The Divergent Roles of STAYGREEN (SGR) Homologs in Chlorophyll Degradation
نویسندگان
چکیده
Degradation of chlorophyll (Chl) by Chl catabolic enzymes (CCEs) causes the loss of green color that typically occurs during senescence of leaves. In addition to CCEs, staygreen1 (SGR1) functions as a key regulator of Chl degradation. Although sgr1 mutants in many plant species exhibit a stay-green phenotype, the biochemical function of the SGR1 protein remains elusive. Many recent studies have examined the physiological and molecular roles of SGR1 and its homologs (SGR2 and SGR-LIKE) in Chl metabolism, finding that these proteins have different roles in different species. In this review, we summarize the recent studies on SGR and discuss the most likely functions of SGR homologs.
منابع مشابه
The senescence-induced staygreen protein regulates chlorophyll degradation.
Loss of green color in leaves results from chlorophyll (Chl) degradation in chloroplasts, but little is known about how Chl catabolism is regulated throughout leaf development. Using the staygreen (sgr) mutant in rice (Oryza sativa), which maintains greenness during leaf senescence, we identified Sgr, a senescence-associated gene encoding a novel chloroplast protein. Transgenic rice overexpress...
متن کاملAccumulation of chlorophyll catabolites photosensitizes the hypersensitive response elicited by Pseudomonas syringae in Arabidopsis.
• The staygreen (SGR) gene encodes a chloroplast-targeted protein which promotes chlorophyll degradation via disruption of light-harvesting complexes (LHCs). • Over-expression of SGR in Arabidopsis (SGR-OX) in a Columbia-0 (Col-0) background caused spontaneous necrotic flecking. To relate this to the hypersensitive response (HR), Col-0, SGR-OX and RNAi SGR (SGRi) lines were challenged with Pseu...
متن کاملAmino acid substitutions in homologs of the STAY-GREEN protein are responsible for the green-flesh and chlorophyll retainer mutations of tomato and pepper.
Color changes often accompany the onset of ripening, leading to brightly colored fruits that serve as attractants to seed-dispersing organisms. In many fruits, including tomato (Solanum lycopersicum) and pepper (Capsicum annuum), there is a sharp decrease in chlorophyll content and a concomitant increase in the synthesis of carotenoids as a result of the conversion of chloroplasts into chromopl...
متن کاملMendel's green cotyledon gene encodes a positive regulator of the chlorophyll-degrading pathway.
Mutants that retain greenness of leaves during senescence are known as "stay-green" mutants. The most famous stay-green mutant is Mendel's green cotyledon pea, one of the mutants used in determining the law of genetics. Pea plants homozygous for this recessive mutation (known as i at present) retain greenness of the cotyledon during seed maturation and of leaves during senescence. We found tigh...
متن کاملSTAY-GREEN and chlorophyll catabolic enzymes interact at light-harvesting complex II for chlorophyll detoxification during leaf senescence in Arabidopsis.
During leaf senescence, plants degrade chlorophyll to colorless linear tetrapyrroles that are stored in the vacuole of senescing cells. The early steps of chlorophyll breakdown occur in plastids. To date, five chlorophyll catabolic enzymes (CCEs), NONYELLOW COLORING1 (NYC1), NYC1-LIKE, pheophytinase, pheophorbide a oxygenase (PAO), and red chlorophyll catabolite reductase, have been identified;...
متن کامل