Comparative Genomics of Astaxanthin-Producing Yeasts

BELLORA N.; ALVAREZ L. P.; LIBKIND D.; MOLINÉ M.

Bariloche

Simposio; 34º International Specialized Symposium on Yeasts; 2018

IPATEC

The basidiomycetous yeast Phaffia rhodozyma (synonym Xanthophyllomycesdendrorhous) possess a set of unique characteristics of outstanding scientificinterest and technological value. P. rhodozyma is the only astaxanthinogenicyeast known, and this carotenoid pigment is considered one of the most potentfree reactive oxygen species scavenger. P. rhodozyma has additionalphotoprotective strategies such as the accumulation of mycosporine-glutaminol-glucoside, a UVB-screening compound that also has antioxidantproperties. Many genetically distinct natural populations of Phaffia spp. areknown worldwide, but most of the diversity is found in the SouthernHemisphere, mainly in Australasia, whereas Holarctic populations are mostlygenetically uniform. The aim of this work was to evaluate the presence ofgenes related to photoprotection and antioxidant activities in Phaffia spp.isolates from different geographical origins. Eight Phaffia spp. genomes fromSouth America, New Zealand, Japan, Northern Europe, Australia and Tasmaniawere studied. An alignment-free method (Kr) retrieved divergence values of0.00076 - 0.0081 between Holarctic strains, but 0.089 between Australasiastrains and 0.06 - 0.084 between South America and Australasia strains. Genesinvolved in the synthesis of astanxanthin (idi, CrtE, FPS, crtI, crtYB, crtR,crtS/Ast, Mig1), mycosporine-glutaminol-glucoside (EEVS-like, O-methyl,ATP-grasp) and ROS scavenging enzymes (SOD1 and 2, Catalase 1, 2 and 3)were identified in the genome assemblies by genBlastG. The sixteen genesanalyzed were identified in every genome of Phaffia spp. with eval = 0, exceptfor CBS6938 that lacks of MGG genes. The predicted proteins were alignedwith Blat to the genome reference CBS7918 and visualized with IGV 2.4.10.Multiple aligments were produced using MUSCLE and protein domains wereconfirmed with PFAM. Our results indicate that the Phaffia spp. genome isenriched in antioxidant mechanisms and that these mechanisms are conservedthrough Phaffia spp. from different geographical origins.