Thematic Session- S48: New molecular breeding technologies for food security
Evaluating potential of germline cells for in vitro morphogenesis and transformation in
an important semi-arid grain legume pigeonpea
Divya Mohantya#, Atika Chandrab and Rajesh Tandona
a
Department of Botany, University of Delhi, Delhi-110007
b
Botany Department, Maitreyi College, University of Delhi, New Delhi-110021
#
E-mail: divy.friends@gmail.com
Abstract
Pigeonpea (Cajanus cajan), an important grain legume of the semi-arid tropics, displays high
adaptability to cropping systems and maintains ecological sustainability by fixing
atmospheric nitrogen. Its production has stagnated due to both biotic and abiotic stresses.
Traditional breeding methods have not been fruitful enough in broadening the narrow genetic
base of the present day cultivars of the crop. Once considered an ‘orphan’ crop, its genome
has recently been decoded; making way for genomics assisted breeding. However, the plant
is refractory to in vitro methods and genetic modifications. The employment of male
germline cells for transformation and recovery of doubled haploids (DH) has been a
successful strategy for many crops. It ensures the production of homozygous lines in a single
generation, providing introgression as well as genetic stability. However, a reproducible
protocol for generating androgenic haploids and DH is not available in pigeonpea. In this
study, a novel strategy was evaluated to improve in vitro response of anthers by
overexpression of an AP2/ERF transcription factor Baby Boom (BBM). Induction of embryos
by ectopic expression of BnBBM has been earlier achieved in Brassica napus, Arabidopsis
thaliana, Nicotiana tabacum and Capsicum annuum. BnBBM was introduced into the male
germline cells via biolistic bombardment of anthers. Transformed microspores and pollen
exhibited rapid cell divisions forming either embryo-like structures or calli in a much shorter
duration as compared to control tissues. The results strengthen the view that altering the
developmental pathways by restructuring of genome will overcome in vitro recalcitrance.
This approach opens the way forward to recovering transgenic plants in pigeonpea.