Filho M Cilião, Bertéli M B D, Valle J S, Paccola-Meirelles L D, Linde G A, Barcellos F G, Colauto N B
Programa de Pós-Graduação em Biotecnologia Aplicada à Agricultura, Universidade Paranaense, Umuarama, PR, Brasil.
Programa de Pós-Graduação em Biotecnologia Aplicada à Agricultura, Universidade Paranaense, Umuarama, PR, Brasil
Genet Mol Res. 2017 Jun 20;16(2):gmr-16-02-gmr.16029698. doi: 10.4238/gmr16029698.
The genetic diversity of epiphytic yeasts from grape carposphere is susceptible to environmental variations that determine the predominant carposphere microbiota. Understanding the diversity of yeasts that inhabit grape carposphere in different environments and their pectinolytic activity is a way to understand the biotechnological potential that surrounds us and help improve winemaking. Therefore, this study aimed to evaluate the pectinolytic activity and characterize the genetic diversity of isolated epiphytic yeasts from grape carposphere. Grapes of the Bordeaux cultivar were collected from different regions of Paraná and Rio Grande do Sul States, in Brazil, and the yeasts were isolated from these grape carpospheres. Monosporic isolates were morphologically and genetically characterized on potato dextrose agar medium and by PCR-RFLP and rep-PCR (BOX-PCR) in the ITS1-5.8S-ITS2 region of rDNA. The index of pectinolytic activity of isolates was also evaluated estimating the ratio between the halo diameter of enzymatic degradation and the diameter of the colony when the isolates were grown in cultivation medium containing 10 g/L pectin, 5 g/L yeast extract, 15 g/L agar, 0.12% (w/v) Congo red, and pH 6.2. We observed that the grape carposphere is an environment with a great genetic diversity of epiphytic yeasts of the following genera: Cryptococcus (31.25%), Pichia (25.0%), Candida (25.0%), Dekkera (12.5%), and Saccharomyces (6.25%). The PCR-RFLP technique allowed analyzing existing polymorphism among individuals of a population based on a more restrict and evolutionarily preserved region, mostly utilized to differentiate isolates at the genus level. Approximately 33% of yeast isolates presented pectinolytic activity with potential biotechnological for wine and fruit juice production. This great genetic variability found indicated that it is a potential reservoir of genes to be applied in viniculture improvement programs.
葡萄果实表面附生酵母的遗传多样性易受环境变化影响，而环境变化决定了果实表面的主要微生物群落。了解不同环境下栖息于葡萄果实表面的酵母多样性及其果胶分解活性，是认识我们周围生物技术潜力并助力改进酿酒工艺的一种途径。因此，本研究旨在评估从葡萄果实表面分离的附生酵母的果胶分解活性，并对其遗传多样性进行表征。从巴西巴拉那州和南里奥格兰德州的不同地区采集了波尔多品种的葡萄，并从这些葡萄果实表面分离出酵母。在马铃薯葡萄糖琼脂培养基上对单孢分离株进行形态学和遗传学表征，并通过PCR-RFLP和rep-PCR（BOX-PCR）对rDNA的ITS1-5.8S-ITS2区域进行分析。当分离株在含有10 g/L果胶、5 g/L酵母提取物、15 g/L琼脂、0.12%（w/v）刚果红和pH 6.2的培养基中生长时，通过估计酶解晕圈直径与菌落直径之比来评估分离株的果胶分解活性指数。我们观察到，葡萄果实表面是一个附生酵母遗传多样性丰富的环境，这些酵母属于以下属：隐球菌属（31.25%）、毕赤酵母属（25.0%）、念珠菌属（25.0%）、德克酵母属（12.5%）和酿酒酵母属（6.25%）。PCR-RFLP技术能够基于一个更具限制性且在进化上保守的区域分析种群个体间存在的多态性，该区域主要用于在属水平上区分分离株。约33%的酵母分离株表现出果胶分解活性，具有用于葡萄酒和果汁生产的潜在生物技术价值。发现的这种巨大遗传变异性表明，它是可应用于葡萄栽培改良计划的基因的潜在储存库。
