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Abstract Hygrophorus russula (Schaeff.) Kauffman is an edible ectomycorrhizal fungus that is widely distributed in the world. In this study, the mitogenome of H. russula was sequenced and assembled. The mitogenome of H. russula is composed of circular DNA molecules, with a total size of 55,769 bp. Further analysis indicated that the frequent use of A and T in codons contributes to the high AT content (80.87%) in the H. russula mitogenome. Comparative analysis indicated that the length and base composition of the core protein-encoding genes, and the number of tRNA genes in the H. russula mitogenome varied from that of other Agaricales mitogenomes. Gene arrangement analysis revealed a novel gene order in the H. russula mitogenome. In addition, the expansion of the mitogenome in Agaricales was found to be closely related to the increase in the number of introns. Phylogenetic analysis of the combined mitochondrial gene set showed strong support for tree topologies, and H. russula was determined to be relatively distant from other Agaricales species. This study is the first report on the mitogenome of a member of genus Hygrophorus as well as family Hygrophoraceae , which improves our understanding of mitochondrial differentiation and evolution in the important ectomycorrhizal fungi Hygrophorus species. [ABSTRACT FROM AUTHOR]

Abstract Lyophyllum decastes and Lyophyllum shimeji are the two primary species within the L. decastes complex, and they differ considerably in their nutritional lifestyles and preferred growth environments. However, differences in their mitogenomes have not yet been investigated. In this study, the mitogenomes of the two species were sequenced by next-generation sequencing technology, successfully assembled, and compared. The two mitogenomes of L. decastes and L. shimeji comprised circular DNA molecules of sizes 50,643 bp and 73,678 bp, respectively. The lengths and base compositions of their core protein coding genes (PCGs) and tRNA genes varied considerably between the two mitogenomes. Further, gene collinearity analysis indicated a large-scale gene rearrangement between the two mitogenomes. Of the 15 core PCGs, the genetic distance of the atp9 gene was the smallest between the two species, indicating that this gene was highly conserved in the two Lyophyllum species. Phylogenetic analysis based on a combined mitochondrial gene dataset resulted in a well-supported topology, wherein the two Lyophyllum species were most closely related to Tricholoma matsutake. This study represents the first report of mitogenomes for the Lyophyllum genus. As such, the results will provide a basis for understanding the differentiation and evolution of mitogenomes in the Lyophyllum genus. [ABSTRACT FROM AUTHOR]

Abstract Lactarius is one of the most prominent genera of mushroom-forming fungi in the world. In the present study, complete mitochondrial genomes (mitogenomes) from six Lactarius species were sequenced and assembled. The six mitogenomes were all composed of circular DNA molecules, with total lengths ranging from 38,445 bp to 60,843 bp. The GC contents, GC skews, and AT skews of the mitogenomes varied among the six species. Mitogenomic synteny analysis revealed the presence of gene rearrangements among the mitogenomes. Among the 15 core protein coding genes (PCGs) within the mitogenomes, nad4L exhibited the least genetic distance among species, indicating a high degree of conservation. In addition, the Ka/Ks values for all 15 core PCGs were <1, suggesting that they were subject to purifying selection. Comparative analyses indicated that the increase of intron numbers and sizes contributed to the expansion of mitogenomes in Lactarius. Phylogenetic analyses based on three combined gene datasets yielded identical and well-supported (BPP ≥ 0.83) topologies, dividing the six Lactarius species into two groups. This study provides the first report of mitogenomes from Lactarius and promotes further understanding of the genetics, evolution, and phylogenetic relationships of this important ectomycorrhizal fungal genus. [ABSTRACT FROM AUTHOR]