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Abstract

In order to modify the early stages of pollen development in a transgenic context microspore-specific promoters are required. We tested two putatively microspore-specific promoters, the Bp4 promoter from rapeseed and the NTM19 promoter from tobacco. Expression of the gus and barnase reporter genes under the control of these two promoters was studied in transgenic tobacco. Contrary to expectations, the Bp4 promoter became active only after the first pollen mitosis, and not in the microspores. The NTM19 promoter turned out to be highly microspore-specific and directed very high levels of gus expression to the unicellular microspores. The NTM19-barnase transgene caused cell-autonomous death at the mid-unicellular microspore stage, whereas Bp4-barnase induced cell ablation of early to mid-bicellular pollen. Both promoter-barnase transgenes did not affect the sporophyte and were inherited through the female germline. These results show that both the NTM19 and Bp4 promoters are expressed only in the male germline, and that the NTM19 promoter is an excellent tool to direct high levels of transgene expression exclusively to the microspores. This may have important biotechnological applications.

The tobacco MAP215/Dis1-family protein TMBP200 is required for the functional organization of microtubule arrays during male germline establishment

“…This strategy required the tightly-regulated gametophyte-specific manipulation of plant MAP215/Dis1 expression, since plant MAP215/Dis1 is broadly expressed in somatic cells as well as gametophytic cells, rendering severe mor1 / gem1 alleles homozygous lethal. Therefore the tobacco microspore-specific NTM19 gene promoter (Custers et al , 1997) was used to induce the post-meiotic TMBP200 deficiency in microspores using a hairpin RNAi construct.…”

Characterization of Genetic Diversity in Accessions of Prunus salicina Lindl: Keeping Fruit Flesh Color Ideotype While Adapting to Water Stressed Environments

“…Furthermore, genes involved in plant growth and development encoding VQ motif-containing proteins and microspore-specific promoter proteins [57,58] were close to CPSCT011.…”