Regulation of Parasitic Development of the Smut Fungus, Ustilago violacea, by Extracts from Host Plants

Day, Alan W.; Castle, Alan J.; Cummins, Joe

doi:10.1086/337203

Cited by 33 publications

(23 citation statements)

References 19 publications

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“…Microbotryum violaceum formed appressoria‐like infection structures, similar to those reported by Day et al . (1981 ), on the hydrophobic surface of polystyrene Petri dishes under humid conditions after 3 days of incubation.…”

Section: Resultssupporting

confidence: 87%

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Intratetrad mating, heterozygosity, and the maintenance of deleterious alleles in Microbotryum violaceum (=Ustilago violacea)

2000

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The mating system of Microbotryum violaceum was investigated in populations that are polymorphic for mating-type bias, where individuals produce viable haploids of only one of the two required mating types. The cause of mating-type bias was identi®ed as deleterious recessive alleles linked to mating type. Maintenance of the deleterious alleles was promoted by early conjugation among products of single meioses, such that the duration of the free-living haploid stage is minimized. This development was also observed in nonbiased isolates. As a consequence, the mating system tends toward mating within the tetrad, which might be expected to reduce heterozygosity. However, complete centromere linkage of mating type ensures conjugation between ®rst division meiotic products, such that mating in M. violaceum is analogous to forms of meiotic parthenogenesis with ®rst division restitution (i.e. automixis with central fusion). This fungus was used to test the prediction that this mating system would maintain heterozygosity in regions of the genome linked to centromeres. Therefore, populations were screened for additional heterozygous lethal recessive alleles linked to centromeres, and several examples were found. Furthermore, the occurrence of intratetrad mating in M. violaceum provides an explanation for low variation among individuals within populations, inconsistent estimates of outcrossing rates, low levels of mating between tetrads of one diploid individual, and high frequencies of haplo-lethal alleles in natural populations.

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Section: Resultssupporting

confidence: 87%

“…The formation of appressoria‐like infection structures ( Day et al ., 1981 ) was observed under humid conditions on the inner surface of polystyrene Petri dishes. Lids of Petri dishes were sprayed with a mist Phytol solution, dusted with teliospores, and placed back on Petri‐dish bottoms containing water agar as a source of humidity.…”

Section: Methodsmentioning

confidence: 99%

Intratetrad mating, heterozygosity, and the maintenance of deleterious alleles in Microbotryum violaceum (=Ustilago violacea)

2000

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“…Leaf extracts were used to mimic the different host environments. Studies by Day et al (1981) and Kaltz and Shykoff (1999) indicate that such extracts evoke the same qualitative conjugation behavior, and conjugation frequencies as found when placing sporidia directly on the leaf surface. Host extracts of S. latifolia and S. dioica were prepared by grinding a few grams of fresh leaf material in a mortar and pestle with 15 ml/g sterile ultrapure water.…”

Section: Conjugation Proceduresmentioning

confidence: 74%

“…A conjugation tube between cells of different mating type is formed (Poon et al 1974), marking the start of the dikaryotic phase in which the infectious hyphae are produced. Fungal development from this point on is regulated by the presence of host plant chemicals (Day et al 1981;Ruddat 1986, 1989). Infectious hyphae grow intercellularly (Spencer and White 1951;Audran and Batcho 1981), and along with the plant's apical meristemic regions (Day 1980).…”

Section: Anther Smutsmentioning

confidence: 99%

“…3), suggesting a predominant role of the a 1 mating type in conjugation success. Conjugation tubes grow from cells with mating type a 2 toward cells with mating type a 1 , as a reaction to the more active signaling of mating type a 1 (Day et al 1981). Indeed, if mating type a 1 is more active in signaling, this may cause reciprocal differences in crosses between strains, that is, mating type a 1 more strongly determining conjugation rate than mating type a 2 .…”

Section: Conjugation Host Extracts and Mating Typementioning

confidence: 99%

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Intraspecific Competition and Mating Between Fungal Strains of the Anther Smut Microbotryum Violaceum From the Host Plants Silene Latifolia and S. Dioica

2003

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Abstract. We studied intraspecific competition and assortative mating between strains of the anther smut fungus Microbotryum violaceum from two of its host species, Silene latifolia and S. dioica. Specifically, we investigated whether strains from allopatric host populations have higher competitive ability on their native host species and show positive assortative mating. In general, strains isolated from S. latifolia outcompeted strains isolated from S. dioica on both host species, but in female hosts, heterotypic dikaryons (i.e., dikaryons composed of a haploid strain originating from S. latifolia and a haploid strain originating from S. dioica) were most successful in competition. Furthermore, the latency period was significantly shorter for heterokaryons that contained at least one strain originating from S. latifolia, compared to heterokaryons that only contained strains originating from S. dioica. The frequencies of conjugations between strains originating from S. latifolia were much higher than conjugation frequencies between strains originating from S. dioica. A significant positive correlation was detected between the relative success of strains in competition and in conjugation, suggesting that success of a strain in competition might be partly determined by its swiftness of mating. In addition, reciprocal differences within heterotypic crosses revealed a significant effect of fungal mating type, with mating type a 1 being the main determinant of mating pace. The observed differences in infection success, conjugation rate, and latency period in favor of strains from S. latifolia relative to strains from S. dioica on both host species are discussed in an evolutionary context of opportunities for the maintenance of differentiation between different formae speciales upon secondary contact.Key words. Competition success, conjugation, formae speciales, mating success, mating type, smut fungus.Received December 19, 2001. Accepted December 26, 2002 Plant parasites are often capable of infecting more than one host species and show intraspecific variation in host use. Understanding the origin and maintenance of such variation and the conditions under which this may lead to host race formation and speciation are central questions in evolutionary biology. Differences in performance of pathogens on different host species and positive assortative mating are expected to play an active role in processes of divergence between strains or in the maintenance of host related differentiation.

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Nodulation of Soybean: Bradyrhizobium Japonicum Physiology and Genetics

Stacey

Halverson

Nieuwkoop

et al. 1986

Recognition in Microbe-Plant Symbiotic and Pathogenic Interactions

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Regulation of Parasitic Development of the Smut Fungus, Ustilago violacea, by Extracts from Host Plants

Cited by 33 publications

References 19 publications

Intratetrad mating, heterozygosity, and the maintenance of deleterious alleles in Microbotryum violaceum (=Ustilago violacea)

Intratetrad mating, heterozygosity, and the maintenance of deleterious alleles in Microbotryum violaceum (=Ustilago violacea)

Intraspecific Competition and Mating Between Fungal Strains of the Anther Smut Microbotryum Violaceum From the Host Plants Silene Latifolia and S. Dioica

Nodulation of Soybean: Bradyrhizobium Japonicum Physiology and Genetics

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