Biosynthesis and degradation of storage protein in spores of the fungus Botryodiplodia theobromae

Abstract

Muiridin, a spore-specific protein of the fungus Botryodiplodia theobromae, comprises about 25% of the mature pycnidiospore protein. It has an apparent molecular weight of 16,000 to 17,000 and is rich in glutamine, asparagine, and arginine. Muiridin is synthesized in developing spores via a precursor with an apparent molecular weight of 24,000. Two other polypeptides present in young developing spores with apparent molecular weights of 18,000 and 15,000 are immunologically related to muiridin. We propose a pathway for muiridin synthesis. Muiridin is actively degraded during the germination of spores from 30-dayold cultures. This degradation is independent of exogenous amino acids in the germination medium. In contrast, glutamine and, to a lesser extent, asparagine partially inhibit the degradation of muiridin during germination of spores from 7day-old cultures.

Germinating spores of Glomus intraradices can use internal and exogenous nitrogen sources for de novo biosynthesis of amino acids

“…1). Fungal spores have been reported to store N as protein bodies (Petersen et al ., 1983; Cruz, 2004), and a decrease in the intensity of protein bands on gels supports the idea that proteins are utilized during germination (Avio & Giovannetti, 1998). The expression of GDH during presymbiotic growth (Fig.…”

Synthesis and localization of a development-specific protein in sclerotia of Sclerotinia sclerotiorum

“…We also have evidence that the development-specific protein muiridin, which makes up 25% of the spore protein in Botryodiplodia theobromae (42), is localized in protein bodies (manuscript in preparation). Muiridin is actively degraded during spore germination and thus presumably functions as a storage protein, i.e., serves as a source of amino acids during spore germination (33).…”