Integrated mRNA – miRNA - metabolite landscape revealed developmental and environment-driven regulation of curcumin biosynthesis in Lakadong turmeric

Abstract

The Lakadong turmeric variety of Meghalaya is globally known for its high curcuminoid content in its rhizome. However, the framework to understand its genotype & environment driven interaction with that of molecular regulatory network is little known. In this context, we performed integrative comparative analysis of Lakadong and a control turmeric variety (Assam turmeric) cultivated at two distinct agroclimatic conditions of Meghalaya and Assam. Correlation analysis of phytochemical profile, antioxidant assays, targeted curcuminoid quantification and its biosynthetic genes, regulatory miRNAs revealed unique metabo-molecular signatures attributing to curcumin biosynthesis. The rhizome of Lakadong variety consistently showed higher curcuminoid levels across studied developmental stages than Assam turmeric. While early biosynthesis genes such as PAL and 4CL expressed higher in the young rhizome, expression of curcumin specific genes ( CS and CCOMT ) genes peaked during rhizome maturation. Expression of CS genes along with curcumin leveled reduced in the rhizome of Lakdong grown in assam as compared to Lakadong grown in Meghalaya. miRNA profiling revealed stage-dependent regulation of biosynthetic genes suggesting multilayered transcriptional and post-transcriptional control. Integration of environmental parameters with biochemical and molecular datasets emphasized the strong influence of climatic and edaphic properties on curcuminoid accumulation. This study highlighted that key insights into curcumin regulation. The results will provide significant value in genetic improvement of turmeric, designing cultivation strategies and advancing over all yield and quality.