A dominant gdcP‐specific marker derived from Moricandia nitens used for introducing the C₃‐C₄ character from M. nitens into Brassica crops

Abstract

Differential localization of decarboxylation and carboxylation in association with Kranz anatomy distinguish species with C 4 or C 3 -C 4 intermediate photosynthesis from species with C 3 photosynthesis. Moricandia nitens has a C 3 -C 4 intermediate photosynthetic mechanism and yet is closely related to C 3 Brassica species. In order to introduce the C 3 -C 4 character from M. nitens into Brassica crops, sesquitetraploids (MACC) were synthesized by crossing Brassica napus (AACC) and a somatic hybrid (M. nitens + B. oleracea, MMCC). Homologous fragments (2966 and 3254 bp) of P-protein gene of glycine decarboxylase (gdcP) were isolated from M. nitens and B. napus, respectively, to develop a PCR-based marker for assisted selection. Reverse transcriptase-polymerase chain reaction (RT-PCR) of the partial encoding regions of both gdcPs indicated that the mRNAs were expressed in the expanded leaf. The characterization of high divergence, but with large conserved island in the regulatory region of the two C 3 species, implies that they may play an important role in maintaining the C 3 photosynthetic pathway. Thereafter, a dominant gene-specific marker was developed within the highly divergent region for subsequent introduction of C 3 -C 4 photosynthesis from Moricandia nitens into Brassica crops.

Inheritance of C3―C4Intermediate Photosynthesis in Reciprocal Hybrids BetweenMoricandia Arvensis(C3―C4) andBrassica Oleracea(C3) That Differ in Their Genome Constitution

“…In this family, interspecific and intergeneric crosses are relatively easier to achieve than in other families (e.g., Bang et al, 1996Bang et al, , 2003reviewed in Matsuzawa et al, 1996). As a result, studies of artificial hybridization between C 3 and C 3 -C 4 intermediate species in this family have been attempted to genetically improve carbon and water economies by the introduction of C 3 -C 4 intermediate characteristics into C 3 plants (Apel et al, 1984;O' Neill et al, 1996;Razmjoo et al, 1996;Rawsthorne et al, 1998;Yan et al, 1999;Zhang et al, 2004). In an early study, Apel et al (1984) reported that hybrids showed Γ values intermediate between those of the parent C 3 plants and C 3 -C 4 intermediate species.…”

Transcriptionally and phylogenetically analyzing the P protein gene of glycine decarboxylase for understanding the evolution of C3–C4 species in Brassicaceae

“…Our previous studies indicated that great variations were found in the 5 -flanking regions of the P protein gene among the C 3 -C 4 species, M. nitens, and 2 C 3 species, B. napus and Arabidopsis. In addition, conserved DNA regions specific to C 3 species were also revealed although B. napus and M. nitens have closer revolutionary relationship than B. napus and Arabidopsis (Zhang et al, 2004). This implies that further investigation of regulatory sequences of P protein gene conserved in C 3 species in Brassicaceae might shed light on understanding the mechanism of C 3 -C 4 photosynthesis and even on the evolutionary process of C 3 -C 4 species in this family.…”

“…Previous studies indicated that the lack of P protein in the mesophyll cells of C 3 -C 4 species from Flaveria is regulated by differential transcription of the P protein gene (Bauwe et al, 1995). Additionally, our previous results indicated that conserved DNA regions in C 3 species (Arabidopsis and B. napus) in the promoter regions of the P protein gene were revealed (Zhang et al, 2004). All this information implies that the lack of P protein from the mesophyll cells of Moricandia (C 3 -C 4 species) may also be regulated by differential transcription.…”

“…Plasmid containing 1.6 kb 5 -flanking region upstream of the AUG initiation codon of B. napus P protein gene of glycine decarboxylase (Zhang et al, 2004;accession No. AY544772) was used as a template for polymerase chain reaction (PCR).…”

Moricandia

“…This compartmentalization has been used to reduce the carbon loss by inhibiting the metabolism of glycine in the mesophyll cell, allowing it to be recovered in the bundle sheath cells. A dominant marker gdcP was developed from the gdc gene for C 3 -C 4 intermediate phenotype in the integration of into B. napus using a M. nitens  B. olereaca somatic hybrid (Zhang et al 2004).…”