A novel tapetum-specific cDNA clone of rice, its corresponding gene designed as RA39, is isolated by RNA subtractive hybridization, differential screening and rapid amplification of cDNA ends. The RA39 cDNA is 1013 bp...A novel tapetum-specific cDNA clone of rice, its corresponding gene designed as RA39, is isolated by RNA subtractive hybridization, differential screening and rapid amplification of cDNA ends. The RA39 cDNA is 1013 bp in length with an open reading frame encoding 298 amino acid residues. mRNA in situ hybridization reveals that RA39 is a tapetum-specific gene, and highly expressed at the meiosis stage of pollen mother cells. The deduced protein contains a signal peptide, a transmembrane region and a cytoplasmic tail, and is predicted to localize in endoplasmic reticulum by PSORT program. This cDNA sequence did not show significant homology to any known sequences in Genbank database. RA39 is the first gene identified to be expressed specifically in tapetal cells at the meiosis stage of pollen mother cells from cereals.展开更多
The indoleacetic-acid-lysine synthetase (iaaL) gene from Pseudomonas syringae subsp. savastanoi was fused to tobacco tapetum-specific expression promoter TA29, and introduced into tobacco. The expression pattern of th...The indoleacetic-acid-lysine synthetase (iaaL) gene from Pseudomonas syringae subsp. savastanoi was fused to tobacco tapetum-specific expression promoter TA29, and introduced into tobacco. The expression pattern of this chimeric gene was studied, and the endogenous indoleacetic acid (IAA) levels in different organs were assayed. The results demonstrated that TA29 promoter was only able to direct the specific expression of iaaL gene in transgenic tobacco anther, and resulted in the decrease of endogenous IAA levels in transgenic tobacco anther. No significant phe-notype variation was observed among the transgenic plants at the whole plant level. However, the percentage of pollen embryogenesis was reduced to 11 % when anthers of the transgenic plants were cultured on the modified hormone-free Nistch H (NH) medium, while those of both CK1 and CK2 (see sec. 1.2.2) were more than 50% ; when the an-thers were cultured on NH medium supplemented with 0. 2 mg/L IAA, the percentage of pollen embryogenesis re-stored to the same level of that of the wild type (up to 55. 7% ). This study demonstrates that the IAA metabolism in anther tapetum cells is of significant importance to the androgenic development in anther culture.展开更多
文摘A novel tapetum-specific cDNA clone of rice, its corresponding gene designed as RA39, is isolated by RNA subtractive hybridization, differential screening and rapid amplification of cDNA ends. The RA39 cDNA is 1013 bp in length with an open reading frame encoding 298 amino acid residues. mRNA in situ hybridization reveals that RA39 is a tapetum-specific gene, and highly expressed at the meiosis stage of pollen mother cells. The deduced protein contains a signal peptide, a transmembrane region and a cytoplasmic tail, and is predicted to localize in endoplasmic reticulum by PSORT program. This cDNA sequence did not show significant homology to any known sequences in Genbank database. RA39 is the first gene identified to be expressed specifically in tapetal cells at the meiosis stage of pollen mother cells from cereals.
基金Project supported by the State Key Laboratory of Plant Molecular Genetics.
文摘The indoleacetic-acid-lysine synthetase (iaaL) gene from Pseudomonas syringae subsp. savastanoi was fused to tobacco tapetum-specific expression promoter TA29, and introduced into tobacco. The expression pattern of this chimeric gene was studied, and the endogenous indoleacetic acid (IAA) levels in different organs were assayed. The results demonstrated that TA29 promoter was only able to direct the specific expression of iaaL gene in transgenic tobacco anther, and resulted in the decrease of endogenous IAA levels in transgenic tobacco anther. No significant phe-notype variation was observed among the transgenic plants at the whole plant level. However, the percentage of pollen embryogenesis was reduced to 11 % when anthers of the transgenic plants were cultured on the modified hormone-free Nistch H (NH) medium, while those of both CK1 and CK2 (see sec. 1.2.2) were more than 50% ; when the an-thers were cultured on NH medium supplemented with 0. 2 mg/L IAA, the percentage of pollen embryogenesis re-stored to the same level of that of the wild type (up to 55. 7% ). This study demonstrates that the IAA metabolism in anther tapetum cells is of significant importance to the androgenic development in anther culture.
