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A DNA-based method for studying root responses to drought in field-grown wheat genotypes.

Huang CY, Kuchel H, Edwards J, Hall S, Parent B, Eckermann P - Sci Rep (2013)

Bottom Line: Root systems are critical for water and nutrient acquisition by crops.Current methods measuring root biomass and length are slow and labour-intensive for studying root responses to environmental stresses in the field.The new method eliminates the need for separation of roots from soil and permits large-scale phenotyping of root responses to drought or other environmental and disease stresses in the field.

View Article: PubMed Central - PubMed

Affiliation: Australian Centre for Plant Functional Genomics, The University of Adelaide, Waite Campus, Glen Osmond, South Australia, 5064, Australia.

ABSTRACT
Root systems are critical for water and nutrient acquisition by crops. Current methods measuring root biomass and length are slow and labour-intensive for studying root responses to environmental stresses in the field. Here, we report the development of a method that measures changes in the root DNA concentration in soil and detects root responses to drought in controlled environment and field trials. To allow comparison of soil DNA concentrations from different wheat genotypes, we also developed a procedure for correcting genotypic differences in the copy number of the target DNA sequence. The new method eliminates the need for separation of roots from soil and permits large-scale phenotyping of root responses to drought or other environmental and disease stresses in the field.

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Effects of cyclic drought and continuous drought on root DNA density (RDD) in soil profile.(a) Soil moisture tension was measured at 15 cm and 35 cm depth. Two cycles of the drought treatment (Drought) were applied to the plants grown in a rain-out shelter at 55 and 65 days after seed sowing, respectively. Well watered (WW) plants were the control. (b) Effects of the cyclic drought on RDD of two wheat genotypes, Kukri and Gladius in 0–30 cm depth. Four soil cores (2.5 cm in diameter) were collected at 70 days after seed sowing from between rows for each plot. Means and standard errors of four replicates are presented for RDD. There are highly significant differences in RDD for cultivars, cyclic drought and depth, and for interactions of cyclic drought × depth × genotypes (P < 0.003). (c) RDD of two wheat genotypes, Krichauff and Berkut in 0–40 cm depth at flowering. Five soil cores (2.5 cm in diameter) were collected from between rows of plots at Roseworthy, South Australia in 2007. Means and standard deviations of three replicates are presented for RDD. There are highly significant differences in RDD for cultivars and depth (P < 0.001). Ct values of TaITS2 were determined for all soil samples using quantitative real-time PCR with ARMS primers and the TaITS2 probe. RDD presented was standardised with the scaling factor for each genotype.
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f3: Effects of cyclic drought and continuous drought on root DNA density (RDD) in soil profile.(a) Soil moisture tension was measured at 15 cm and 35 cm depth. Two cycles of the drought treatment (Drought) were applied to the plants grown in a rain-out shelter at 55 and 65 days after seed sowing, respectively. Well watered (WW) plants were the control. (b) Effects of the cyclic drought on RDD of two wheat genotypes, Kukri and Gladius in 0–30 cm depth. Four soil cores (2.5 cm in diameter) were collected at 70 days after seed sowing from between rows for each plot. Means and standard errors of four replicates are presented for RDD. There are highly significant differences in RDD for cultivars, cyclic drought and depth, and for interactions of cyclic drought × depth × genotypes (P < 0.003). (c) RDD of two wheat genotypes, Krichauff and Berkut in 0–40 cm depth at flowering. Five soil cores (2.5 cm in diameter) were collected from between rows of plots at Roseworthy, South Australia in 2007. Means and standard deviations of three replicates are presented for RDD. There are highly significant differences in RDD for cultivars and depth (P < 0.001). Ct values of TaITS2 were determined for all soil samples using quantitative real-time PCR with ARMS primers and the TaITS2 probe. RDD presented was standardised with the scaling factor for each genotype.

Mentions: Next, root responses to a Mediterranean-type drought scenario32 was measured using RDD. Plants of the two wheat cultivars, Kukri and Gladius were grown in field soil under a rain-out shelter, and exposed to two cycles of drought during flowering (Fig. 3a). The cyclic drought reduced soil moisture potential to −0.5 MPa (Fig. 3a), leading to a significant reduction of RDD in both cultivars (at least 64% relatively compared to well watered plants) in the top 10-cm soil layer (Fig. 3b). There was no effect of the cyclic drought on RDD of either cultivar below 10-cm depth (Fig. 3b). This indicates that RDD in the top 10-cm soil is particularly sensitive to the cyclic drought. RDD of both genotypes in the well watered and cyclic drought plots was significantly lower in 20–30 cm layer than in the top soil layers (Fig. 3b). Furthermore, RDD of Gladius across the three depths and the drought treatments was significantly higher than that of Kukri, revealing the genotypic variation in response to the cyclic drought between the two genotypes.


A DNA-based method for studying root responses to drought in field-grown wheat genotypes.

Huang CY, Kuchel H, Edwards J, Hall S, Parent B, Eckermann P - Sci Rep (2013)

Effects of cyclic drought and continuous drought on root DNA density (RDD) in soil profile.(a) Soil moisture tension was measured at 15 cm and 35 cm depth. Two cycles of the drought treatment (Drought) were applied to the plants grown in a rain-out shelter at 55 and 65 days after seed sowing, respectively. Well watered (WW) plants were the control. (b) Effects of the cyclic drought on RDD of two wheat genotypes, Kukri and Gladius in 0–30 cm depth. Four soil cores (2.5 cm in diameter) were collected at 70 days after seed sowing from between rows for each plot. Means and standard errors of four replicates are presented for RDD. There are highly significant differences in RDD for cultivars, cyclic drought and depth, and for interactions of cyclic drought × depth × genotypes (P < 0.003). (c) RDD of two wheat genotypes, Krichauff and Berkut in 0–40 cm depth at flowering. Five soil cores (2.5 cm in diameter) were collected from between rows of plots at Roseworthy, South Australia in 2007. Means and standard deviations of three replicates are presented for RDD. There are highly significant differences in RDD for cultivars and depth (P < 0.001). Ct values of TaITS2 were determined for all soil samples using quantitative real-time PCR with ARMS primers and the TaITS2 probe. RDD presented was standardised with the scaling factor for each genotype.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3824167&req=5

f3: Effects of cyclic drought and continuous drought on root DNA density (RDD) in soil profile.(a) Soil moisture tension was measured at 15 cm and 35 cm depth. Two cycles of the drought treatment (Drought) were applied to the plants grown in a rain-out shelter at 55 and 65 days after seed sowing, respectively. Well watered (WW) plants were the control. (b) Effects of the cyclic drought on RDD of two wheat genotypes, Kukri and Gladius in 0–30 cm depth. Four soil cores (2.5 cm in diameter) were collected at 70 days after seed sowing from between rows for each plot. Means and standard errors of four replicates are presented for RDD. There are highly significant differences in RDD for cultivars, cyclic drought and depth, and for interactions of cyclic drought × depth × genotypes (P < 0.003). (c) RDD of two wheat genotypes, Krichauff and Berkut in 0–40 cm depth at flowering. Five soil cores (2.5 cm in diameter) were collected from between rows of plots at Roseworthy, South Australia in 2007. Means and standard deviations of three replicates are presented for RDD. There are highly significant differences in RDD for cultivars and depth (P < 0.001). Ct values of TaITS2 were determined for all soil samples using quantitative real-time PCR with ARMS primers and the TaITS2 probe. RDD presented was standardised with the scaling factor for each genotype.
Mentions: Next, root responses to a Mediterranean-type drought scenario32 was measured using RDD. Plants of the two wheat cultivars, Kukri and Gladius were grown in field soil under a rain-out shelter, and exposed to two cycles of drought during flowering (Fig. 3a). The cyclic drought reduced soil moisture potential to −0.5 MPa (Fig. 3a), leading to a significant reduction of RDD in both cultivars (at least 64% relatively compared to well watered plants) in the top 10-cm soil layer (Fig. 3b). There was no effect of the cyclic drought on RDD of either cultivar below 10-cm depth (Fig. 3b). This indicates that RDD in the top 10-cm soil is particularly sensitive to the cyclic drought. RDD of both genotypes in the well watered and cyclic drought plots was significantly lower in 20–30 cm layer than in the top soil layers (Fig. 3b). Furthermore, RDD of Gladius across the three depths and the drought treatments was significantly higher than that of Kukri, revealing the genotypic variation in response to the cyclic drought between the two genotypes.

Bottom Line: Root systems are critical for water and nutrient acquisition by crops.Current methods measuring root biomass and length are slow and labour-intensive for studying root responses to environmental stresses in the field.The new method eliminates the need for separation of roots from soil and permits large-scale phenotyping of root responses to drought or other environmental and disease stresses in the field.

View Article: PubMed Central - PubMed

Affiliation: Australian Centre for Plant Functional Genomics, The University of Adelaide, Waite Campus, Glen Osmond, South Australia, 5064, Australia.

ABSTRACT
Root systems are critical for water and nutrient acquisition by crops. Current methods measuring root biomass and length are slow and labour-intensive for studying root responses to environmental stresses in the field. Here, we report the development of a method that measures changes in the root DNA concentration in soil and detects root responses to drought in controlled environment and field trials. To allow comparison of soil DNA concentrations from different wheat genotypes, we also developed a procedure for correcting genotypic differences in the copy number of the target DNA sequence. The new method eliminates the need for separation of roots from soil and permits large-scale phenotyping of root responses to drought or other environmental and disease stresses in the field.

Show MeSH
Related in: MedlinePlus