The Arabidopsis thaliana gene annotated by the locus tag At3g08860 encodes alanine aminotransferase

Abstract

The aminotransferase gene family in the model plant Arabidopsis thaliana consists of 44 genes, eight of which are suggested to be alanine aminotransferases. One of the putative alanine aminotransferases genes, At3g08860, was attributed the function of alanine:glyoxylate aminotransferase/β‐alanine:pyruvate aminotransferase based on the analysis of gene expression networks and homology to other β‐alanine aminotransferases in plants. It was earlier demonstrated that At3g08860 is specifically upregulated in response to osmotic stress, but not other stresses (β‐alanine is an osmoprotectant in plants). Furthermore, it was shown that the expression of At3g08860 is highly coordinated with the genes of the uracil degradation pathway leading to the non‐proteinogenic amino acid β‐alanine. These evidence were suggestive of the involvement of At3g08860 in β‐alanine metabolism. However, direct experimental evidence for the function of At3g08860 was lacking, and therefore, the goal of this study was to elucidate the function of the uncharacterized aminotransferase annotated by the locus tag At3g08860. The cDNA of At3g08860 was demonstrated to functionally complement two E. coli mutants auxotrophic for the amino acids, L‐alanine (proteinogenic) and β‐alanine (non‐proteinogenic). Enzyme activity using purified recombinant At3g08860 further demonstrated that the enzyme is endowed with L‐alanine:glyoxylate aminotransferase activity.

Unlocking the mystery of plants’ survival capability under waterlogging stress

“…Alanine aminotransferase (AlaAT) is a complex pathway, act as a survival mechanism in Lotus, Prunus, grapevine and Arabidopsis against waterlogging stress (53,69,70,71). In this pathway, previously produced pyruvate from glycolysis reacts with glutamate (Glu) to form 2-oxoglutarate by alanine aminotransferase (AlaAT) (Fig.…”

Origin and Function of Amino Acids in Nectar and Nectaries of Pitcairnia Species with Particular Emphasis on Alanine and Glutamine

“…In addition to alanine, β-alanine, a non-proteinogenic amino acid and precursor of various biochemical molecules, also occurs in plants as a stress-response molecule, for example in heat or hypoxia [ 76 ]. The metabolism of L-alanine and β-alanine are linked because L-alanine can act as an amino donor in the synthesis of β-alanine by the β-alanine/L-alanine aminotransferase.…”

New insights into the regulation of plant metabolism by O-acetylserine: sulfate and beyond

“…PYD4 (AT3G08860) belongs to the aminotransferase gene family, and it functions as an alanine:glyoxylate aminotransferase/β-alanine:pyruvate aminotransferase ( Parthasarathy et al , 2019 ). PYD4 is up-regulated in response to osmotic stress and has been shown to be putatively involved in β-alanine metabolism ( Parthasarathy et al , 2019 ). Studies have identified that PYD4 is involved in multiple processes in plants, such as changes in light and carbon availability ( Parthasarathy et al , 2019 ).…”

“…PYD4 is up-regulated in response to osmotic stress and has been shown to be putatively involved in β-alanine metabolism ( Parthasarathy et al , 2019 ). Studies have identified that PYD4 is involved in multiple processes in plants, such as changes in light and carbon availability ( Parthasarathy et al , 2019 ). PYD4 is localized in the mitochondria or the peroxisome ( Niessen et al , 2012 ) and it is down-regulated in the microarray of Hubberten et al (2012b) , where OAS is induced internally; however, in sulfur deficiency microarrays and RNA-seq, PYD4 is co-regulated with the OAS cluster genes ( Fig.…”