Multiple elements of the S 2  -RNase promoter from potato (Solanum tuberosum L.) are required for cell type-specific expression in transgenic potato and tobacco

Abstract

A functional analysis of the promoter of the S2-RNase gene from potato was performed in transgenic potato and tobacco plants, using a deletion series of S2-RNase promoter GUS fusions. A detailed histochemical and quantitative analysis of the transgenic tobacco plants revealed that S2 promoter fragments ranging in size from 5.6 kb in length down to 0.2 kb mediate a weak developmentally regulated expression in the pistil, and strong ectopic expression in pollen. In the pistil, different expression patterns were seen depending on the transformant, the predominant one being characterized by expression in the stigma and the transmitting tract of the style, whereas a few plants showed expression exclusively either in the stigma or in the stylar transmitting tissue. All transformants also showed GUS expression in the placental epidermis of the ovary. Two sequences that are conserved between the potato S1-RNase and S2-RNase promoters, termed motif and motif III, are located in a fragment of the S2 promoter extending from position of -200 to bp -100, and motif II, located between by -498 and -480, was identified on the basis of sequence comparisons between pistil-specific promoters. Motif II was found to be dispensible for pistil-specific and for pollen-specific expression. Two submotifs, A and B, were identified with the motif I. Both were essential for expression in the pistil but only B was necessary for expression in pollen. Although motif III has a similar bipartite structure and sequence to motif I, it was not sufficient to confer-either pollen- or pistil-specific expression. However, deletion of motif III abolished pollen-specific expression in transient expression experiments, suggesting that an interaction between the two sequence motifs may be needed to specify cell type-specific expression. In transgenic potato the S2-RNase promoter also mediates expression in pollen and in the pistil; however, significantly fewer plants showed expression than in tobacco, with most plants also exhibiting GUS expression in other issues.

Analysis of the S-locus structure in Prunus armeniaca L. Identification ofS-haplotype specific S-RNase and F-box genes

“…An IB-like motif, similar to that reported in potato as necessary for S-RNase expression (Ficker et al, 1998) and also found in sweet cherry (Ishizaka et al, 2003), was detected within this conserved region (between )136 and )143) (Figure 2a). No other motifs were identified.…”

Structural and molecular analysis of self-incompatibility in almond ( Prunus dulcis )

“…It is therefore not surprising to find S-RNases accumulated intercellularly, as they are presumed to interact directly, in some yet unknown way, with growing pollen tubes. In fact, in several solanaceous and one rosaceous species (apple), S-RNases were found to accumulate in the extracellular matrix of both the stigmatic secretory zone and the transmitting tissue (Anderson et al 1989;Kandasamy et al 1990;Certal et al 1999;Feijó et al 1999) and S-allele mRNA and S-promoter-driven β-glucuronidase expression were also detected in these tissues (Cornish et al 1987;Ficker et al 1998). By immunological localisation, we have shown that in almond there is also an overlapping between the distribution pattern of S-RNases and the pathway of growing pollen tubes.…”

Cloning, characterization and promoter analysis of S-RNase gene promoter from Chinese pear (Pyrus pyrifolia)

“…The sequences upstream of box 1 are also very divergent among the other seven S-RNase genes, not like the further 180-bp region of sequence identity just upstream of box 1 [box 2 (Ushijima et al, 1998a), from −357 to −482] between the S 3 -and S 5 -RNase genes. Conserved sequence motif 1 and motif 2 in the 5′-flanking regions of solanaceous S-RNase genes (Ficker et al, 1998;Kaufmann et al, 1991) are not found in those rosaceous pear S-RNase genes except for the motif IA-like sequence (TTGAATA) which is located in box 1, but is was replaced by (TTGAAAA) in S 13 -RNase and (TTGAAAA) in MdS 9 -RNase (Fig. 4).…”