A rice mutant lacking a large subunit of ADP-glucose pyrophosphorylase has drastically reduced starch content in the culm but normal plant morphology and yield

A mutant of rice (Oryza sativa L.) was identified with a Tos17 insertion in Os05g50380, a gene encoding a plastidial large subunit (LSU) of ADP-glucose pyrophosphorylase (AGPase) that was previously called OsAPL3 or OsAGPL1. The insertion prevents the production of a normal transcript. Characterisation of the mutant showed that this LSU is required for 97% of the starch synthesised in the flowering stem (culm), approximately half of the AGPase activity in developing embryos and that it contributes to AGPase activity in the endosperm. Despite the near absence of starch in the culms and reduced starch content in the embryos, the mutant rice plants grow and develop normally, and show no reduction in productivity. The starch content of leaves is increased in the mutant, revealing plasticity in the distribution of photosynthates among different temporary carbohydrate storage pools within the plant.

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A mutant of rice lacking the leaf large subunit of ADP-glucose pyrophosphorylase has drastically reduced leaf starch content but grows normally

Functional Plant Biology ◽

10.1071/fp06257 ◽

2007 ◽

Vol 34 (6) ◽

pp. 480 ◽

Cited By ~ 37

Author(s):

Sandrine Rösti ◽

Brendan Fahy ◽

Kay Denyer

Keyword(s):

Environmental Conditions ◽

No Reduction ◽

Starch Content ◽

Large Subunit ◽

Starch Synthesis ◽

Small Subunit ◽

Wild Type ◽

Gene Encoding ◽

Subunit Protein ◽

Adp Glucose Pyrophosphorylase

A mutant of rice was identified with a Tos17 insertion in OsAPL1, a gene encoding a large subunit (LSU) of ADP-glucose pyrophosphorylase (AGPase). The insertion prevents production of a normal transcript from OsAPL1. Characterisation of the mutant (apl1) showed that the LSU encoded by OsAPL1 is required for AGPase activity in rice leaf blades. In mutant leaf blades, the AGPase small subunit protein is not detectable and the AGPase activity and starch content are reduced to <1 and <5% of that in wild type blades, respectively. The mutation also leads to a reduction in starch content in the leaf sheaths but does not significantly affect AGPase activity or starch synthesis in other parts of the plant. The sucrose, glucose and fructose contents of the leaves are not affected by the mutation. Despite the near absence of starch in the leaf blades, apl1 mutant rice plants grow and develop normally under controlled environmental conditions and show no reduction in productivity.

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Suppression of starch synthesis in rice stems splays tiller angle due to gravitropic insensitivity but does not affect yield

Functional Plant Biology ◽

10.1071/fp14159 ◽

2015 ◽

Vol 42 (1) ◽

pp. 31 ◽

Cited By ~ 12

Author(s):

Masaki Okamura ◽

Tatsuro Hirose ◽

Yoichi Hashida ◽

Ryu Ohsugi ◽

Naohiro Aoki

Keyword(s):

Double Mutant ◽

Oryza Sativa L ◽

Starch Content ◽

Large Subunit ◽

Starch Synthesis ◽

Starch Accumulation ◽

Gravitropic Response ◽

Rice Mutant ◽

Matter Production ◽

Tiller Angle

In rice (Oryza sativa L.), tiller angle – defined as the angle between the main culm and its side tillers – is one of the important factors involved in light use efficiency. To clarify the relationship between tiller angle, gravitropism and stem-starch accumulation, we investigated the shoot gravitropic response of a low stem-starch rice mutant which lacks a large subunit of ADP-glucose pyrophosphorylase (AGP), called OsAGPL1 and exhibits relatively spread tiller angle. The insensitive gravitropic response exhibited by the mutant led us to the conclusion that insensitivity of gravitropism caused by stem-starch reduction splayed the tiller angle. Furthermore, since another AGP gene called OsAGPL3 was expressed at considerable levels in graviresponding sites, we generated a double mutant lacking both OsAGPL1 and OsAGPL3. The double mutant exhibited still lower stem-starch content, less sensitive gravitropic response and greater tiller angle spread than the single mutants. This indicated that the expansion of the tiller angle caused by the reduction in starch level was intense according to the extent of the reduction. We found there were no significant differences between the double mutant and wild-type plants in terms of dry matter production. These results provided new insight into the importance of stem-starch accumulation and ideal plant architecture.

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Starch reduction in rice stems due to a lack of OsAGPL1 or OsAPL3 decreases grain yield under low irradiance during ripening and modifies plant architecture

Functional Plant Biology ◽

10.1071/fp13105 ◽

2013 ◽

Vol 40 (11) ◽

pp. 1137 ◽

Cited By ~ 21

Author(s):

Masaki Okamura ◽

Tatsuro Hirose ◽

Yoichi Hashida ◽

Tohru Yamagishi ◽

Ryu Ohsugi ◽

...

Keyword(s):

Grain Yield ◽

Plant Architecture ◽

Oryza Sativa L ◽

Large Subunit ◽

Dry Weight ◽

Leaf Sheath ◽

Starch Accumulation ◽

Wild Type ◽

Gene Encoding ◽

Rice Mutant

Starch accumulated in rice (Oryza sativa L.) stems before heading as nonstructural carbohydrates (NSCs) is reported to be important for improving and stabilising grain yield. To evaluate the importance of stem starch, we investigated a retrotransposon (Tos17) insertion rice mutant lacking a gene encoding a large subunit of ADP-glucose pyrophosphorylase (AGP) called OsAGPL1 or OsAPL3. The AGP activity and starch contents of the mutant were drastically reduced in the stem (i.e. leaf sheath and culm) but not in the leaf blade or endosperm. This starch reduction in the leaf sheaths of the mutant was complemented by the introduction of wild-type OsAGPL1. These results strongly suggest that OsAGPL1 plays a principal role in stem starch accumulation. Field experimentations spanning 2 years revealed that the mutant plants were shorter than the wild-type plants. Moreover, the tiller number and angle were larger in the mutant plants than the wild-type plants, but the dry weight at heading stage was not different. The grain yield was slightly lower in control plots without shading treatment. However, this difference increased substantially with shading. Therefore, stem starch is indispensable for normal ripening under low irradiance conditions and probably contributes to the maintenance of appropriate plant architecture.

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Escherichia coli exonuclease VII. Cloning and sequencing of the gene encoding the large subunit (xseA).

Journal of Biological Chemistry ◽

10.1016/s0021-9258(18)66806-1 ◽

1986 ◽

Vol 261 (32) ◽

pp. 14929-14935

Author(s):

J W Chase ◽

B A Rabin ◽

J B Murphy ◽

K L Stone ◽

K R Williams

Keyword(s):

Escherichia Coli ◽

Large Subunit ◽

Cloning And Sequencing ◽

Gene Encoding ◽

Exonuclease Vii

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Evidence that the rb Locus Alters the Starch Content of Developing Pea Embryos through an Effect on ADP Glucose Pyrophosphorylase

PLANT PHYSIOLOGY ◽

10.1104/pp.89.4.1279 ◽

1989 ◽

Vol 89 (4) ◽

pp. 1279-1284 ◽

Cited By ~ 63

Author(s):

Alison M. Smith ◽

Mary Bettey ◽

Ian D. Bedford

Keyword(s):

Starch Content ◽

Adp Glucose Pyrophosphorylase

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Molecular Cloning and Spatial Expression of an ApL1 cDNA for the Large Subunit of ADP-Glucose Pyrophosphorylase from Arabidopsis thaliana

Zeitschrift für Naturforschung C ◽

10.1515/znc-1999-5-610 ◽

1999 ◽

Vol 54 (5-6) ◽

pp. 353-358 ◽

Cited By ~ 3

Author(s):

Leszek A. Kleszkowski ◽

Lubomir N. Sokolov ◽

Cheng Luo ◽

Per Villand

Keyword(s):

Arabidopsis Thaliana ◽

Large Subunit ◽

Critical Role ◽

Starch Synthesis ◽

Transit Peptide ◽

Homologous Proteins ◽

Peptide Cleavage ◽

Reading Frame ◽

Calculated Molecular Weight ◽

Adp Glucose Pyrophosphorylase

Abstract A cDNA, A p L 1a , corresponding to a homologue of the large subunit of ADP-glucose pyrophosphorylase (AG Pase), has been isolated/characterised by screening a cDNA library prepared from leaves of Arabidopsis thaliana, followed by rapid amplification of cDNA 3′-ends (3′-RACE). Within the 1685 nucleotide-long sequence (excluding polyA tail), an open reading frame encodes a protein of 522 amino acids (aa), with a calculated molecular weight of 57.7 kDa. The derived aa sequence does not contain any discernible transit peptide cleavage site motif, similarly to two other recently sequenced full-length Arabidopsis homo-logues for AGPase, and shows ca. 58–78 % identity to homologous proteins from other plants/tissues. The corresponding gene was found (rosette and stem leaves, stems, flowers and fruits), consistent with its critical role in starch synthesis in

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