Seasonal Variations in Fungal Communities on the Surfaces of Lan Na Sandstone Sculptures and Their Biodeterioration Capacities.

Environmental factors and climate are the primary factors influencing the microbial colonization and deterioration of cultural heritage in outdoor environments. Hence, it is imperative to investigate seasonal variations in microbial communities and the biodeterioration they cause. This study investigated the surfaces of sandstone sculptures at Wat Umong Suan Phutthatham, Chiang Mai, Thailand, during wet and dry seasons using culture-dependent and culture-independent approaches. The fungi isolated from the sandstone sculptures were assessed for biodeterioration attributes including drought tolerance, acid production, calcium crystal formation, and calcium precipitation. The results show that most of the fungal isolates exhibited significant potential for biodeterioration activities. Furthermore, a culture-independent approach was employed to investigate the fungal communities and assess their diversity, interrelationship, and predicted function. The fungal diversity and the communities varied seasonally. The functional prediction indicated that pathotroph-saprotroph fungi comprised the main fungal guild in the dry season, and pathotroph-saprotroph-symbiotroph fungi comprised the dominant guild in the wet season. Remarkably, a network analysis revealed numerous positive correlations among fungal taxa within each season, suggesting a potential synergy that promotes the biodeterioration of sandstone. These findings offer valuable insights into seasonal variations in fungal communities and their impacts on the biodeterioration of sandstone sculptures. This information can be utilized for monitoring, management, and maintenance strategies aimed at preserving this valuable cultural heritage.

Quinclorac resistance in Echinochloa phyllopogon is associated with reduced ethylene synthesis rather than enhanced cyanide detoxification by ß-cyanoalanine synthase.

BACKGROUND: Multiple herbicide resistant Echinochloa phyllopogon exhibits resistance to the auxin herbicide quinclorac. Previous research observed enhanced activity of the cyanide-detoxifying enzyme ß-cyanoalanine synthase (ß-CAS) and reduced ethylene production in the resistant line, suggesting ß-CAS-mediated cyanide detoxification and insensitivity to quinclorac stimulation as the resistance mechanisms. To investigate the molecular mechanisms of quinclorac resistance, we characterized the ß-CAS genes alongside plant transformation studies. The association of ß-CAS activity and ethylene production to quinclorac resistance was assayed in the F6 progeny of susceptible and resistant lines of E. phyllopogon. RESULTS: A single nucleotide polymorphism in a ß-CAS1 intron deleted aberrantly spliced mRNAs and enhanced ß-CAS activity in the resistant line. The enhanced activity, however, was not associated with quinclorac resistance in F6 lines. The results were supported by lack of quinclorac resistance in Arabidopsis thaliana expressing E. phyllopogon ß-CAS1 and no difference in quinclorac sensitivity between ß-CAS knockout and wild-type rice. Reduced ethylene production co-segregated with quinclorac resistance in F6 lines which were previously characterized to be resistant to other herbicides by an enhanced metabolism. CONCLUSION: ß-CAS does not participate in quinclorac sensitivity in E. phyllopogon. Our results suggest that a mechanism(s) leading to reduced ethylene production is behind the resistance. © 2019 Society of Chemical Industry.