Mating type and sexual fruiting body of Botrytis elliptica, the causal agent of fire blight in lily

Razak Bin Terhem,Martijn Staats,Jan A L Van Kan

doi:10.1007/s10658-015-0639-2

Razak Bin Terhem, Martijn Staats + Show 1 more

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https://doi.org/10.1007/s10658-015-0639-2

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Abstract

Botrytis elliptica is a necrotrophic pathogen that specifically infects Lilium species. Previous records show that B. elliptica collected in the field can successfully develop apothecia in vitro, however, there are no formal descriptions of apothecia of B. elliptica. The aim of this study was to analyse the sequence of the mating type loci of B. elliptica and produce apothecia in the laboratory in order to describe their morphology. The sequences of both MAT alleles (MAT1-1 or MAT1-2) of B. elliptica were determined and compared to the sister taxa, Botrytis cinerea and Sclerotinia sclerotiorum. Two strains of each mating type were used in crosses under controlled conditions to produce apothecia. Primordium rupture from sclerotial tissue occurred 74 days after fertilization and a mature apothecium formed within 1 month after rupture. The apothecia are 7 to 12 mm in height with a disk of 3 to 4 mm in diameter and 0.5 to 1 mm in thickness. The apothecial disk is usually umbilicate, depressed to funnel and rounded in shape. The number of apothecia growing on a sclerotium was one to nine. Asci are long, cylindrical with a size of 208 × 14 μm, thin walled and bearing eight ascospores. Ascospores are hyaline in colour, ellipsoidal with rounded ends, usually 18 to 24 μm in length and 6 to 10 μm in width (mean 19.5 × 8 μm). Ascospores were infectious on lily leaves.

Highlights

IntroductionHost specificity of B. elliptica was proposed to be caused by the production of an as yet unidentified, secreted necrosis-inducing protein that causes programmed cell death (Van Baarlen et al 2004) and presumably serves as a host-specific necrotrophic effector (Vleeshouwers and Oliver 2014)
There are various modern lily cultivars on the market which originate from the genus Lilium of the family Liliaceae
Apothecia of B. elliptica can be produced in the laboratory after sexual crosses of two strains of opposite mating types, using a standard protocol developed for B. cinerea (Faretra et al 1988; van der VlugtBergmans et al 1993) B. elliptica apothecia

Summary

Introduction

Host specificity of B. elliptica was proposed to be caused by the production of an as yet unidentified, secreted necrosis-inducing protein that causes programmed cell death (Van Baarlen et al 2004) and presumably serves as a host-specific necrotrophic effector (Vleeshouwers and Oliver 2014). Symptoms such as necrotic spots on leaves and petals are the early signs of infection. Control measures using fungicides for B. elliptica are common practice worldwide, it has been reported that B. elliptica acquires resistance to several fungicides including benzimidazoles, dicarboximides, diethofencarb, and two sterol biosynthesis inhibitors (Chastagner and Riley 1990; Migheli et al 1990)

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