Genetic transformation of Sorghum [Sorghum bicolor (L.) Moench]

Abstract

Sorghum (Sorghum bicolor (L.) Moench) is a major dual-purpose and forage crop in India. Sorghum is an economical important cultivated cereal around the world and many studies have been done to develop a more productive crop, resistant to diseases and pests, and adapted to adverse conditions. Unfortunately, variation for many such traits is limited in natural gene pool and biotechnological approaches to improve sorghum have been limited. One of the important reasons for limited application of biotechnological tools in sorghum is due to its extreme recalcitrance to produce transgenic plants in vitro. The objective of this work was to enhance the efficiency of Agrobacterium-mediated sorghum transformation protocol. We have attempted to optimize transformation using shoot apices obtained aseptically from in vitro germinated seedlings of sorghum genotypes. Transformation was best obtained using Agrobacterium tumefaciens strain EHA105 harbouring the plasmid pCAMBIA1305, as evinced by transient GUS expression. Maximum number of explants showed GUS expression at 200μM acetosyringone in the co-cultivation medium compared to its absence or lower doses. Addition of Lcysteine in the co-cultivation medium reduced necrosis and death of explants. This investigation asserted the feasibility of the genetic transformation of the sorghum genotypes used.