Frequency and biodiversity of 2,4-diacetylphloroglucinol-producing rhizobacteria are differentially affected by the genotype of two maize inbred lines and their hybrid

Picard, Christine; Frascaroli, Elisabetta; Bosco, Marcella

doi:10.1016/j.femsec.2004.03.016

Cited by 35 publications

(47 citation statements)

References 44 publications

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“…A major challenge in screening for enhanced microbial rootcolonization is the design of effective procedures that provide a reproducible classification in the field environment. Level of root colonization exhibits dramatic variation related to plant age (Picard et al 2000(Picard et al , 2004Roesh et al 2006), thus genotype rank can vary significantly depending upon plant age at the time of analysis. For example, the frequency of beneficial root-colonizing microorganisms was found to be very low in the initial stage of plant growth, greatly increased at the flowering stage, and then decreased with physiological maturation, at least for maize (Picard et al 2000, Roesh et al 2006 and for Achillea ageratum L plants (Picard and Bosco 2003).…”

Section: Useful Traits For Better Nutrition Via Beneficial Plant-micrmentioning

confidence: 99%

Novel approaches in plant breeding for rhizosphere-related traits

2008

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Selection of modern varieties has typically been performed in standardized, high fertility systems with a primary focus on yield. This could have contributed to the loss of plant genes associated with efficient nutrient acquisition strategies and adaptation to soil-related biotic and abiotic stresses if such adaptive strategies incurred a cost to the plant that compromised yield. Furthermore, beneficial interactions between plants and associated soil organisms may have been made obsolete by the provision of nutrients in high quantity and in readily plant available forms. A review of evidence from studies comparing older traditional varieties to modern high yielding varieties indeed showed that this has been the case. Given the necessity to use scarce and increasingly costly fertilizer inputs more efficiently while also raising productivity on poorer soils, it will be crucial to reintroduce desirable rhizosphere-related traits into elite cultivars. Traits that offer possibilities for improving nutrient acquisition capacity, plantmicrobe interactions and tolerance to abiotic and biotic soil stresses in modern varieties were reviewed. Despite the considerable effort devoted to the identification of suitable donors and of genetic factors associated with these beneficial traits, progress in developing improved varieties has been slow and has so far largely been confined to modifications of traditional breeding procedures. Modern molecular tools have only very recently started to play a rather small role. The few successful cases reviewed in this paper have shown that novel breeding approaches using molecular tools do work in principle. When successful, they involved close collaboration between breeders and scientists conducting basic research, and confirmation of phenotypes in field tests as a 'reality check'. We concluded that for novel molecular approaches to make a significant contribution to breeding for rhizosphere related traits it will be essential to narrow the gap between basic sciences and applied breeding through more interdisciplinary research that addresses rather than avoids the complexity of plant-soil interactions.

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Section: Useful Traits For Better Nutrition Via Beneficial Plant-micrmentioning

confidence: 99%

Novel approaches in plant breeding for rhizosphere-related traits

2008

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“…Chasselas was grafted, which might also have influenced results. Morano and Kliewer (1994) showed that root growth and activity may vary according to grapevine cultivar or rootstock, and the diversity of rhizosphere bacteria can differ when comparing different plant cultivars (Okubara et al, 2004;Picard et al, 2004). …”

Section: Discussionmentioning

confidence: 99%

Distribution of Pseudomonas populations harboring phlD or hcnAB biocontrol genes is related to depth in vineyard soils

Švercel¹,

Hamelin²,

Duffy³

et al. 2010

Soil Biology and Biochemistry

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; Défago, G (2010) Distribution of Pseudomonas populations harboring phlD or hcnAB biocontrol genes is related to depth in vineyard soils AbstractThe abundance and population structure of pseudomonads in soils collected from long-(1006 years) and short-(54 years) term grapevine monocultures in Switzerland were examined across five soil horizons within the 1.20e1.35 m range. Soil samples were baited with grapevine, and rhizosphere pseudomonads containing the biocontrol genes phlD (2,4-diacetylphloroglucinol synthesis) and/or hcnAB (hydrogen cyanide synthesis) were analyzed by MPN-PCR. The numbers of total, phlDþ and hcnABþ pseudomonads decreased with depth by 1.5e2 log (short-term monoculture) and 3e3.5 log (long-term monoculture). In addition, the percentages of phlDþ (except in short-term monoculture) and hcnABþ pseudomonads were also lower in deeper horizons. RFLP-profiling of phlDþ and hcnABþ pseudomonads revealed three phlD and twelve hcnAB alleles overall, but the number of alleles for both decreased in relation to depth. The only phlD allele found in deeper horizons was also found in topsoil, whereas one hcnAB allele (k) found in deeper horizons in long-term monoculture was absent in the topsoil. This suggests that certain Pseudomonas ecotypes are adapted to specific depths. Four hcnAB alleles enabled discrimination between monocultures. We conclude that soil depth is a factor selecting phlD and hcnAB genotypes, and that the allelic diversity of the two biocontrol genes decreases with depth. Distribution ofPseudomonas populations harboring phlD or hcnAB biocontrol genes is related a b s t r a c tThe abundance and population structure of pseudomonads in soils collected from long-(1006 years) and short-(54 years) term grapevine monocultures in Switzerland were examined across five soil horizons within the 1.20e1.35 m range. Soil samples were baited with grapevine, and rhizosphere pseudomonads containing the biocontrol genes phlD (2,4-diacetylphloroglucinol synthesis) and/or hcnAB (hydrogen cyanide synthesis) were analyzed by MPN-PCR. The numbers of total, phlD þ and hcnAB þ pseudomonads decreased with depth by 1.5e2 log (short-term monoculture) and 3e3.5 log (long-term monoculture). In addition, the percentages of phlD þ (except in short-term monoculture) and hcnAB þ pseudomonads were also lower in deeper horizons. RFLP-profiling of phlD þ and hcnAB þ pseudomonads revealed three phlD and twelve hcnAB alleles overall, but the number of alleles for both decreased in relation to depth. The only phlD allele found in deeper horizons was also found in topsoil, whereas one hcnAB allele (k) found in deeper horizons in long-term monoculture was absent in the topsoil. This suggests that certain Pseudomonas ecotypes are adapted to specific depths. Four hcnAB alleles enabled discrimination between monocultures. We conclude that soil depth is a factor selecting phlD and hcnAB genotypes, and that the allelic diversity of the two biocontrol genes decreases with depth.

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“…To compare climatic conditions without altering soil parameters, Picard et al (2004a) performed two trials on maize, sown 3 weeks apart in the same field. DAPG producers were isolated from maize rhizospheres sampled at the same physiological stages.…”

Section: Geographic Location and Climatementioning

confidence: 99%

“…Unfortunately, no similar research was done specifically on PFP populations. However, by comparing DAPG pseudomonads populations isolated from hybrid maizes and from their respective linear parental ones, it was suggested that root colonization by this type of rhizobacteria is an inherited trait, probably related to heterosis (Picard et al 2004a;Picard and Bosco 2006). In fact, repeated experiments in the field give evidence that maize hybrids are colonized more by DAPG-producing Pseudomonas strains characterized by an efficient disease suppression potential than parental lines.…”

Section: Genotypes Within the Same Plant Speciesmentioning

confidence: 99%

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Genotypic and phenotypic diversity in populations of plant-probiotic Pseudomonas spp. colonizing roots

Picard

Bosco

2007

Naturwissenschaften

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Several soil microorganisms colonizing roots are known to naturally promote the health of plants by controlling a range of plant pathogens, including bacteria, fungi, and nematodes. The use of theses antagonistic microorganisms, recently named plant-probiotics, to control plant-pathogenic fungi is receiving increasing attention, as they may represent a sustainable alternative to chemical pesticides. Many years of research on plant-probiotic microorganisms (PPM) have indicated that fluorescent pseudomonads producing antimicrobial compounds are largely involved in the suppression of the most widespread soilborne pathogens. Phenotype and genotype analysis of plant-probiotic fluorescent pseudomonads (PFP) have shown considerable genetic variation among these types of strains. Such variability plays an important role in the rhizosphere competence and the biocontrol ability of PFP strains. Understanding the mechanisms by which genotypic and phenotypic diversity occurs in natural populations of PFP could be exploited to choose those agricultural practices which best exploit the indigenous PFP populations, or to isolate new plant-probiotic strains for using them as inoculants. A number of different methods have been used to study diversity within PFP populations. Because different resolutions of the existing microbial diversity can be revealed depending on the approach used, this review first describes the most important methods used for the assessment of fluorescent Pseudomonas diversity. Then, we focus on recent data relating how differences in genotypic and phenotypic diversity within PFP communities can be attributed to geographic location, climate, soil type, soil management regime, and interactions with other soil microorganisms and host plants. It becomes evident that plant-related parameters exert the strongest influence on the genotypic and phenotypic variations in PFP populations.

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Frequency and biodiversity of 2,4-diacetylphloroglucinol-producing rhizobacteria are differentially affected by the genotype of two maize inbred lines and their hybrid

Cited by 35 publications

References 44 publications

Novel approaches in plant breeding for rhizosphere-related traits

Novel approaches in plant breeding for rhizosphere-related traits

Distribution of Pseudomonas populations harboring phlD or hcnAB biocontrol genes is related to depth in vineyard soils

Genotypic and phenotypic diversity in populations of plant-probiotic Pseudomonas spp. colonizing roots

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