TRANSCRIPTOME CHARACTERIZATION TO IDENTIFY PUTATIVE GENES RELATED TO AMINO ACID BIOSYNTHESIS PATHWAY AND D-AMINO ACID METABOLISM IN LATHYRUS SATIVUS
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Date
2020
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Indira Gandhi Krishi Vishwavidyalaya, Raipur
Abstract
Grasspea (Lathyrus sativus L.) is considered as a hardy and wonderful crop owing to its ability to withstand abiotic stress like drought, waterlogging, salinity and cold conditions and some insect herbivory. It can be grown as mixed crop or as “utera” crop with minimal agronomical inputs. Although it is highly nutritious but its cultivation is highly restricted due to its association with a neurotoxic disorder – Neurolathyrism which causes paralysis of lower limbs. The neurolathyrism is caused by a non-protein amino acid β-N-oxalyl-L-α,β-diaminopropionic acid (β-ODAP). β-ODAP is considered to form from the substrate o-acetyl serine (OAS) (Malathi et al.,1970). The immediate precursor of β-ODAP is the BIA which is formed from a ringed structure isoxazolin-5-one. β-ODAP biosynthesis also follows a cyanide detoxification pathway which is supposed to be interlinked with nitrogen and sulphur metabolism pathway. Although the β-ODAP biosynthesis pathway was investigated long back but the genes associated with it are still not known. So in a view to identify the putative genes related to amino acid biosynthesis pathway in Lathyrus sativus , functional annotation of transcripts of Mahateora and RLK-1950 was performed.
To functionally annotate the transcriptome data of Mahateora and RLK-1950, a new pipeline MapMan Mercator was approached. This pipeline was specially designed to functionally categorize the orphan plant omics data. The Mercator output (excel sheet) functionally described total 94,793 transcripts and assigned a specific functional category to the 20,562 transcripts in to 34 functional category. This pipeline provided us with more functionally described orphan Lathyrus sativus transcripts as compared to previously approached CLC Genomics Workbench which described functions to only 28,132 transcripts.
The Mercator output (excel sheet) was screened was enzymes related to the amino acid biosynthesis, cyanide metabolism, ROS metabolism and d-amino acid metabolism pathways. Among amino acid biosynthesis, alanine aminotransferase, Cysteine synthase, asparagines metabolism and ornithine decycloaminase. Alanine aminotransferase was selected as earlier study suggested a differential correlation between L-alanine synthase and β-ODAP. Cysteine synthase was selected due to its involvement in the cyanide metabolism pathway which leads to formation of Cyanoalanine from OAS which subsequently forms isoxazolin-5-one(precursor for BIA) via asparagine. Consequently, Cyanoalanine synthase, asparaginase and asparagine synthase is also selected. The selection of ROS is dependent due to the fact that whenever the content of ROS increases in the leaves, β-ODAP content reduces significantly and vice-vesa (Jiao et al., 2011). One enzyme associated with d-amino acid namely D-aminoacyl-tRNAdeacylase or D-Tyr-tRNA(Tyr) deacylase was selected due to the fact that β-ODAP is a d-amino acid. Also the cyanoamino pathway from KEGG showed interrelation between Cyanoalanine synthase, D-aminoacyl-tRNAdeacylase and Cysteine synthase.
Consequently, 17 transcripts were selected to assess the expression of primers designed from corresponding transcripts in different genotypes of Lathyrus.
Description
TRANSCRIPTOME CHARACTERIZATION TO IDENTIFY PUTATIVE GENES RELATED TO AMINO ACID BIOSYNTHESIS PATHWAY AND D-AMINO ACID METABOLISM IN LATHYRUS SATIVUS