From Robert J. Spreitzer, University of Nebraska, March 2014

Phenotype: requires acetate at 35 °C, temperature-conditional

This photosynthesis-competent revertant was selected from the Rubisco rbcL-mRNA deficient 76-5EN nuclear mutant (Hong and Spreitzer 1994, 1998). It can grow on minimal medium at 25 °C, but dies on minimal medium at 35 °C because of decreased expression of Rubisco. R107-4D is a double mutant (76-5EN/S107-4D) that results from a nuclear-gene intergenic suppressor (S107-4D) of 76-5EN. When separated from 76-5EN, S107-4D does not have a temperature-conditional phenotype (Hong and Spreitzer 1998), and does not appear to affect Rubisco expression. This strain has been maintained with acetate medium in darkness since its isolation.


Hong S, Spreitzer RJ (1994) Nuclear mutation inhibits expression of the chloroplast gene that encodes the large subunit of ribulose-1,5-bisphosphate carboxylase/oxygenase. Plant Physiol 106:673-678

Hong S, Spreitzer RJ (1998) Nuclear-gene mutations suppress a defect in the expression of the chloroplast-encoded large subunit of ribulosebisphosphate carboxylase/oxygenase. Plant Physiol 116:1387-1392

From Robert J. Spreitzer, University of Nebraska, March 2014

This strain was recovered from a cross between R107-4D mt+ and “wild-type” mt- (Hong and Spreitzer 1998). It has been maintained with acetate medium in darkness since its isolation. The R107-4D photosynthesis-competent revertant was selected from the Rubisco rbcL-mRNA deficient 76-5EN nuclear mutant (Hong and Spreitzer 1994, 1998). When R107-4D mt+ was crossed with “wild-type” mt-, tetrad analysis indicated that R107-4D resulted from a nuclear-gene intergenic-suppressor mutation (S107-4D). Thus, S107-4D suppresses 76-5EN by restoring Rubisco holoenzyme expression.


Hong S, Spreitzer RJ (1994) Nuclear mutation inhibits expression of the chloroplast gene that encodes the large subunit of ribulose-1,5-bisphosphate carboxylase/oxygenase. Plant Physiol 106:673-678

Hong S, Spreitzer RJ (1998) Nuclear-gene mutations suppress a defect in the expression of the chloroplast-encoded large subunit of ribulosebisphosphate carboxylase/oxygenase. Plant Physiol 116:1387-1392

From Robert J. Spreitzer, University of Nebraska, March 2014

Phenotype: requires acetate at 35 °C, temperature-conditional

This photosynthesis-competent revertant was selected from the Rubisco rbcL-mRNA deficient 76-5EN nuclear mutant (Hong and Spreitzer 1994, 1998). It can grow on minimal medium at 25 °C, but dies on minimal medium at 35 °C because of decreased expression of Rubisco. R118-1E is a double mutant (76-5EN/S118-1E) that results from a nuclear-gene intergenic suppressor (S118-1E) of 76-5EN. When separated from 76-5EN, S118-1E does not have a temperature-conditional phenotype (Hong and Spreitzer 1998), and does not appear to affect Rubisco expression. This strain has been maintained with acetate medium in darkness since its isolation.


Hong S, Spreitzer RJ (1994) Nuclear mutation inhibits expression of the chloroplast gene that encodes the large subunit of ribulose-1,5-bisphosphate carboxylase/oxygenase. Plant Physiol 106:673-678

Hong S, Spreitzer RJ (1998) Nuclear-gene mutations suppress a defect in the expression of the chloroplast-encoded large subunit of ribulosebisphosphate carboxylase/oxygenase. Plant Physiol 116:1387-1392

From Robert J. Spreitzer, University of Nebraska, March 2014

This strain was recovered from a cross between R118-1E mt+ and “wild-type” mt- (Hong and Spreitzer 1998). It has been maintained with acetate medium in darkness since its isolation. The R118-1E photosynthesis-competent revertant was selected from the Rubisco rbcL-mRNA deficient 76-5EN nuclear mutant (Hong and Spreitzer 1994, 1998). When R118-1E mt+ was crossed with “wild-type” mt-, tetrad analysis indicated that R118-1E resulted from a nuclear-gene intergenic-suppressor mutation (S118-1E). Thus, S118-1E suppresses 76-5EN by restoring Rubisco holoenzyme expression.


Hong S, Spreitzer RJ (1994) Nuclear mutation inhibits expression of the chloroplast gene that encodes the large subunit of ribulose-1,5-bisphosphate carboxylase/oxygenase. Plant Physiol 106:673-678

Hong S, Spreitzer RJ (1998) Nuclear-gene mutations suppress a defect in the expression of the chloroplast-encoded large subunit of ribulosebisphosphate carboxylase/oxygenase. Plant Physiol 116:1387-1392

From Robert J. Spreitzer, University of Nebraska, March 2014

Phenotype: requires acetate at 35 °C, temperature-conditional

This photosynthesis-competent revertant was selected from the Rubisco rbcL-mRNA deficient 76-5EN nuclear mutant (Hong and Spreitzer 1994, 1998). It can grow on minimal medium at 25 °C, but dies on minimal medium at 35 °C. R118-5E could not be crossed because it may have a number of metabolic defects. This strain has been maintained with acetate medium in darkness since its isolation.


Hong S, Spreitzer RJ (1994) Nuclear mutation inhibits expression of the chloroplast gene that encodes the large subunit of ribulose-1,5-bisphosphate carboxylase/oxygenase. Plant Physiol 106:673-678

Hong S, Spreitzer RJ (1998) Nuclear-gene mutations suppress a defect in the expression of the chloroplast-encoded large subunit of ribulosebisphosphate carboxylase/oxygenase. Plant Physiol 116:1387-1392

From Robert J. Spreitzer, University of Nebraska, March 2014

This strain was recovered from a cross between R118-25G mt+ and pf2 mt- (Hong and Spreitzer 1998). It has been maintained with acetate medium in darkness since its isolation. The R118-25G photosynthesis-competent revertant was selected from the Rubisco rbcL-mRNA deficient 76-5EN nuclear mutant (Hong and Spreitzer 1994, 1998). When R118-25G mt+ was crossed with “wild-type” pf2 mt-, tetrad analysis indicated that R118-25G resulted from a nuclear-gene intergenic-suppressor mutation (S118-25G). Thus, S118-25G suppresses 76-5EN by restoring Rubisco holoenzyme expression.


Hong S, Spreitzer RJ (1994) Nuclear mutation inhibits expression of the chloroplast gene that encodes the large subunit of ribulose-1,5-bisphosphate carboxylase/oxygenase. Plant Physiol 106:673-678

Hong S, Spreitzer RJ (1998) Nuclear-gene mutations suppress a defect in the expression of the chloroplast-encoded large subunit of ribulosebisphosphate carboxylase/oxygenase. Plant Physiol 116:1387-1392


  • Locus:
  • PF2
  • Chromosome:
  • 11

From Robert J. Spreitzer, University of Nebraska, March 2014

This photosynthesis-competent revertant was selected from the Rubisco rbcL-mRNA deficient 76-5EN nuclear mutant (Hong and Spreitzer 1994, 1998). It can grow on minimal medium at 25 °C, but dies on minimal medium at 35 °C because of decreased expression of Rubisco. R118-26G is a double mutant (76-5EN/S118-26G) that results from a nuclear-gene intergenic suppressor (S118-26G) of 76-5EN. When separated from 76-5EN, S118-26G does not have a temperature-conditional phenotype (Hong and Spreitzer 1998), and does not appear to affect Rubisco expression. This strain has been maintained with acetate medium in darkness since its isolation.


Hong S, Spreitzer RJ (1994) Nuclear mutation inhibits expression of the chloroplast gene that encodes the large subunit of ribulose-1,5-bisphosphate carboxylase/oxygenase. Plant Physiol 106:673-678

Hong S, Spreitzer RJ (1998) Nuclear-gene mutations suppress a defect in the expression of the chloroplast-encoded large subunit of ribulosebisphosphate carboxylase/oxygenase. Plant Physiol 116:1387-1392

From Robert J. Spreitzer, University of Nebraska, March 2014

This strain was recovered from a cross between R118-26G mt+ and “wild-type” mt- (Hong and Spreitzer 1998). It has been maintained with acetate medium in darkness since its isolation. The R118-26G photosynthesis-competent revertant was selected from the Rubisco rbcL-mRNA deficient 76-5EN nuclear mutant (Hong and Spreitzer 1994, 1998). When R118-26G mt+ was crossed with “wild-type” mt-, tetrad analysis indicated that R118-26G resulted from a nuclear-gene intergenic-suppressor mutation (S118-26G). Thus, S118-26G suppresses 76-5EN by restoring Rubisco holoenzyme expression.


Hong S, Spreitzer RJ (1994) Nuclear mutation inhibits expression of the chloroplast gene that encodes the large subunit of ribulose-1,5-bisphosphate carboxylase/oxygenase. Plant Physiol 106:673-678

Hong S, Spreitzer RJ (1998) Nuclear-gene mutations suppress a defect in the expression of the chloroplast-encoded large subunit of ribulosebisphosphate carboxylase/oxygenase. Plant Physiol 116:1387-1392

From Robert J. Spreitzer, University of Nebraska, March 2014

Phenotype: spectinomycin resistant

Lawrence Bogorad gave this strain to Bob Spreitzer in 1995. It is presumed to have the rbcL 5′ promoter sequence -390 to +97 and rbcL 3′ sequence fused to the aadA gene, and this construction is inserted into the chloroplast genome after the 3′ end of atpB (Salvador et al. 1993). The strain can grow photosynthetically, and is resistant to 250 µg/mL spectinomycin when grow on acetate medium in darkness (Hong 1996). This strain was used to investigate the effect of the 76-5EN nuclear mutation (Hong and Spreitzer 1994) on chloroplast gene expression (Hong 1996).


Hong S (1996) Nuclear mutations affect the catalysis, stability, and expression of chloroplast ribulose-1,5-bisphosphate carboxylase/oxygenase in Chlamydomonas reinhardtii. Ph. D. thesis, University of Nebraska

Hong S, Spreitzer RJ (1994) Nuclear mutation inhibits expression of the chloroplast gene that encodes the large subunit of ribulose-1,5-bisphosphate carboxylase/oxygenase. Plant Physiol 106:673-678

Salvador ML, Klein U, Bogorad L (1993) 5' Sequences are important positive and negative determinants of the longevity of Chlamydomonas chloroplast gene transcripts. Proc Natl Acad Sci USA 90:1556-1560

From Robert J. Spreitzer, University of Nebraska, March 2014

Phenotype: requires acetate, sensitive to light

This is progeny 1 from tetrad 11 from a cross between PAADA mt+ and 76-5EN mt- (Hong 1996). The strain can grow on acetate medium with 50 µg/mL spectinomycin in darkness, but dies with 250 µg/mL spectinomycin, indicating that 76-5EN partially blocks expression of aadA from the engineered rbcL promoter (Hong 1996). This strain requires acetate for growth because 76-5EN also blocks expression of the native rbcL gene (Hong and Spreitzer 1994). It has been maintained with acetate medium in darkness since it was isolated.


Hong S (1996) Nuclear mutations affect the catalysis, stability, and expression of chloroplast ribulose-1,5-bisphosphate carboxylase/oxygenase in Chlamydomonas reinhardtii. Ph. D. thesis, University of Nebraska

Hong S, Spreitzer RJ (1994) uclear mutation inhibits expression of the chloroplast gene that encodes the large subunit of ribulose-1,5-bisphosphate carboxylase/oxygenase. Plant Physiol 106:673-678

From Robert J. Spreitzer, University of Nebraska, March 2014

Phenotype: spectinomycin resistant

This is progeny 2 from tetrad 11 from a cross between PAADA mt+ and 76-5EN mt- (Hong and Spreitzer 1994; Hong 1996). The strain can grow photosynthetically, and is resistant to 250 µg/mL spectinomycin in acetate medium when grown in darkness (Hong 1996). This strain has been maintained with acetate medium in darkness since it was isolated.


Hong S (1996) Nuclear mutations affect the catalysis, stability, and expression of chloroplast ribulose-1,5-bisphosphate carboxylase/oxygenase in Chlamydomonas reinhardtii. Ph. D. thesis, University of Nebraska

Hong S, Spreitzer RJ (1994) Nuclear mutation inhibits expression of the chloroplast gene that encodes the large subunit of ribulose-1,5-bisphosphate carboxylase/oxygenase. Plant Physiol 106:673-678

From Robert J. Spreitzer, University of Nebraska, March 2014

Phenotype: spectinomycin resistant

This is progeny 3 from tetrad 11 from a cross between PAADA mt+ and 76-5EN mt- (Hong and Spreitzer 1994; Hong 1996). The strain can grow photosynthetically, and is resistant to 250 µg/mL spectinomycin in acetate medium when grown in darkness (Hong 1996). This strain has been maintained with acetate medium in darkness since it was isolated.


Hong S (1996) Nuclear mutations affect the catalysis, stability, and expression of chloroplast ribulose-1,5-bisphosphate carboxylase/oxygenase in Chlamydomonas reinhardtii. Ph. D. thesis, University of Nebraska

Hong S, Spreitzer RJ (1994) Nuclear mutation inhibits expression of the chloroplast gene that encodes the large subunit of ribulose-1,5-bisphosphate carboxylase/oxygenase. Plant Physiol 106:673-678

From Robert J. Spreitzer, University of Nebraska, March 2014

Phenotype: requires acetate, sensitive to light

This is progeny 4 from tetrad 11 from a cross between PAADA mt+ and 76-5EN mt- (Hong 1996). The strain can grow on acetate medium with 50 µg/mL spectinomycin in darkness, but dies with 250 µg/mL spectinomycin, indicating that 76-5EN partially blocks expression of aadA from the engineered rbcL promoter (Hong 1996). This strain requires acetate for growth because 76-5EN also blocks expression of the native rbcL gene (Hong and Spreitzer 1994). It has been maintained with acetate medium in darkness since it was isolated.


Hong S (1996) Nuclear mutations affect the catalysis, stability, and expression of chloroplast ribulose-1,5-bisphosphate carboxylase/oxygenase in Chlamydomonas reinhardtii. Ph. D. thesis, University of Nebraska

Hong S, Spreitzer RJ (1994) Nuclear mutation inhibits expression of the chloroplast gene that encodes the large subunit of ribulose-1,5-bisphosphate carboxylase/oxygenase. Plant Physiol 106:673-678

From Robert J. Spreitzer, University of Nebraska, March 2014

Phenotype: requires acetate at 35 °C, temperature-conditional

This nuclear mutant was isolated by screening for temperature-conditional, acetate-requiring mutants (Spreitzer et al. 1988). It can grow on minimal medium at 25 °C, but dies on minimal medium at 35 °C. The nuclear mutation is not in the Rubisco rbcS genes, but it causes a decrease in Rubisco stability and CO2/O2 specificity (Gotor et al. 1994). Some clones of 68-11AR have been observed to become acetate-requiring at 25 °C after many years of culture. This strain has been maintained with acetate medium in darkness since its isolation.


Spreitzer RJ, Al-Abed SR, Huether MJ (1988) Temperature-sensitive, photosynthesis-deficient mutants of Chlamydomonas reinhardtii. Plant Physiol 86:773-777

Gotor C, Hong S, Spreitzer RJ (1994) Temperature-conditional nuclear mutation of Chlamydomonas reinhardtii decreases the CO2/O2 specificity of chloroplast ribulose-bisphosphate carboxylase/oxygenase. Planta 193:313-319

From Robert J. Spreitzer, University of Nebraska, March 2014

Phenotype: requires acetate at 35 °C, temperature-conditional

The 68-11AR nuclear mutant was isolated by screening for temperature-conditional, acetate-requiring mutants (Spreitzer et al. 1988). The mutant was crossed with pf2 mt- to confirm mendelian inheritance, and this mt+ progeny clone was retained for further genetic analysis. 68-11AR grows on minimal medium at 25 °C, but dies on minimal medium at 35 °C. The nuclear mutation is not in the Rubisco rbcS genes, but it causes a decrease in Rubisco stability and CO2/O2 specificity (Gotor et al. 1994). Some clones of 68-11AR have been observed to become acetate-requiring at 25 °C after many years of culture. This strain has been maintained with acetate medium in darkness since its isolation.


Spreitzer RJ, Al-Abed SR, Huether MJ (1988) Temperature-sensitive, photosynthesis-deficient mutants of Chlamydomonas reinhardtii. Plant Physiol 86:773-777

Gotor C, Hong S, Spreitzer RJ (1994) Temperature-conditional nuclear mutation of Chlamydomonas reinhardtii decreases the CO2/O2 specificity of chloroplast ribulose-bisphosphate carboxylase/oxygenase. Planta 193:313-319

From Robert J. Spreitzer, University of Nebraska, March 2014

Phenotype: requires acetate at 35 °C, temperature-conditional

The 68-11AR nuclear mutant was isolated by screening for temperature-conditional, acetate-requiring mutants (Spreitzer et al. 1988). The mutant was crossed with pf2 mt- to confirm mendelian inheritance, and this mt- progeny clone was retained for further genetic analysis. 68-11AR grows on minimal medium at 25 °C, but dies on minimal medium at 35 °C. The nuclear mutation is not in the Rubisco rbcS genes, but it causes a decrease in Rubisco stability and CO2/O2 specificity (Gotor et al. 1994). Some clones of 68-11AR have been observed to become acetate-requiring at 25 °C after many years of culture. This strain has been maintained with acetate medium in darkness since its isolation.


Spreitzer RJ, Al-Abed SR, Huether MJ (1988) Temperature-sensitive, photosynthesis-deficient mutants of Chlamydomonas reinhardtii. Plant Physiol 86:773-777

Gotor C, Hong S, Spreitzer RJ (1994) Temperature-conditional nuclear mutation of Chlamydomonas reinhardtii decreases the CO2/O2 specificity of chloroplast ribulose-bisphosphate carboxylase/oxygenase. Planta 193:313-319

From Robert J. Spreitzer, University of Nebraska, March 2014

Phenotype: requires acetate at 35 °C, temperature-conditional

The 72-7JJ nuclear mutant was isolated by Spreitzer et al. (1992) by screening a collection of acetate-requiring mutants for lack of complementation with a known Rubisco rbcL mutant (e. g., Spreitzer and Ogren 1983; Spreitzer et al. 1988). 72-7JJ grows on minimal medium at 25 °C, but dies on minimal medium at 35 °C. The mutant was crossed with pf2 mt- to confirm mendelian inheritance, and this mt+ progeny clone was retained for further analysis. 72-7JJ has normal whole-chain electron transport and chlorophyll levels. The 72-7JJ mutation is not in the Rubisco rbcS genes, but it causes a decrease in Rubisco stability and alters Rubisco catalytic properties (Hong 1996). When 72-7JJ mt+ was crossed with the very similar 68-11AR mt- mutant (Gotor et al. 1994), the two genes appeared to be linked (PD=12, NPD=0, T=1), and the 68-11AR/72-7JJ double mutant had a non-temperature-conditional, acetate-requiring phenotype (Hong 1996). When 68-11AR/72-7JJ mt+ was crossed with “wild-type” mt- a similar result was observed (PD=21, NPD=0, T=2). Thus, 68-11AR and 72-7JJ are separated by 4 map units. However, some clones of 72-7JJ have been observed to become acetate-requiring at 25 °C after many years of culture. This strain has been maintained with acetate medium in darkness since its isolation.


Hong S (1996) Nuclear mutations affect the catalysis, stability, and expression of chloroplast ribulose-1,5-bisphosphate carboxylase/oxygenase in Chlamydomonas reinhardtii. Ph. D. thesis, University of Nebraska

Spreitzer RJ, Al-Abed SR, Huether MJ (1988) Temperature-sensitive, photosynthesis-deficient mutants of Chlamydomonas reinhardtii. Plant Physiol 86:773-777

Gotor C, Hong S, Spreitzer RJ (1994) Temperature-conditional nuclear mutation of Chlamydomonas reinhardtii decreases the CO2/O2 specificity of chloroplast ribulose-bisphosphate carboxylase/oxygenase. Planta 193:313-319

Spreitzer RJ, Ogren WL (1983) Rapid recovery of chloroplast mutations affecting ribulosebisphosphate carboxylase/oxygenase in Chlamydomonas reinhardtii. Proc Natl Acad Sci USA 80:6293-6297

Spreitzer RJ, Thow G, Zhu G, Chen Z, Gotor C, Zhang D, Hong S (1992) Chloroplast and nuclear mutations that affect Rubisco structure and function in Chlamydomonas reinhardtii. Murata N ed Research in Photosynthesis 3:593-600

From Robert J. Spreitzer, University of Nebraska, March 2014

Phenotype: requires acetate at 35 °C, temperature-conditional

The 72-7JJ nuclear mutant was isolated by Spreitzer et al. (1992) by screening a collection of acetate-requiring mutants for lack of complementation with a known Rubisco rbcL mutant. 72-7JJ grows on minimal medium at 25 °C, but dies on minimal medium at 35 °C. The mutant was crossed with pf2 mt- to confirm mendelian inheritance, and this mt- progeny clone was retained for further analysis (Hong 1996). This strain has been maintained with acetate medium in darkness since its isolation.


Hong S (1996) Nuclear mutations affect the catalysis, stability, and expression of chloroplast ribulose-1,5-bisphosphate carboxylase/oxygenase in Chlamydomonas reinhardtii. Ph. D. thesis, University of Nebraska

Spreitzer RJ, Thow G, Zhu G, Chen Z, Gotor C, Zhang D, Hong S (1992) Chloroplast and nuclear mutations that affect Rubisco structure and function in Chlamydomonas reinhardtii. Murata N ed Research in Photosynthesis 3:593-600

From Robert J. Spreitzer, University of Nebraska, March 2014

Phenotype: requires acetate at 35 °C, temperature-conditional

The 72-7JJ nuclear mutant was isolated by Spreitzer et al. (1992) by screening a collection of acetate-requiring mutants for lack of complementation with a known Rubisco rbcL mutant. 72-7JJ grows on minimal medium at 25 °C, but dies on minimal medium at 35 °C. The mutant was crossed with pf2 mt- to confirm mendelian inheritance, and this pf2 mt- progeny clone was retained for further analysis (Hong 1996). This strain has been maintained with acetate medium in darkness since its isolation.


Hong S (1996) Nuclear mutations affect the catalysis, stability, and expression of chloroplast ribulose-1,5-bisphosphate carboxylase/oxygenase in Chlamydomonas reinhardtii. Ph. D. thesis, University of Nebraska

Spreitzer RJ, Thow G, Zhu G, Chen Z, Gotor C, Zhang D, Hong S (1992) Chloroplast and nuclear mutations that affect Rubisco structure and function in Chlamydomonas reinhardtii. Murata N ed Research in Photosynthesis 3:593-600


  • Locus:
  • PF2
  • Chromosome:
  • 11

From Robert J. Spreitzer, University of Nebraska, March 2014

The 70-5Y nuclear mutant was isolated by Spreitzer et al. (1992) by screening a collection of acetate-requiring mutants for lack of complementation with a known Rubisco rbcL mutant (e. g., Spreitzer and Ogren 1983; Spreitzer et al. 1988). 70-5Y grows on minimal medium at 25 °C, but dies on minimal medium at 35 °C. When grown with acetate medium at 35 °C, it has normal whole-chain electron transport and chlorophyll levels, but lacks Rubisco holoenzyme. Purified Rubisco has altered catalytic properties. The 70-5Y mutation is not in the Rubisco rbcS genes, and it is not linked to the 68-11AR and 72-7JJ Rubisco nuclear-mutant genes (Hong 1996). This strain has been maintained with acetate medium in darkness since its isolation.


Hong S (1996) Nuclear mutations affect the catalysis, stability, and expression of chloroplast ribulose-1,5-bisphosphate carboxylase/oxygenase in Chlamydomonas reinhardtii. Ph. D. thesis, University of Nebraska

Spreitzer RJ, Al-Abed SR, Huether MJ (1988) Temperature-sensitive, photosynthesis-deficient mutants of Chlamydomonas reinhardtii. Plant Physiol 86:773-777

Spreitzer RJ, Ogren WL (1983) Rapid recovery of chloroplast mutations affecting ribulosebisphosphate carboxylase/oxygenase in Chlamydomonas reinhardtii. Proc Natl Acad Sci USA 80:6293-6297

Spreitzer RJ, Thow G, Zhu G, Chen Z, Gotor C, Zhang D, Hong S (1992) Chloroplast and nuclear mutations that affect Rubisco structure and function in Chlamydomonas reinhardtii. Murata N ed Research in Photosynthesis 3:593-600

From Robert J. Spreitzer, University of Nebraska, March 2014

Phenotype: requires acetate at 35 °C, temperature-conditional

The 70-5Y nuclear mutant was isolated by Spreitzer et al. (1992) by screening a collection of acetate-requiring mutants for lack of complementation with a known Rubisco rbcL mutant. 70-5Y grows on minimal medium at 25 °C, but dies on minimal medium at 35 °C. The mutant was crossed with pf2 mt- to confirm mendelian inheritance, and this mt+ progeny clone was retained for further analysis (Hong 1996). This strain has been maintained with acetate medium in darkness since its isolation.


Hong S (1996) Nuclear mutations affect the catalysis, stability, and expression of chloroplast ribulose-1,5-bisphosphate carboxylase/oxygenase in Chlamydomonas reinhardtii. Ph. D. thesis, University of Nebraska

Spreitzer RJ, Thow G, Zhu G, Chen Z, Gotor C, Zhang D, Hong S (1992) Chloroplast and nuclear mutations that affect Rubisco structure and function in Chlamydomonas reinhardtii. Murata N ed Research in Photosynthesis 3:593-600

From Robert J. Spreitzer, University of Nebraska, March 2014

Phenotype: requires acetate at 35 °C, temperature-conditional

The 70-5Y nuclear mutant was isolated by Spreitzer et al. (1992) by screening a collection of acetate-requiring mutants for lack of complementation with a known Rubisco rbcL mutant. 70-5Y grows on minimal medium at 25 °C, but dies on minimal medium at 35 °C. The mutant was crossed with pf2 mt- to confirm mendelian inheritance, and this mt- progeny clone was retained for further analysis (Hong 1996). This strain has been maintained with acetate medium in darkness since its isolation.


Hong S (1996) Nuclear mutations affect the catalysis, stability, and expression of chloroplast ribulose-1,5-bisphosphate carboxylase/oxygenase in Chlamydomonas reinhardtii. Ph. D. thesis, University of Nebraska

Spreitzer RJ, Thow G, Zhu G, Chen Z, Gotor C, Zhang D, Hong S (1992) Chloroplast and nuclear mutations that affect Rubisco structure and function in Chlamydomonas reinhardtii. Murata N ed Research in Photosynthesis 3:593-600

From Robert J. Spreitzer, University of Nebraska, March 2014

Phenotype: requires acetate at 35 °C, temperature-conditional

The 70-5Y nuclear mutant was isolated by Spreitzer et al. (1992) by screening a collection of acetate-requiring mutants for lack of complementation with a known Rubisco rbcL mutant. 70-5Y grows on minimal medium at 25 °C, but dies on minimal medium at 35 °C. The mutant was crossed with pf2 mt- to confirm mendelian inheritance, and this pf2 mt- progeny clone was retained for further analysis (Hong 1996). This strain has been maintained with acetate medium in darkness since its isolation.


Hong S (1996) Nuclear mutations affect the catalysis, stability, and expression of chloroplast ribulose-1,5-bisphosphate carboxylase/oxygenase in Chlamydomonas reinhardtii. Ph. D. thesis, University of Nebraska

Spreitzer RJ, Thow G, Zhu G, Chen Z, Gotor C, Zhang D, Hong S (1992) Chloroplast and nuclear mutations that affect Rubisco structure and function in Chlamydomonas reinhardtii. Murata N ed Research in Photosynthesis 3:593-600


  • Locus:
  • PF2
  • Chromosome:
  • 11

From Robert J. Spreitzer, University of Nebraska, March 2014

Phenotype: requires acetate

Mutant F-60 was originally isolated as a photosynthesis-deficient strain that lacked phosphoribulokinase activity and protein (Bennoun and Levine 1967; Moll and Levine 1970; Roesler et al. 1992). Spreitzer received this F-60 mt- strain from Bob Togasaki in the late 1970s. The strain has been maintained with acetate medium in darkness since then, and has been cloned several times. Bryan D. Smith in Spreitzer’s group cloned and completely sequenced the prk1 gene from wild-type 2137 mt+ (GenBank: AF228914.1). When the prk1 gene of F-60 mt- was sequenced, an E267Amber (GAG-TAG) nonsense mutation was discovered (Smith 2000).


Bennoun P, Levine RP (1967) Detecting mutants that have impaired photosynthesis by their increased level of fluorescence. Plant Physiol 42:1284-1287

Moll B, Levine R (1970) Characterization of a photosynthetic mutant strain of Chlamydomonas reinhardtii deficient in phosphoribulokinase activity. Plant Physiol 46:576-580

Smith BD (2000) Isolation and analysis of Chlamydomonas reinhardtii phosphoribulokinase mutants and revertants. Undergraduate Honors Thesis, Department of Biochemistry, University of Nebraska (available from the Chlamydomonas Resource Center)


  • Locus:
  • AC214 [PRK1]
  • Chromosome:
  • 12

From Robert J. Spreitzer, University of Nebraska, March 2014

Phenotype: requires acetate, sensitive to light

This strain was recovered from a cross between the original 12-2B mt+ isolate (CC-1227) and pf2 mt-. It has been maintained on acetate medium in darkness since its isolation, and was used for the selection of photosynthesis-competent revertants by Bryan D. Smith in Spreitzer’s group (Smith 2000). The 12-2B mutant was recovered as a light-sensitive, acetate-requiring mutant (Spreitzer and Mets 1981), and was subsequently found to lack phosphoribulokinase activity (Salvucci and Ogren 1985) due to a missense mutation (R64C; CGC-TGC) in the prk1 gene (Roesler et al. 1992).


Roesler K, Marcotte B, Ogren W (1992) Functional importance of arginine 64 in Chlamydomonas reinhardtii phosphoribulokinase. Plant Physiol 98:1285-1289

Salvucci M, Ogren W (1985) A Chlamydomonas reinhardtii mutant with catalytically and structurally altered ribulose-5-phosphate kinase. Planta 165:340-347

Smith BD (2000) Isolation and analysis of Chlamydomonas reinhardtii phosphoribulokinase mutants and revertants. Undergraduate Honors Thesis, Department of Biochemistry, University of Nebraska (available from the Chlamydomonas Resource Center)

Spreitzer RJ, Mets L (1981) Photosynthesis-deficient mutants of Chlamydomonas reinhardtii with associated light-sensitive phenotypes. Plant Physiol 67:565-569


  • Locus:
  • AC214 [PRK1]
  • Chromosome:
  • 12

From Robert J. Spreitzer, University of Nebraska, March 2014

Phenotype: requires acetate, sensitive to light

This strain was recovered from a cross between the original 12-2B mt+ isolate (CC-1227) and pf2 mt-. It has been maintained on acetate medium in darkness since its isolation, and was used to screen for additional prk1 mutants by Bryan D. Smith in Spreitzer’s group (Smith 2000).. The 12-2B mutant was recovered as a light-sensitive, acetate-requiring mutant (Spreitzer and Mets 1981), and was subsequently found to lack phosphoribulokinase activity (Salvucci and Ogren 1985) due to a missense mutation (R64C; CGC-TGC) in the prk1 gene (Roesler et al. 1992).


Roesler K, Marcotte B, Ogren W (1992) Functional importance of arginine 64 in Chlamydomonas reinhardtii phosphoribulokinase. Plant Physiol 98:1285-1289

Salvucci M, Ogren W (1985) A Chlamydomonas reinhardtii mutant with catalytically and structurally altered ribulose-5-phosphate kinase. Planta 165:340-347

Smith BD (2000) Isolation and analysis of Chlamydomonas reinhardtii phosphoribulokinase mutants and revertants. Undergraduate Honors Thesis, Department of Biochemistry, University of Nebraska (available from the Chlamydomonas Resource Center)

Spreitzer RJ, Mets L (1981) Photosynthesis-deficient mutants of Chlamydomonas reinhardtii with associated light-sensitive phenotypes. Plant Physiol 67:565-569


  • Locus:
  • AC214 [PRK1]
  • Chromosome:
  • 12

From Robert J. Spreitzer, University of Nebraska, March 2014

Phenotype: requires acetate, sensitive to light

This strain was recovered from a cross between the original 12-2B mt+ isolate (CC-1227) and pf2 mt-. It has been maintained on acetate medium in darkness since its isolation. The 12-2B mutant was recovered as a light-sensitive, acetate-requiring mutant (Spreitzer and Mets 1981), and was subsequently found to lack phosphoribulokinase activity (Salvucci and Ogren 1985) due to a missense mutation (R64C; CGC-TGC) in the prk1 gene (Roesler et al. 1992).


Roesler K, Marcotte B, Ogren W (1992) Functional importance of arginine 64 in Chlamydomonas reinhardtii phosphoribulokinase. Plant Physiol 98:1285-1289

Salvucci M, Ogren W (1985) A Chlamydomonas reinhardtii mutant with catalytically and structurally altered ribulose-5-phosphate kinase. Planta 165:340-347

Spreitzer RJ, Mets L (1981) Photosynthesis-deficient mutants of Chlamydomonas reinhardtii with associated light-sensitive phenotypes. Plant Physiol 67:565-569


  • Locus:
  • AC214 [PRK1], PF2
  • Chromosome:
  • 12,11

From Robert J. Spreitzer, University of Nebraska, March 2014

Phenotype: requires acetate, sensitive to light

This strain was recovered from a cross between the original 12-2B mt+ isolate (CC-1227) and pf2 mt-. It has been maintained on acetate medium in darkness since its isolation. The 12-2B mutant was recovered as a light-sensitive, acetate-requiring mutant (Spreitzer and Mets 1981), and was subsequently found to lack phosphoribulokinase activity (Salvucci and Ogren 1985) due to a missense mutation (R64C; CGC-TGC) in the prk1 gene (Roesler et al. 1992).


Roesler K, Marcotte B, Ogren W (1992) Functional importance of arginine 64 in Chlamydomonas reinhardtii phosphoribulokinase. Plant Physiol 98:1285-1289

Salvucci M, Ogren W (1985) A Chlamydomonas reinhardtii mutant with catalytically and structurally altered ribulose-5-phosphate kinase. Planta 165:340-347

Spreitzer RJ, Mets L (1981) Photosynthesis-deficient mutants of Chlamydomonas reinhardtii with associated light-sensitive phenotypes. Plant Physiol 67:565-569


  • Locus:
  • AC214 [PRK1], PF2
  • Chromosome:
  • 12,11

From Robert J. Spreitzer, University of Nebraska, March 2014

Phenotype: requires acetate, sensitive to light

A collection of over 350 acetate-requiring mutants (Spreitzer et al. 1988) was screened for complementation (Spreitzer and Ogren 1983) with the prk1-R64C mt- strain (12-2B mt-) (Smith 2000). Mutant 69-2P failed to complement, and lacked phosphoribulokinase activity and protein. Bryan D. Smith in Spreitzer’s group sequenced prk1, and discovered that 69-2P results from a 50-bp deletion (nucleotides 1296 through 1345 relative to the first nucleotide encoding the start codon; GenBank: AF228914.1) (Smith 2000). This strain has been maintained with acetate medium in darkness since its isolation.


Spreitzer RJ, Al-Abed SR, Huether MJ (1988) Temperature-sensitive, photosynthesis-deficient mutants of Chlamydomonas reinhardtii. Plant Physiol 86:773-777

Spreitzer RJ, Ogren WL (1983) Rapid recovery of chloroplast mutations affecting ribulosebisphosphate carboxylase/oxygenase in Chlamydomonas reinhardtii. Proc Natl Acad Sci USA 80:6293-6297

Smith BD (2000) Isolation and analysis of Chlamydomonas reinhardtii phosphoribulokinase mutants and revertants. Undergraduate Honors Thesis, Department of Biochemistry, University of Nebraska (available from the Chlamydomonas Resource Center)


  • Locus:
  • AC214 [PRK1]
  • Chromosome:
  • 12

From Robert J. Spreitzer, University of Nebraska, March 2014

Phenotype: requires acetate, sensitive to light

This strain was recovered from a cross between prk1-Δ50 mt+ and pf2 mt-. It lacks phosphoribulokinase activity and protein due to a 50-bp deletion in prk1 (Smith 2000). This strain has been maintained with acetate medium in darkness since its isolation.


Smith BD (2000) Isolation and analysis of Chlamydomonas reinhardtii phosphoribulokinase mutants and revertants. Undergraduate Honors Thesis, Department of Biochemistry, University of Nebraska


  • Locus:
  • AC214 [PRK1]
  • Chromosome:
  • 12