Biological Characteristics of Verticillium dahliae MAT1-1 and MAT1-2 Strains.

Lin Liu,Dan Wang,Zhi-Qiang Kong,Jun Zhao,Jian Song,Dan-Dan Zhang,Jie-Yin Chen,Jian Zhang,Steven J Klosterman,Yuan-Yuan Zhang,Ya-Duo Zhang,Ran Li,Krishna V Subbarao,Xiao-Feng Dai

doi:10.3390/ijms22137148

Abstract

Verticillium dahliae is a soil-borne plant pathogenic fungus that causes Verticillium wilt on hundreds of dicotyledonous plant species. V. dahliae is considered an asexually (clonal) reproducing fungus, although both mating type idiomorphs (MAT1-1 and MAT1-2) are present, and is heterothallic. Most of the available information on V. dahliae strains, including their biology, pathology, and genomics comes from studies on isolates with the MAT1-2 idiomorph, and thus little information is available on the MAT1-1 V. dahliae strains in the literature. We therefore evaluated the growth responses of MAT1-1 and MAT1-2 V. dahliae strains to various stimuli. Growth rates and melanin production in response to increased temperature, alkaline pH, light, and H2O2 stress were higher in the MAT1-2 strains than in the MAT1-1 strains. In addition, the MAT1-2 strains showed an enhanced ability to degrade complex polysaccharides, especially starch, pectin, and cellulose. Furthermore, several MAT1-2 strains from both potato and sunflower showed increased virulence on their original hosts, relative to their MAT1-1 counterparts. Thus, compared to MAT1-1 strains, MAT1-2 strains derive their potentially greater fitness from an increased capacity to adapt to their environment and exhibit higher virulence. These competitive advantages might explain the current abundance of MAT1-2 strains relative to MAT1-1 strains in the agricultural and sylvicultural ecosystems, and this study provides the baseline information on the two mating idiomorphs to study sexual reproduction in V. dahliae under natural and laboratory conditions.

Highlights

P48 with MAT1-1 and P50 with MAT1-2 isolated from potato in Inner Mongolia, China, were selected
The upper sides of the P48 and P50 cultures displayed white dense mycelia on the potato dextrose agar (PDA) medium that progressively darkened on the undersurface of the cultures as the melanized microsclerotia were produced, at about 7 days after incubation (Figure 1A)
The polymerase chain reaction (PCR) assays indicated that strain P48 had the MAT1-1 marker and P50 the MAT1-2 marker, confirming that P48 and P50 represented strains with MAT1-1 and MAT1-2 idiomorphs, respectively (Figure 1B)

Summary

Introduction

A ubiquitous feature of the eukaryotic kingdom, can accelerate the adaptation to continuously changing ecological niches. It allows the repair of random epigenetic or conventional genetic damage by recombination with homologous chromosomes [1,2]. 40% of the taxa were deemed asexual [5] Such strictly asexual organisms are thought to be less flexible than sexual organisms, relying solely on random mutations to adapt to changing environments; they are often considered evolutionary dead ends, mainly due to the absence of meiotic recombination, resulting in increased accumulation of deleterious mutations, an effect known as the Muller’s ratchet [6,7,8,9]. Examples include Candida albicans, Aspergillus flavus, Aspergillus fumigatus, and Aspergillus parasiticus [13,14,15,16,17], as well as the biotechnologically relevant species Penicillium chrysogenum, Penicillium roqueforti, and Trichoderma reesei [18,19,20,21]

Methods

Results

Conclusion