Induction of Phytoalexins Gliceoline and Proteins Related to Defense in Soybean Cotyledon Treated With Yeast

Yeasts can induce mechanisms of plant resistance due to compounds with eliciting characteristics, so the aim of this work was to evaluate the effect of yeast on the induction of phytoalexins gliceoline, peroxidase, polyphenoloxidase and phenylalanine ammonia-lyase from soy cotyledons. To determine the defense enzymes, soybean seeds were sown and the cotyledons treated with sterile distilled water, Cryptococcus laurentii (AH 03-1), Pichia guilliermondii (AH 16-2), Rhodotorula glutinis (AH 14-3), Sporidiobolus johnsonii (AH 16-1) and Zygoascus hellenicus (AH 14-1). Biochemical analyzes of the formation of phytoalexins and the activity of the enzymes peroxidase, polyphenoloxidase, phenylalanine ammonia-lyase and total proteins were performed. For phytoalexins glycerolins the yeasts Cryptococcus laurentii (AH 03-1) and Zygoascus hellenicus (AH 14-1) promoted an increase of 83.65% and 78.75% in the formation of this compound. Cryptococcus laurentii (AH 03-1) increased peroxidase activity by 36.84%, while for polyphenoloxidase, the Pichiaguilliermondii e yeasts (AH 16-2), Rhodotorula glutinis (AH 14-3), Sporidiobolus johnsonii (AH 16-1) and Zygoascus hellenicus (AH 14-1), increased the activity of this enzyme by 33.33%, 28.00%, 33.33% and 33.33%, respectively. For phenylalanine ammonia-lyase, Cryptococcus laurentii (AH 03-1) and Zygoascushellenicus (AH 14-1) promoted an increase of 75.57% and 78.86%, respectively, in their activity. The results demonstrate the potential of yeasts studied in the induction of phytoalexins glyceolins and in the activity of peroxidase, polyphenoloxidase and phenylalanine ammonia-lyase in soybean cotyledons.

Management of the Common Bacterial Blight of the Bean by Rhodotorula glutinis and Sporidiobolus johnsonii

Bean common bacterial blight reduces crop productivity and is difficult to control. However, biological control by yeast can be an efficient complementary measure in management. The objective was to evaluate the ability of Rhodotorula glutinis and Sporidiobolus johnsonii to reduce the severity of bean common bacterial blight. The cultivar used was IAPAR Tuiuiú. The first experiment was sown in March and repeated in October, in a 4 × 3 factorial scheme (zero, one, two and three applications and three treatments R. glutinis, S. johnsonii and Acibenzolar-S-Methyl (ASM)). For this purpose were evaluated the area under the disease progress curve (AACPD), number of pods per plant (NVP), number of grains per pod (NGV), thousand grain mass (MMG) and productivity. For the results of the March cultivation, due to the low temperature, the maximum severity of bean common bacterial blight was 8% and the applications of yeasts were not significant for AACPD. The isolate R. glutinis showed the highest average of productivity with two applications, being 1006.44 kg ha-1. For October cultivation, R. glutinis and S. johnsonii isolates reduced AACPD by 66.84 and 58.42%, respectively with three applications. For productivity, R. glutinis and S. johnsonii showed no difference between the number of applications. The ASM showed a productivity of 4418.56 kg ha-1 with three applications. The results indicate that the yeasts R. glutinis and S. johnsonii reduce the severity of bean common bacterial blight and the most appropriate number of applications are two for both isolates.

Mixia osmundae: transfer from the Ascomycota to the Basidiomycota based on evidence from molecules and morphology

To determine phylogenetic placement of Mixia osmundae (T. Nishida) Kramer (Mixiaceae, Protomycetales), we sequenced the nuclear small subunit ribosomal RNA (18S rRNA) gene from M. osmundae IFO-32408 and compared it with that from 4 archiascomycetes (Ascomycota) and 24 basidiomycetes. Our molecular phylogeny indicates that M. osmundae and the basidiomycetes Rhodosporidium toruloides, Leucosporidium scottii, Sporobolomyces roseus, Sporidiobolus johnsonii, Cronartium ribicola, Peridermium harknessii, and Erythrobasidium hasegawianum group together in 100% of bootstrap replicates. The M. osmundae spores on the host fern Osmunda japonica have been regarded as ascospores (i.e., endogenously produced within an ascus), but our light microscopic, SEM, and TEM observations for fresh materials of M. osmundae on O. japonica in Japan clearly demonstrated that these are produced exogenously, blastically, and simultaneously from the sporogenous cell. Evidence from both molecular and morphological characters suggests that M. osmundae is not a member of the ascomycetes and is not related to either the Taphrinales or Protomycetales. Obviously Mixia osmundae is a member of the basidiomycetes and placed within the simple septate basidiomycete lineage. Key words: fungal evolution, basidiomycete phylogeny, Mixia osmundae, Taphrinales, Protomycetales, 18S rRNA.

Conjugation and chlamydospores in Sporobolomyces odorus

Conjugation was observed in mix-mated pairs of 16 Sporobolomyces odorus isolates. The mating tests suggest a simple bipolar mating system. Conjugation resulted in the development of dikaryotic hyphae with clamp connections, and in chlamydospore formation. This dikaryotic phase closely resembled that of Sporidiobolus johnsonii. The chlamydospores germinated by the production of promycelium-like structures or of dikaryotic hyphae.