Waxy and non-waxy barley cultivars exhibit differences in the targeting and catalytic activity of GBSS1a
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Waxy and non-waxy barley cultivars exhibit differences in the targeting and catalytic activity of GBSS1a. / Hebelstrup, Kim H.; Nielsen, Morten Munch; Carciofi, Massimiliano; Andrzejczak, Olga; Shaik, Shahnoor Sultana; Blennow, Andreas; Palcic, Monica.
In: Journal of Experimental Botany, Vol. 68, No. 5, 2017, p. 931-941.Research output: Contribution to journal › Journal article › Research › peer-review
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TY - JOUR
T1 - Waxy and non-waxy barley cultivars exhibit differences in the targeting and catalytic activity of GBSS1a
AU - Hebelstrup, Kim H.
AU - Nielsen, Morten Munch
AU - Carciofi, Massimiliano
AU - Andrzejczak, Olga
AU - Shaik, Shahnoor Sultana
AU - Blennow, Andreas
AU - Palcic, Monica
N1 - © The Author 2017. Published by Oxford University Press on behalf of the Society for Experimental Biology.
PY - 2017
Y1 - 2017
N2 - Amylose synthesis is strictly associated with activity of granule-bound starch synthase (GBSS) enzymes. Among several crops there are cultivars containing starch types with either little or no amylose known as near-waxy or waxy. This (near) amylose-free phenotype is associated with a single locus (waxy) which has been mapped to GBSS-type genes in different crops. Most waxy varieties are a result of either low or no expression of a GBSS gene. However, there are some waxy cultivars where the GBSS enzymes are expressed normally. For these types, single nucleotide polymorphisms have been hypothesized to represent amino-acid substitutions leading to loss of catalytic activity. We here confirm that the HvGBSSIa enzyme from one such waxy barley variety, CDC_Alamo, has a 90% reduction in catalytic activity. We also engineered plants with expression of transgenic C-terminal green fluorescent protein-tagged HvGBSSIa of both the non-waxy type and of the CDC_Alamo type to monitor their subcellular localization patterns in grain endosperm. HvGBSSIa from non-waxy cultivars was found to localize in discrete concentric spheres strictly within starch granules. In contrast, HvGBSSIa from waxy CDC_Alamo showed deficient starch targeting mostly into unknown subcellular bodies of 0.5-3 µm in size, indicating that the waxy phenotype of CDC_Alamo is associated with deficient targeting of HvGBSSIa into starch granules.
AB - Amylose synthesis is strictly associated with activity of granule-bound starch synthase (GBSS) enzymes. Among several crops there are cultivars containing starch types with either little or no amylose known as near-waxy or waxy. This (near) amylose-free phenotype is associated with a single locus (waxy) which has been mapped to GBSS-type genes in different crops. Most waxy varieties are a result of either low or no expression of a GBSS gene. However, there are some waxy cultivars where the GBSS enzymes are expressed normally. For these types, single nucleotide polymorphisms have been hypothesized to represent amino-acid substitutions leading to loss of catalytic activity. We here confirm that the HvGBSSIa enzyme from one such waxy barley variety, CDC_Alamo, has a 90% reduction in catalytic activity. We also engineered plants with expression of transgenic C-terminal green fluorescent protein-tagged HvGBSSIa of both the non-waxy type and of the CDC_Alamo type to monitor their subcellular localization patterns in grain endosperm. HvGBSSIa from non-waxy cultivars was found to localize in discrete concentric spheres strictly within starch granules. In contrast, HvGBSSIa from waxy CDC_Alamo showed deficient starch targeting mostly into unknown subcellular bodies of 0.5-3 µm in size, indicating that the waxy phenotype of CDC_Alamo is associated with deficient targeting of HvGBSSIa into starch granules.
KW - Journal Article
U2 - 10.1093/jxb/erw503
DO - 10.1093/jxb/erw503
M3 - Journal article
C2 - 28199682
VL - 68
SP - 931
EP - 941
JO - Journal of Experimental Botany
JF - Journal of Experimental Botany
SN - 0022-0957
IS - 5
ER -
ID: 179924507