Catabolism of chlorophyll <i>in vivo</i>: significance of polar chlorophyll catabolites in a non‐yellowing senescence mutant of <i>Festuca pratensis</i> Huds.

Thomas, Howard; Bortlik, Karlheinz; Rentsch, Doris; Schellenberg, Maya; Matile, Philippe

doi:10.1111/j.1469-8137.1989.tb04211.x

Cited by 70 publications

(35 citation statements)

References 23 publications

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“…In the normal, yellowing genot\-pe, LHCII has a similar liability to rubisco, but degradation of the protein was greatly reduced in tbe stay-green mutant. The light-harvesting complex of photosystem II is the major chlorophyll-binding membrane structure, and studies of its assembly and breakdown have revealed that pigments and apoproteins are mutually essential for survival of the holocomplex in vivo (Terao, Matsuoka & Katoh, 1988;Thomas et al, 1989). Not unexpectedly, therefore, chlorophyll and LHCII levels are usually highly correlated (Mae et al, 1993) and senescent leaf tissue of stay-green Phaseolus is no exception.…”

Section: Proteins During Senescence Of Stay-green and Normally Yellowmentioning

confidence: 99%

Stay‐green genotypes of Phaseolus vulgaris L.: chloroplast proteins and chlorophyll catabolites during foliar senescence

et al. 1994

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SUMMARYLeaf senescetYce was analyzed in stay-green mutants of Phaseolus vulgaris. Impaired yellowing in these genotypes was accompanied by abnormal retention of tbylakoid membrane proteins including tbe ligbt-bar\'esting cblorophyll-binding protein of photosystem II, tbe 33 kDa polypeptide of tbe oxygen-evolving complex, cytocbrome/ and tbe psaF protein of pbotosystem I. On tbe other band, ribulose bispbospbate carboxylase was somewbat more labile in tbe mutant than tbe wild-type. Tbe stay-green cbaracter was not associated with unusual persistence of cbloropbyll biosynthesis etizymes. During senescence, normal leaf tissue accunnulated an array of fluorescent (FCC) and non-fluorescent (NCC) compounds witb cbromatograpbic and spectropbotometric properties similar to tbose of cbloropbyll catabolites previously identified in otber species. Witb the exception of one prominent NCC and a trace of one FCC, tbese constituents were absent from extracts of stay-green genotypes, strongly supporting tbe proposal tbat tbey are indeed products of cbloropbyll breakdown. Tbe kinetics of tbeir accumulation during senescence was consistent witb a primary or intermediary role for FCCs in tbe catabolic pathway wbereas NCCs seem to be final products. Tbe complement of FCCs and NCCs in Phaseolus vulgaris was as distinct from that of tbe previously-studied species barley and rape as tbe latter are from each otber. Genotj'pic and interspecific variations in tbe biochemistry of senescence are discussed in relation to genetic regulation of tbe process.

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Section: Proteins During Senescence Of Stay-green and Normally Yellowmentioning

confidence: 99%

Stay‐green genotypes of Phaseolus vulgaris L.: chloroplast proteins and chlorophyll catabolites during foliar senescence

et al. 1994

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“…The first step is dephytylation to give chlorophyllides and phaeophorbides. The intact tetrapyrrole ring system of chlorophyllide has been shown to be still associated with LHCP-2 (26). An ATP dependent opening of the macrocycle follows (M Schellenberg, Ph Matile, H Thomas, unpublished data).…”

Section: Discussionmentioning

confidence: 96%

“…The nongreen ultimate catabolites of Chl are absent from senescent leaves of Bf993 (14). The pattern of accumulation of intermediates in the degradative sequence points strongly to the ring-opening reaction as the site of the metabolic lesion in the nonyellowing mutant (26).…”

Section: Discussionmentioning

confidence: 98%

Leaf Senescence in a Nonyellowing Mutant of Festuca pratensis

Davies¹,

Thomas²,

Thomas³

et al. 1990

Plant Physiol.

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In a mutant genotype of Festuca pratensis Huds., net degradation of a number of thylakoid membrane proteins during senescence is impaired. Previous studies have suggested that the highly hydrophobic intrinsic chlorophyll-binding proteins were the definitive subjects of the metabolic lesion. In the present study we find that cytochrome f, as determined by haem-staining, Western blotting, enzyme-linked immunosorbent assay, and immunogold electron microscopy, is also abnormally stable in the mutant. The structural feature common to all the proteins in the mutant so far recognized to be abnormally stable is possession of a tetrapyrrole prosthetic group. It is suggested that degradation of chlorophyll and haem may regulate degradation of the associated apoproteins, and hence has an important role to play in membrane protein turnover and in mobilisation of amino acids during chloroplast disassembly.In most graminaceous species, each leaf has only a limited life span. During vegetative growth the older leaves at the base tend to senesce as the shoot extends. One of the most striking changes seen in senescing leaves is the appearance of a yellow coloration as Chl is degraded. A mutant of Festuca pratensis exists in which the syndrome of leaf senescence is no longer accompanied by Chl breakdown (25). The nonyellowing character is associated with a marked structural stability of thylakoids during senescence. The mutant genotype therefore presents a unique opportunity to study the processes responsible for the degradation of chloroplast membranes. Previous investigations have focused on the proteins ofPSII ( 11). Intrinsic components such as the nuclear-encoded LHCP-22 and the chloroplast-encoded Dl protein were found to be retained by the mutant during senescence of detached leaves. By contrast, PSII proteins extrinsic to the membrane, such as the 33-kD

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“…The dU2 and cyt-GI mutations may directly influence the turnover of the LHCBs. Alternatively, these mutations may indirectly influence LHCB accumulation by altering the turnover of nonprotein components of the thylakoid membranes; a similar model was proposed for the sid mutation in Festuca (Thomas et al, 1989;Nock et al, 1992).…”

Section: Discussionmentioning

confidence: 99%

The Impact of Chlorophyll-Retention Mutations, d1d2 and cyt-G1, during Embryogeny in Soybean

et al. 1995

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The ultrastructural, physiological, and molecular changes in developing and mature seeds were monitored in a control line (Glycine max [LI Merr., cv Clark) that exhibited seed degreening and two mutant lines (dld2 and cyt-C1) that retained chlorophyll upon seed maturation. Ultrastructural studies showed that the control line had no interna1 membranes, whereas stacked thylakoid membranes were detected in the green seed from the mutant lines. Pigment analyses indicated that total chlorophyll was lowest in the mature seeds of the control line. Mature dld2 and cyt-Cl seed had elevated Chl a and Chl b levels, respectively. In both control and mutant lines, Lhcbl, Lhcb2, and RbcS mRNAs were abundant in embryos prior to cotyledon filling, declined after the onset of storage protein accumulation, and were barely detectable or undetectable in all later stages of seed development. Therefore, the chlorophyll-retention phenotype must be a result of the alteration of a process that occurs after translation of photosynthesis-related mRNAs to stabilize apoprotein and pigment levels. Furthermore, different elements controlling either the synthesis or turnover of Chl a and Chl b must be impaired in the dld2 and cyt-C1 lines. N o reproducible differences in total leaf, embryonic, and chloroplast protein profiles and plastid DNAs could be correlated with the mutations that induced chlorophyll retention.

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Catabolism of chlorophyll in vivo: significance of polar chlorophyll catabolites in a non‐yellowing senescence mutant of Festuca pratensis Huds.

Cited by 70 publications

References 23 publications

Stay‐green genotypes of Phaseolus vulgaris L.: chloroplast proteins and chlorophyll catabolites during foliar senescence

Stay‐green genotypes of Phaseolus vulgaris L.: chloroplast proteins and chlorophyll catabolites during foliar senescence

Leaf Senescence in a Nonyellowing Mutant of Festuca pratensis

The Impact of Chlorophyll-Retention Mutations, d1d2 and cyt-G1, during Embryogeny in Soybean

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