Limits...
Additional nitrogen fertilization at heading time of rice down-regulates cellulose synthesis in seed endosperm.

Midorikawa K, Kuroda M, Terauchi K, Hoshi M, Ikenaga S, Ishimaru Y, Abe K, Asakura T - PLoS ONE (2014)

Bottom Line: As a result, it was assessed that genes associated with molecular processes such as photosynthesis, trehalose metabolism, carbon fixation, amino acid metabolism, and cell wall metabolism were differentially expressed.Moreover, additional nitrogen fertilization caused accumulation of storage proteins and up-regulated Cys-poor prolamin mRNA expression.These data suggest that additional nitrogen fertilization at heading time changes the expression of some storage substance-related genes and reduces cellulose levels in endosperm.

View Article: PubMed Central - PubMed

Affiliation: Department of Applied Biological Chemistry, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Bunkyo-ku, Tokyo, Japan.

ABSTRACT
The balance between carbon and nitrogen is a key determinant of seed storage components, and thus, is of great importance to rice and other seed-based food crops. To clarify the influence of the rhizosphere carbon/nitrogen balance during the maturation stage of several seed components, transcriptome analysis was performed on the seeds from rice plants that were provided additional nitrogen fertilization at heading time. As a result, it was assessed that genes associated with molecular processes such as photosynthesis, trehalose metabolism, carbon fixation, amino acid metabolism, and cell wall metabolism were differentially expressed. Moreover, cellulose and sucrose synthases, which are involved in cellulose synthesis, were down-regulated. Therefore, we compared cellulose content of mature seeds that were treated with additional nitrogen fertilization with those from control plants using calcofluor staining. In these experiments, cellulose content in endosperm from plants receiving additional nitrogen fertilization was less than that in control endosperm. Other starch synthesis-related genes such as starch synthase 1, starch phosphorylase 2, and branching enzyme 3 were also down-regulated, whereas some α-amylase and β-amylase genes were up-regulated. On the other hand, mRNA expression of amino acid biosynthesis-related molecules was up-regulated. Moreover, additional nitrogen fertilization caused accumulation of storage proteins and up-regulated Cys-poor prolamin mRNA expression. These data suggest that additional nitrogen fertilization at heading time changes the expression of some storage substance-related genes and reduces cellulose levels in endosperm.

Show MeSH
Changes in gene expression and rice seed compounds with additional fertilization.Notable change in mRNA expression and seed compounds are summarized. Molecules in the open oval are DEGs from DNA microarray experiments. Rectangles show the compound whose content was measured in this study. Red and blue arrows indicate up- and down-regulation by additional nitrogen fertilization, respectively. SUS3, sucrose synthase 3; CESA, cellulose synthase A catalytic subunit; SBE3, starch-branching enzyme 3; SS1, starch synthase 1; SP2, starch phosphorylase 2; αAmy, α-amylase; βAmy, β-amylase.
© Copyright Policy
Related In: Results  -  Collection

License
getmorefigures.php?uid=PMC4048278&req=5

pone-0098738-g007: Changes in gene expression and rice seed compounds with additional fertilization.Notable change in mRNA expression and seed compounds are summarized. Molecules in the open oval are DEGs from DNA microarray experiments. Rectangles show the compound whose content was measured in this study. Red and blue arrows indicate up- and down-regulation by additional nitrogen fertilization, respectively. SUS3, sucrose synthase 3; CESA, cellulose synthase A catalytic subunit; SBE3, starch-branching enzyme 3; SS1, starch synthase 1; SP2, starch phosphorylase 2; αAmy, α-amylase; βAmy, β-amylase.

Mentions: The present data reveal rapid changes in C/N balance in response to rhizosphere nitrogen fertilization at heading time. Notable changes in mRNA expression and seed compounds are summarized in Figure 7. Leaf color showed a darker green and the mRNA expression of Rubisco and chlorophyll-binding protein in seed pericarp was greater in the N-fertilized plot. In general, such situation contributes to increased total photosynthesis, carbon fixation, and nitrogen absorption in the rice plant body, and can improve final yield of grains per unit area [10]. More amounts of sucrose and glutamine/glutamate and asparagine/aspartic acid may be transported into seeds in N-fertilized plot. However, compounds of seeds were not always increased in the N-fertilized plot. The accumulation of nitrogen compounds such as storage proteins increased, whereas that of polysaccharides such as cellulose decreased, correlating with changes in mRNA expression for synthetic processes of these compounds. The mRNA expression profile for starch biosynthesis and starch degradation suggested that levels of other polysaccharides such as starch may also change. The possible mechanism underlying our result is that the amount of carbon backbones may be a limiting factor in seed and it may be primarily used for nitrogen accumulation in endosperm under high nitrogen fertilization (Fig. 7). This study provides new insights into the relationship between fertilization and grain maturation and contributes to the understanding of nutrient distribution during rice production.


Additional nitrogen fertilization at heading time of rice down-regulates cellulose synthesis in seed endosperm.

Midorikawa K, Kuroda M, Terauchi K, Hoshi M, Ikenaga S, Ishimaru Y, Abe K, Asakura T - PLoS ONE (2014)

Changes in gene expression and rice seed compounds with additional fertilization.Notable change in mRNA expression and seed compounds are summarized. Molecules in the open oval are DEGs from DNA microarray experiments. Rectangles show the compound whose content was measured in this study. Red and blue arrows indicate up- and down-regulation by additional nitrogen fertilization, respectively. SUS3, sucrose synthase 3; CESA, cellulose synthase A catalytic subunit; SBE3, starch-branching enzyme 3; SS1, starch synthase 1; SP2, starch phosphorylase 2; αAmy, α-amylase; βAmy, β-amylase.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4048278&req=5

pone-0098738-g007: Changes in gene expression and rice seed compounds with additional fertilization.Notable change in mRNA expression and seed compounds are summarized. Molecules in the open oval are DEGs from DNA microarray experiments. Rectangles show the compound whose content was measured in this study. Red and blue arrows indicate up- and down-regulation by additional nitrogen fertilization, respectively. SUS3, sucrose synthase 3; CESA, cellulose synthase A catalytic subunit; SBE3, starch-branching enzyme 3; SS1, starch synthase 1; SP2, starch phosphorylase 2; αAmy, α-amylase; βAmy, β-amylase.
Mentions: The present data reveal rapid changes in C/N balance in response to rhizosphere nitrogen fertilization at heading time. Notable changes in mRNA expression and seed compounds are summarized in Figure 7. Leaf color showed a darker green and the mRNA expression of Rubisco and chlorophyll-binding protein in seed pericarp was greater in the N-fertilized plot. In general, such situation contributes to increased total photosynthesis, carbon fixation, and nitrogen absorption in the rice plant body, and can improve final yield of grains per unit area [10]. More amounts of sucrose and glutamine/glutamate and asparagine/aspartic acid may be transported into seeds in N-fertilized plot. However, compounds of seeds were not always increased in the N-fertilized plot. The accumulation of nitrogen compounds such as storage proteins increased, whereas that of polysaccharides such as cellulose decreased, correlating with changes in mRNA expression for synthetic processes of these compounds. The mRNA expression profile for starch biosynthesis and starch degradation suggested that levels of other polysaccharides such as starch may also change. The possible mechanism underlying our result is that the amount of carbon backbones may be a limiting factor in seed and it may be primarily used for nitrogen accumulation in endosperm under high nitrogen fertilization (Fig. 7). This study provides new insights into the relationship between fertilization and grain maturation and contributes to the understanding of nutrient distribution during rice production.

Bottom Line: As a result, it was assessed that genes associated with molecular processes such as photosynthesis, trehalose metabolism, carbon fixation, amino acid metabolism, and cell wall metabolism were differentially expressed.Moreover, additional nitrogen fertilization caused accumulation of storage proteins and up-regulated Cys-poor prolamin mRNA expression.These data suggest that additional nitrogen fertilization at heading time changes the expression of some storage substance-related genes and reduces cellulose levels in endosperm.

View Article: PubMed Central - PubMed

Affiliation: Department of Applied Biological Chemistry, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Bunkyo-ku, Tokyo, Japan.

ABSTRACT
The balance between carbon and nitrogen is a key determinant of seed storage components, and thus, is of great importance to rice and other seed-based food crops. To clarify the influence of the rhizosphere carbon/nitrogen balance during the maturation stage of several seed components, transcriptome analysis was performed on the seeds from rice plants that were provided additional nitrogen fertilization at heading time. As a result, it was assessed that genes associated with molecular processes such as photosynthesis, trehalose metabolism, carbon fixation, amino acid metabolism, and cell wall metabolism were differentially expressed. Moreover, cellulose and sucrose synthases, which are involved in cellulose synthesis, were down-regulated. Therefore, we compared cellulose content of mature seeds that were treated with additional nitrogen fertilization with those from control plants using calcofluor staining. In these experiments, cellulose content in endosperm from plants receiving additional nitrogen fertilization was less than that in control endosperm. Other starch synthesis-related genes such as starch synthase 1, starch phosphorylase 2, and branching enzyme 3 were also down-regulated, whereas some α-amylase and β-amylase genes were up-regulated. On the other hand, mRNA expression of amino acid biosynthesis-related molecules was up-regulated. Moreover, additional nitrogen fertilization caused accumulation of storage proteins and up-regulated Cys-poor prolamin mRNA expression. These data suggest that additional nitrogen fertilization at heading time changes the expression of some storage substance-related genes and reduces cellulose levels in endosperm.

Show MeSH