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Augmenting iron accumulation in cassava by the beneficial soil bacterium Bacillus subtilis (GBO3).

Freitas MA, Medeiros FH, Carvalho SP, Guilherme LR, Teixeira WD, Zhang H, Paré PW - Front Plant Sci (2015)

Bottom Line: Cassava (Manihot esculenta), a major staple food in the developing world, provides a basic carbohydrate diet for over half a billion people living in the tropics.Biochemical analyses reveal that shoot-propagated cassava with GB03-inoculation exhibit elevated iron accumulation after 140 days of plant growth as determined by X-ray microanalysis and total foliar iron analysis.Growth promotion and increased photosynthetic efficiency were also observed for greenhouse-grown plants with GB03-exposure.

View Article: PubMed Central - PubMed

Affiliation: Department of Plant Pathology, Agriculture and Soil Science, Federal University of Lavras Lavras, Brazil.

ABSTRACT
Cassava (Manihot esculenta), a major staple food in the developing world, provides a basic carbohydrate diet for over half a billion people living in the tropics. Despite the iron abundance in most soils, cassava provides insufficient iron for humans as the edible roots contain 3-12 times less iron than other traditional food crops such as wheat, maize, and rice. With the recent identification that the beneficial soil bacterium Bacillus subtilis (strain GB03) activates iron acquisition machinery to increase metal ion assimilation in Arabidopsis, the question arises as to whether this plant-growth promoting rhizobacterium also augments iron assimilation to increase endogenous iron levels in cassava. Biochemical analyses reveal that shoot-propagated cassava with GB03-inoculation exhibit elevated iron accumulation after 140 days of plant growth as determined by X-ray microanalysis and total foliar iron analysis. Growth promotion and increased photosynthetic efficiency were also observed for greenhouse-grown plants with GB03-exposure. These results demonstrate the potential of microbes to increase iron accumulation in an important agricultural crop and is consistent with idea that microbial signaling can regulate plant photosynthesis.

No MeSH data available.


Related in: MedlinePlus

Growth promotion of cassava (Manihot esculenta) cv. IAC 576-70 mediated by Bacillus subtilis GBO3 compared to the water control. Mean (n = 3) shoot dry weight and plant height at 150 days after planting.
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Figure 1: Growth promotion of cassava (Manihot esculenta) cv. IAC 576-70 mediated by Bacillus subtilis GBO3 compared to the water control. Mean (n = 3) shoot dry weight and plant height at 150 days after planting.

Mentions: Since inducible iron uptake by B. subtilis (GB03) is associated with growth promotion in the model plant Arabidopsis, growth parameters including plant height and biomass were measured in cassava plants exposed to GB03. Surface-sterilized shoot cuttings, inoculated with GB03 or water (as a control) were grown in soil and harvested after 140 days. Although all plants were grown under the same environmental conditions in terms of light, soil-nutrients, and water, GB03-treated plants exhibited significant growth promotion with respect to plant height and total above-ground dry biomass at 28 and 59% greater values, respectively, when compared with GBO3 untreated plants (Figure 1). As a first approximation, cassava plants exhibiting increased height, branching, and shoot biomass can be correlated with greater root yields (Ntawuruhunga and Dixon, 2010) albeit harvest index (root biomass/total biomass) is the preferred parameter with breeders for cultivar selection. GBO3-treated plants also exhibited a delay in leaf senescence and abscission. Moreover, external symptoms of nutrient deficiency were less visible in GB03-exposed plants compared to water controls. Such visual indicators of micronutrient deficiency included leaf interveinal chlorosis that is symptomatic of iron deficiency and development of leaf necrotic spots/early defoliation symptomatic of senescence (Figure 1).


Augmenting iron accumulation in cassava by the beneficial soil bacterium Bacillus subtilis (GBO3).

Freitas MA, Medeiros FH, Carvalho SP, Guilherme LR, Teixeira WD, Zhang H, Paré PW - Front Plant Sci (2015)

Growth promotion of cassava (Manihot esculenta) cv. IAC 576-70 mediated by Bacillus subtilis GBO3 compared to the water control. Mean (n = 3) shoot dry weight and plant height at 150 days after planting.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4524923&req=5

Figure 1: Growth promotion of cassava (Manihot esculenta) cv. IAC 576-70 mediated by Bacillus subtilis GBO3 compared to the water control. Mean (n = 3) shoot dry weight and plant height at 150 days after planting.
Mentions: Since inducible iron uptake by B. subtilis (GB03) is associated with growth promotion in the model plant Arabidopsis, growth parameters including plant height and biomass were measured in cassava plants exposed to GB03. Surface-sterilized shoot cuttings, inoculated with GB03 or water (as a control) were grown in soil and harvested after 140 days. Although all plants were grown under the same environmental conditions in terms of light, soil-nutrients, and water, GB03-treated plants exhibited significant growth promotion with respect to plant height and total above-ground dry biomass at 28 and 59% greater values, respectively, when compared with GBO3 untreated plants (Figure 1). As a first approximation, cassava plants exhibiting increased height, branching, and shoot biomass can be correlated with greater root yields (Ntawuruhunga and Dixon, 2010) albeit harvest index (root biomass/total biomass) is the preferred parameter with breeders for cultivar selection. GBO3-treated plants also exhibited a delay in leaf senescence and abscission. Moreover, external symptoms of nutrient deficiency were less visible in GB03-exposed plants compared to water controls. Such visual indicators of micronutrient deficiency included leaf interveinal chlorosis that is symptomatic of iron deficiency and development of leaf necrotic spots/early defoliation symptomatic of senescence (Figure 1).

Bottom Line: Cassava (Manihot esculenta), a major staple food in the developing world, provides a basic carbohydrate diet for over half a billion people living in the tropics.Biochemical analyses reveal that shoot-propagated cassava with GB03-inoculation exhibit elevated iron accumulation after 140 days of plant growth as determined by X-ray microanalysis and total foliar iron analysis.Growth promotion and increased photosynthetic efficiency were also observed for greenhouse-grown plants with GB03-exposure.

View Article: PubMed Central - PubMed

Affiliation: Department of Plant Pathology, Agriculture and Soil Science, Federal University of Lavras Lavras, Brazil.

ABSTRACT
Cassava (Manihot esculenta), a major staple food in the developing world, provides a basic carbohydrate diet for over half a billion people living in the tropics. Despite the iron abundance in most soils, cassava provides insufficient iron for humans as the edible roots contain 3-12 times less iron than other traditional food crops such as wheat, maize, and rice. With the recent identification that the beneficial soil bacterium Bacillus subtilis (strain GB03) activates iron acquisition machinery to increase metal ion assimilation in Arabidopsis, the question arises as to whether this plant-growth promoting rhizobacterium also augments iron assimilation to increase endogenous iron levels in cassava. Biochemical analyses reveal that shoot-propagated cassava with GB03-inoculation exhibit elevated iron accumulation after 140 days of plant growth as determined by X-ray microanalysis and total foliar iron analysis. Growth promotion and increased photosynthetic efficiency were also observed for greenhouse-grown plants with GB03-exposure. These results demonstrate the potential of microbes to increase iron accumulation in an important agricultural crop and is consistent with idea that microbial signaling can regulate plant photosynthesis.

No MeSH data available.


Related in: MedlinePlus