Title : Molecular characterization of 3-Hydroxy-3-methylglutaryl-CoA reductase (HMGR) multigene family in legume crop Cicer arietinum
Isoprenoids, the largest and most varied class of plant secondary metabolites, are synthesized either via mevalonic acid pathway (MVA) or the methyl erythritol pathway (MEP) to help the plants to avoid or adapt to unfavorable environmental conditions. The 3-hydroxy-3-methylglutaryl-CoA reductase (HMGR) (EC 126.96.36.199) is the most significant enzyme of the MVA pathway and occurs in plants as a multi-genic family.
Due to its essential role in providing the defense to the plant by producing isoprenoids, the identification and differential expression of three isoforms of HMGR gene (HMGR1, HMGR2 and HMGR3) in different tissues of the chickpea (Cicer arietinum) legume plant is carried out under different abiotic stress conditions. Out of three isoform, HMGR1 gene is having constitutive expression and not induced by the stress but the HMGR2 and HMGR3 isoforms are highly induced during abiotic stress. So, it suggests that HMGR1 is having housekeeping function. Besides this, they have variation in their sub cellular localization also. Housekeeping isoform (HMGR1) is endomembranous and it is distributed like spherical bodies along the membrane while the other two isoforms (HMGR2 and HMGR3) share the same localization pattern along with nuclear localization. The promoter activity of all the isoforms reveals that they are highly active during reproductive stage of plant development as they have high GUS expression in anthers. The stress induced isoforms have some activity during vegetative growth also. Similarly, phylogenetic analysis also shows that all the stress induced isoforms make separate clades in comparison with housekeeping gene.
So, the outcome of the study will help in elucidating the role and regulation of different isoforms of the HMGR gene in the legume plant and provide the new insight for isoprenoid dependent plant response during abiotic or biotic stress condition.
Take Away Notes:
• It offers an opportunity to study suitable system to understand stress responses in cold season food legume crops through a combination of bioinformatics and molecular biology techniques.
• It will help in crop improvement by altering the plant metabolism.
• Helps in understanding molecular signatures that may regulate isoform activity under abiotic stress.
• Provide information to make changes in the plant system for increased production of volatile compounds.