Massarilactones D and H, phytotoxins produced by Kalmusia variispora, associated with grapevine trunk diseases (GTDs) in Iran

Abstract

A strain of Kalmusia variispora associated with grapevine trunk diseases (GTDs) was identified in Iran and induced disease symptoms on the host in greenhouse conditions. The grapevine pathogens are able to produce a plethora of toxic metabolites belonging to different classes of naturally occurring compounds. Two homogeneous compounds were isolated from the organic extract of K. variispora culture filtrates. They were identified by physic (specific optical rotation), and spectroscopic (essentially 1D and 2D 1 H and 13 C NMR and HR ESIMS) methods as the fungal polyketides massarilactones D and H (1 and 2). The unassigned absolute configuration of massarilactone D was unambiguously determined by X-ray diffractometric analysis.Massarilactones D and H showed phytotoxic activity on Vitis vinifera L. at both concentrations used and depending from the days of inoculation. Phytotoxicity is also increased when the O,O',O"triacetyl derivative of massarilactone D (3) was assayed on the host plant. This is the first report on the investigation of phytotoxic metabolites produced by K. variispora isolated from infected grapevine in Iran and they seem to be involved in the development of disease symptoms.

Grapevine wood microbiome analysis identifies key fungal pathogens and potential interactions with the bacterial community implicated in grapevine trunk disease appearance

“…In Greece, this fungus has been described as a causal agent of wood necrosis and fruit rot on apples [ 59 ]. The fungus produces two polyketide massarilactones that were phytotoxic, reproducing grapevine decline symptoms on plant leaves [ 18 ]. Conversely, we identified an Alternaria ASV that was consistently associated with asymptomatic plants regardless of cultivar/viticultural zones.…”

“…Foliar symptoms often appear years after infestation [ 6 ] and show transitory patterns of appearance [ 14 ]. Fungal pathogens have not been recovered yet from symptomatic leaves suggesting that leaf symptoms are associated with the production and translocation to leaves of (1) secondary metabolites produced by the wood pathogens [ 15 – 18 ] (2) phytotoxic by-products of wood decay or phytotoxic metabolites produced by the plant–fungi interaction [ 19 ].…”

WITHDRAWN: Fungi associated with grapevine trunk diseases (GTDs) with emphasize on pestalotioid species in Kurdistan Province, Iran

“…Pestalotia-like fungi are among various fungi reported from grapevines showing trunk diseases symptoms in some countries (Larignon and Dubos 1997;Mugnai et al 1999;Graniti et al 2000;Mostert et al 2006;Steel et al 2007;Gramaje et al 2009;Úrbez-Torres et al 2009;Úrbez-Torres et al 2013;Mohammadi et al 2013;Úrbez-Torres et al 2014;Maharachchikumbura et al 2016;Pintos et al 2018;Abed-Ashtiani et al 2019;Cimmino et al 2020). Pestalotioid fungi are found as saprobes, endophytes and plant pathogens in association with mainly woody plants and human pathogens in different climates worldwide (De Hoog et al 2000;Watanabe et al 2010;Tanaka et al 2011;Liu et al 2019).…”

Biscogniauxia rosacearum the charcoal canker agent as a pathogen associated with grapevine trunk diseases in Zagros region of Iran

“…Paraconiothyrium ) are associated with trunk diseases of grapevines 3 , 5 – 13 . More recently, other fungal groups such as Acremonium , Cadophora , Cytospora , pestalotioid and Phoma -like fungi, have also been reported in association with grapevine trunk diseases, which have proven to be pathogenic on grapevine in pathogenicity assays 14 – 16 .…”