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1.
Phytochelatins (PCs) are post-translationally synthesized thiol reactive peptides that play important roles in detoxification
of heavy metal and metalloids in plants and other living organisms. The overall goal of this study is to develop transgenic
plants with increased tolerance for and accumulation of heavy metals and metalloids from soil by expressing an Arabidopsis
thaliana
AtPCS1 gene, encoding phytochelatin synthase (PCS), in Indian mustard (Brassica juncea L.). A FLAG-tagged AtPCS1 gDNA, under its native promoter, is expressed in Indian mustard, and transgenic pcs lines have been compared with wild-type
plants for tolerance to and accumulation of cadmium (Cd) and arsenic (As). Compared to wild type plants, transgenic plants
exhibit significantly higher tolerance to Cd and As. Shoots of Cd-treated pcs plants have significantly higher concentrations
of PCs and thiols than those of wild-type plants. Shoots of wild-type plants accumulated significantly more Cd than those
of transgenic plants, while accumulation of As in transgenic plants was similar to that in wild type plants. Although phytochelatin
synthase improves the ability of Indian mustard to tolerate higher levels of the heavy metal Cd and the metalloid As, it does
not increase the accumulation potential of these metals in the above ground tissues of Indian mustard plants. 相似文献
2.
Phytochelatins (PCs) are heavy metal binding peptides that play an important role in sequestration and detoxification of heavy
metals in plants. In this study, our goal was to develop transgenic plants with increased tolerance for and accumulation of
heavy metals from soil by expressing an Arabidopsis
thaliana
AtPCS1 gene, encoding phytochelatin synthase (PCS), in Indian mustard (Brassica juncea L.). A 35S promoter fused to a FLAG–tagged AtPCS1 cDNA was expressed in Indian mustard, and transgenic lines, designated pc lines, were evaluated for tolerance to and accumulation
of Cd and Zn. Transgenic plants with moderate AtPCS1 expression levels showed significantly higher tolerance to Cd and Zn
stress, but accumulated significantly less Cd and Zn than wild type plants in both shoot and root tissues. However, transgenic
plants with highest expression of the transgene did not exhibit enhanced Cd and Zn tolerance. Shoots of Cd-treated pc plants
had significantly higher levels of phytochelatins and thiols than wild-type plants. Significantly lower concentrations of
gluthatione in Cd-treated shoot and root tissues of transgenic plants were observed. Moderate expression levels of phytochelatin
synthase improved the ability of Indian mustard to tolerate certain levels of heavy metals, but at the same time did not increase
the accumulation potential for Cd and Zn. 相似文献
3.
The effect of excessive Cd on the growth and metal uptake by leafy vegetables Brassica chinensis L. (cv. Wuyueman) and Brassica pekinensis (Lour.) Rupr. (cv. Qingyan 87-114) were studied in hydroponic solution culture. The Cd concentration higher than 10 μM significantly
decreased the root elongation and leaf chlorophyll contents of both plant species. The shoots of B. pekinensis had significantly higher concentrations of total and water-soluble Cd than B. chinensis. The roots of both species accumulated more Cd than the shoots in all the Cd treatments. Most of the Cd in the roots was
found in the cell walls. The shoot/root ratio of Cd concentrations in B. pekinensis was always greater than that in B. chinensis. But, the concentration and proportion of Cd in the cell walls in B. chinensis were higher than that in B. pekinensis. Cadmium treatments also increased the concentrations of total non-protein thiols (NPT) in the shoots of the both species.
A significant correlation was found between the concentrations of soluble Cd and NPT in plant shoots. 相似文献
4.
Reinerio Benega Garcia Aroldo Cisneros Bert Schneider Noemi Tel-Zur 《Plant cell reports》2009,28(5):719-726
Gynogenesis was investigated on the allotetraploid Selenicereus megalanthus and the diploid Hylocereus polyrhizus and Hylocereus undatus vine cactus species. Unpollinated ovules from developing flower buds containing microspores at middle uninucleate developmental
stage were cultured on MS basal medium containing 2,4-D/TDZ with different sucrose concentrations. Ovule size increased under
dark culture conditions in all the three species and the level of response was species and sucrose concentration dependent.
The best responses were achieved in the two S. megalanthus accessions, E-123 and J-80, at 0.18 and 0.26 M sucrose. Only ovule enlargement was obtained in H. undatus and both ovule enlargement and callus were obtained in H. polyrhizus. Development in both species ceased and embryoids were not formed. Plant regeneration was directly and indirectly obtained
in both S. megalanthus accessions. Ploidy level was determined for a total of 29 S. megalanthus gynogenic plants using flow cytometry: 15 were found to be dihaploid (plants with the gametophytic chromosome number) and
the other 14 were found to have higher ploidy levels. This is the first report of successful gynogenesis in Cactaceae. The
dihaploids of S. megalanthus successfully produced by ovule culture techniques opens new perspectives in vine cacti breeding. 相似文献
5.
Zuzana Vatehová Karin Kollárová Ivan Zelko Danica Richterová-Kučerová Marek Bujdoš Desana Lišková 《Biologia》2012,67(3):498-504
The objective of this study was to determine the effect of silicon (Si) and cadmium (Cd) on root and shoot growth and Cd uptake
in two hydroponically cultivated Brassica species (B. juncea (L.) Czern. cv. Vitasso and B. napus L. cv. Atlantic). Both species are potentially usable for phytoextraction. Inhibitory effects of Cd on root elongation were
diminished by the impact of Si. Primary roots elongation in the presence of Cd + Si compared with Cd was stronger and the
number of lateral roots was lower in B. juncea than in B. napus. Cd content per plant was higher in B. napus roots and shoots compared with B. juncea. Suberin lamellae were formed closer to the root apex in Cd + Si than in Cd treated plants and this effect was stronger in
B. napus than in B. juncea. Accelerated maturation of endodermis was associated with reduced Cd uptake. Cd decreased the content of chlorophylls and
carotenoids in both species, but Si addition positively influenced the content of photosynthetic pigments which was higher
in B. napus than in B. juncea. Si enhanced more substantially translocation of Cd into the shoot of B. napus than of B. juncea. Based on our results B. napus seems to be more suitable for Cd phytoextraction than B. juncea because these plants produce more biomass and accumulate
higher amount of Cd. The protective effect of Si on Cd treated Brassica plants could be attributed to more extensive development of suberin lamellae in endodermis. 相似文献
6.
Hua Zhang Rui Xia Zhou Li Jing Zhang Ruo Yu Wang Li Zhe An 《Journal of Plant Biology》2007,50(3):336-343
A novel late embryogenesis abundant (LEA) gene (AY804193), namedCbLEA, has now been isolated fromChorispora bungeana. This rare alpine subnival plant can survive sudden snowstorms and low temperatures. The full-lengthCbLEA is 842 bp, with an open reading frame encoding 169 ami no acids. The putative molecular weight ofCbLEA protein is 17.9 kDa, with an estimatedpl of 6.45. To investigate the functioning of thisCbLEA protein in cold-stress tolerance,CbLEA was introduced into tobacco under the control of the CaMV35S promoter. Second-generation (R1) transgenic tobacco plants exhibited significantly increased tolerance to cold. These transgenics maintained lower malondialdehyde
(MDA) contents and electrolyte leakage (EL) but their relative water content (RWC) was significantly higher compared with
non-transgenic plants under chilling stress. Further experimental results showed that non-transgenic plants had severe freezing
damage after exposure to -2°C for 1 h, whereas the transgenics suffered only slight injury under the same conditions. Moreover,
survival was longer in the latter genotype at that temperature. The extent of increased cold tolerance was positive correlated
with the level ofCbLEA protein accumulation, and was also reflected by the delayed development of damage symptoms. This indicates thatCbLEA is an excellent stress tolerance gene, and holds considerable potential as a new molecular tool for engineering improved
plant genetics. 相似文献
7.
The life cycle and developmental stages of Aylax hypecoi (Trotter, 1913, Hymenoptera: Cynipidae: Aylacini) were studied in detail. Aylax hypecoi is known to induce galls in fruits of two Hypecoum species — H. imberbe and H. geslini (Papaveraceae) and the larva develops in host plant fruits. The morphology and development of egg, larva and pupa were investigated, which
has previously not been done. The shape and size of terminal-instar larvae and associated galls are sex-specific. Overwintering
stage, adult emergence and flying periods, and egg productivity were studied also. 相似文献
8.
Ondřej Koukol 《Mycological Progress》2010,9(3):369-378
Survey of seven strains determined as Septonema ochraceum (Dothideomycetes, inc. sed.) isolated from pine litter or obtained from public collections revealed three new species, Fusicladium cordae, F. sicilianum (Venturiaceae), Cladophialophora matsushimae (Herpotrichiellaceae) and a cryptic species morphologically identical to Devriesia americana (Teratosphaeriaceae), but phylogenetically distinct. Morphological survey and phylogenetic analysis using nucleotide sequence data from the nuclear
ribosomal subunit genes indicate a close relationship within three species colonising pine litter needles, F. cordae, F. pini and F. ramoconidii. F. sicilianum is most related to F. rhodense. C. matsushimae represents a species belonging to one of the lineages of the polyphyletic genus Cladophialophora. None of the strains observed can be classified morphologically as S. ochraceum, of which the type material does not exist. 相似文献
9.
E. Chevreau F. Dupuis J. P. Taglioni S. Sourice R. Cournol C. Deswartes A. Bersegeay J. Descombin M. Siegwart K. Loridon 《Plant Cell, Tissue and Organ Culture》2011,106(1):161-168
The development of alternative selection systems without antibiotic resistance genes is a key issue to produce safer and more
acceptable transgenic plants. Eutypine is a toxin produced by Eutypa lata, the causal agent of eutypa dieback of grapevine, which is detoxified in mung bean (Vigna radiata) by the gene Vr-ERE. Many phytotoxic compounds containing an aldehyde group can act as substrates for the Vr-ERE enzyme. The aim of the present
work was to evaluate the effects of the overexpression of Vr-ERE in transgenic apple plants, as a first step towards the development of an alternative selection system. Viable transgenic
apple clones expressing Vr-ERE were produced from the cultivar Greensleeves under kanamycin selection. Although the Vr-ERE transgene was normally expressed at the RNA and protein levels, the increase in aldehyde reductase activity tested on a range
of potential substrates was very low in these clones. None of them revealed a significant increase in tolerance to toxic aldehydes
compared to their non-transgenic control. This work with transgenic apple plants overexpressing the detoxifying gene Vr-ERE illustrates some of the difficulties in developing an alternative selection pressure. 相似文献
10.
Helena T Funk Sabine Berg Karin Krupinska Uwe G Maier Kirsten Krause 《BMC plant biology》2007,7(1):45
Background
The holoparasitic plant genus Cuscuta comprises species with photosynthetic capacity and functional chloroplasts as well as achlorophyllous and intermediate forms with restricted photosynthetic activity and degenerated chloroplasts. Previous data indicated significant differences with respect to the plastid genome coding capacity in different Cuscuta species that could correlate with their photosynthetic activity. In order to shed light on the molecular changes accompanying the parasitic lifestyle, we sequenced the plastid chromosomes of the two species Cuscuta reflexa and Cuscuta gronovii. Both species are capable of performing photosynthesis, albeit with varying efficiencies. Together with the plastid genome of Epifagus virginiana, an achlorophyllous parasitic plant whose plastid genome has been sequenced, these species represent a series of progression towards total dependency on the host plant, ranging from reduced levels of photosynthesis in C. reflexa to a restricted photosynthetic activity and degenerated chloroplasts in C. gronovii to an achlorophyllous state in E. virginiana. 相似文献11.
I. Rosario G. Soro S. Déniz O. Ferrer F. Acosta D. Padilla B. Acosta 《Mycopathologia》2010,169(4):315-319
Columba livia is an important reservoir and carrier of Cryptococcus neoformans, Cryptococcus uniguttulatus, Cryptococcus laurentii and Cryptococcus albidus. Upper digestive tract of this species is also known as a habitat for Cryptococcus neoformans. Given the increasing clinical interest of this microorganism, 331 swabs from crop and 174 dropping samples from pigeon lofts
in Grand Canary Island have been studied. The obtained results show an extensive presence samples 81 positive (24.47%) of
Cryptococcus spp. in analysed crops: 32 (9.66%) for C. neoformans, 24 (7.2%) for C. uniguttulatus, 23 (6.9%) for C. albidus and 2 (0.6%) for C. laurentii. In the same way, Cryptococcus spp was also isolated in 82 (47.13%), dropping samples: C. neoformans in 59 (33.9%), C. uniguttulatus, in 9 (5.17%), C. laurentii in 8 (4.59%) and C. albidus in 6 (3.44%) of the investigated samples, respectively. The cryptococcosis produced by species of cryptococci other than C. neoformans has become more important during the last decade, supporting the study on the role of pigeon in the epidemiology of this
disease. 相似文献
12.
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14.
The mechanisms of plant tolerance to cadmium stress were studied by short-term exposure of Potamogeton crispus L. to various concentrations of Cd ranging from 0 to 0.09 mM. The accumulation of Cd and its influence on nutrient elements,
chlorophyll pigments, ultrastructure, proline and MDA contents, and free radical production, as well as the activities of
superoxide dismutase (SOD), peroxidase (POD), ascorbate peroxidase (APX), and glutathione reductase (GR) were investigated.
The higher Cd concentration in the medium resulted in a significant enhancement of Cd accumulation. Photosynthetic pigment
content decreased and ultrastructural damage to the leaf cells was aggravated with the increase in the Cd concentrations.
Disruption of chloroplasts and mitochondria was observed even at the lowest concentration of Cd. Meantime, the rate of O2*− generation and the contents of H2O2 and MDA significantly increased under Cd stress, suggesting that Cd caused oxidative stress. In addition, the antioxidant
system was clearly activated following Cd exposure. SOD and POD activities increased initially and then decreased, while APX
and GR activities markedly increased. Simultaneously, mineral nutrition was disturbed. While K, P, Ca, and Cu contents decreased,
Na, Fe, and Mn contents increased. Induction of antioxidant enzyme activities in leaves exposed to elevated Cd concentrations
may be involved in Cd tolerance of P. crispus. 相似文献
15.
Cadmium accumulation, the relative content of different chemical forms of Cd, as well as the toxic effect of Cd on nutrient
element uptake, physiological parameters, and ultrastructure of Sagittaria sagittifolia L. seedlings were determined after the seedlings were exposed to different Cd concentrations for 4 days. The results showed
that S. sagittifolia had the ability to accumulate large amounts of Cd. In the root, stem, and bulb, the predominant chemical Cd forms were NaCl
extractable. With an increase in the Cd2+ concentration, the chlorophyll content, the relative membrane penetrability (RMP) of root cells, peroxidase (POD) activity,
superoxide dismutase (SOD) activity in leaves, malondiadehyde (MDA) content and the superoxide anion (O2−) generation rate in roots all decreased following an initial increase. On the other hand, catalase (CAT) activity, SOD activity
in roots, MDA content, and the generation rate of O2− in leaves all increased gradually. The toxic effect of Cd2+ was more severe on roots than on leaves at the same concentration. Cadmium affected the mineral nutrition balance; mainly,
it promoted the uptake of Ca, Cu, Mn, and Fe, while inhibited Mg, Na, and K uptake. The physiological toxic effect of Cd2+ was close to the ultrastructural damage induced by Cd contamination. A significant correspondence was observed between the
Cd dose and its toxic effect. Cadmium could destroy the normal ultrastructure, disturb the ion balance, and interfere with
cell metabolism. 相似文献
16.
Rameswor Maharjan Hwijong Yi Hyuntae Kim Youngnam Yoon Yunwoo Jang Soondo Bae 《Applied Entomology and Zoology》2018,53(1):55-66
The Azuki bean weevil, Callosobruchus chinensis (L.), is a destructive pest of stored mung bean [Vigna radiata (L.) Wilczek] as well as other leguminous seeds. The development of resistant seeds to manage this pest is of current great interest to plant breeders. In this study, we investigated the oviposition preference and development of C. chinensis on two susceptible mung bean cultivars (Seonhwa and Gyeongseon) and one previously reported resistant cultivar (Jangan), compared to the susceptible cowpea (Vigna unguiculata L.), cultivar (Yeonbun) using both multiple-choice and no-choice tests. In addition, the development of C. chinensis was also examined at four constant temperatures (20, 25, 30, and 35 °C). Both tests found cowpea to be the most suitable seed for oviposition. Total developmental time from oviposition to adult emergence ranged from 27.01 to 38.2 days, being shortest on cowpea and longest on the mung bean, cv. Jangan. However, no successful development of C. chinensis larvae on mung bean, cv. Jangan, occurred at any temperature. The highest rate of adult emergence and the longest adult longevity both occurred on cowpea and certain mung bean cultivars (Seonhwa and Gyeongseon), with the dramatic exception of cv. Jangan. These results suggest that the higher preference and performance of C. chinensis on cowpea (3.3 egg/seed) and least on mung bean, cv. Jangan (0.4 egg/seed). This information may facilitate the exploration of resistant genetic materials and chemicals associated with seeds for successful breeding. Further studies should examine the chemicals associated with mung bean cultivars and its resistant mechanism to develop a control method against bruchines. 相似文献
17.
Plants of Indian mustard (Brassica juncea) were treated with either 50 μM Cd, 250 μM Zn, or 25 μM Cd+125 μM Zn and the progression of chlorosis in the mature leaves
monitored. As relative chlorophyll (Chl) contents in the mature leaves decreased to 75, 50, and 25 % relative to controls,
both mature and young leaves were harvested and the Chl pools extracted. The metal treatments caused a greater loss of Chl
b than Chl a. As mature leaves underwent progressive chlorosis, the young leaves displayed a characteristic over-greening, due largely
to increased content of Chl b. However, as the young leaves began to experience chlorosis, a greater loss of Chl b was also observed. Thus during metal induced chlorosis, there is a preferential turnover of the Chl b pool in mature and young leaves. 相似文献
18.
An experiment was taken up to find out possibilities of manipulating the in vitro flowering in moth bean. Abscisic acid (ABA) and proline both alone and in combination influenced days to flower induction,
number of flowers per plant, number of pods per plant and seeds per pod. Frequency of flowering plants approached 100 % at
1 and 3 μM ABA and 800 μM proline. The range of flowering period (3 to 23.6 d) has also been influenced by various treatments. 相似文献
19.
Mario C. N. Saparrat Geraldine E. Fermoselle Sebastián A. Stenglein Mónica B. Aulicino Pedro A. Balatti 《Mycopathologia》2009,168(1):41-47
Pseudocercospora griseola is the causal agent of angular leaf spot of common bean (ALS). It has undergone parallel coevolution with its host and two
major groups have been defined, “Andean” (P. griseola f. griseola) and “Mesoamerican” (P. griseola f. mesoamericana). The aim of this study was to analyze the nature and the level of the dark pigment synthesized by the representatives of
each group. After 21 days of incubation on potato dextrose agar medium, P. griseola f. griseola isolate S3b developed colonies with diameters of 17.5 ± 1.3 mm and concentric rings of pigmentation. Isolate T4 of P. griseola f. mesoamericana presented smaller colonies (9.9 ± 0.3 mm) with a uniform dark-gray color. Both isolates, S3b and T4, produced the same pigment,
a 1,8-dihydroxynaphthalene-melanin, although different in quantity and structural features as suggested by the IR spectrum.
The P. griseola f. griseola isolate S3b had a higher growth rate and melanin content as well as smaller sensitivity to melanin synthesis inhibitors compared
to the isolate T4 of P. griseola f. mesoamericana. These results suggest a possible link between melanin and growth in P. griseola. 相似文献
20.
Tuo Chen Zhiguang Zhao Youfu Zhang Weiya Qiang Huyuan Feng Lizhe An Zhongqin Li 《Acta Physiologiae Plantarum》2012,34(3):1007-1015
For centuries in Asia, Rhodiola
coccinea has been used as a valuable adaptogen medicinal plant known for its remarkable resistance to various stress factors. Physiological
tolerance in chloroplasts is believed to be an important factor, which affects the geographic distribution of plant species.
However, there is currently no report on how the physiological tolerance in the chloroplasts of R. coccinea varies along an altitudinal gradient in a semi-arid mountain region. In this work, we investigated the physiological variations of the chloroplasts of R. coccinea plants along an altitudinal gradient in the Tianshan Mountains, which are located in northwest China. It was found that the
physiological parameters of chloroplasts in R. coccinea plants, including superoxide generation, fatty acid compositions, thylakoid membrane fluidity, chlorophyll a/b ratios and
photosynthetic electron transport rates (ETRs), varied nonlinearly with altitude. Indeed, an inflection point was observed
at approximately 3,800 m. For altitudes were higher or lower than 3,800 m, the ETR, index of unsaturated fatty acids in the
thylakoid membrane and Chl a/b ratios decreased with increasing altitude, whereas the superoxide generation and DPH polarisation of thylakoid membranes
increased. In addition, variations in the AsA and GSH contents of chloroplasts could be divided into two distinct phases along
the altitudinal gradient. The AsA content slowly decreased with increasing altitudes up to 3,800 m and rapidly decreased above
3,800 m. However, there was a gradual increase in the GSH content between 3,570 and 3,750 m, followed by an abrupt rise to
a plateau level. These results demonstrate that the physiological tolerance of chloroplasts widely varies with altitude and
have a tight relationship with the range of growth altitude of R. coccinea in Tianshan Mountains. 相似文献