A Novel Suppressor of Cell Death in Plants Encoded by the Lls1 Gene of Maize

Gray, John C.; Close, Pam S.; Briggs, Steven P.; Johal, Gurmukh S.

doi:10.1016/s0092-8674(00)80179-8

Cited by 247 publications

(167 citation statements)

References 38 publications

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“…It is interesting to notice that spc1-1 has a lower level of chlorophylls a and b, which appears to be correlated to the reduced expression of PORB and CAO. The impaired chlorophyll metabolism and abnormal chloroplast development have been attributed as an important mechanism to trigger spontaneous cell death in a number of mutants, including Arabidopsis-accelerated cell death2 (acd2) [63,64], acd1 [65][66][67] and maize lethal leaf spot-1 (lls1) [68,69]. ACD1 and LLS1 are believed to be ortholog genes in Arabidopsis and maize [65,66,69].…”

Section: Discussionmentioning

confidence: 99%

The Arabidopsis Spontaneous Cell Death1 gene, encoding a ζ-carotene desaturase essential for carotenoid biosynthesis, is involved in chloroplast development, photoprotection and retrograde signalling

et al. 2007

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Carotenoids, a class of natural pigments found in all photosynthetic organisms, are involved in a variety of physiological processes, including coloration, photoprotection, biosynthesis of abscisic acid (ABA) and chloroplast biogenesis. Although carotenoid biosynthesis has been well studied biochemically, the genetic basis of the pathway is not well understood. Here, we report the characterization of two allelic Arabidopsis mutants, spontaneous cell death1-1 (spc1-1) and spc1-2. The weak allele spc1-1 mutant showed characteristics of bleached leaves, accumulation of superoxide and mosaic cell death. The strong mutant allele spc1-2 caused a complete arrest of plant growth and development shortly after germination, leading to a seedling-lethal phenotype. Genetic and molecular analyses indicated that SPC1 encodes a putative z-carotene desaturase (ZDS) in the carotenoid biosynthesis pathway. Analysis of carotenoids revealed that several major carotenoid compounds downstream of SPC1/ZDS were substantially reduced in spc1-1, suggesting that SPC1 is a functional ZDS. Consistent with the downregulated expression of CAO and PORB, the chlorophyll content was decreased in spc1-1 plants. In addition, expression of Lhcb1.1, Lhcb1.4 and RbcS was absent in spc1-2, suggesting the possible involvement of carotenoids in the plastid-to-nucleus retrograde signaling. The spc1-1 mutant also displays an ABA-deficient phenotype that can be partially rescued by the externally supplied phytohormone. These results suggest that SPC1/ZDS is essential for biosynthesis of carotenoids and plays a crucial role in plant growth and development.

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Section: Discussionmentioning

confidence: 99%

The Arabidopsis Spontaneous Cell Death1 gene, encoding a ζ-carotene desaturase essential for carotenoid biosynthesis, is involved in chloroplast development, photoprotection and retrograde signalling

et al. 2007

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“…In 2003, two groups succeeded in identifying Arabidopsis PAO at the molecular level (Pružinská et al 2003;Tanaka et al 2003). PAO is identical to ACCELERATED CELL DEATH (ACD) 1 (Greenberg and Ausubel 1993) and the ortholog of LETHAL LEAF SPOT 1 in maize (Gray et al 1997). The absence of PAO in mutants or antisense lines from different plant species results in premature cell death (Gray et al 2002;Pružinská et al 2003Pružinská et al , 2005Greenberg and Ausubel 1993;Tanaka et al 2003;Spassieva and Hille 2002).…”

Section: Mg-dechelation and Dephytylationmentioning

confidence: 99%

Update on the biochemistry of chlorophyll breakdown

2012

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In land plants, chlorophyll is broken down to colorless linear tetrapyrroles in a highly conserved multi-step pathway. The pathway is termed the 'PAO pathway', because the opening of the chlorine macrocycle present in chlorophyll catalyzed by pheophorbide a oxygenase (PAO), the key enzyme of the pathway, provides the characteristic structural basis found in all further downstream chlorophyll breakdown products. To date, most of the biochemical steps of the PAO pathway have been elucidated and genes encoding many of the chlorophyll catabolic enzymes been identified. This review summarizes the current knowledge on the biochemistry of the PAO pathway and provides insight into recent progress made in the field that indicates that the pathway is more complex than thought in the past. Abstract In land plants, chlorophyll is broken down to colorless linear tetrapyrroles in a highly conserved multistep pathway. The pathway is termed the 'PAO pathway', because the opening of the chlorine macrocycle present in chlorophyll catalyzed by pheophorbide a oxygenase (PAO), the key enzyme of the pathway, provides the characteristic structural basis found in all further downstream chlorophyll breakdown products. To date, most of the biochemical steps of the PAO pathway have been elucidated and genes encoding many of the chlorophyll catabolic enzymes been identified. This review summarizes the current knowledge on the biochemistry of the PAO pathway and provides insight into recent progress made in the field that indicates that the pathway is more complex than thought in the past.

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“…3). Whereas Lls1 was proposed to operate as a suppressor of cell death in plants (37), Tic55 has been identified as part of the Tic complex (38). Cao, by contrast, is implicated in chlorophyllide b synthesis (40,41).…”

Section: The Ptc Complex Contains Pchlide and A Putative Pchlide A Oxmentioning

confidence: 99%

Identification of plastid envelope proteins required for import of protochlorophyllide oxidoreductase A into the chloroplast of barley

Reinbothe

Quigley

Gray

et al. 2004

Proc. Natl. Acad. Sci. U.S.A.

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Chloroplasts synthesize an abundance of different tetrapyrrole compounds. Among them are chlorophyll and its precursor protochlorophyllide (Pchlide), which accumulate in light-and dark-grown plants, respectively. Pchlide is converted to chlorophyllide by virtue of the NADPH:Pchlide oxidoreductase (POR), which, in angiosperms, is the only known light-dependent enzyme of the chlorophyll biosynthetic pathway. In etiolated barley plants, two closely related POR proteins exist termed PORA and PORB, which are nuclear gene products. Here we identified plastid envelope proteins that interact with the cytosolic PORA precursor (pPORA) during its posttranslational chloroplast import. We demonstrate that pPORA interacts with several previously unreported components. Among them is a Pchlide a oxygenase, which provides Pchlide b as import substrate for pPORA, and a tyrosine aminotransferase thought to be involved in the synthesis of photoprotective vitamin E. Two other constituents were found to be orthologs of the GTP-binding proteins Toc33͞34 and of the outer plastid envelope protein Oep16.

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A Novel Suppressor of Cell Death in Plants Encoded by the Lls1 Gene of Maize

Cited by 247 publications

References 38 publications

The Arabidopsis Spontaneous Cell Death1 gene, encoding a ζ-carotene desaturase essential for carotenoid biosynthesis, is involved in chloroplast development, photoprotection and retrograde signalling

The Arabidopsis Spontaneous Cell Death1 gene, encoding a ζ-carotene desaturase essential for carotenoid biosynthesis, is involved in chloroplast development, photoprotection and retrograde signalling

Update on the biochemistry of chlorophyll breakdown

Identification of plastid envelope proteins required for import of protochlorophyllide oxidoreductase A into the chloroplast of barley

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