Role of plant long noncoding RNAs in the regulation of plant metabolism

Abstract Recent high-throughput DNA sequencing technologies indicated that only 2%–25% genome could translate itself into proteins, the remaining known as noncoding RNAs. Previously, the noncoding DNA was identified as junk DNA, but recent biological interventions suggest that it contains valuable information regarding the regulation of genetic machinery. Long noncoding RNAs (lncRNAs) are a type of noncoding RNAs, with a length of >  200 nucleotides without having any coding potential. They are not only involved in the gene regulatory mechanism, but also indulge in several other functions like chromatin remodeling, regulation of other noncoding RNAs like miRNA, blocking expression of sense mRNA, etc. Recent studies suggested that lncRNAs play a critical role in primary metabolic processes like flowering, cell cycle, organ development, reproduction, photomorphogenesis, vernalization, biotic and abiotic stress responses, respiration, photosynthesis, etc. Besides primary metabolism, their role in the regulation of secondary metabolism was also predicted. The functioning of lncRNAs remains to be completely explored. The progressive in-depth research in this area may provide a new direction toward the gene regulation machinery. Therefore, it becomes immensely important to explore lncRNAs from the plant system and their involvement in the regulation of different metabolic pathways. This chapter discusses the identification, importance, and regulation of lncRNAs in the context of plant metabolism. This opens the door toward understanding the functionality of the plant’s lncRNAs.