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Analysis of the trehalose synthesis pathway of Physarum polycehalum.

Authors :: Morita, Rihito
Okano, Shohei
Furukawa, Atsushi
Ishii, Kazuo
Teramoto, Chise
Minami, Yoshiko
Source :: Biochemical & Biophysical Research Communications. Nov2023, Vol. 682, p299-307. 9p.
Publication Year :: 2023
Abstract: Desiccation is a severe survival problem for organisms. We have been studying the desiccation tolerance mechanisms in the true slime mold Physarum polycephalum. We measured the trehalose content of P. polycephalum vegetative cells (plasmodia) and drought cells (sclerotia). Surprisingly, we found that the content in sclerotia was about 473-fold greater than in the plasmodia. We then examined trehalose metabolism-related genes via RNAseq, and consequently found that trehalose 6-phosphate phosphorylase (T6pp) expression levels increased following desiccation. Next, we cloned and expressed the genes for T6pp, trehalose 6-phosphate synthase/phosphatase (Tps/Tpp), maltooligosyltrehalose trehalohydrolase (TreZ), and maltooligosyltrehalose synthase (TreY) in E. coli. Incidentally, TreY and TreZ clones have been reported in several prokaryotes, but not in eukaryotes. This report in P. polycephalum is the first evidence of their presence in a eukaryote species. Recombinant T6pp, TreY, and TreZ were purified and confirmed to be active. Our results showed that these enzymes catalyze reactions related to trehalose production, and their reaction kinetics follow the Michaelis-Menten equation. The t6pp mRNA levels of the sclerotia were about 15-fold higher than in the plasmodia. In contrast, the expression levels of TreZ and TreY showed no significant change between the sclerotia and plasmodia. Thus, T6pp is probably related to desiccation tolerance, whereas the contribution of TreY and TreZ is insufficient to account for the considerable accumulation of trehalose in sclerotia. • Study for the desiccation tolerance mechanisms in a true slime mold Physarum polycephalum. • A large amount of trehalose was accumulated in the drought cells (sclerotia). • The genes (t6pp , tps/tpp , treZ , treY) related to trehalose metabolism were cloned. • T6pp is probably related to desiccation tolerance. • This is the first report of treY and treZ genes from eukaryotic species. [ABSTRACT FROM AUTHOR]