Genetic analysis of two new mutations resulting in herbicide resistance in the cyanobacterium Synechococcus sp. PCC 7002

Gingrich, Jeffrey C.; Buzby, Jeffrey S.; Stirewalt, Veronica L.; Bryant, Donald A.

doi:10.1007/978-94-009-2269-3_16

Cited by 21 publications

(27 citation statements)

References 41 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…As expected, Western blot analysis of thylakoid membranes from cells cultured under high light showed more form II and less form I of Dl, compared with analysis of membranes from cells cultured under low light (20a). As PPFD decreased from 482 ,uE-m2 s-' to 5 ,uE m-2 s, the relative amount of form I increased 58% while the relative amount of form II decreased 60%. These data suggest that form II of Dl may provide a unique functional role in photosystem II under conditions of high light.…”

Section: (2)mentioning

confidence: 92%

Differential expression of members of a cyanobacterial psbA gene family in response to light

1989

View full text Add to dashboard Cite

The genome of the cyanobacterium Synechococcus sp. strain PCC 7942 contains three psbA genes encoding two forms of the Dl protein: form I, the product of psbAI, differs from form II, the product of both psbAII and psbAIII, at 25 of 360 residues. DI is essential for photosynthesis as a core component of the photosystem II reaction center. Translational gene fusions between each of the Synechococcus psbA genes and the Escherichia coli lacZ gene were inserted into the chromosome of wild-type Synechococcus sp. at the respective psbA loci to serve as in vivo reporters of psbA expression. ji-Galactosidase activities indicated differential expression of the psbA-lacZ gene fusions related to light availability. Expression of psbAI was 500-fold greater than expression of psbAII and 50-fold greater than psbAIII under similar conditions. As light intensity decreased from 600 ,uE-m2 s'-to 2 ,uE. m-2 s , expression of the psbAI reporter increased eightfold while expression of the psbAlI and psbAIII reporters decreased 10-fold, suggesting differential production of the two forms of Dl in photosystem II in response to light availability. Relative levels of psbA-1acZ fusion transcripts directly reflected I-galactosidase activities in the transformants, although the fusion transcripts were less stable than native psbA messages.

show abstract

Section: (2)mentioning

confidence: 92%

Differential expression of members of a cyanobacterial psbA gene family in response to light

1989

View full text Add to dashboard Cite

show abstract

“…Thus, it is thought to play a role in protection of PSII against photoinhibition and may be designed to be removed and replaced as fast as possible (35). Light (5,12,14,20), whereas Anabaena sp. strain PCC 7120 has four psbA genes (42).…”

mentioning

confidence: 99%

Adaptation to high light intensity in Synechococcus sp. strain PCC 7942: regulation of three psbA genes and two forms of the D1 protein

1994

View full text Add to dashboard Cite

The three psbA genes in the cyanobacterium Synechococcus sp. strain PCC 7942 encode two distinct forms of the DI protein of photosystem II. ThepsbAI message, which encodes form I, dominates the psbA transcript pool at low to moderate light intensities; however, exposure to high light triggers a response in which the psbAI message is actively degraded while psbAII and psbAIII, which encode form II, are transcriptionally induced. We addressed whether these changes result from a generalized stress response and examined the consequence of light-responsive psbA regulation on the composition of DI in thylakoid membranes. Heat shock and oxidative stress had some effect on levels of the three psbA transcripts but did not produce the responses generated by an increase in light intensity. Prolonged exposure to high light (24-h time course) was characterized by elevated levels of all psbA transcripts through maintenance of high levels ofpsbAII and psbAIII messages and a rebound of the psbAI transcript after its initial decline. Form II-encoding transcripts were enriched relative to those encoding form I at all high-light time points. Form II replaced form I in the thylakoid membrane at high light despite an abundance of psbAI transcript at later time points; this may be explained by the observed faster turnover of form I than form II in the membrane. We propose that form II is less susceptible to damage at high light and that this qualitative alteration, coupled with increased turnover of Dl, protects the cells from photoinhibition.Photosystem II (PSII) is a membrane-embedded proteinpigment complex involved in key reactions of oxygenic photosynthesis: charge separation in response to excitation of a chlorophyll molecule by light and by oxygen evolution. This mode of photosynthesis, which requires two photosystems (PSII and photosystem I), is conserved in cyanobacteria, algae, and higher plants. The reaction center of PSII contains two structurally similar proteins, Dl and D2, which harbor the photoreactants involved in the primary reactions. Dl and D2, along with cytochrome b559 and the 4.8-kDapsbI gene product, form the core of the PSII reaction center (16,31,33).Light intensity modulates the composition of thylakoid membranes in plants as well as in cyanobacteria to best use the available light (2,3,30). This involves variation in the relative proportions of light-harvesting pigments, PSII and photosystem I reaction centers, electron carriers, and ATP synthase (2). On exposure to light intensities in excess of those found in optimal growth conditions, a decline in photosynthetic capacity, i.e., oxygen evolution and CO2 fixation, which is termed photoinhibition, occurs. The Dl protein is believed to be the initial site of photoinhibition, with its damage reflected in the loss of PSII activity (26,35). The DI protein of plants is rapidly turned over in the light, with the rate being proportional to light intensity. Thus, it is thought to play a role in protection of PSII against photoinhibition and may be designed to be re...

show abstract

“…strain PCC 7942 (26,42), and Synechococcus sp. strain PCC 7002 (4,6,17), have been used in these investigations. Ancient cyanobacteria have been suggested to be the progenitors of higher plant chloroplasts (18).…”

mentioning

confidence: 99%

“…Synechococcus sp. strain PCC 7002 (3,17) and Synechocystis sp. strain PCC 6803 (24) possess three psbA genes, whereas Anabaena sp.…”

mentioning

confidence: 99%

Physical and genetic map of the chromosome of the unicellular cyanobacterium Synechocystis sp. strain PCC 6803

et al. 1995

View full text Add to dashboard Cite

A combined physical and genetic map of the cyanobacterium Synechocystis sp. strain PCC 6803 chromosome was constructed. An estimated genome size of 3.82 Mb was obtained by summing the sizes of 25 MluI or 40 NotI fragments seen by pulsed-field electrophoresis. The order of the restriction fragments was determined by using two independent experimental approaches: pulsed-field fragment hybridization and linking clone analysis. The relative positions of 30 known genes or gene clusters were localized.

show abstract

Genetic analysis of two new mutations resulting in herbicide resistance in the cyanobacterium Synechococcus sp. PCC 7002

Cited by 21 publications

References 41 publications

Differential expression of members of a cyanobacterial psbA gene family in response to light

Differential expression of members of a cyanobacterial psbA gene family in response to light

Adaptation to high light intensity in Synechococcus sp. strain PCC 7942: regulation of three psbA genes and two forms of the D1 protein

Physical and genetic map of the chromosome of the unicellular cyanobacterium Synechocystis sp. strain PCC 6803

Contact Info

Product

Resources

About