Molecular Evolution of Lysine Biosynthesis in Agaricomycetes

Abstract

As an indispensable essential amino acid in the human body, lysine is extremely rich in edible mushrooms. The α-aminoadipic acid (AAA) pathway is regarded as the biosynthetic pathway of lysine in higher fungal species in Agaricomycetes. However, there is no deep understanding about the molecular evolutionary relationship between lysine biosynthesis and species in Agaricomycetes. Herein, we analyzed the molecular evolution of lysine biosynthesis in Agaricomycetes. The phylogenetic relationships of 93 species in 34 families and nine orders in Agaricomycetes were constructed with six sequences of LSU, SSU, ITS (5.8 S), RPB1, RPB2, and EF1-α datasets, and then the phylogeny of enzymes involved in the AAA pathway were analyzed, especially homocitrate synthase (HCS), α-aminoadipate reductase (AAR), and saccharopine dehydrogenase (SDH). We found that the evolution of the AAA pathway of lysine biosynthesis is consistent with the evolution of species at the order level in Agaricomycetes. The conservation of primary, secondary, predicted tertiary structures, and substrate-binding sites of the enzymes of HCS, AAR, and SDH further exhibited the evolutionary conservation of lysine biosynthesis in Agaricomycetes. Our results provide a better understanding of the evolutionary conservation of the AAA pathway of lysine biosynthesis in Agaricomycetes.

Fungal secondary metabolism is governed by an RNA-binding protein CsdA/RsdA complex

“…The nucleotide sequences of lsu, ssu, rpb1, rpb2, its and ef1 genes from 163 species were downloaded from the NCBI database (https://www.ncbi.nlm.nih.gov/), aligned with MEGA6.06 software, and manually adjusted. Sequence Matrix 1.7.8 was used to splice lsu, ssu, rpb1, rpb2, its and ef1 genes of each strain in 163 species to construct the phylogenetic tree by RAxML 1.3.1 software 61 . The nucleotide substitution model was set as the default GTRGAMMA and clustering was performed by the maximum likelihood (ML) method, while the other parameters were default.…”

Spermidine Synthase and Saccharopine Reductase Have Co-Expression Patterns Both in Basidiomycetes with Fusion Form and Ascomycetes with Separate Form

“…In C. neoformans , the spe3-LYS9 mutants (the SPE3-homologous region was replaced by the NAT1 gene cassette) showed reduced capsule and melanin production and growth rate, and the SPE3-lys9 mutants (the LYS9-homologous region was replaced by the NAT1 gene cassette) grew slowly and died upon lysine starvation, while the spe3-lys9 mutants (both the SPE3 and LYS9-homologous region were replaced by the NAT1 gene cassette) were avirulent and unable to survive in vivo [ 7 ]. Due to the biosynthesis of lysine by higher fungi (basidomycetes and ascomycetes), it adopts the α-aminoadipate (AAA) pathway, in which the saccharopine dehydrogenase (also known as saccharopine reductase) catalyzes the penultimate step of the lysine biosynthesis [ 9 , 10 , 11 ]. This suggests that the chimeric SPE3-LYS9 gene may link spermidine and lysine biosynthesis, and their close connection is important for the growth and metabolism of C. neoformans .…”