The tetrapyrrolic chlorophyll catabolites (or phyllobilins, PBs) were analyzed in yellow fall leaves of the grape Chardonnay, a common Vitis vinifera white wine cultivar. The major fractions in leaf extracts of V. vinifera, tentatively assigned to PBs, were isolated and their structures elucidated. The dominant fraction is a dioxobilin‐type non‐fluorescent Chl‐catabolite of a previously observed type. Two less polar fluorescent PBs were characterized as a novel dioxobilin‐type fluorescent Chl‐catabolite with a bicyclo‐1′,6′‐glycosyl architecture, and its new fluorescent formyloxobilin‐type analogue. The discovery of persistent hypermodified fluorescent PBs with the architecture of bicyclo‐[17.3.1]‐PBs (bcPBs), suggests the activity of an unknown enzyme that forges the 20‐membered macroring at the tetrapyrrolic core of a fluorescent PB. bcPBs may play specific physiological roles in grapevine plants and represent endogenous anti‐infective agents, as found similarly for other organic bicyclo‐[n.3.1]‐1′,6′‐glycosyl derivatives.

Phytoplasmoses such as apple proliferation (AP) and European stone fruit yellows (ESFY) cause severe economic losses in fruit production. A common symptom of both phytoplasma diseases is early yellowing or leaf chlorosis. Even though chlorosis is a well-studied symptom of biotic and abiotic stresses, its biochemical pathways are hardly known. In particular, in this context, a potential role of the senescence-related pheophorbide a oxygenase/phyllobilin (PaO/PB) pathway is elusive, which degrades chlorophyll (Chl) to phyllobilins (PBs), most notably to colorless nonfluorescent Chl catabolites (NCCs). In this work, we identified the Chl catabolites in extracts of healthy senescent apple and apricot leaves. In extracts of apple tree leaves, a total of 12 Chl catabolites were detected, and in extracts of leaves of the apricot tree 16 Chl catabolites were found. The seven major NCC fractions in the leaves of both fruit tree species were identical and displayed known structures. All of the major Chl catabolites were also found in leaf extracts from AP- or ESFY-infected trees, providing the first evidence that the PaO/PB pathway is relevant also for pathogen-induced chlorosis. This work supports the hypothesis that Chl breakdown in senescence and phytoplasma infection proceeds via a common pathway in some members of the Rosaceae family.

6 -Pfatten (Vadena), IT-39040 Auer (Ora), BZ Dedicated to Professor Ernst-Peter Kündig on the occcasion of his 70th birthdayIn cold extracts of senescent leaves of the plum tree (Prunus domestica ssp. domestica), six colorless nonfluorescent chlorophyll catabolites (NCCs) were characterized, named Pd-NCCs. In addition, several minor NCC fractions were tentatively classified. The structure of the most polar one of the NCCs, named Pd-NCC-32, featured an unprecedented twofold glycosidation pattern. Three of the NCCs are also functionalized at their 3 2 -position by a glucopyranosyl group. In addition, two of these glycosidated NCCs carry a dihydroxyethyl group at their 18-position. In the polar Pd-NCC-32, the latter group is further glycosidated at the terminal 18 2 -position. Four other major Pd-NCCs and one minor Pd-NCC were identified with five NCCs from higher plants known to belong to the 'epi'-series. In addition, tentative structures were derived for two minor fractions, classified as yellow chlorophyll catabolites, which represented (formal) oxidation products of two of the observed Pd-NCCs. The chlorophyll catabolites in leaves of plum feature the same basic structural pattern as those found in leaves of apple and pear trees.

All structure‐based information on chlorophyll (Chl) breakdown in the higher plants relies on studies with angiosperms. Herein, the first investigation of a fern is reported, revealing a novel type of Chl catabolites (phyllobilins) in leaves of this large division of the vascular plants, and providing structural insights into an astounding metabolic process of the higher plants that appears to have played a role even in early phases of plant evolution. The tetrapyrrolic Chl catabolites in the cosmopolitan bracken fern were discovered to be phyllobilin isomers with an unprecedented skeleton, proposed to be the striking result of a rearrangement of a hypothetical phyllobilin precursor.

In senescent leaves chlorophyll (Chl) catabolites typically accumulate as colorless tetrapyrroles, classified as formyloxobilin‐type (or type‐I) or dioxobilin‐type (type‐II) phyllobilins (PBs). Yellow type‐I Chl catabolites (YCCs) also occur in some senescent leaves, in which they are generated by oxidation of colorless type‐I PBs. A yellow type‐II PB was recently proposed to occur in extracts of fall leaves of grapevine ( Vitis vinifera ), tentatively identified by its mass and UV/Vis absorption characteristics. Here, the first synthesis of a yellow type‐II Chl catabolite (DYCC) from its presumed natural colorless type‐II precursor is reported. A homogenate of a Spatiphyllum wallisii leaf was used as “green” means of effective and selective oxidation. The synthetic DYCC was fully characterized and identified with the yellow grapevine leaf pigment. As related yellow type‐I PBs do, the DYCC functions as a reversible photoswitch by undergoing selective photo‐induced Z / E isomerization of its C15=C16 bond.

In view of the common use of the herb basil (Ocimum basilicum) in nutrition and in phytomedicine, the contents of its leaves are of obvious interest. In extracts of fresh yellowish-green basil leaves, phyllobilins (PBs), which are bilin-type catabolites of chlorophyll (Chl), were detected using high-performance liquid chromatography (HPLC). Two such PBs, provisionally named Ob-nonfluorescent chlorophyll catabolite (NCC)-40 and Ob-YCC-45, exhibited previously unknown structures that were delineated by a thorough spectroscopic characterization. When basil leaves were infested with aphids or thrips or underwent fungal infections, areas with chlorosis were observed. HPLC analyses of the infested parts of leaves compared to those of the healthy parts showed a significant accumulation of PBs in the infested areas, demonstrating that the senescence-associated pheophorbide a oxygenase/ phyllobilin (PAO/PB) pathway is activated by herbivore feeding and fungal infection.

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Alle strukturchemischen Erkenntnisse über den Abbau von Chlorophyll (Chl) in höheren Pflanzen stützen sich auf Untersuchungen von Angiospermen. Hier wird ein neuer Typ von Chl‐Kataboliten (Phyllobilinen) aus den Blättern eines Farns, einem Vertreter aus einer anderen großen Subgruppe der Gefäßpflanzen, vorgestellt. Dadurch eröffnen sich Einblicke in einen erstaunlichen metabolischen Prozess in höheren Pflanzen, die bereits in frühen Phasen der Pflanzenevolution eine Rolle gespielt haben. Es stellte sich heraus, dass diese tetrapyrrolischen Chl‐Kataboliten des weltweit verbreiteten Adlerfarns Phyllobilin‐Isomere mit einem neuartigen Grundgerüst sind und Produkte einer Umlagerung ihrer hypothetischen Phyllobilin‐Vorläufer darstellen.