Nuclear DNA content of Pongamia pinnata L. and genome size stability of in vitro-regenerated plantlets

Abstract

Pongamia pinnata L. is a multipurpose versatile legume that is well known as a prospective feedstock biodiesel species. However, to date, there has been little genomic research aimed at the exploitation of the biotechnological potential of this species. Genetic characterization of any plant is a challenging task when there is no information about the genome size and organization of the species. Therefore, the genome size of P. pinnata was estimated by flow cytometry with respect to two standards (Zea mays and Pisum sativum), and compared with that of in vitro-raised plants (nodal segment, in vitro-rooted plantlets and acclimatized in vitro plants) to study the potential effect of somaclonal variation on genome size. This method can be used to support the establishment of true-to-type plants to encourage afforestation programs. Modified propidium iodide/hypotonic citrate buffer was used for isolation of the intact nuclei. The 2C DNA value of this species was estimated to be 2.51 ± 0.01pg. Statistically, there was no significant difference in the DNA content of the in vitro-grown plants and mother plant at α = 0.05. As a result of the low genome size of P. pinnata, a species that has adapted itself to a wide range of edaphic and ecological condition, we can now proceed for its next generation sequencing and genomic diversity studies.