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Allelic effects on starch structure and properties of six starch biosynthetic genes in a rice recombinant inbred line population.

Luo J, Jobling SA, Millar A, Morell MK, Li Z - Rice (N Y) (2015)

Bottom Line: Both major alleles (Wxi and SSIIaj) reduced peak viscosity (PV), onset, peak and end gelatinization temperatures (GTs) of amylopectin, and increased amylose-lipid complex dissociation enthalpy compared with their counterpart-alleles, respectively.SBEIIai and SBEIIbj decreased PV, whereas SSIi and SBEIIbj decreased FV.SBEIi reduced setback viscosity and gelatinization enthalpy.

View Article: PubMed Central - PubMed

Affiliation: CSIRO Agriculture Flagship, GPO Box 1600, Canberra, ACT 2601 Australia ; College of Medicine, Biology and Environment, Australian National University, Canberra, ACT 0200 Australia.

ABSTRACT

Background: The genetic diversity of six starch biosynthetic genes (Wx, SSI, SSIIa, SBEI, SBEIIa and SBEIIb) in indica and japonica rices opens an opportunity to produce a new variety with more favourable grain starch quality. However, there is limited information about the effects of these six gene allele combinations on starch structure and properties. A recombinant inbred line population from a cross between indica and japonica varieties offers opportunities to combine specific alleles of the six genes.

Results: The allelic (indica vs japonica) effects of six starch biosynthetic genes on starch structure, functional properties, and abundance of granule bound proteins in rice grains were investigated in a common genetic background using a recombinant inbred line population. The indica Wx (Wxi) allele played a major role while indica SSI (SSIi), japonica SSIIa (SSIIaj) and indica SBEI (SBEIi) alleles had minor roles on the increase of amylose content. SSIIaj and japonica SBEIIb (SBEIIbj) alleles had a major and a minor role on high ratio of ∑DP ≤ 10 to ∑DP ≤ 24 fractions (RCL10/24), respectively. Both major alleles (Wxi and SSIIaj) reduced peak viscosity (PV), onset, peak and end gelatinization temperatures (GTs) of amylopectin, and increased amylose-lipid complex dissociation enthalpy compared with their counterpart-alleles, respectively. SBEIIai and SBEIIbj decreased PV, whereas SSIi and SBEIIbj decreased FV. SBEIi reduced setback viscosity and gelatinization enthalpy. RCL10/24 of chain length distribution in amylopectin is negatively correlated with PV and BD of paste property and GTs of thermal properties. We also report RILs with superior starch properties combining Wxi, SSIj, SSIIaj, SBEIi and SBEIIbj alleles. Additionally, a clear relation is drawn to starch biosynthetic gene alleles, starch structure, properties, and abundance of granule bound starch biosynthetic enzymes inside starch granules.

Conclusions: Rice Wxi and SSIIaj alleles play major roles, while SSIi, SBEIi, SBEIIai and SBEIIbj alleles have minor roles in the determination of starch properties between indica and japonica rice through starch structural modification. The combination of these alleles is a key factor for starch quality improvement in rice breeding programs. RCL10/24 value is critical for starch structure and property determination.

No MeSH data available.


Related in: MedlinePlus

Comparison of chain length distribution of debranched starch of six allele groups for six starch synthetic genes. Starches from five plants of each allele were used for the analysis. Two replicates were set up for each sample. For each allele group, values of chain lengths for japonica allele lines were subtracted from values of chain length for the indica allele lines. A: Wx, B: SSI, C: SSIIa, D: SBEI, E: SBEIIa, F: SBEIIb. Each bar corresponds to the difference of a chain length in mole percentage. The error bars are the standard errors.
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Fig3: Comparison of chain length distribution of debranched starch of six allele groups for six starch synthetic genes. Starches from five plants of each allele were used for the analysis. Two replicates were set up for each sample. For each allele group, values of chain lengths for japonica allele lines were subtracted from values of chain length for the indica allele lines. A: Wx, B: SSI, C: SSIIa, D: SBEI, E: SBEIIa, F: SBEIIb. Each bar corresponds to the difference of a chain length in mole percentage. The error bars are the standard errors.

Mentions: In this study, linear glucan chains of DP ≤ 24 comprised up to 80% mole of molecules in amylopectin of rice grains (Table 2). SSIIai played a major role, while SBEIIbi played a minor role in accumulating intermediate chains (DP12 ~ 22). The differences in % normalised distribution were obtained by subtracting the CLD of japonica allele from indica allele in each gene group, respectively (Figure 3). The profound difference in CLD was obtained in SSIIa allele group (Figure 3C). SSIIai allele starch contained fewer short chains at DP6 ~ DP11, more intermediate chains at DP12 ~ 22 and long chains at DP30 ~ 45 compared with that of SSIIaj allele starch. Limited variations were found in the other five gene groups, however, SBEIIbi allele showed up to 0.5% normalised distribution of fewer chains at DP10 ~ 13 than SBEIIbj allele (Figure 3F).Table 2


Allelic effects on starch structure and properties of six starch biosynthetic genes in a rice recombinant inbred line population.

Luo J, Jobling SA, Millar A, Morell MK, Li Z - Rice (N Y) (2015)

Comparison of chain length distribution of debranched starch of six allele groups for six starch synthetic genes. Starches from five plants of each allele were used for the analysis. Two replicates were set up for each sample. For each allele group, values of chain lengths for japonica allele lines were subtracted from values of chain length for the indica allele lines. A: Wx, B: SSI, C: SSIIa, D: SBEI, E: SBEIIa, F: SBEIIb. Each bar corresponds to the difference of a chain length in mole percentage. The error bars are the standard errors.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4385112&req=5

Fig3: Comparison of chain length distribution of debranched starch of six allele groups for six starch synthetic genes. Starches from five plants of each allele were used for the analysis. Two replicates were set up for each sample. For each allele group, values of chain lengths for japonica allele lines were subtracted from values of chain length for the indica allele lines. A: Wx, B: SSI, C: SSIIa, D: SBEI, E: SBEIIa, F: SBEIIb. Each bar corresponds to the difference of a chain length in mole percentage. The error bars are the standard errors.
Mentions: In this study, linear glucan chains of DP ≤ 24 comprised up to 80% mole of molecules in amylopectin of rice grains (Table 2). SSIIai played a major role, while SBEIIbi played a minor role in accumulating intermediate chains (DP12 ~ 22). The differences in % normalised distribution were obtained by subtracting the CLD of japonica allele from indica allele in each gene group, respectively (Figure 3). The profound difference in CLD was obtained in SSIIa allele group (Figure 3C). SSIIai allele starch contained fewer short chains at DP6 ~ DP11, more intermediate chains at DP12 ~ 22 and long chains at DP30 ~ 45 compared with that of SSIIaj allele starch. Limited variations were found in the other five gene groups, however, SBEIIbi allele showed up to 0.5% normalised distribution of fewer chains at DP10 ~ 13 than SBEIIbj allele (Figure 3F).Table 2

Bottom Line: Both major alleles (Wxi and SSIIaj) reduced peak viscosity (PV), onset, peak and end gelatinization temperatures (GTs) of amylopectin, and increased amylose-lipid complex dissociation enthalpy compared with their counterpart-alleles, respectively.SBEIIai and SBEIIbj decreased PV, whereas SSIi and SBEIIbj decreased FV.SBEIi reduced setback viscosity and gelatinization enthalpy.

View Article: PubMed Central - PubMed

Affiliation: CSIRO Agriculture Flagship, GPO Box 1600, Canberra, ACT 2601 Australia ; College of Medicine, Biology and Environment, Australian National University, Canberra, ACT 0200 Australia.

ABSTRACT

Background: The genetic diversity of six starch biosynthetic genes (Wx, SSI, SSIIa, SBEI, SBEIIa and SBEIIb) in indica and japonica rices opens an opportunity to produce a new variety with more favourable grain starch quality. However, there is limited information about the effects of these six gene allele combinations on starch structure and properties. A recombinant inbred line population from a cross between indica and japonica varieties offers opportunities to combine specific alleles of the six genes.

Results: The allelic (indica vs japonica) effects of six starch biosynthetic genes on starch structure, functional properties, and abundance of granule bound proteins in rice grains were investigated in a common genetic background using a recombinant inbred line population. The indica Wx (Wxi) allele played a major role while indica SSI (SSIi), japonica SSIIa (SSIIaj) and indica SBEI (SBEIi) alleles had minor roles on the increase of amylose content. SSIIaj and japonica SBEIIb (SBEIIbj) alleles had a major and a minor role on high ratio of ∑DP ≤ 10 to ∑DP ≤ 24 fractions (RCL10/24), respectively. Both major alleles (Wxi and SSIIaj) reduced peak viscosity (PV), onset, peak and end gelatinization temperatures (GTs) of amylopectin, and increased amylose-lipid complex dissociation enthalpy compared with their counterpart-alleles, respectively. SBEIIai and SBEIIbj decreased PV, whereas SSIi and SBEIIbj decreased FV. SBEIi reduced setback viscosity and gelatinization enthalpy. RCL10/24 of chain length distribution in amylopectin is negatively correlated with PV and BD of paste property and GTs of thermal properties. We also report RILs with superior starch properties combining Wxi, SSIj, SSIIaj, SBEIi and SBEIIbj alleles. Additionally, a clear relation is drawn to starch biosynthetic gene alleles, starch structure, properties, and abundance of granule bound starch biosynthetic enzymes inside starch granules.

Conclusions: Rice Wxi and SSIIaj alleles play major roles, while SSIi, SBEIi, SBEIIai and SBEIIbj alleles have minor roles in the determination of starch properties between indica and japonica rice through starch structural modification. The combination of these alleles is a key factor for starch quality improvement in rice breeding programs. RCL10/24 value is critical for starch structure and property determination.

No MeSH data available.


Related in: MedlinePlus