Differentiation and secondary metabolism are correlated processes in fungi that respond to light. In
Aspergillus nidulans
, light inhibits sexual reproduction as well as secondary metabolism. We identified
the heterotrimeric
velvet
complex VelB/VeA/LaeA connecting light-responding developmental
regulation and control of secondary metabolism. VeA, which is primarily expressed in the dark,
physically interacts with VelB, which is expressed during sexual development. VeA bridges VelB to the
nuclear master regulator of secondary metabolism, LaeA. Deletion of either
velB
or
veA
results in
defects in both sexual fruiting-body formation and the production of secondary metabolites.

VelB/VeA/LaeA Complex CoordinatesLight Signal with Fungal Developmentand Secondary Metabolism

Citrus (Citrus spp.) species produce a variety of fruits that are popular worldwide. Citrus fruits, however, are susceptible to postharvest decays caused by various pathogenic fungi, including Penicillium digitatum, Penicillium italicum, Geotrichum citri-aurantii, Aspergillus niger, and Aspergillus flavus. Decays resulting from infections by these pathogens cause a significant reduction in citrus quality and marketable yield. Biological control of postharvest decay utilizing antagonistic bacteria and fungi has been explored as a promising alternative to synthetic fungicides. In the present article, the isolation of antagonists utilized to manage postharvest decays in citrus is reviewed, and the mechanism of action including recent molecular and genomic studies is discussed as well. Several recently-postulated mechanisms of action, such as biofilm formation and an oxidative burst of reactive oxygen species have been highlighted. Improvements in biocontrol efficacy of antagonists through the use of a combination of microbial antagonists and additives are also reviewed. Biological control utilizing bacterial and yeast antagonists is a critical component of an integrated management approach for the sustainable development of the citrus industry. Further research will be needed, however, to explore and utilize beneficial microbial consortia and novel approaches like CRISPR/Cas technology for management of postharvest decays.

Biological control of postharvest fungal decays in citrus: a review

Effects of exogenous methyl jasmonate on quality and preservation of postharvest fruits: A review

Biotechnological applications of the non-conventional yeast Meyerozyma guilliermondii.

Biocontrol efficiency of Meyerozyma guilliermondii Y-1 against apple postharvest decay caused by Botryosphaeria dothidea and the possible mechanisms of action.

Investigating the effect of methyl jasmonate on the biocontrol activity of Meyerozyma guilliermondii against blue mold decay of apples and the possible mechanisms involved

Penicillium digitatum is one of the most important pathogens known widely to cause postharvest losses of citrus. It is significant to explore its infection mechanism to improve the control technology of postharvest diseases of citrus. This research aimed to study the changes in gene expression of P. digitatum at its early stages of citrus infection by transcriptomics sequencing and bioinformatics analysis in order to explore the molecular mechanism of its infection. The results showed that genes associated with pathogenic factors, such as cell wall degrading enzymes, ethylene, organic acids, and effectors, were significantly up-regulated. Concurrently, genes related to anti-oxidation and iron transport were equally up-regulated at varying degrees. From this study, we demonstrated a simple blueprint for the infection mechanism of P. digitatum in Citrus reticulata Blanco, which provided a new direction for subsequent pathological research and paves the way for developing new control strategies.

Study on the Infection Mechanism of Penicillium Digitatum on Postharvest Citrus (Citrus Reticulata Blanco) Based on Transcriptomics.

The biological control ability of the yeast, Meyerozyma guilliermondii, in restaining Penicillium expansum infection in apples, has been reported to be enhanced by methy jasmonate (MeJA). Our previous research unveiled the possible physiological biocontrol mechanisms of the yeast; however, the related molecular mechanisms were unclear. This study aimed to investigate the possible molecular mechanisms behind the enhanced biological control efficacy of M. guilliermondii cultured with MeJA through transcriptomic approaches. The transcriptome analysis of MeJA cultured M. guilliermondii indicated that MeJA induced changes in oxidative stress response, energy metabolism, cell wall synthesis and stability and cell growth. Meanwhile, transcriptomic analysis of apples treated with M. guilliermondii and MeJA cultured M. guilliermondii was also investigated. Our results witnessed that MeJA cultured M. guilliermondii enhanced the cell wall synthesis, antioxidant activity, plant disease resistance, increased peroxisome proliferation, energy metabolism, phenylpropane metabolism and other pathways of apples. Expression levels of PPO, EXPA1, TFT6, GHR5, CYP73 and other genes were increased, which enhanced the apple's stability, antioxidant, stress resistance and energy metabolism. This study will provide a theoretical basis for improving the biocontrol efficacy of antagonistic yeast cultured with MeJA. 

Transcriptomic analysis of the mechanisms involved in enhanced antagonistic efficacy of Meyerozyma guilliermondii by methyl jasmonate and disease resistance of postharvest apples

Fangtao He

Papers

Investigating the effect of methyl jasmonate on the biocontrol activity of Meyerozyma guilliermondii against blue mold decay of apples and the possible mechanisms involved

Study on the Infection Mechanism of Penicillium Digitatum on Postharvest Citrus (Citrus Reticulata Blanco) Based on Transcriptomics.

Transcriptomic analysis of the mechanisms involved in enhanced antagonistic efficacy of Meyerozyma guilliermondii by methyl jasmonate and disease resistance of postharvest apples