Inheritance of cellulose- and lignin-degrading ability as well as endoglucanase isozyme pattern in Dichomitus squalens

Abstract

The progeny of Dichornitus squalens CBS-432-34 is heterogeneous with respect to specific growth rate on glucose, cellulolytic ([U14C]cellulose ~ 14CO2) and ligninolytic ([~4C]synthetic lignin -~ 14CO2) activities with little correlation between these metric characters. Variations do not show clear-cut phenotypes but rather a continuous range between extreme values pointing to multigenic control of these characters. Most homocaryons showed decreased cellulolytic or ligninolytic activity compared to the parent dicaryon. However a few homocaryons were comparable or even superior to the parent dicaryon for ligninolytic or cellulolytic activity with no correlation between each factor. Strains with reduced cellulolytic activity and altered isozyme patterns of endoglucanases were isolated in the progeny of D. squalens CBS-432-34. While the parent strain produced three main endoglucanase multiple enzymes designated EnI, EnlI and EnlIl, several strains in the progeny produced a different multiple enzyme pattern. In contrast to the quantitative ability to degrade cellulose, multiple enzyme pattern variation in the progeny did not show continuous variations. Characterization of heterocaryon phenotypes derived from Ien ÷ and Ienl homocaryons and first filial generation (fl) analysis showed that genetic control of the multiple enzyme pattern (Ienl phenotype) in D. squalens is complex.

Functional diversity in Dichomitus squalens monokaryons

“…Most Dichtomitus squalens strains used in this study have previously been described ( Pham et al . 1990 ), but their genotypes and phenotypes had not been analyzed in detail.…”

“…This species is commonly found in North America and northern regions of Europe and Asia ( Andrews & Gill 1943 ), and it usually grows on softwood, but is also able to grow and degrade hardwood ( Blanchette et al 1987 , Fackler et al 2007 ). Dichomitus squalens has a tetrapolar mating system, and in a previous study 20 monokaryotic progeny derived from a single wild-type dikaryon of D. squalens (FBCC312, CBS 432.34) were isolated and their growth rate, cellulose and lignin degrading ability, and isoenzyme patterns were compared ( Pham et al . 1990 ).…”

The White-Rot Basidiomycete Dichomitus squalens Shows Highly Specific Transcriptional Response to Lignocellulose-Related Aromatic Compounds

“…The monokaryotic D. squalens CBS464.89 strain derived from the FBCC312 dikaryon (Pham et al, 1990; Casado López et al, 2017) is currently the best D. squalens reference genome available (Casado López et al, 2019), and was therefore used to map the filtered reads from each library. The reads from each of the RNA-seq samples were deposited in the Sequence Read Archive at NCBI with individual sample BioProject Accession numbers (PRJNA500193 to PRJNA500234).…”

Dichomitus squalens partially tailors its molecular responses to the composition of solid wood

“…Previous published work on D. squalens used the only available D. squalens genome annotation (LYAD‐421 SS1, Dicsq1), but here for read mapping and peptide matching the annotation of a monokaryotic strain (CBS464.89; Dicsqu464_1) was used. CBS464.89 is a monobasidiospore isolate from the dikaryotic strain FBCC312 (CBS 432.34) (Pham et al ., ) used for the birch and spruce cultures. To facilitate comparisons with previous D. squalens studies, the orthologs between the two D. squalens strains (Dicsqu464_1 (https://genome.jgi.doe.gov/Dicsqu464_1/Dicsqu464_1.home.html) and Dicsq1 (http://genome.jgi.doe.gov/Dicsq1/Dicsq1.home.html)) were identified using a bidirectional best hit (BBH) method (Overbeek et al ., ; Altenhoff and Dessimoz, ).…”