Evaluation of pathogenicity of Botrytis species isolated from different legumes

Abstract

Fungi of genus Botrytis are important pathogens of legumes, causing gray mold and chocolate spot diseases. The use of molecular methods to identify pathogens has resulted in the discovery of several new Botrytis species and new associations of pathogens with diseases. Thus, chocolate spot of faba bean is now associated with at least four species: B. fabae, B. cinerea, B. pseudocinerea and B. fabiopsis. Species of Botrytis differ in host plant, pathogenicity, fungicide resistance and other relevant properties that affect disease control. The aim of this study was to identify the species of Botrytis isolated from different legume crops and to evaluate their in vitro pathogenicity. Between 2014 and 2019, 278 isolates of Botrytis were obtained from infected legumes in Latvia. A phylogenetic analysis was carried out by sequencing three nuclear genes, RPB2, HSP60, and G3PDH, considered to be diagnostic for species in this genus. A set of 21 representative isolates was selected for pathogenicity tests on detached leaves of faba bean, field pea, lupin and soybean using 5-mm mycelium-agar plugs. The diameter of the formed lesions under the inoculated plug was measured crosswise each day. The datasets were subjected to analysis of variance with the split-plot design of the experiment and repeated-measures model. Six species were identified: B. cinerea, B. fabae, B. pseudocinerea, B. fabiopsis, B. euroamericana and B. medusae. In addition to the expected combinations of host and pathogen, naturally occurring infections of B. fabiopsis were found on chickpea, B. euroamericana on faba bean and B. medusae in lupin seeds. Species and isolate had significant effects on pathogenicity on all crops tested. Several isolates were pathogenic on two or more host species: two of B. pseudocinerea, two of B. cinerea, two of B. fabiopsis and the one of B. medusae. One isolate of B. pseudocinerea and two of B. fabiopsis caused primary lesions on all five host species. The results show that these Botrytis species have a broad host range that should be borne in mind when planning crop sequences and rotations.

Sclerotinia rot of Zephyranthes candida caused by Sclerotinia sclerotiorum and Sclerotinia minor

“…ITS, G3PDH, HSP60, and RPB2 gene sequences were aligned with other sclerotinia sequences downloaded from the NCBI nucleotide database, including Botrytis cinerea as an outgroup taxon. Sequence alignment was performed via multiple alignment using fast fourier transform ( Achilonu et al, 2023 ) and clustered using MEGA11 software employing the neighbor joining algorithm ( Brauna-Morževska et al, 2023 ; Albert et al, 2024 ) to construct a phylogenetic tree.…”

“…In this study, we combined morphological and multigene analyses based on internal transcribed spacer (ITS), RNA polymerase II second largest subunit (RPB2), glyceraldehyde-3-phosphate dehydrogenase (G3PDH), and heat shock protein 60 (HSP60) ( Brauna-Morževska et al, 2023 ) to determine the pathogen species causing sclerotinia rot in Z. candida . The results of this study provide a reference for the prevention and control of sclerotinia rot in Z. candida .…”

Assessing agronomic performance, chocolate spot resistance, and heat tolerance for diverse Vicia faba genotypes under varying environmental conditions

“…Biotic and environmental stresses including chocolate spot and high temperature cause devastating influences on faba bean production in particular under the current climate crisis 9 , 10 . Chocolate spot caused by Botrytis fabae is a common fungal infection in different regions worldwide that generates substantial devastation in faba bean growth resulting in considerable production loss 11 , 12 . Therefore, faba bean breeders focus on identifying resistant genotypes to maintain acceptable productivity and sustain its production 13 .…”

Genome Comparisons between Botrytis fabae and the Closely Related Gray Mold Fungus Botrytis cinerea Reveal Possible Explanations for Their Contrasting Host Ranges

“…It has been described as the major pathogen of broad bean ( Vicia faba ) and induces typical chocolate spot lesions [ 10 ]. B. fabae broad beans are also infected by other Botrytis species, such as B. cinerea , B. pseudocinerea and B. fabiopsis [ 9 , 10 , 11 , 12 , 13 ]. Phenotypically, B. fabae is clearly distinguishable from B. cinerea based on reduced sporulation on artificial media, larger conidia, and smaller sclerotia [ 10 , 14 ].…”