Co-Infections by Fusarium circinatum and Phytophthora spp. on Pinus radiata: Complex Phenotypic and Molecular Interactions

Abstract

This study investigated the complex phenotypic and genetic response of Monterey pine (Pinus radiata) seedlings to co-infections by F. circinatum, the causal agent of pine pitch canker disease, and the oomycetes Phytophthora xcambivora and P. parvispora. Monterey pine seedlings were wound-inoculated with each single pathogen and with the combinations F. circinatum/P. xcambivora and F. circinatum/P. parvispora. Initially, seedlings inoculated only with F. circinatum showed less severe symptoms than seedlings co-inoculated or inoculated only with P. xcambivora or P. parvispora. However, 30 days post-inoculation (dpi), all inoculated seedlings, including those inoculated only with F. circinatum, showed severe symptoms with no significant differences among treatments. The transcriptomic profiles of three genes encoding pathogenesis-related proteins, i.e., chitinase (PR3), thaumatin-like protein (PR5), phenylalanine ammonia-lyase (PAL), and the pyruvate decarboxylase (PDC)-encoding gene were analyzed at various time intervals after inoculation. In seedlings inoculated with single pathogens, F. circinatum stimulated the up-regulation of all genes, while between the two oomycetes, only P. xcambivora induced significant up-regulations. In seedlings co-inoculated with F. circinatum and P. xcambivora or P. parvispora none of the genes showed a significant over-expression 4 dpi. In contrast, at 11 dpi, significant up-regulation was observed for PR5 in the combination F. circinatum/P. xcambivora and PDC in the combination F. circinatum/P. parvispora, thus suggesting a possible synergism of multiple infections in triggering this plant defense mechanism.

Antifungal activity of selected lactic acid bacteria from olive drupes

“…inhibited by LABs isolated from olive drupes, such as A. alternata, C. acutatum, C. gloeosporioides, F. oxysporum and Ph. nicotianae, are very polyphagous pathogens (Aloi et al, 2021;Biasi et al, 2016;Dean et al, 2012;Kamali-Sarvestani et al, 2022;Kamoun et al, 2015;Riolo et al, 2021) Colletotrichum species, but P. nordicum was an exception as its sensitivity to CFSs of most bacterial isolates was even lower than the sensitivity showed by Colletotrichum species. This sensitivity of P. nordicum to fermentates of LABs is consistent with the results of Guimarães et al (2018).…”

“…oleae were grown on Oat Meal Agar (OMA, Thermo Fisher, Waltham, Massachusetts, USA) at 22°C in the dark for 7 days. Zoospore production was performed according to Aloi et al (2021). Zoospore concentration was determined with a Neubauer chamber and adjusted to 10 4 zoospores/mL.…”

DEFHAZ: A Mechanistic Weather-Driven Predictive Model for Diaporthe eres Infection and Defective Hazelnut Outbreaks

“…Other authors have reported co-occurring fungi in hazelnuts in different geographic areas [17,34,35]. Co-occurring microorganisms of other pathosystems are catching the attention of scientists [36,37], and they have acquired increasing relevance due to climate change for mycotoxin-producing fungi [38][39][40]. In particular, the co-occurrence of Diaporthe with the Aspergillus section Flavi has safety relevance due to the large proportion of nuts that fail quality standards for human consumption, and especially in Europe [41][42][43].…”

Phytophthora Root and Collar Rot of Paulownia, a New Disease for Europe

“…Even though simultaneous infections by more than a single pathogen of the same genus or different genera in plants are frequent in natural conditions, the complex phenotypic and genetic responses of plants to multiple infections are still scarcely known. However, they are receiving increasing attention, and recent studies focused also on co-infections by species of Phytophthora [37,38].…”