ABSTRACT
The world has never faced a challenge graver than climate change. It is not only threatening to put lives of billions in jeopardy, but to alter the fine balance that exists between various biotic and abiotic components of ecosystems. Climate change is also altering the land-use pattern by not only making existing agricultural land unfit for productive cultivation, but also opening up newer areas to crop cultivation. Incorporating climate resilience in crop plants that can adapt to altered climate conditions is a major challenge and is urgently required to address the issue of food and nutritional security for the rapidly growing world population. Given this scenario, efforts towards modification of developmental and adaptive traits in crop plants are absolutely essential and need to be undertaken with utmost urgency. Breeding-based trait introgression from crop wild relatives, although a viable option, is a long and laborious process with the added disadvantage of having to deal with linkage drag. Structural and functional genomics, coupled with forward and reverse genetics, has allowed researchers to identify genetic elements that are key regulators of agronomic and adaptive traits. Transcription factors and small RNAs are the two major categories of genetic elements that have a dramatic effect on plant traits. Transcription factor proteins can be considered critical transcriptional regulators. MiRNAs, a class of small RNAs, on the other hand, are known to regulate expression levels of transcription factors and other target genes through transcriptional as well as post-transcriptional mechanisms. These may therefore be considered “master regulators”. MiRNAs have also now been deployed as effective and specific gene silencing tools for traits modification. In the present chapter, we review recent developments in plant miRNA research with special emphasis on agronomic traits, and argue whether small RNA may prove to be a panacea for developing climate resilient crops.
