Minas Gerais, Brazil, is vulnerable to the activities of mineral extraction industries, posing an imminent risk to United Nations Educational, Scientific and Cultural Organization (UNESCO) recognized cities, e.g. Congonhas. Many of these municipalities hold many soapstone religious sculptures and historical monuments. Consequently, soapstone is susceptible to filamentous fungi attack causing irreversible biodeterioration. Despite the concern related to nondestructive sampling of 18th century sculptures, in this study, we have discussed the factors that lead to biodeterioration of soapstone due to organic acid excretion by the fungi that damage the stone, thereby providing an insight in conserving and preserving the soapstone monuments.

Fusarium verticillioides is pathogenic to maize and mycotoxin-producer, causing yield losses, feed and food contamination, and risks to human and animal health. Endophytic (ISD04 and IPR45) and epiphytic (CT02 and IM14) bacteria from maize silks were tested in vitro and greenhouse against F. verticillioides and for hydrolytic enzyme production (cellulase, pectinase, protease, lipase, and chitinase). The strains were assigned as Achromobacter xylosoxidans (ISD04), Pseudomonas aeruginosa (IPR45), and Bacillus velezensis (CT02 and IM14) by 16S gene sequencing. All strains showed antifungal activity in vitro with inhibition values from 58.5–100%; they changed hyphae morphology and inhibited the conidial germination by up to 100% (IPR45). The four strains produced at least one enzyme with antifungal activity. The microbiolized seeds reduced the fungal development in stored grains and stalk rot severity in the greenhouse by 72.6% (ISD04). These results highlight the potential of these strains as biocontrol agents against F. verticillioides

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Abstract:The present study aims to evaluate the environmental effect on fungal community composition associated with biodeterioration occurring in stones (soapstone) at two distinct locations in Minas Gerais State, Brazil: Congonhas city and Sanctuary of Caraça. Four collections of fungal communities over one year were obtained from both research sites from the soapstone block surfaces exposed for over two decades. The molecular diversity profile of the fungal community at the two localities was obtained by DGGE (Denaturing Gradient Gel Electrophoresis), and the genomes of the most representative population were sequenced. DGGE showed the formation of two clusters with filamentous fungal communities. Sequencing of the most representative bands revealed the presence of fungi associated with the biodeterioration of soapstone. In addition, many of the identified species were associated with photobionts that could generate lichens, indicating that environmental characteristics affect the occurrence of filamentous fungi, which leads to biodeterioration of stones. Authors' study focused on an environmental variation of an extreme habitat for fungi associated with soapstone in the state of Minas Gerais, Brazil and identified the presence of interesting rock-inhabiting fungal communities including species related to lichens, which can accelerate the deterioration of stones by the production of organic acids.

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