Isolation and Cloning of Suppressor Mutants with Improved Pollen Fertility

Author(s):  
Steven Beuder ◽  
Cora A. MacAlister
Crop Science ◽  
1990 ◽  
Vol 30 (4) ◽  
pp. 952-955 ◽  
Author(s):  
David M. Stelly ◽  
Kenneth C. Kautz ◽  
William L. Rooney
Keyword(s):  

Genetics ◽  
1996 ◽  
Vol 143 (3) ◽  
pp. 1383-1394
Author(s):  
Roger P Wise ◽  
Carren L Dill ◽  
Patrick S Schnable

Abstract Dominant alleles of the rf1 and rf2 nuclear-encoded fertility restorer genes are necessary for restoration of pollen fertility in T-cytoplasm maize. To further characterize fertility restoration mediated by the Rf1 allele, 123,500 gametes derived from plants carrying the Mutator transposable element family were screened for rf1-mutant alleles (rf1-m) Four heritable rf1-m alleles were recovered from these populations. Three rf1-m alleles were derived from the progenitor allele Rf1-IAl53 and one was derived from Rf1-Ky21. Cosegregation analysis revealed 5.5- and 2.4kb Mu1-hybridizing EcoRI restriction fragments in all of the male-sterile and none of the male-fertile plants in families segregating for rf1-m3207 and rf1-m3310, respectively. Mitochondrial RNA gel blot analyses indicated that all four rf1-m alleles in male-sterile plants cosegregated with the altered steady-state accumulation of 1.6 and O.6-kb T-urf13 transcripts, demonstrating that these transcripts are Rf1 dependent. Plants carrying a leaky mutant, rf1-m7323, revealed variable levels of Rf1-associated, T-urf13 transcripts and the degree of pollen fertility. The ability to obtain rf1-m derivatives from Rf1 indicates that Rf1 alleles produce a functional gene product necessary for the accumulation of specific T-urf13 transcripts in T-cytoplasm maize.


2007 ◽  
Vol 81 (17) ◽  
pp. 9004-9012 ◽  
Author(s):  
Robert M. Yarrington ◽  
Jichao Chen ◽  
Eric C. Bolton ◽  
Jef D. Boeke

ABSTRACT Ty1 reverse transcriptase/RNase H (RT/RH) is exquisitely sensitive to manganese concentrations. Elevated intracellular free Mn2+ inhibits Ty1 retrotransposition and in vitro Ty1 RT-polymerizing activity. Furthermore, Mn2+ inhibition is not limited to the Ty1 RT, as this ion similarly inhibits the activities of both avian myeloblastosis virus and human immunodeficiency virus type 1 RTs. To further characterize Mn2+ inhibition, we generated RT/RH suppressor mutants capable of increased Ty1 transposition in pmr1Δ cells. PMR1 codes for a P-type ATPase that regulates intracellular calcium and manganese ion homeostasis, and pmr1 mutants accumulate elevated intracellular manganese levels and display 100-fold less transposition than PMR1 + cells. Mapping of these suppressor mutations revealed, surprisingly, that suppressor point mutations localize not to the RT itself but to the RH domain of the protein. Furthermore, Mn2+ inhibition of in vitro RT activity is greatly reduced in all the suppressor mutants, whereas RH activity and cleavage specificity remain largely unchanged. These intriguing results reveal that the effect of these suppressor mutations is transmitted to the polymerase domain and suggest biochemical communication between these two domains during reverse transcription.


2020 ◽  
Vol 80 (01) ◽  
Author(s):  
J. Jorben ◽  
S. P. Singh ◽  
C. Tara Satyavathi ◽  
S. Mukesh Sankar ◽  
Jayant S. Bhat ◽  
...  

Present investigation was carried out to study the mode of inheritance of fertility restoration for A4 cytoplasm using pollen fertility and seed set per cent as criterion in determining the fertile and sterile plants. Two CMS lines of A4 cytoplasm were crossed with two fertility restorers generating four F1 crosses, namely, ICMA 99111 x PPMI 1003, ICMA 99111 x PPMI 1087, ICMA 03999 x PPMI 1003 and ICMA 03999 x PPMI 1087, their F2s and backcross generations. All the F1s were completely fertile indicating complete fertility restoration. F2s and backcross generations were evaluated at IARI, New Delhi and IARI Regional Centre, Dharwad during summer 2017 and χ 2 test was applied to test the significance. At both the locations, all the F2 segregating populations fit well into a Mendelian ratio of 15:1 indicating digenic duplicate dominance of fertility restoring genes with χ 2 value of 0.82, 2.90, 0.04, 3.97, 4.86, 4.98, 0.02, 1.26, 3.15, 4.98, 3.15 and 0.02. The F2 hypothesis was verified with the observed frequency of segregating plants fitting well into 3:1 ration with χ 2 value of 5.45, 1.93, 4.93, 0.60, 2.83, 0.44, 4.94, 2.77, 3.33, 0.13, 4.08 and 1.51. It is further confirmation of the findings that fertility restoration is indeed governed by two duplicate genes. Association between pollen fertility and seed set per cent was significant and positive.


2021 ◽  
Vol 7 (3) ◽  
pp. 64-69
Author(s):  
L. Bayramov

Abstract. The zones of distribution of varieties and forms of quince on the territory of the Nakhchivan Autonomous Republic have been established, phenological observations have been carried out, their flowering and fruiting have been studied. On the territory of the Autonomous Republic, flowering of varieties and forms of quince begins in the second decade of April, depending on the distribution zone, with an average daily temperature of 12–13 °C and lasts 12–13 days, depending on weather conditions. Each flower has 10–12 stamens arranged in one row. The article also studied the viability of pollen in a number of quince varieties. Pollen viability was studied in the varieties Sary, Tursh, Ordubad, Gara and wild forms. Pollen fertility was determined by staining with acetocarmine. Pollen germinates in 2–5–10–15 and 20% glucose solution. Counting of germinated pollen grains was carried out under a microscope. The study showed that of all the experimental varieties, the pollen fertility of the Sary quince and Tursh quince varieties is high (up to 96.6–97.1%). The best medium for the germination of quince pollen is a 10–15% glucose solution. Pollen germination in this solution reaches 47.4–88.0%. In distilled water (control), the germination of quince pollen reached from 9.7% to 35.6% for varieties. Quince pollen remains viable for 31–43 days.


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