An efficient protocol for shoot regeneration and genetic transformation of pigeonpea [Cajanus cajan (L.) Millsp.] using leaf explants

A protocol for efficient plant regeneration from leaf explants of pigeonpea [Cajanus cajan (L.) Millsp.] was developed for the production of transgenic plants. Leaf explants from 4- to 5-day-old in vitro raised seedlings were most efficient in producing multiple adventitious shoots in 90% of the explants on shoot induction medium [Murashige and Skoog (MS) medium +5.0 μM benzyladenine +5.0 μM kinetin]. Shoot buds originated from the petiolar cut end of the explants and elongated rapidly on medium containing 0.58 μM gibberellic acid. Over 80% of the elongated shoots rooted well on MS medium containing 11.42 μM indole-3-acetic acid and were transplanted with 100% success. The procedure reported here is very simple, efficient and reproducible, and is applicable across diverse genotypes of pigeonpea. The usefulness of this system for further studies on the genetic transformation of pigeonpea has been demonstrated in biolistics-mediated gene transfer by using nptII and uidA as marker genes, where 50% of the selected plants showed gene integration and expression.