Alternative strategies for multi-stress tolerance and yield improvement in millets

Authors: NUMAN, MUHAMMAD - University Of North Carolina Greensboro; Serba, Desalegn; LIGABA-OSENA, AYALEW - University Of North Carolina Greensboro

Submitted to: Genes
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 5/10/2021
Publication Date: 5/14/2021
Citation: Numan, M., Serba, D.D., Ligaba-Osena, A. 2021. Alternative strategies for multi-stress tolerance and yield improvement in millets. Genes. 12. https://doi.org/10.3390/genes12050739.
DOI: https://doi.org/10.3390/genes12050739

Interpretive Summary: Millets are important cereal crops cultivated in arid and semiarid regions of the world. Although millets are tolerant to most environmental stresses such as drought and heat, climate change has aggravated the stresses to impact the performance of the crops. On the other hand, the genetic improvement of millets has lagged behind other major crops and the productivity is still very low. To enhance the genetic improvement of millets, different approaches needs to be utilized. We reviewed the literature for the application of two alternative genetic improvement approaches. The application of plant growth regulating bacteria that improve growth and development as well as stress tolerance in other crops has a potential to enhance environmental stress tolerance and yield improvement in millets. Secondly, the newly discovered genome-editing approach is increasingly applied in the genetic improvement of different crops especially for biotic stress resistance. From the information available, genome-editing is applicable in millets to facilitate the improvement for drought and heat tolerance. These two alternative genetic improvement strategies are expected to bring these groups of orphan crops to the forefront of scientific research and improvement for tolerance to stresses and genetic yield potential to play their role in the global food security

Technical Abstract: Millets are important cereal crops cultivated in arid and semiarid regions of the world, particularly, Africa and southeast Asia. Climate change has triggered multiple abiotic stresses in plants that are the main cause of crop loss worldwide, reducing average yield for most crops by more than 50%. Although millets are tolerant to most abiotic stresses such as drought and high temperatures, further improvement is needed to make millets more resilient to unprecedented effects of climate change and associated environmental stresses. Incorporation of stress tolerance traits in millets will improve productivity in marginal environments in order to overcome future food shortage due to climate change. Recently, approaches such as application of plant growth promoting rhizobacteria (PGPRs) have been used to improve growth and development as well as stress tolerance of crops. Moreover, with the advance of next-generation sequencing technology, genome editing technology using Clusters Regularly Interspaced Short Palindromic Repeats (CRSIPR-Cas9) system are increasingly used to develop stress tolerant varieties in different crops. In this paper, the innate ability of millets to tolerate abiotic stresses and alternative approaches to boost stress resistance thoroughly reviewed. Moreover, stress resistant genes have been identified in related monocot crops such as rice (Oryza sativa), wheat (Triticum aestivum) and maize (Zea mays), and other related species for which orthologs in millets could be manipulated by CRISPR-cas and related genome editing techniques to improve stress resilience and productivity. These cutting-edge alternative strategies are expected to bring this group of orphan crops at the forefront of scientific research for their potential contribution in global food security.