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Pou Alícia Medrano Hipólito Tomàs Magdalena Martorell Sebastià Ribas-Carbó Miquel Flexas Jaume 《Plant and Soil》2012,354(1-2):335-345
Aims
Arbuscular mycorrhizal fungi (AMF) can control root-knot nematode infection, but the mode of action is still unknown. We investigated the effects of AMF and mycorrhizal root exudates on the initial steps of Meloidogyne incognita infection, namely movement towards and penetration of tomato roots.Methods
M. incognita soil migration and root penetration were evaluated in a twin-chamber set-up consisting of a control and mycorrhizal (Glomus mosseae) plant compartment (Solanum lycopersicum cv. Marmande) connected by a bridge. Penetration into control and mycorrhizal roots was also assessed when non-mycorrhizal or mycorrhizal root exudates were applied and nematode motility in the presence of the root exudates was tested in vitro.Results
M. incognita penetration was significantly reduced in mycorrhizal roots compared to control roots. In the twin-chamber set-up, equal numbers of nematodes moved to both compartments, but the majority accumulated in the soil of the mycorrhizal plant compartment, while for the control plants the majority penetrated the roots. Application of mycorrhizal root exudates further reduced nematode penetration in mycorrhizal plants and temporarily paralyzed nematodes, compared with application of water or non-mycorrhizal root exudates.Conclusions
Nematode penetration was reduced in mycorrhizal tomato roots and mycorrhizal root exudates probably contributed at least partially by affecting nematode motility. 相似文献3.
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Devendra?Singh Neelam?Geat Mahendra?Vikram?Singh?Rajawat Mahesh?M.?Mahajan Radha?Prasanna Surender?Singh Rajeev?Kaushik Ram?Nageena?Singh Kanika?Kumar Anil?Kumar?Saxena
An investigation was carried out to understand the mechanism(s) underlying enhanced Fe or Zn uptake in low Fe–Zn accumulator wheat genotype 4HPYT-414, due to inoculation of siderophore-producing and zinc-solubilizing endophytes—Arthrobacter sulfonivorans DS-68 and Arthrobacter sp. DS-179. Root anatomical features, using transmission electron microscopy (TEM), qualitative and quantitative aspects of production of organic acids and sugars in root exudates, and expression of TaZIP genes were analysed to relate to endophyte-mediated higher concentrations of Fe and Zn in the roots and shoots of wheat plants. TEM studies revealed that the endodermis, cortical region, root hair extension, xylem and xylem vessels, pericycle and vascular bundles were more pronounced and thicker in inoculated treatments, as compared to control. The organic acid profile of root exudates revealed five types of organic acids, with citric acid being predominant. Inoculation of A. sulfonivorans and Arthrobacter sp. brought about 5- and eightfold increases in the amounts of acids, respectively, as compared to control, particularly citric acid, succinic acid and acetic acid. Among the four TaZIP genes targeted, expression was achieved only for TaZIP3 and TaZIP7 genes, which showed 1–2 fold increases in the inoculated treatments. The results clearly indicated that the endophyte-mediated overexpression of TaZIP3 and TaZIP7 genes in roots and shoots, and the observed anatomical and exudate changes were acting synergistically in facilitating higher Fe and Zn translocation in roots and shoots. 相似文献
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Nan Zhang Dandan Wang Yunpeng Liu Shuqing Li Qirong Shen Ruifu Zhang 《Plant and Soil》2014,374(1-2):689-700
Aim
It is necessary to understand the roles of root exudates involved in plant-microbe interactions to inform practical application of beneficial rhizosphere microbial strains.Methods
Colonization of Bacillus amyloliquefaciens SQR9 (isolated from cucumber rhizosphere) and Bacillus subtilis N11 (isolated from banana rhizosphere) of their original host was found to be more effective as compared to the colonization of the non-host plant. Organic acids in the root exudates of the two plants were identified by High performance liquid chromatography (HPLC). The chemotactic response and effects on biofilm formation were assessed for SQR9 and N11 in response to cucumber and banana root exudates, as well as their organic acids components.Results
Citric acid detected exclusively in cucumber exudates could both attract SQR9 and induce its biofilm formation, whereas only chemotactic response but not biofilm formation was induced in N11. Fumaric acid that was only detected in banana root exudates revealed both significant roles on chemotaxis and biofilm formation of N11, while showing only effects on biofilm formation but not chemotaxis of SQR9.Conclusion
The relationship between PGPR strain and root exudates components of its original host might contribute to preferential colonization. This study advances a clearer understanding of the mechanisms relevant to application of PGPR strains in agricultural production. 相似文献9.
Wan-Ze Zhu San-Gen Wang De-Zhen Yu Yong Jiang Mai-He Li 《Trees - Structure and Function》2014,28(2):359-372
Key message
Above- and belowground tissues showed different trends in IAA, CTK and CTK/IAA ratios with elevations, and coppicing changed the levels of endogenous hormones that are related to resprouting ability.Abstract
Little is known about how plant hormones and nitrate concentrations change in plants with increasing elevations, and whether the alpine treeline formation and the decreased resprouting ability of plants at high elevations are correlated with such changes. We studied tissue hormones and nitrate concentrations in Quercus aquifolioides plants before and after coppicing at 3,000, 3,500 m, and their uppermost distribution of 3,950 m a.s.l. in southwestern China. Concentrations of indole-3-acetic acid (IAA) significantly increased, but concentrations of cytokinins (CTK) and CTK/IAA ratios decreased in aboveground tissues of intact plants with increasing elevations. The altitude had reverse effects on these parameters in belowground tissue. Coppicing changed the levels of IAA, CTK, and nitrate concentrations, as well as the CTK/IAA ratios, but not their elevational patterns in either stumps or roots. These results imply that the elevational patterns of plant hormones reflect mainly the effects of altitude associated with gradual changes in temperature and radiation condition on hormones along an elevational gradient. Both CTK concentrations and CTK/IAA ratios in stumps were significantly positively correlated with resprouting ability, but in fine roots they were negatively correlated. This indicates that CTK, which is synthesized in the root cap, needs to move from the roots into the stumps to initiate the growth of lateral buds. Our results suggest that for coppice regeneration management practices to be successful, the root system needs to be carefully protected from damage. 相似文献10.
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Lili Geng Jing Chi Changlong Shu Peter M. Gresshoff Fuping Song Dafang Huang Jie Zhang 《Plant cell reports》2013,32(8):1211-1218
Key message
Peanuts transformed with the synthetic cry8Ea1 gene flanked by MARs are a potentially effective control strategy against white grubs. Cry8Ea1 protein levels of the construct containing MARs were increased by 2.5 times.Abstract
White grubs are now recognized as the most important pests of peanut worldwide. A synthetic cry8Ea1 gene, which was toxic to Holotrichia parallela larvae, was expressed in chimeric peanut roots using an Agrobacterium rhizogenes-mediated transformation system. The relative mRNA and protein levels of the cry8Ea1 gene were confirmed by quantitative real-time PCR and ELISA, respectively. The effects of matrix attachment regions (MARs) on the expression and activity of the cry8Ea1 gene were analyzed. The average expression level of cry8Ea1 in peanut roots was higher for the plants harboring constructs flanked by MARs from tobacco. Moreover, differing from previous studies, the synthetic cry8Ea1 gene flanked by MARs showed more variation in protein levels than mRNA levels. These composite plants containing cry8Ea1 gene flanked by MARs exhibited a high toxicity against Holotrichia parallela larvae as shown by bioassay analysis, thus offering a potential effective combination to control subterranean insects in peanuts. 相似文献12.
William S. Cuddy Brett A. Summerell Michelle M. Gehringer Brett A. Neilan 《Plant and Soil》2013,370(1-2):317-332
Background and aims
This study investigated the effect of cyanobacterial inoculants on salt tolerance in wheat.Methods
Unicyanobacterial crusts of Nostoc, Leptolyngbya and Microcoleus were established in sand pots. Salt stress was targeted at 6 and 13 dS m?1, corresponding to the wheat salt tolerance and 50 % yield reduction thresholds, respectively. Germinated wheat seeds were planted and grown for 14 (0 and 6 dS m?1) and 21 (13 dS m?1) days by which time seedlings had five emergent leaves. The effects of cyanobacterial inoculation and salinity on wheat growth were quantified using chlorophyll fluorescence, inductively coupled plasma-optical emission spectrometry and biomass measurements.Results
Chlorophyll fluorescence was negatively affected by soil salinity and no change was observed in inoculated wheat. Effective photochemical efficiency correlated with a large range of plant nutrient concentrations primarily in plant roots. Inoculation negatively affected wheat biomass and nutrient concentrations at all salinities, though the effects were fewer as salinity increased.Conclusions
The most likely explanation of these results is the sorption of nutrients to cyanobacterial extracellular polymeric substances, making them unavailable for plant uptake. These results suggest that cyanobacterial inoculation may not be appropriate for establishing wheat in saline soils but that cyanobacteria could be very useful for stabilising soils. 相似文献13.
Key message
The present work with transgenic poplar lines producing varying levels of trans -zeatin suggests the existence of a switching threshold for triggering ckx gene expression or suppressing cytokinin-induced auxin.Abstract
Cytokinins have an important role in growth and developmental processes of plants. Transgenic plants with varying levels of cellular cytokinin are convenient tools for studying its role in morphogenetic as well as molecular responses. In this work, the transgenic lines producing either high level of cellular trans-zeatin (HX lines) or moderate level (MX lines) were compared with regard to their cytokinin oxidase activities and cellular auxin content. The HX lines showed typical cytokinin phenotypes including leafy shoots and spontaneous shoot formation on hormone free medium. In contrast, the MX lines did not show any striking phenotypes. However, in leaf disk culture on hormone free medium, they regenerated roots and subsequently formed shoots from the roots. Determination of cellular IAA content revealed a significant increase in the level in MX lines but not in HX lines. Of nine cytokinin oxidase genes (ckx) examined by qPCR, five were activated in HX lines but not in MX lines. Among them, ckx4 appeared to play a key role in maintaining cellular cytokinin level since it showed more than 1,000-fold increase in HX lines and in the leaf disks of untransformed control exposed to exogenous cytokinins. Although low level of cellular cytokinin did not induce the expression of ckx genes, it appeared to trigger cellular IAA biosynthesis. 相似文献14.
Aluminum tolerance of wheat does not induce changes in dominant bacterial community composition or abundance in an acidic soil 总被引:1,自引:0,他引:1
Chao Wang Xue Qiang Zhao Rong Fu Chen Hai Yan Chu Ren Fang Shen 《Plant and Soil》2013,367(1-2):275-284
Aims
Aluminum-tolerant wheat plants often produce more root exudates such as malate and phosphate than aluminum-sensitive ones under aluminum (Al) stress, which provides environmental differences for microorganism growth in their rhizosphere soils. This study investigated whether soil bacterial community composition and abundance can be affected by wheat plants with different Al tolerance.Methods
Two wheat varieties, Atlas 66 (Al-tolerant) and Scout 66 (Al-sensitive), were grown for 60 days in acidic soils amended with or without CaCO3. Plant growth, soil pH, exchangeable Al content, bacterial community composition and abundance were investigated.Results
Atlas 66 showed better growth and lower rhizosphere soil pH than Scout 66 irrespective of CaCO3 amendment or not, while there was no significant difference in the exchangeable Al content of rhizosphere soil between the two wheat lines. The dominant bacterial community composition and abundance in rhizosphere soils did not differ between Atlas 66 and Scout 66, although the bacterial abundance in rhizosphere soil of both wheat lines was significantly higher than that in bulk soil. Sphingobacteriales, Clostridiales, Burkholderiales and Acidobacteriales were the dominant bacteria phylotypes.Conclusions
The difference in wheat Al tolerance does not induce the changes in the dominant bacterial community composition or abundance in the rhizosphere soils. 相似文献15.
Albino midrib 1, encoding a putative potassium efflux antiporter,affects chloroplast development and drought tolerance in rice 总被引:2,自引:0,他引:2
Peike Sheng Junjie Tan Mingna Jin Fuqing Wu Kunneng Zhou Weiwei Ma Yueqin Heng Jiulin Wang Xiuping Guo Xin Zhang Zhijun Cheng Linglong Liu Chunming Wang Xuanming Liu Jianmin Wan 《Plant cell reports》2014,33(9):1581-1594
Key message
Mutation of the AM1 gene causes an albino midrib phenotype and enhances tolerance to drought in riceAbstract
K+ efflux antiporter (KEA) genes encode putative potassium efflux antiporters that are mainly located in plastid-containing organisms, ranging from lower green algae to higher flowering plants. However, little genetic evidence has been provided on the functions of KEA in chloroplast development. In this study, we isolated a rice mutant, albino midrib 1 (am1), with green- and white-variegation in the first few leaves, and albino midrib phenotype in older tissues. We found that AM1 encoded a putative KEA in chloroplast. AM1 was highly expressed in leaves, while lowly in roots. Chloroplast gene expression and proteins accumulation were affected during chlorophyll biosynthesis and photosynthesis in am1 mutants. Interestingly, AM1 was induced by salt and PEG, and am1 showed enhanced sensitivity to salinity in seed germination and increased tolerance to drought. Taken together, we concluded that KEAs were involved in chloroplast development and played important roles in drought tolerance. 相似文献16.
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Sara Tomassetti Alberto Cavazza Thomas V Colby Jay H Ryu Oriana Nanni E Scarpi Paola Tantalocco Matteo Buccioli Alessandra Dubini Sara Piciucchi Claudia Ravaglia Christian Gurioli Gian Luca Casoni Carlo Gurioli Micaela Romagnoli Venerino Poletti 《Respiratory research》2012,13(1):1-7
Background
The development of COPD in subjects with alpha-1 antitrypsin (AAT) deficiency is likely to be influenced by modifier genes. Genome-wide association studies and integrative genomics approaches in COPD have demonstrated significant associations with SNPs in the chromosome 15q region that includes CHRNA3 (cholinergic nicotine receptor alpha3) and IREB2 (iron regulatory binding protein 2). We investigated whether SNPs in the chromosome 15q region would be modifiers for lung function and COPD in AAT deficiency.Methods
The current analysis included 378 PIZZ subjects in the AAT Genetic Modifiers Study and a replication cohort of 458 subjects from the UK AAT Deficiency National Registry. Nine SNPs in LOC123688, CHRNA3 and IREB2 were selected for genotyping. FEV1 percent of predicted and FEV1/FVC ratio were analyzed as quantitative phenotypes. Family-based association analysis was performed in the AAT Genetic Modifiers Study. In the replication set, general linear models were used for quantitative phenotypes and logistic regression models were used for the presence/absence of emphysema or COPD.Results
Three SNPs (rs2568494 in IREB2, rs8034191 in LOC123688, and rs1051730 in CHRNA3) were associated with pre-bronchodilator FEV1 percent of predicted in the AAT Genetic Modifiers Study. Two SNPs (rs2568494 and rs1051730) were associated with the post-bronchodilator FEV1 percent of predicted and pre-bronchodilator FEV1/FVC ratio; SNP-by-gender interactions were observed. In the UK National Registry dataset, rs2568494 was significantly associated with emphysema in the male subgroup; significant SNP-by-smoking interactions were observed.Conclusions
IREB2 and CHRNA3 are potential genetic modifiers of COPD phenotypes in individuals with severe AAT deficiency and may be sex-specific in their impact. 相似文献18.
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Gang-Ping Xue Anne L. Rae Rosemary G. White Janneke Drenth Terese Richardson C. Lynne McIntyre 《Plant cell reports》2016,35(2):469-481
Key message
A strong, stable and root-specific expression system was developed from a rice root-specific GLYCINE - RICH PROTEIN 7 promoter for use as an enabling technology for genetic manipulation of wheat root traits.Abstract
Root systems play an important role in wheat productivity. Genetic manipulation of wheat root traits often requires a root-specific or root-predominant expression system as an essential enabling technology. In this study, we investigated promoters from rice root-specific or root-predominant expressed genes for development of a root expression system in bread wheat. Transient expression analysis using a GREEN FLUORESCENT PROTEIN (GFP) reporter gene driven by rice promoters identified six promoters that were strongly expressed in wheat roots. Extensive organ specificity analysis of three rice promoters in transgenic wheat revealed that the promoter of rice GLYCINE-RICH PROTEIN 7 (OsGRP7) gene conferred a root-specific expression pattern in wheat. Strong GFP fluorescence in the seminal and branch roots of wheat expressing GFP reporter driven by the OsGRP7 promoter was detected in epidermal, cortical and endodermal cells in mature parts of the root. The GFP reporter driven by the promoter of rice METALLOTHIONEIN-LIKE PROTEIN 1 (OsMTL1) gene was mainly expressed in the roots with essentially no expression in the leaf, stem or seed. However, it was also expressed in floral organs including glume, lemma, palea and awn. In contrast, strong expression of rice RCg2 promoter-driven GFP was found in many tissues. The GFP expression driven by these three rice promoters was stable in transgenic wheat plants through three generations (T1–T3) examined. These data suggest that the OsGRP7 promoter can provide a strong, stable and root-specific expression system for use as an enabling technology for genetic manipulation of wheat root traits.20.
Anne-Sophie Mathieu Charlotte Tinel Hélène Dailly Muriel Quinet Stanley Lutts 《Plant and Soil》2018,424(1-2):273-288