Lentisone, a New Phytotoxic Anthraquinone Produced by Ascochyta lentis, the Causal Agent of Ascochyta Blight in Lens culinaris

Abstract

An aggressive isolate of Ascochyta lentis obtained from lentil (Lens culinaris L.) produced various metabolites in vitro. The metabolites were isolated from the culture filtrates and characterized by spectroscopic, chemical, and optical methods. A new phytotoxic anthraquinone, named lentisone, was isolated and characterized as (1S*,2S*,3S*)-1,2,3,8-tetrahydroxy-1,2,3,4tetrahydro-6-methylanthraquinone together with the well-known pachybasin (1-hydroxy-3-methylanthraquinone), tyrosol, and pseurotin A. Lentisone, tyrosol, and pseurotin A were phytotoxic to lentil, with lentisone the most toxic of all. The toxicity of these compounds is light-dependent. Finally, lentisone was also found to be phytotoxic to chickpea, pea, and faba bean, with toxicity in the latter higher than in any other tested legume, including lentil.

Controlling weeds with fungi, bacteria and viruses: a review

“…Additionally, an anthraquinone pigment has been isolated from a P. macrostoma strain and shown to have herbicidal effects on several prominent weeds of Central India ( Quereshi et al, 2011 ). Anthraquinone pigments produced by other fungi have also been demonstrated to cause necrosis on wheat leaf blades ( Bouras and Strelkov, 2008 ) and a variety of cultivated legumes ( Andolfi et al, 2013 ). Although the phytotoxic mechanism underlying the effects of these compounds has not been fully characterized, the development of necrosis after exposure to the anthraquinone lentisone was found to be light dependent, a potential clue for the eventual determination of the mechanism associated with this class of molecules ( Andolfi et al, 2013 ).…”

“…Anthraquinone pigments produced by other fungi have also been demonstrated to cause necrosis on wheat leaf blades ( Bouras and Strelkov, 2008 ) and a variety of cultivated legumes ( Andolfi et al, 2013 ). Although the phytotoxic mechanism underlying the effects of these compounds has not been fully characterized, the development of necrosis after exposure to the anthraquinone lentisone was found to be light dependent, a potential clue for the eventual determination of the mechanism associated with this class of molecules ( Andolfi et al, 2013 ). Also of note within this genus is Phoma chenopodicola , which has been investigated as a potential control agent for lamb’s quarters ( Chenopodium album ) ( Cimmino et al, 2013 ).…”

Achievements and Challenges in Legume Breeding for Pest and Disease Resistance

“…A wide range of secondary phytotoxic metabolites has been reported from legume pathogens. Ascochitine has been isolated from Ascochyta fabae and A. pisi (Foremska et al, 1990;Beed et al, 1994), ascosalitoxin from A. pisi (Evidente et al, 1993), solanapyrones A-C from A. rabiei (Alam et al, 1989;Chen and Strange, 1991), pinolidoxin, pinolide, and herbarumin II from Didymella pinodes (Cimmino et al, 2012), lentisone from A. lentis (Andolfi et al, 2013), botrytone from Botrytis fabae . Those secondary metabolites often show phytotoxicity to host both host and non-host plants (Evidente et al, 1993), and are frequently assumed to play a role in pathogenesis (Kaur, 1995).…”

Use of metabolomics for the chemotaxonomy of legume-associated Ascochyta and allied genera

“…Ascochitine, the signature SM of the ‘chemical group 1′, was not detected in the A. lentis subclade (chemical group 2), whose metabolic features were vastly different from those of clade A and the A. viciae-villosae subclade B, despite the close phylogenetic relationship. It was recently reported that an A. lentis isolate produces anthraquinones and some other SMs 46 , which have not been found in other Ascochyta and Phoma spp. so far.…”