bioassays included egg hatching, mortality and infectivity on tomato plants in pots under glasshouse conditions. The percentage
mortality and inhibition of hatching of root-knot nematode were directly proportional to the concentration of culture filtrates
of B. bassiana. Soil drenching with culture filtrate of B. bassiana significantly reduced nematode population densities in soil and in the roots and subsequent gall formation and egg-mass production
by M. hapla under glasshouse conditions. 相似文献
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11.
Kexue Li Youning Wang Chunyu Han Wensheng Zhang Huizhen Jia Xia Li 《Plant Growth Regulation》2007,53(3):195-206
Flowering timing is very important for the reproductive success of higher plants. However, effects of salt on plant flowering
and the underlying molecular mechanisms are largely unknown. Here, we show that salt stress delays flowering in Arabidopsis in a dose-dependent manner. Mild salt stress (≤50 mM NaCl) promoted and prolonged the vegetative growth, whereas high salinity
(≥100 mM NaCl) largely delayed or inhibited the transition from vegetative growth to reproductive development. The gibberellin
(GA)-pathway plays an important role in this phenotype, and application of exogenous GA could restore late flowering induced
by salt. In addition, the CONSTANS (CO)/FLOWERING LOCUS T (FT) module may also play a critical role in mediating the effects of salt on flowering. The mRNA abundance of CO was significantly reduced by salt stress in a dose-dependent manner. The constans (co-2) mutants did not respond to moderate salt stress, whereas over-expressing CO manifested no delay in flowering time in response to salinity. Expression of FT, SOC1 and LFY in the downstream of the pathways was also reduced by salt according to dose. Moreover, salt-sensitive mutant salt overly sensitive3 (sos3) exhibited greater sensitivity in flowering, further suggesting that ion disequilibrium mediates salt-induced late flowering.
Kexue Li and Youning Wang contributed equally to this report. 相似文献
12.
Zahir Ahmad Zahir Usman Ghani Muhammad Naveed Sajid Mahmood Nadeem Hafiz Naeem Asghar 《Archives of microbiology》2009,191(5):415-424
Ethylene synthesis is accelerated in response to various environmental stresses like salinity. Ten rhizobacterial strains
isolated from wheat rhizosphere taken from different salt affected areas were screened for growth promotion of wheat under
axenic conditions at 1, 5, 10 and 15 dS m−1. Three strains, i.e., Pseudomonas putida (N21), Pseudomonas aeruginosa (N39) and Serratia proteamaculans (M35) showing promising performance under axenic conditions were selected for a pot trial at 1.63 (original), 5, 10 and 15 dS m−1. Results showed that inoculation was effective even in the presence of higher salinity levels. P. putida was the most efficient strain compared to the other strains and significantly increased the plant height, root length, grain
yield, 100-grain weight and straw yield up to 52, 60, 76, 19 and 67%, respectively, over uninoculated control at 15 dS m−1. Similarly, chlorophyll content and K+/Na+ of leaves also increased by P. putida over control. It is highly likely that under salinity stress, 1-aminocyclopropane-1-carboxylic acid-deaminase activity of
these microbial strains might have caused reduction in the synthesis of stress (salt)-induced inhibitory levels of ethylene.
The results suggested that these strains could be employed for salinity tolerance in wheat; however, P. putida may have better prospects in stress alleviation/reduction. 相似文献
13.
An <Emphasis Type="Italic">Arabidopsis</Emphasis> senescence-associated protein SAG29 regulates cell viability under high salinity 总被引:1,自引:0,他引:1
The plasma membrane is an important cellular organ that perceives incoming developmental and environmental signals and integrates
these signals into cellular regulatory mechanisms. It also acts as a barrier against unfavorable extracellular factors to
maintain cell viability. Despite its importance for cell viability, molecular components determining cell viability and underlying
mechanisms are largely unknown. Here, we show that a plasma membrane-localized MtN3 protein SAG29 regulates cell viability
under high salinity in Arabidopsis. The SAG29 gene is expressed primarily in senescing plant tissues. It is induced by osmotic stresses via an abscisic acid-dependent
pathway. Whereas the SAG29-overexpressing transgenic plants (35S:SAG29) exhibited an accelerated senescence and were hypersensitive to salt stress, the SAG29-deficient mutants were less sensitive to high salinity. Consistent with this, the 35S:SAG29 transgenic plants showed reduced cell viability in the roots under normal growth condition. In contrast, cell viability in
the SAG29-deficient mutant roots was indistinguishable from that in the roots of control plants. Notably, the mutant roots exhibited
enhanced cell viability under high salinity. Our observations indicate that the senescence-associated SAG29 protein is associated
with cell viability under high salinity and other osmotic stress conditions. We propose that the SAG29 protein may serve as
a molecular link that integrates environmental stress responses into senescing process. 相似文献
14.
Nitraria retusa and Atriplex halimus (xero-halophytes) plants were grown in the range 0–800 mM NaCl while Medicago arborea (glycophyte) in 0–300 mM NaCl. Salt stress caused a marked decrease in osmotic potential and a significant accumulation of
Na+ and Cl− in leaves of both species. Moderate salinity had a stimulating effect on growth rate, net CO2 assimilation, transpiration and stomatal conductance for the xero-halophytic species. At higher salinities, these physiological
parameters decreased significantly, and their percentages of reduction were higher in A. halimus than in N. retusa whereas, in M. arborea they decreased linearly with salinity. Nitraria retusa PSII photochemistry and carotenoid content were unaffected by salinity, but a reduction in chlorophyll content was observed
at 800 mM NaCl. Similar results were found in A. halimus, but with a decrease in the efficiency of PSII (F′v/F′m) occurred at 800 mM. Conversely, in M. arborea plants we observed a significant reduction in pigment concentrations and chlorophyll fluorescence parameters. The marked
toxic effect of Na+ and/or Cl− observed in M. arborea indicates that salt damage effect could be attributed to ions’ toxicity, and that the reduction in photosynthesis is most
probably due to damages in the photosynthetic apparatus rather than factors affecting stomatal closure. For the two halophyte
species, it appears that there is occurrence of co-limitation of photosynthesis by stomatal and non-stomatal factors. Our
results suggest that both N. retusa and A. halimus show high tolerance to both high salinity and photoinhibition while M. arborea was considered as a slightly salt tolerant species. 相似文献
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Plant aquaporins are believed to facilitate water transport across cell membranes. However, the relationship between aquaporins
and drought resistance in plants remains unclear. VfPIP1, a putative aquaporin gene, was isolated from Vicia faba leaf epidermis, and its expression was induced by abscisic acid (ABA). Our results indicated that the VfPIP1 protein was
localized in the plasma membrane, and its expression in V. faba was induced by 20% polyethylene glycol 6000. To further understand the function of VfPIP1, we obtained VfPIP1-expressing transgenic Arabidopsis thaliana plants under the control of the CaMV35S promoter. As compared to the wild-type control plants, the transgenic plants exhibited
a faster growth rate, a lower transpiration rate, and greater drought tolerance. In addition, the stomata of the transgenic
plants closed significantly faster than those of the control plants under ABA or dark treatment. These results suggest that
VfPIP1 expression may improve drought resistance of the transgenic plants by promoting stomatal closure under drought stress. 相似文献
18.
Priyanka Sharma Amit C. Kharkwal M. Z. Abdin Ajit Varma 《Symbiosis (Philadelphia, Pa.)》2017,72(2):103-115
Piriformospora indica, a root endophytic fungus, has been reported to promote growth of many plants under normal condition and allow the plants to survive under stress conditions. However, its impact on an important medicinal plant Aloe vera L. has not been well studied. Therefore, this study was undertaken to investigate the effect of P. indica on salinity stress tolerance of A. vera plant. P. indica inoculated and non-inoculated A. vera plantlets were subjected to four levels of salinity treatment- 0, 100, 200 and 300 mM NaCl. The salinity stress decreased the ability of the fungus to colonize roots of A. vera but the interaction of A. vera with P. indica resulted in an overall increase in plant biomass and greater shoot and root length as well as number of shoots and roots. The photosynthetic pigment (Chl a, Chl b and total Chl) and gel content were significantly higher for the fungus inoculated A. vera plantlets, at respective salinity concentrations. Furthermore, the inoculated plantlets had higher phenol, flavonoid, flavonol, aloin contents and radical scavenging activity at all salinity concentrations. The higher phenolic and flavonoid content may help the plants ameliorate oxidative stress resulting from high salinity. 相似文献
19.
H. EL Arroussi R. Benhima A. Elbaouchi B. Sijilmassi N. EL Mernissi A. Aafsar I. Meftah-Kadmiri N. Bendaou A. Smouni 《Journal of applied phycology》2018,30(5):2929-2941
Microalgal exopolysaccharides represent a potential sustainable alternative for the enhancement and protection of agricultural crops including management of both biotic and abiotic stress. In the present study, we investigated the potential of Dunaliella salina exopolysaccharides (PS) to attenuate the effect of salt stress on growth of Solanum lycopersicum, which was grown under different salinity levels (3 and 6 g L?1 NaCl). The effects of PS treatment on plant growth, osmoprotectant molecules, protein content, and antioxidant enzymes activities of tomato plants under salt stress were analyzed. A metabolomics study showed that the exopolysaccharides released by D. salina contained sulfated moiety along with carbohydrates and uronic acids. The application of sulfated exopolysaccharides on tomato plants alleviated the salt stress and mitigated the decrease in length and dry weight of the plant’s shoot and root systems, as well as that of potassium (K+), and K+/Na+ ratio. Furthermore, the increase in proline, phenolic compounds, Na+, and antioxidant enzymes (CAT, POD, SOD) activities caused by salt stress were attenuated after the exopolysaccharide treatment. GC-MS metabolomics analysis showed that PS treatment allowed the activation and/or inhibition of various metabolic pathways involved in the plant’s tolerance to stress such as jasmonic acid-dependent pathways. This study shows the potential of microalgal exopolysaccharides for enhancing tomato tolerance to salt stress and highlights the possibility of their use as plant growth biostimulants under harsh environmental conditions. 相似文献
20.
Increased salinization of arable land is expected to have devastating global effects in the coming years. Arbuscular mycorrhizal
fungi (AMF) have been shown to improve plant tolerance to abiotic environmental factors such as salinity, but they can be
themselves negatively affected by salinity. In this study, the first in vitro experiment analyzed the effects of 0, 50, or 100 mM NaCl on the development and sporulation of Glomus intraradices. In the second experiment, the effects of mycorrhization on the expression of key plant genes expected to be affected by
salinity was evaluated. Results showed that the assayed isolate G. intraradices DAOM 197198 can be regarded as a moderately salt-tolerant AMF because it did not significantly decrease hyphal development
or formation of branching absorbing structures at 50 mM NaCl. Results also showed that plants colonized by G. intraradices grew more than nonmycorrhizal plants. This effect was concomitant with a higher relative water content in AM plants, lower
proline content, and expression of Lsp5cs gene (mainly at 50 mM NaCl), lower expression of the stress marker gene Lslea gene, and lower content of abscisic acid in roots of mycorrhizal plants as compared to nonmycorrhizal plants, which suggest
that the AM fungus decreased salt stress injury. In addition, under salinity, AM symbiosis enhanced the expression of LsPIP1. Such enhanced gene expression could contribute to regulating root water permeability to better tolerate the osmotic stress
generated by salinity. 相似文献