Transgenic broccoli (Brassica oleracea var. italica) with antisense chlorophyllase (BoCLH1) delays postharvest yellowing

Chen, Long-Fang O.; Lin, Chin-Hong; Kelkar, S. M.; Chang, Yu-Ming; Shaw, Jei‐Fu

doi:10.1016/j.plantsci.2007.09.006

Cited by 55 publications

(37 citation statements)

References 30 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…In agreement with this, chlorophyllase, which hydrolyzes phytol from Chl, was believed to be active during senescence-related Chl breakdown (Takamiya et al 2000). Chlorophyllase genes (CLH) were cloned from different species including Arabidopsis and in all cases chlorophyllase activity could indeed be demonstrated with the recombinant enzymes (Tsuchiya et al 1999;JakobWilk et al 1999;Arkus et al 2005;Tang et al 2004;Chen et al 2008). Some of the cloned CLHs were predicted to localize outside the chloroplast, i.e.…”

Section: Mg-dechelation and Dephytylationmentioning

confidence: 86%

Update on the biochemistry of chlorophyll breakdown

2012

View full text Add to dashboard Cite

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.

show abstract

Section: Mg-dechelation and Dephytylationmentioning

confidence: 86%

Update on the biochemistry of chlorophyll breakdown

2012

View full text Add to dashboard Cite

show abstract

“…From these observations, we infer that CLD1 catalyzes a dephytylation reaction functionally distinct from that catalyzed by CLH. CLH was shown to be involved in chlorophyll breakdown in postharvest citrus fruits and broccoli (Brassica oleracea var italica) florets (Azoulay Shemer et al, 2008;Chen et al, 2008) but not in senescent leaves and maturing seeds of Arabidopsis Zhang et al, 2014). The exact role of CLH in chlorophyll catabolism remains controversial, but it was shown to function in defense against pathogens and herbivores, which may disrupt the integrity of chloroplasts and render accessibility of chlorophyll to CLH (Kariola et al, 2005;Hu et al, 2015).…”

Section: Cld1 Is a "Chlorophyllase" Distinct From Clhmentioning

confidence: 99%

Identification of a Chlorophyll Dephytylase Involved in Chlorophyll Turnover in Arabidopsis

Lin

Charng

2016

Plant Cell

View full text Add to dashboard Cite

Chlorophyll turns over in green organs during photosystem repair and is salvaged via de-and rephytylation, but the enzyme involved in dephytylation is unknown. We have identified an Arabidopsis thaliana thylakoid protein with a putative hydrolase domain that can dephytylate chlorophyll in vitro and in vivo. The corresponding locus, CHLOROPHYLL DEPHYTYLASE1 (CLD1), was identified by mapping a semidominant, heat-sensitive, missense allele (cld1-1). CLD1 is conserved in oxygenic photosynthetic organisms, sharing structural similarity with pheophytinase, which functions in chlorophyll breakdown during leaf senescence. Unlike pheophytinase, CLD1 is predominantly expressed in green organs and can dephytylate chlorophyll in vitro. The specific activity is significantly higher for the mutant protein encoded by cld1-1 than the wild-type enzyme, consistent with the semidominant nature of the cld1-1 mutation. Supraoptimal CLD1 activities in cld1-1 mutants and transgenic seedlings led to the proportional accumulation of chlorophyllides derived from chlorophyll dephytylation after heat shock, which resulted in light-dependent cotyledon bleaching. Reducing CLD1 expression diminished thermotolerance and the photochemical efficiency of photosystem II under prolonged moderate heat stress. Taken together, our results suggest that CLD1 is the long-sought enzyme for removing the phytol chain from chlorophyll during its turnover at steady state within the chloroplast.

show abstract

“…By contrast, CLHs have been implicated in the postharvest senescence of broccoli (Brassica oleracea var italica) and citrus (Citrus spp.) fruit ripening (JacobWilk et al, 1999;Azoulay Shemer et al, 2008;Chen et al, 2008; see below). Pheophorbide a, the last chlorin-type intermediate of chlorophyll breakdown, is oxygenolytically opened by PHEOPHORBIDE A OXYGENASE (PAO) to yield a red chlorophyll catabolite, which is further reduced to pFCC by RED CHLOROPHYLL CA-TABOLITE REDUCTASE (RCCR; Rodoni et al, 1997).…”

mentioning

confidence: 99%

Different Mechanisms Are Responsible for Chlorophyll Dephytylation during Fruit Ripening and Leaf Senescence in Tomato

et al. 2014

View full text Add to dashboard Cite

Chlorophyll breakdown occurs in different green plant tissues (e.g. during leaf senescence and in ripening fruits). For different plant species, the PHEOPHORBIDE A OXYGENASE (PAO)/phyllobilin pathway has been described to be the major chlorophyll catabolic pathway. In this pathway, pheophorbide (i.e. magnesium-and phytol-free chlorophyll) occurs as a core intermediate. Most of the enzymes involved in the PAO/phyllobilin pathway are known; however, the mechanism of dephytylation remains uncertain. During Arabidopsis (Arabidopsis thaliana) leaf senescence, phytol hydrolysis is catalyzed by PHEOPHYTINASE (PPH), which is specific for pheophytin (i.e. magnesium-free chlorophyll). By contrast, in fruits of different Citrus spp., chlorophyllase, hydrolyzing phytol from chlorophyll, was shown to be active. Here, we enlighten the process of chlorophyll breakdown in tomato (Solanum lycopersicum), both in leaves and fruits. We demonstrate the activity of the PAO/phyllobilin pathway and identify tomato PPH (SlPPH), which, like its Arabidopsis ortholog, was specifically active on pheophytin. SlPPH localized to chloroplasts and was transcriptionally up-regulated during leaf senescence and fruit ripening. SlPPH-silencing tomato lines were impaired in chlorophyll breakdown and accumulated pheophytin during leaf senescence. However, although pheophytin transiently accumulated in ripening fruits of SlPPH-silencing lines, ultimately these fruits were able to degrade chlorophyll like the wild type. We conclude that PPH is the core phytol-hydrolytic enzyme during leaf senescence in different plant species; however, fruit ripening involves other hydrolases, which are active in parallel to PPH or are the core hydrolases in fruits. These hydrolases remain unidentified, and we discuss the question of whether chlorophyllases might be involved.

show abstract

Transgenic broccoli (Brassica oleracea var. italica) with antisense chlorophyllase (BoCLH1) delays postharvest yellowing

Cited by 55 publications

References 30 publications

Update on the biochemistry of chlorophyll breakdown

Update on the biochemistry of chlorophyll breakdown

Identification of a Chlorophyll Dephytylase Involved in Chlorophyll Turnover in Arabidopsis

Different Mechanisms Are Responsible for Chlorophyll Dephytylation during Fruit Ripening and Leaf Senescence in Tomato

Contact Info

Product

Resources

About