“…Even though wheat seedlings were not under a typical saline stress condition, the gene that encodes a flavonol 3-sulfotransferase, which catalyzes flavonoid sulfation, was down-regulated in colonized roots, suggesting that colonized plants are more resistant to saline stress. Taken together, these results suggest that A. brasilense colonization besides promoting enhancement of the root system may play a role in plant stress tolerance, an effect previously observed in other studies (Figure 6) [56, 58–64]. Figure 6
Proposed effects of
Azospirillum brasilense
inoculation.…”
BackgroundThe rapid growth of the world’s population demands an increase in food production that no longer can be reached by increasing amounts of nitrogenous fertilizers. Plant growth promoting bacteria (PGPB) might be an alternative to increase nitrogenous use efficiency (NUE) in important crops such wheat. Azospirillum brasilense is one of the most promising PGPB and wheat roots colonized by A. brasilense is a good model to investigate the molecular basis of plant-PGPB interaction including improvement in plant-NUE promoted by PGPB.ResultsWe performed a dual RNA-Seq transcriptional profiling of wheat roots colonized by A. brasilense strain FP2. cDNA libraries from biological replicates of colonized and non-inoculated wheat roots were sequenced and mapped to wheat and A. brasilense reference sequences. The unmapped reads were assembled de novo. Overall, we identified 23,215 wheat expressed ESTs and 702 A. brasilense expressed transcripts. Bacterial colonization caused changes in the expression of 776 wheat ESTs belonging to various functional categories, ranging from transport activity to biological regulation as well as defense mechanism, production of phytohormones and phytochemicals. In addition, genes encoding proteins related to bacterial chemotaxi, biofilm formation and nitrogen fixation were highly expressed in the sub-set of A. brasilense expressed genes.ConclusionsPGPB colonization enhanced the expression of plant genes related to nutrient up-take, nitrogen assimilation, DNA replication and regulation of cell division, which is consistent with a higher proportion of colonized root cells in the S-phase. Our data support the use of PGPB as an alternative to improve nutrient acquisition in important crops such as wheat, enhancing plant productivity and sustainability.Electronic supplementary materialThe online version of this article (doi:10.1186/1471-2164-15-378) contains supplementary material, which is available to authorized users.
“…Even though wheat seedlings were not under a typical saline stress condition, the gene that encodes a flavonol 3-sulfotransferase, which catalyzes flavonoid sulfation, was down-regulated in colonized roots, suggesting that colonized plants are more resistant to saline stress. Taken together, these results suggest that A. brasilense colonization besides promoting enhancement of the root system may play a role in plant stress tolerance, an effect previously observed in other studies (Figure 6) [56, 58–64]. Figure 6
Proposed effects of
Azospirillum brasilense
inoculation.…”
BackgroundThe rapid growth of the world’s population demands an increase in food production that no longer can be reached by increasing amounts of nitrogenous fertilizers. Plant growth promoting bacteria (PGPB) might be an alternative to increase nitrogenous use efficiency (NUE) in important crops such wheat. Azospirillum brasilense is one of the most promising PGPB and wheat roots colonized by A. brasilense is a good model to investigate the molecular basis of plant-PGPB interaction including improvement in plant-NUE promoted by PGPB.ResultsWe performed a dual RNA-Seq transcriptional profiling of wheat roots colonized by A. brasilense strain FP2. cDNA libraries from biological replicates of colonized and non-inoculated wheat roots were sequenced and mapped to wheat and A. brasilense reference sequences. The unmapped reads were assembled de novo. Overall, we identified 23,215 wheat expressed ESTs and 702 A. brasilense expressed transcripts. Bacterial colonization caused changes in the expression of 776 wheat ESTs belonging to various functional categories, ranging from transport activity to biological regulation as well as defense mechanism, production of phytohormones and phytochemicals. In addition, genes encoding proteins related to bacterial chemotaxi, biofilm formation and nitrogen fixation were highly expressed in the sub-set of A. brasilense expressed genes.ConclusionsPGPB colonization enhanced the expression of plant genes related to nutrient up-take, nitrogen assimilation, DNA replication and regulation of cell division, which is consistent with a higher proportion of colonized root cells in the S-phase. Our data support the use of PGPB as an alternative to improve nutrient acquisition in important crops such as wheat, enhancing plant productivity and sustainability.Electronic supplementary materialThe online version of this article (doi:10.1186/1471-2164-15-378) contains supplementary material, which is available to authorized users.
“…Azospirillum restricted sodium uptake and enhanced potassium and calcium uptake. Azospirillum inoculation stimulated nitrate reductase and nitrogenase activity in both shoots and roots of both cultivars Hamdia et al (2004) but phosphorus uptake increased in maize under salinity stress, and salicylic acid reversed it with considerable reductions in sodium and chloride accumulation. Furthermore, iron, manganese, zinc, and copper contents increased with salinity and salicylic acid application further aggravated their uptake except for zinc (Gunes et al 2007).…”
Section: Bacillus Megateriummentioning
confidence: 94%
“…This may further enhance water flow which significantly improves dry matter production (Hamdia et al 2004). The inoculation of maize with Azospirillum under a salt-stressed environment significantly decreased proline concentration.…”
Section: Arbuscular Mycorrhizal Fungimentioning
confidence: 99%
“…The comparatively high salt resistance of maize, particularly the salt-sensitive cultivar, significantly changed the selectivity of potassium, calcium, and sodium. Azospirillum inoculation reduced the rate of sodium uptake and increased the uptake of major cations particularly calcium and potassium (Table 3; Hamdia et al 2004). RojasTapias et al (2012) demonstrated that inoculation with Azotobacter chroococcum strains C5 and C9 protected plants against the inhibitory effects of NaCl by improving sodium exclusion and potassium uptake in maize, thereby increasing the potassium/sodium ratio.…”
Maize is grown under a wide spectrum of soil and climatic conditions. Maize is moderately sensitive to salt stress; therefore, soil salinity is a serious threat to its production worldwide. Understanding maize response to salt stress and resistance mechanisms and overviewing management options may help to devise strategies for improved maize performance in saline environments. Here, we reviewed the effects, resistance mechanisms, and management of salt stress in maize. Our main conclusions are as follows: (1) germination and stand establishment are more sensitive to salt stress than later developmental stages. (2) High rhizosphere sodium and chloride decrease plant uptake of nitrogen, potassium, calcium, magnesium, and iron. (3) Reduced grain weight and number are responsible for low grain yield in maize under salt stress. Sink limitations and reduced acid invertase activity in developing grains is responsible for poor kernel setting under salt stress. (4) Exclusion of excessive sodium or its compartmentation into vacuoles is an important adaptive strategy for maize under salt stress. (5) Apoplastic acidification, required for cell wall extensibility, is an important indicator of salt resistance, but not essential for better maize growth under salt stress. (6) Upregulation of antioxidant defense genes and β-expansin proteins is important for salt resistance in maize. (7) Arbuscular mycorrhizal fungi improve salt resistance in maize due to better plant nutrient availability. (8) Seed priming is an effective approach for improving maize germination under salt stress. (9) Integration of screening, breeding and ion homeostasis mechanisms into a functional paradigm for the whole plant may help to enhance salt resistance in maize.
“…Interestingly, it has been found that colonization of plants by certain specific plant growth promoting rhizobacteria (PGPR) can lead to enhanced resistance to abiotic challenges, such as water deficit (Naveed et al, 2014), salinity (Sziderics et al, 2007), adaptation to transplantation (Nowak and Shulaev, 2003), and chilling (Ait Barka et al, 2006). Over the last few years, several studies have reported the ability of isolated microorganisms to induce plant tolerance to salinity once they have been inoculated to seeds or young plantlets (reviewed in Yang et al, 2009; Dodd and Pérez-Alfocea, 2012; Shrivastava and Kumar, 2015), including a variety of hosts, like wheat (Nadeem et al, 2013; Singh et al, 2015), maize (Hamdia et al, 2004; Nadeem et al, 2009), cotton (Liu et al, 2013; Egamberdieva et al, 2015), tomato (Mayak et al, 2004; Ali et al, 2014), lettuce (Barassi et al, 2006; Kohler et al, 2009), sunflower (Shilev et al, 2010; Tewari and Arora, 2014) and Arabidopsis (Zhang et al, 2008; Kim et al, 2014; Sukweenadhi et al, 2015). Among the PGPR that have been demonstrated to play a role in salt stress tolerance induction, a wide diversity of bacteria is included, encompassing several members of the γ-proteobacteria class, specially within the genus Pseudomonas (Ahmad et al, 2013; Nadeem et al, 2013; Chang et al, 2014; Han et al, 2015), α-proteobacteria belonging to the Azospirillum genus (del Amor and Cuadra-Crespo, 2011; Nia et al, 2012; Sahoo et al, 2014), and β-proteobacteria like Achromobacter (Mayak et al, 2004) or Paraburkholderia (Talbi et al, 2013; Pinedo et al, 2015).…”
Abiotic stress has a growing impact on plant growth and agricultural activity worldwide. Specific plant growth promoting rhizobacteria have been reported to stimulate growth and tolerance to abiotic stress in plants, and molecular mechanisms like phytohormone synthesis and 1-aminocyclopropane-1-carboxylate deamination are usual candidates proposed to mediate these bacterial effects. Paraburkholderia phytofirmans PsJN is able to promote growth of several plant hosts, and improve their tolerance to chilling, drought and salinity. This work investigated bacterial determinants involved in PsJN stimulation of growth and salinity tolerance in Arabidopsis thaliana, showing bacteria enable plants to survive long-term salinity treatment, accumulating less sodium within leaf tissues relative to non-inoculated controls. Inactivation of specific bacterial genes encoding ACC deaminase, auxin catabolism, N-acyl-homoserine-lactone production, and flagellin synthesis showed these functions have little influence on bacterial induction of salinity tolerance. Volatile organic compound emission from strain PsJN was shown to reproduce the effects of direct bacterial inoculation of roots, increasing plant growth rate and tolerance to salinity evaluated both in vitro and in soil. Furthermore, early exposure to VOCs from P. phytofirmans was sufficient to stimulate long-term effects observed in Arabidopsis growth in the presence and absence of salinity. Organic compounds were analyzed in the headspace of PsJN cultures, showing production of 2-undecanone, 7-hexanol, 3-methylbutanol and dimethyl disulfide. Exposure of A. thaliana to different quantities of these molecules showed that they are able to influence growth in a wide range of added amounts. Exposure to a blend of the first three compounds was found to mimic the effects of PsJN on both general growth promotion and salinity tolerance. To our knowledge, this is the first report on volatile compound-mediated induction of plant abiotic stress tolerance by a Paraburkholderia species.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
