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Osmotin-regulated reserve accumulation and germination in genetically transformed tea somatic embryos: a step towards regulation of stress tolerance and seed recalcitrance1

Published online by Cambridge University Press:  22 February 2007

Amita Bhattacharya*
Affiliation:
Division of Biotechnology, Institute of Himalayan Bioresource Technology, Palampur, -176061, Himachal Pradesh, India
Uksha Saini
Affiliation:
Division of Biotechnology, Institute of Himalayan Bioresource Technology, Palampur, -176061, Himachal Pradesh, India
Preeti Sharma
Affiliation:
Division of Biotechnology, Institute of Himalayan Bioresource Technology, Palampur, -176061, Himachal Pradesh, India
P.K. Nagar
Affiliation:
Division of Biotechnology, Institute of Himalayan Bioresource Technology, Palampur, -176061, Himachal Pradesh, India
Paramvir Singh Ahuja
Affiliation:
Division of Biotechnology, Institute of Himalayan Bioresource Technology, Palampur, -176061, Himachal Pradesh, India
*
*Correspondence: Email: [email protected]

Abstract

The osmotin gene was introduced into tea [Camellia sinensis (L.) O. Kuntze] somatic embryos at the globular stage of development via microprojectile bombardment, to determine the effects of this stress-tolerance-related gene on the accumulation of storage reserves and acquisition of desiccation tolerance during embryo maturation. Changes in total soluble sugars, starch and proteins in response to osmotin were estimated in the stably transformed embryos, using standard biochemical and histochemical methods, after the globular embryos had matured to the heart stage of development. These changes also were compared with two types of controls, comprising (1) untransformed embryos and (2) embryos that were bombarded without osmotin DNA. The control embryos showed poor reserve accumulation and negligible germination but, in contrast, the embryos bombarded with the osmotin gene showed a several-fold increase in storage reserves, normal maturation and 57–63% germination. When these transformed embryos were desiccated to 15.5% moisture content, only 40% germinated, although a further increase in the accumulation of storage reserves occurred. In contrast, the control embryos became necrotic and failed to germinate. This study demonstrates the use of somatic embryogenesis as a tool for understanding seed recalcitrance in tea, and suggests that transformation with stress-tolerance genes can overcome the developmental problems associated with recalcitrant seeds.

Type
Research Article
Copyright
Copyright © Cambridge University Press 2006

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