Metabolic engineering was used to disrupt glutamine metabolism in microspores in order to block pollen development. We used a dominant-negative mutant (DNM) approach of cytosolic glutamine synthetase (GS1) gene under the microspore-specific promoter NTM19 to block glutamine synthesis in developing pollen grains. We observed partial male sterility in primary transgenic plants by using light micr...

It is currently accepted that 'stress' triggers induction of microspore embryogenesis, and for Brassica napus L. cv. Topas it is heat-shock. It has been postulated that the heat-shock proteins (HSPs) generated during heat stress have a central role in the induction mechanism. To test this hypothesis we developed a microspore induction procedure, using colchicine instead of heat treatment. The l...

Lipid transfer proteins (LTPs) are small secretory proteins in plants with defined lipid-binding structures for possible lipid exocytosis. Special groups of LTPs unique to the anther tapetum are abundant, but their functions are unclear. We studied a special group of LTPs, type III LTPs, in Arabidopsis (Arabidopsis thaliana). Their transcripts were restricted to the anther tapetum, with levels ...

HE cause and nature of chromosomal alterations has become an imT portant genetic problem since it has been shown that both mutation and speciation often are associated with structural alterations of the chromosomes (DOBZHANSKY 1937). The frequency of spontaneous structural changes is too low in most organisms to permit a statistical analysis of types or frequencies of alterations, although rece...

The Arabidopsis sporophytic tapetum undergoes a programmed degeneration process to secrete lipid and other materials to support pollen development. However, the molecular mechanism regulating the degeneration process is unknown. To gain insight into this molecular mechanism, we first determined that the most critical period for tapetal secretion to support pollen development is from the vacuola...

To obtain detailed information about gene expression during stamen development in Arabidopsis (Arabidopsis thaliana), we compared, by microarray analysis, the gene expression profile of wild-type inflorescences to those of the floral mutants apetala3, sporocyteless/nozzle, and male sterile1 (ms1), in which different aspects of stamen formation are disrupted. These experiments led to the identif...

Lipid transfer proteins (LTPs) are small secretory proteins in plants with defined lipid-binding structures for possible lipid exocytosis. Special groups of LTPs unique to the anther tapetum are abundant, but their functions are unclear. We studied a special group of LTPs, type III LTPs, in Arabidopsis (Arabidopsis thaliana). Their transcripts were restricted to the anther tapetum, with levels ...

Background: Okra [Abelmoschus esculentus (L.) Moench.] is a nutrient-rich vegetable crop widely grown in the tropics and sub-tropics mainly for its edible pods. The haploid technique has been used plant breeding improvements of plants to develop new varieties relatively short time. Hence, we have optimized several factors such as growth regulators (PGR), sucrose concentration, cold treatment, t...