TY - JOUR

T1 - Co-ordination of minor amino acid contents in crop species : significance and interpretation.

AU - Noctor, G.

AU - Novitskaya, L.

AU - Lea, P. J.

AU - Foyer, C. H.

PY - 2002/4

Y1 - 2002/4

N2 - The question of whether general control of amino acid synthesis exists in plants remains to be resolved. It is not known whether there is overall co-ordination of the biosynthesis of amino acids that are formed through distinct pathways. In this work, amino acid contents were measured in a large number of samples taken from wheat, potato and barley leaves under different photosynthetic conditions. The variability in total soluble amino acid contents between samples was approximately 6-fold in wheat and potato. Subtracting the major amino acids from the total soluble amino acids showed that the variability in summed minor amino acid contents was approximately 20-fold. This variability was not correlated with short-term changes in primary carbon and nitrogen metabolism, and only poorly correlated with total leaf amino acids. By contrast, striking linear relationships between the contents of most minor amino acids were observed, demonstrating that the contents of many minor amino acids vary in concert. These observations show that amino acid contents are co-ordinated across biosynthetic families. While these data might be interpreted as an indication of cross-pathway regulation of the expression of key biosynthetic enzymes, the impact of factors such as protein degradation and storage cannot be ignored.

AB - The question of whether general control of amino acid synthesis exists in plants remains to be resolved. It is not known whether there is overall co-ordination of the biosynthesis of amino acids that are formed through distinct pathways. In this work, amino acid contents were measured in a large number of samples taken from wheat, potato and barley leaves under different photosynthetic conditions. The variability in total soluble amino acid contents between samples was approximately 6-fold in wheat and potato. Subtracting the major amino acids from the total soluble amino acids showed that the variability in summed minor amino acid contents was approximately 20-fold. This variability was not correlated with short-term changes in primary carbon and nitrogen metabolism, and only poorly correlated with total leaf amino acids. By contrast, striking linear relationships between the contents of most minor amino acids were observed, demonstrating that the contents of many minor amino acids vary in concert. These observations show that amino acid contents are co-ordinated across biosynthetic families. While these data might be interpreted as an indication of cross-pathway regulation of the expression of key biosynthetic enzymes, the impact of factors such as protein degradation and storage cannot be ignored.

KW - Amino acid synthesis

KW - barley

KW - co-ordination of biosynthesis

KW - leaves

KW - minor amino acids

KW - potato

KW - wheat.

U2 - 10.1093/jexbot/53.370.939

DO - 10.1093/jexbot/53.370.939

M3 - Journal article

VL - 53

SP - 939

EP - 946

JO - Journal of Experimental Botany

JF - Journal of Experimental Botany

SN - 1460-2431

IS - 370

ER -