Genetic and epigenetic uniformity of polyembryony derived multiple seedlings of Hevea brasiliensis

Abstract

Hevea brasiliensis Muell. Arg (Para rubber tree) is a tropical tree species of Amazonian origin widely cultivated in several parts of the world for natural rubber, a highly priced commodity inevitable for the world rubber industry. Large, tree to tree variation in growth and latex yield among individual plants of high yielding Hevea clones is a common phenomenon observed in mature rubber plantations. The genetic heterogeneity of the seedlings which are used as rootstocks for propagation through budgrafting is considered as a major factor responsible for this variation. In order to minimize this variation, attempts were made to develop highly uniform rootstock material via an in vitro technique by inducing zygotic polyembryony in Hevea. Immature open pollinated fruits of a high yielding clone RRII 105 were cultured by half ovulo embryo culture technique. Multiple embryos were induced from the 8-10-week-old zygote with a novel combination of gibberellic acid (GA3), kinetin, and zeatin. Plantlets were successfully generated from the multiple embryos and raised in the field post hardening. Screening using genetic and epigenetic molecular markers revealed that the multiple seedlings developed are highly uniform and are of single zygotic origin. Development of plants having genetic and epigenetic uniformity suggests that this technique is ideal for raising uniform rootstock material in Hevea which may significantly reduce intraclonal variations. Moreover, these plants could serve as ideal material for physiological and molecular investigations towards the understanding of stock-scion interaction process in rubber.

True-to-type micropropagated plants of para rubber (Hevea brasiliensis Müll. Arg.) via somatic embryogenesis

“…In para rubber, two RAPD makers, OPAA-07 and OPJ-19 were used to detect genetic viability of plant derived from zygotic polyembryony (Karumamkandathil et al, 2015). In African hyacinth (Ledebouria revoluta), 17 RAPD markers were used to confirm the genetic stability in plants derived from somatic embryogenesis (Haque and Ghosh, 2016).…”

“…True to type somatic embryos of para rubber, without somaclonal variation, are required for large scale production of elite clones (Wang et al, 2017). Based on this requirement, genetic and epigenetic changes have been studied in para rubber using molecular markers [including randomly amplified polymorphic DNA (RAPD) and simple sequence repeats (SSRs)] and DNA methylation [including methylation-sensitive amplification polymorphism (MSAP)] (Karumamkandathil et al, 2015;Wang et al, 2017). RAPD and SSRs are a simple, rapid, reproducible, and costly techniques to identify the genetic similarity in both intergeneric and intrageneric diversity (Thakur et al, 2016;Rohela et al, 2019).…”

Somatic Embryogenesis as Key Technology for Shaping the Rubber Tree of the Future

“…The fruit is a capsule that usually contains three carpels each inclosing a seed (Muzik, 1954). They are harvested before the inner fruit wall starts lignifying.…”