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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 amylose content among 12 alleles of six starch synthetic genes using the SEC method. Starches from five plants of each allele were isolated and analysed seperately. Two replicates were set up for each sample. The columns indicate starch AC of RIL grains. Black columns indicate those allelles containing Wxi allele and grey columns indicate those allelles containing Wxj allele. The error bars show the standard error of the mean. The identity of each column is indicated underneath. Columns with different letters are significantly different at p < 0.05.
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Fig2: Comparison of amylose content among 12 alleles of six starch synthetic genes using the SEC method. Starches from five plants of each allele were isolated and analysed seperately. Two replicates were set up for each sample. The columns indicate starch AC of RIL grains. Black columns indicate those allelles containing Wxi allele and grey columns indicate those allelles containing Wxj allele. The error bars show the standard error of the mean. The identity of each column is indicated underneath. Columns with different letters are significantly different at p < 0.05.

Mentions: Although the Wxi allele played a major role in the determination of increased AC, other alleles also showed impacts on AC. The range of AC of selected RILs was 11 ~ 35% approximately of rice grain starch (Figure 2). Six allele groups can be classified into two AC groups depending on the Wx allele. The Wxi allele group contained 17.7 ~ 35.3% amylose in starch (including Wxi allele and SSI, SSIIa and SBEIIa groups), whereas Wxj allele group contained 11.1 ~ 18.4% (including Wxj allele and SBEI and SBEIIb groups), with parental lines IR64 (21.2%) and Nipponbare (11.8%) fitting in their respective Wx groups. Between the Wxi allele group (containing average 22.0% amylose) and the Wxj allele group (containing average 13.1% amylose), the former contained ~9% significantly higher AC than the latter. Within Wxi allele group, starch samples from Wxi allele lines contained significantly higher AC (35.3%) than all other allele groups, and starch from SSIi (22.8%) and SSIIaj (20.9%) alleles contained higher AC than other four alleles (SSIj, SSIIai, SBEIIai and SBEIIaj) (Figure 2). Within Wxj allele group, SBEIi allele lines (18.4%) contained significantly higher AC than those from other four allele groups, among which AC was not significantly different.Figure 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 amylose content among 12 alleles of six starch synthetic genes using the SEC method. Starches from five plants of each allele were isolated and analysed seperately. Two replicates were set up for each sample. The columns indicate starch AC of RIL grains. Black columns indicate those allelles containing Wxi allele and grey columns indicate those allelles containing Wxj allele. The error bars show the standard error of the mean. The identity of each column is indicated underneath. Columns with different letters are significantly different at p < 0.05.
© Copyright Policy - open-access
Related In: Results  -  Collection

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

Fig2: Comparison of amylose content among 12 alleles of six starch synthetic genes using the SEC method. Starches from five plants of each allele were isolated and analysed seperately. Two replicates were set up for each sample. The columns indicate starch AC of RIL grains. Black columns indicate those allelles containing Wxi allele and grey columns indicate those allelles containing Wxj allele. The error bars show the standard error of the mean. The identity of each column is indicated underneath. Columns with different letters are significantly different at p < 0.05.
Mentions: Although the Wxi allele played a major role in the determination of increased AC, other alleles also showed impacts on AC. The range of AC of selected RILs was 11 ~ 35% approximately of rice grain starch (Figure 2). Six allele groups can be classified into two AC groups depending on the Wx allele. The Wxi allele group contained 17.7 ~ 35.3% amylose in starch (including Wxi allele and SSI, SSIIa and SBEIIa groups), whereas Wxj allele group contained 11.1 ~ 18.4% (including Wxj allele and SBEI and SBEIIb groups), with parental lines IR64 (21.2%) and Nipponbare (11.8%) fitting in their respective Wx groups. Between the Wxi allele group (containing average 22.0% amylose) and the Wxj allele group (containing average 13.1% amylose), the former contained ~9% significantly higher AC than the latter. Within Wxi allele group, starch samples from Wxi allele lines contained significantly higher AC (35.3%) than all other allele groups, and starch from SSIi (22.8%) and SSIIaj (20.9%) alleles contained higher AC than other four alleles (SSIj, SSIIai, SBEIIai and SBEIIaj) (Figure 2). Within Wxj allele group, SBEIi allele lines (18.4%) contained significantly higher AC than those from other four allele groups, among which AC was not significantly different.Figure 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