Evolution of nucleotide sequences and expression patterns of hydrophobin genes in the ectomycorrhizal fungus Paxillus involutus

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Evolution of nucleotide sequences and expression patterns of hydrophobin genes in the ectomycorrhizal fungus Paxillus involutus. / Rajashekar, Balaji; Samson, Peter; Johansson, Tomas; Tunlid, Anders.

I: New Phytologist, Vol. 174, Nr. 2, 2007, s. 399-411.

Forskningsoutput: TidskriftsbidragArtikel i vetenskaplig tidskrift

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T1 - Evolution of nucleotide sequences and expression patterns of hydrophobin genes in the ectomycorrhizal fungus Paxillus involutus

AU - Rajashekar, Balaji

AU - Samson, Peter

AU - Johansson, Tomas

AU - Tunlid, Anders

PY - 2007

Y1 - 2007

N2 - Hydrophobins are small, secreted proteins that play important roles in the development of pathogenic and symbiotic fungi. Evolutionary mechanisms generating sequence and expression divergence among members in hydrophobin gene families are largely unknown. Seven hydrophobin (hyd) genes and one hyd pseudogene were isolated from strains of the ectomycorrhizal fungus Paxillus involutus. Sequences were analysed using phylogenetic methods. Expression profiles were inferred from microarray experiments. The hyd genes included both young (recently diverged) and old duplicates. Some young hyd genes exhibited an initial phase of enhanced sequence evolution owing to relaxed or positive selection. There was no significant association between sequence divergence and variation in expression levels. However, three hyd genes displayed a shift in the expression levels or an altered tissue specificity following duplication. The Paxillus hyd genes evolve according to the so-called birth-and-death model in which some duplicates are maintained for a long time, whereas others are inactivated through mutations. The role of subfunctionalization and/or neofunctionalization for preserving the hyd duplicates in the genome is discussed.

AB - Hydrophobins are small, secreted proteins that play important roles in the development of pathogenic and symbiotic fungi. Evolutionary mechanisms generating sequence and expression divergence among members in hydrophobin gene families are largely unknown. Seven hydrophobin (hyd) genes and one hyd pseudogene were isolated from strains of the ectomycorrhizal fungus Paxillus involutus. Sequences were analysed using phylogenetic methods. Expression profiles were inferred from microarray experiments. The hyd genes included both young (recently diverged) and old duplicates. Some young hyd genes exhibited an initial phase of enhanced sequence evolution owing to relaxed or positive selection. There was no significant association between sequence divergence and variation in expression levels. However, three hyd genes displayed a shift in the expression levels or an altered tissue specificity following duplication. The Paxillus hyd genes evolve according to the so-called birth-and-death model in which some duplicates are maintained for a long time, whereas others are inactivated through mutations. The role of subfunctionalization and/or neofunctionalization for preserving the hyd duplicates in the genome is discussed.

KW - ectomycorrhiza

KW - expression patterns

KW - gene duplication

KW - neofunctionalization

KW - hydrophobin

KW - subfunctionalization

KW - Paxillus involutus

U2 - 10.1111/j.1469-8137.2007.02022.x

DO - 10.1111/j.1469-8137.2007.02022.x

M3 - Article

VL - 174

SP - 399

EP - 411

JO - New Phytologist

T2 - New Phytologist

JF - New Phytologist

SN - 1469-8137

IS - 2

ER -