Attachment Capability of Antagonistic Yeast Rhodotorula glutinis to Botrytis cinerea Contributes to Biocontrol Efficacy.

Boqiang Li,Shiping Tian,Huaimin Peng

doi:10.3389/fmicb.2016.00601

Abstract

Rhodotorula glutinis as an antagonism show good biocontrol performance against various post-harvest diseases in fruits. In the present study, strong attachment capability of R. glutinis to spores and hyphae of Botrytis cinerea was observed. Further analysis showed that certain protein components on the yeast cell surface played critical role during the interaction between R. glutinis and B. cinerea. The components mainly distributed at the poles of yeast cells and might contain glycosylation modification, as tunicamycin treated yeast cells lost attachment capability to B. cinerea. To investigate contributions of attachment capability of R. glutinis to its biocontrol efficacy, yeast cells were mutagenized with 3% methane-sulfonic acid ethyl ester (EMS), and a mutant CE4 with stable non-attaching phenotype was obtained. No significant difference was found on colony, cell morphology, reproductive ability, and capsule formation between the mutant and wild-type. However, there was a distinct difference in India ink positive staining patterns between the two strains. Moreover, wild-type strain of R. glutinis showed better performance on inhibiting spore germination and mycelial growth of B. cinerea than CE4 strain when yeast cells and B. cinerea were co-cultured in vitro. In biocontrol assay, both wild-type and CE4 strains showed significant biocontrol efficacy against gray mold caused by B. cinerea in apple fruit, whereas, control effect of CE4 strain was lower than that of wild-type. Our findings provided new evidences that attachment capability of R. glutinis to B. cinerea contributed to its biocontrol efficacy.

Highlights

Post-harvest decay of fruits and vegetables results in major economic losses
Scanning Electron Microscopy (SEM) observation suggested that fibers on the cell surface might play important role in the attachment between yeast cells and spores of B. cinerea (Figure 2)
The attachment was observed between yeast cells of R. glutinis and mycelia of B. cinerea or other fungal pathogens, such as Monilinia fructicola

Summary

Introduction

Post-harvest decay of fruits and vegetables results in major economic losses. By far, the use of synthetic fungicide remains the main method for controlling post-harvest diseases (Droby et al, 2009). In comparison with other microbial antagonists, yeasts have a number of attributes which make them suitable as biocontrol agents for post-harvest disease control, such as simple nutritional. Allen et al (2004) tested attachment capability of 294 phylloplane yeast isolates to spores of Botrytis cinerea and found that 260 isolates showed positive attachment Among these isolates, several yeast species were reported as biocontrol agents, such as Cryptococcus laurentii, Pichia guilliermondii, and Rhodotorula glutinis, and showed good performance against various post-harvest pathogens (Yu et al, 2007, 2013; Zhang et al, 2010, 2011; Lahlali et al, 2014; Yan et al, 2014). Attachment of antagonistic yeasts to fungal pathogens is considered as contributing to the biocontrol efficacy, few data by far has indicated that how important the attachment capability is

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Conclusion