During anther development,the transformation of the microspore into mature pollen occurs under the pro-tection of first the tetrad wall and later the pollen wall.Mutations in genes involved in this wall transition oft...During anther development,the transformation of the microspore into mature pollen occurs under the pro-tection of first the tetrad wall and later the pollen wall.Mutations in genes involved in this wall transition often lead to microspore rupture and male sterility;some such mutants,such as the reversible male sterile(rvms)mutant,are thermo/photoperiod-sensitive genic male sterile(P/TGMS)lines.Previous studies have shown that slow development is a general mechanism of P/TGMS fertility restoration.In this study,we iden-tified restorer of rvms-2(res2),which is an allele of QUARTET3(QRT3)encoding a polygalacturonase that shows delayed degradation of the tetrad pectin wall.We found that MS188,a tapetum-specific transcrip-tion factor essential for pollen wall formation,can activate QRT3 expression for pectin wall degradation,indicating a non-cell-autonomous pathway involved in the regulation of the cell wall transition.Further as-says showed that a delay in degradation of the tetrad pectin wall is responsible for the fertility restoration of rvms and other P/TGMS lines,whereas early expression of QRT3 eliminates low temperature restoration of rvms-2 fertility.Taken together,these results suggest a likely cellular mechanism of fertility restoration in P/TGMS lines,that is,slow development during the cell wall transition of P/TGMS microspores may reduce the requirement for their wall protection and thus support their development into functional pollens,leading to restored fertility.展开更多
基金supported by grants from the National Natural Science Foundation of China(31930009,31770348,32000371)Shanghai Municipal Education Commission(2019-01-07-00-02-E00006,2017-01-07-00-02-E00039)Science and Technology Commission of Shanghai Municipality(18DZ2260500 and 17DZ2252700).
文摘During anther development,the transformation of the microspore into mature pollen occurs under the pro-tection of first the tetrad wall and later the pollen wall.Mutations in genes involved in this wall transition often lead to microspore rupture and male sterility;some such mutants,such as the reversible male sterile(rvms)mutant,are thermo/photoperiod-sensitive genic male sterile(P/TGMS)lines.Previous studies have shown that slow development is a general mechanism of P/TGMS fertility restoration.In this study,we iden-tified restorer of rvms-2(res2),which is an allele of QUARTET3(QRT3)encoding a polygalacturonase that shows delayed degradation of the tetrad pectin wall.We found that MS188,a tapetum-specific transcrip-tion factor essential for pollen wall formation,can activate QRT3 expression for pectin wall degradation,indicating a non-cell-autonomous pathway involved in the regulation of the cell wall transition.Further as-says showed that a delay in degradation of the tetrad pectin wall is responsible for the fertility restoration of rvms and other P/TGMS lines,whereas early expression of QRT3 eliminates low temperature restoration of rvms-2 fertility.Taken together,these results suggest a likely cellular mechanism of fertility restoration in P/TGMS lines,that is,slow development during the cell wall transition of P/TGMS microspores may reduce the requirement for their wall protection and thus support their development into functional pollens,leading to restored fertility.
