Development of rapeseed with high erucic acid content by asymmetric somatic hybridization between Brassica napus and Crambe abyssinica

Abstract

PEG-induced asymmetric somatic hybridization between Brassica napus and Crambe abyssinica was carried out. C. abyssinica is an annual cruciferous oil crop with a high content of erucic acid in the seed oil valuable for technical purposes. UV-irradiated mesophyll protoplasts of C. abyssinica cv 'Carmen' and cv 'Galactica' were fused with hypocotyl protoplasts of different genotypes of B. napus cv 'Maplus' and breeding line '11502'. Shoot regeneration frequency varied between 6.1% and 20.8% among the different doses of UV-irradiation, ranging from 0.05 J/cm(2) to 0.30 J/cm(2). In total, 124 shoots were regenerated, of which 20 asymmetric somatic hybrids were obtained and verified by nuclear DNA content and AFLP analysis. AFLP data showed that some of the characteristic bands from C. abyssinica were present in the hybrids. Cytological analysis of these hybrids showed that 9 out of 20 asymmetric hybrids had 38 chromosomes, the others contained 40-78 chromosomes, having additional chromosomes between 2 and 40 beyond the 38 expected for B. napus. The investigation into the fertility of asymmetric somatic hybrids indicated that the fertility increased with increasing UV-doses ranging from 0.05 J/cm(2) to 0.15 J/cm(2). All of the hybrids were cultured to full maturity, and could be fertilized and set seeds after self-pollination or backcrosses with B. napus. An analysis of fatty acid composition in the seeds was conducted and found to contain significantly greater amounts of erucic acid than B. napus. This study indicates that UV-irradiation could be used as a tool to produce asymmetric somatic hybrids and to promote the fertility of the hybrids.

Intergeneric Somatic Hybridization Between Brassica napus L. and Sinapis alba L.

“…The oil quality of B. napus depends on the composition, chain length, degree of desaturation, and functional groups of fatty acids (Friedt and Lühs 1998). In order to make the oil suitable for industrial purposes, some attempts have been made to modify the fatty acid composition of rapeseed using modern biotechnology, such as somatic hybridization (Fahleson et al 1994;Earle 1995, 1997;Wang et al 2003) and genetic transformation (Voelker et al 1992;Weier et al 1998;Schröder-Pontoppidan et al 2000;Taylor et al 2001;Wang et al 2004a).…”

“…ex R E Fr. (Wang et al 2003(Wang et al , 2004b and Sinapis alba L. (Yaniv et al 1993). Sinapis alba is phylogenetically close to Brassica species and has sufficient genetic homoeology (Gaikward et al 1996).…”

Leaf anatomy of Crambe abyssinica Hochst. during in vitro shoot induction

“…The genetic breeding of species like C. abyssinica, with the aim of increasing their oil production or altering any compound of interest, has been often employed (Wang and Peng, 1998;Murphy, 1999;Wang et al, 2003;Wang et al, 2004;Li et al, 2010). However, in order for the genetic breeding to be successful, biotechnological steps beforehand must be efficiently concluded.…”

“…In previously published protocols, the in vitro regeneration of crambe was achieved by using hypocotyls as explants to enable studies related to genetic breeding of the species, such as transgenesis and somatic hybridization (Wang et al, 2004(Wang et al, , 2003Wang and Peng, 1998). However, studies related to the induction of shoots and regeneration of whole plants from the apical segment have not been described yet.…”

Production and genetic characterization of interspecific hybrids among Crambe abyssinica, Crambe hispanica and Crambe kralikii

“…In many cases, these difficulties may be overcome by embryo rescue and protoplast fusion, which greatly facilitate the production of interspecific hybrids (Zhang et al, 2004;Wen et al, 2008;Prakash et al, 2009). There are numerous examples of successful gene introgressions, with respect to diseases (Hu et al, 2002;Chen et al, 2007), novel fatty acid composition (Wang et al, 2003), and fertility restorer genes for a number of cytoplasmic male sterility systems (Banga et al, 2003). In this study, interspecific crosses of C. abyssinica with C. hispanica and C. kralikii were undertaken to produce hybrids and progenies for the improvement of C. abyssinica.…”