Anthers of male sterile line and its maintainer line of Zidao type rice, Yingxiang A and Yingxiang B were studied by cytological methods, such as F-KI staining, silver nitrate staining and paraffin sections, It is fou...Anthers of male sterile line and its maintainer line of Zidao type rice, Yingxiang A and Yingxiang B were studied by cytological methods, such as F-KI staining, silver nitrate staining and paraffin sections, It is found that in Yingxiang A, there are some abnormalities in meiosis, represented by unequal division at the meiotic phase; the abortion of CMS line arises at the meiotic phase and is almost completed at the phase of monomicrospore, but only a tiny amount of aborted mi- crospores are observed; the abortion is complete and thorough, and none normal functional pollens are found; the morphology of aborted pollens is similar to that of typically aborted pollens; the tapetal cells still exist in anthers from the microsporocyte stage to the tetrad stage, but they are abnormally hyperplastic. However, in Yingxiang B, there are no abnormalities in meiosis at the meiotic phase; the tapetal cells exist in anthers before the tetrad stage, but they disappear completely when the pollen are mature. It is indicated that the abortion of CMS Yingxiang line mainly occurs at the meiotic phase, and is basically completed at the phase of monomicrospore. The abortion is probably caused by the abnormally hyperplastic tapetal cells. The abnormalities in tapetal cells may affect the normal development of pollens, resulting in the emergence of abortion. In addition, the abortion in Yingxiang A is complete and thorough, which is of great significance in hybrid breeding.展开更多
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
During anther development, the tapetum pro- vides materials and nutrients for pollen development. In Arabidopsis, several transcription factors have been iden- tified to form a genetic pathway （DYT1-TDF1-AMS- MS188-...During anther development, the tapetum pro- vides materials and nutrients for pollen development. In Arabidopsis, several transcription factors have been iden- tified to form a genetic pathway （DYT1-TDF1-AMS- MS188-MS1） for tapetal development and function. DEFECTIVE in TAPETAL DEVELOPMENT and FUNCTION1 （TDF1） is a member of the R2R3 MYB family and is essential for early tapetum development in Arabidopsis. Here, we characterized an ortholog of Ara- bidopsis TDF1 in rice, OsTDF1 （LOC_Os03g18480）. OsTDF1 shares 69 % amino acid sequence identity with AtTDF1 in the putative MYB domain near the N-terminal region. RT-PCR and in situ hybridization show that OsTDF1 is specifically expressed in tapetal cells of rice anthers. The expression of OsTDF1 in Arabidopsis tdfl mutant restores its fertility, suggesting that this homolog can fulfill the normal function of TDF1 in Arabidopsis. The ostdfl knockout mutant exhibits a male-sterile phenotype. Its tapetal cells exhibit a vacuolated and hypertrophic phenotype similar to that of Arabidopsis tdfl mutants. Terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling assays revealed OsTDF1 acts as an essential regulator for tapetum programmed cell death. The qRT-PCR analysis revealed that OsTDF1 acts downstream of UDT1 and upstream of TDR, EAT1, OsMYBI03 and PTCI in rice, suggesting that the genetic pathway for tapetum development is generally conserved between rice and Arabidopsis,展开更多
文摘Anthers of male sterile line and its maintainer line of Zidao type rice, Yingxiang A and Yingxiang B were studied by cytological methods, such as F-KI staining, silver nitrate staining and paraffin sections, It is found that in Yingxiang A, there are some abnormalities in meiosis, represented by unequal division at the meiotic phase; the abortion of CMS line arises at the meiotic phase and is almost completed at the phase of monomicrospore, but only a tiny amount of aborted mi- crospores are observed; the abortion is complete and thorough, and none normal functional pollens are found; the morphology of aborted pollens is similar to that of typically aborted pollens; the tapetal cells still exist in anthers from the microsporocyte stage to the tetrad stage, but they are abnormally hyperplastic. However, in Yingxiang B, there are no abnormalities in meiosis at the meiotic phase; the tapetal cells exist in anthers before the tetrad stage, but they disappear completely when the pollen are mature. It is indicated that the abortion of CMS Yingxiang line mainly occurs at the meiotic phase, and is basically completed at the phase of monomicrospore. The abortion is probably caused by the abnormally hyperplastic tapetal cells. The abnormalities in tapetal cells may affect the normal development of pollens, resulting in the emergence of abortion. In addition, the abortion in Yingxiang A is complete and thorough, which is of great significance in hybrid breeding.
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This work was supported by the grants from the Ministry of Science and Technology of China （2013CB945100）, the National Natural Science Foundation of China （31100227）.
文摘During anther development, the tapetum pro- vides materials and nutrients for pollen development. In Arabidopsis, several transcription factors have been iden- tified to form a genetic pathway （DYT1-TDF1-AMS- MS188-MS1） for tapetal development and function. DEFECTIVE in TAPETAL DEVELOPMENT and FUNCTION1 （TDF1） is a member of the R2R3 MYB family and is essential for early tapetum development in Arabidopsis. Here, we characterized an ortholog of Ara- bidopsis TDF1 in rice, OsTDF1 （LOC_Os03g18480）. OsTDF1 shares 69 % amino acid sequence identity with AtTDF1 in the putative MYB domain near the N-terminal region. RT-PCR and in situ hybridization show that OsTDF1 is specifically expressed in tapetal cells of rice anthers. The expression of OsTDF1 in Arabidopsis tdfl mutant restores its fertility, suggesting that this homolog can fulfill the normal function of TDF1 in Arabidopsis. The ostdfl knockout mutant exhibits a male-sterile phenotype. Its tapetal cells exhibit a vacuolated and hypertrophic phenotype similar to that of Arabidopsis tdfl mutants. Terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling assays revealed OsTDF1 acts as an essential regulator for tapetum programmed cell death. The qRT-PCR analysis revealed that OsTDF1 acts downstream of UDT1 and upstream of TDR, EAT1, OsMYBI03 and PTCI in rice, suggesting that the genetic pathway for tapetum development is generally conserved between rice and Arabidopsis,
