Mycelial development preceding basidioma formation in Moniliophthora perniciosa is associated to chitin, sugar and nutrient metabolism alterations involving autophagy

Abstract

We identified and characterized two chitinases, named MpCHIT1 and MpCHIT2, from the fungus Moniliophthora perniciosa - the etiologic agent of witches' broom disease in cacao tree (Theobroma cacao L.) - during its development, mainly in the mycelia phases preceding the basidioma formation. The expression of MpCHIT1 and MpCHIT2, together with MpCHS and MpATG8 (chitin synthase and autophagy genes, respectively), was analyzed during the M. perniciosa growth and development on bran-based solid medium as well as in liquid medium containing H2O2 or rapamycin (oxidative and nutritional related-autophagy stress agents, respectively). In order to link the expression of chitin metabolism-related genes to nutritional composition influencing fungus development, we also quantified total and reduced sugars, as well as macro- and micronutrients in the bran-based solid medium. The expression analysis showed that the MpCHS expression increased through mycelial development and then decreased in the primordium and basidioma phases, while the expression of MpCHIT1 and MpCHIT2 was higher in basidioma and primordium phases, respectively. Moreover, the expression pattern of MpCHIT1 and MpCHIT2 is distinct, the second correlated with the MpATG8 expression pattern and possibly with autophagy process, while the first may be related to the basidioma formation. The quantification of total and reduced sugars, as well as macro- and micronutrients supported the idea that the cell wall restructuration due to MpCHS, MpCHIT1 and MpCHIT2 is related to stress and fungal nutrient reallocation, allowing the formation and development of the basidioma. Experiments involving M. perniciosa growth on liquid medium containing H2O2 or rapamycin showed that MpCHIT1 and MpCHIT2 were over-expressed in response to oxidative but also to nutritional related-autophagy stresses. Interestingly, the expression level of MpCHS, MpCHIT1 and MpCHIT2 in presence of rapamycin is similar to the one observed in the primordium and basidioma from bran-based solid medium. The analysis of the overall data allowed designing a general scheme of chitin metabolism and autophagy during M. perniciosa development, focusing on the mycelium phases as crucial and environmentally influenced steps preceding the primordium and basidioma formation. These data support the idea that the nutritional environment of M. perniciosa influences its development and life cycle.

State of the Art of the Molecular Biology of the Interaction between Cocoa and Witches’ Broom Disease: A Systematic Review

“…Biochemical modifications of hosts when infected by M. perniciosa have also been investigated [ 27 ]. Cultivation protocols have been established, such as the artificial cultivation in cookies that allow the production of basidiocarps [ 28 ], followed by molecular studies of the fungus’ necrotrophic phase based on this type of cultivation [ 23 , 29 ]. With technological advances, improvements in the cultivation and manipulation techniques of the fungus have been achieved [ 30 , 31 ].…”

Genome‐wide in vitro and in vivo RNAi screens reveal Fer3 to be an important regulator of kkv transcription in Drosophila

“…7). Although the effect of autophagy on chitin synthesis in insects has not been reported to date, the effects of nutritional‐related autophagy stresses on the transcription of chitin synthase genes have been reported in the fungi Moniliophthora perniciosa (Gomes et al ., 2016). We suspect that autophagy may also affect chitin synthase in Drosophila by altering nutrient distribution.…”

Saprotrophic proteomes of biotypes of the witches' broom pathogen Moniliophthora perniciosa

“…Due to their economic impact and global threat, much research has been devoted to the genomes of both species, M. perniciosa (Mondego et al 2008) and, more recently, M. roreri (Meinhardt et al 2014;Díaz-Valderrama and Aime 2016). Genome information has underpinned recent studies on transcripts expressed in vitro or in planta during the M. perniciosa life-cycle, by revealing or confirming potential pathogenesis and developmental functions (Pires et al 2009;Leal et al 2010;De Oliveira et al 2012;Thomazella et al 2012;Franco et al 2015;Gomes et al 2016).…”