Functional Analysis of a Novel ABL (Abnormal Browning Related to Light) Gene in Mycelial Brown Film Formation of Lentinula edodes

Abstract

Lentinula edodes is a globally important edible mushroom species that is appreciated for its medicinal properties as well as its nutritional value. During commercial cultivation, a mycelial brown film forms on the surface of the sawdust growth medium at the late vegetative stage. Mycelial film formation is a critical developmental process that contributes to the quantity and quality of the mushroom yield. However, little is known regarding the genetic underpinnings of brown film formation on the surface of mycelial tissue. A novel causal gene associated with the formation of the mycelial brown film, named ABL (Abnormal browning related to light), was identified in this study. The comparative genetic analysis by dihybrid crosses between normal and abnormal browning film cultivars demonstrated that a single dominant allele was responsible for the abnormal mycelium browning phenotype. Whole-genome sequencing analysis of hybrid isolates revealed five missense single-nucleotide polymorphisms (SNPs) in the ABL locus of individuals forming abnormal partial brown films. Additional whole-genome resequencing of a further 16 cultivars showed that three of the five missense SNPs were strongly associated with the abnormal browning phenotype. Overexpression of the dominant abl-D allele in a wild-type background conferred the abnormal mycelial browning phenotype upon transformants, with slender hyphae observed as a general defective mycelial growth phenotype. Our methodology will aid the future discovery of candidate genes associated with favorable traits in edible mushrooms. The discovery of a novel gene, ABL, associated with mycelial film formation will facilitate marker-associated breeding in L. edodes.

Corncob as a Substrate for the Cultivation of Lentinula edodes

“…Browning, a critical developmental process that contributes to the quantity and quality of L. edodes production, largely affects resistance potential against disease and insect, yield, and number of fruiting flushes [15]. Our study suggested that partly substituting corncob for sawdust promoted log browning.…”

Current Advances in the Functional Genes of Edible and Medicinal Fungi: Research Techniques, Functional Analysis, and Prospects

“…Similarly, the blue light and its receptor white collar complex coding genes FfWc1 and FfWc2 in F. filiformis can regulate the role of morphogenesis [185]. In addition, Gf.BMR1 from G. frondosa contributes to fruiting body development and pigment accumulation [186], abl-D from L. edodes promotes the formation of brown film in mycelia [187], and Pabs from A. bisporus [188] enhances UV tolerance. These studies can provide references for light control in the production of edible and medicinal fungi in factories.…”

Intraspecific Comparative Analysis Reveals Genomic Variation of Didymella arachidicola and Pathogenicity Factors Potentially Related to Lesion Phenotype

“…Next-generation sequencing technologies have been widely used to study plant pathogens and greatly facilitated understanding of fungal evolution and virulence factors [ 22 , 23 , 24 , 25 , 26 , 27 ]. The lifestyle of fungal species in Dothideomycetes evolves in four major transitions from non-phytopathogenic to phytopathogenic, along with the pathogenicity-related genes carried in different genera varying considerably [ 28 ].…”