Genetic engineering of millets: current status and future prospects

Abstract

This review summarizes progress on the genetic transformation of millets and discusses the future prospects for the development of improved varieties. Only a limited number of studies have been carried out on genetic improvement of millets despite their nutritional importance in supplying minerals, calories and protein. Most genetic transformation studies of millets have been restricted to pearl millet and bahiagrass and most studies have been limited to the assessment of reporter and marker gene expression. Biolistic-mediated gene delivery has been frequently used for the transformation of millets but Agrobacterium-mediated transformation is still lagging. Improved transformation of millets, allied to relevant gene targets which may offer, for example, improved nutritional quality, resistance to abiotic and biotic stresses, and resistance to fungal infection will play important roles in millet improvement.

Factors influencing Agrobacterium tumefaciens-mediated genetic transformation of Eleusine coracana (L.) Gaertn

“…Therefore, mature embryos have also been used in cereals (Bi et al 2007;Chen et al 2006;He and Jia 2008). There are several reports of in vitro studies of finger millet (reviewed by Kothari et al 2005;Ceasar and Ignacimuthu 2009), but there are no reports of Agrobacterium-mediated genetic transformation, although it has been transformed using particle gun (Latha et al 2005). Gene transfer using a biolistic method has also been reported in Eleusine coracana and Echinochloa crusgalli (Gupta et al 2001), and in Paspalum notatum (Smith et al 2002;Grando et al 2002;Gondo et al 2003Gondo et al , 2005Altpeter and James 2005;James et al 2008).…”

“…in transgenic plants at the seedling stage (Latha et al 2005). However, this millet crop still lacked any Agrobacterium-mediated protocol for gene transfer (Ceasar and Ignacimuthu 2009). Considering this, we standardized an Agrobacterium-mediated transformation protocol for Eleusine coracana by optimizing various physical and chemical parameters.…”

Effects of cytokinins, carbohydrates and amino acids on induction and maturation of somatic embryos in kodo millet (Paspalum scorbiculatum Linn.)

“…Production of millets is also constrained by biotic and abiotic stresses; development of rapid in vitro propagation system is more helpful in the improvement of millets. Establishment of an efficient somatic embryogenesis and regeneration system is also a vital prerequisite for the successful transformation and recovery of transgenic millet crops (reviewed by Ceasar and Ignacimuthu 2009). Any further improvement in the system for somatic embryogenesis and plant regeneration is essential for transformation and molecular studies of kodo millet in the future.…”

In vitro transformation of pearl millet (Pennisetum glaucum (L). R. BR.): Selection of chlorsulfuron-resistant plants and long term expression of the gus gene under the control of the emu promoter

“…This result indicates that the regenerated plants have been stably transformed. Pearl millet transformation has been performed for resistance to some herbicides and some pathogens (Girgi et al, 2002;Goldman et al, 2003;Ceasar and Ignacimuthu, 2009). However, to the knowledge of the authors, the first transgenic plants of P. glaucum resistant to the chlorsulfuron herbicide were obtained Tiécoura et al 3121 in the current study.…”

“…Stable calli have been selected and analysed by Lambé et al (1995) after introducing the neomycin phosphotransferase gene (NPTII). Transgenic plants resistant to phosphinothricin and hygromycin (Goldman et al, 2003;O'Kennedy et al, 2004;Ceasar and Ignacimuthu, 2009;Ramadevi et al, 2014), kanamycin (Plaza-Wüthrich and Tadele, 2012) and mildew (Latha et al, 2006) have been studied. However, to date, no stable P. glaucum transformed calli and plant resistant to the chlorsulfuron herbicide have been reported yet.…”