Genetic Analysis of Pigmentation inCordyceps militaris

Abstract

Pigmentation of ascospore-derived isolates from seven different natural specimens of Cordyceps militaris EFCC C-5888, EFCC C-7159, EFCC C-7833, EFCC C-7991, EFCC C-8021, EFCC C-8023 and EFCC C-8179 was observed on the plates of Sabouraud Dextrose agar plus Yeast Extract at 25℃ under continuous illumination (500 lux). Pigmentation of the wild-type isolates of C. militaris was diverse ranging from yellowish white to orange, while white color was believed as a mutant. Inheritance of pigmentation was found to be controlled by both parental isolates when F1 progeny were analyzed. Pigmentation and mating type were shown to be either independent or distantly linked each other due to the high percentage of non-parental phenotypes among F1 progeny. Crosses between white mutant isolates of C. militaris yielded progeny with wild type pigmentations, indicating that the albino mutations in the parents were unlinked to each other.

Observations on Some of the Mycelial Growth and Pigmentation Characteristics ofCordyceps militarisIsolates

“…Since C. militaris shows heterothallism during in vitro fruiting (Shrestha et al, 2004, 2005), phenotypic characteristics of the isolates of this fungus can be utilized for the selection of superior isolates for higher fruit body production and for the isolation of bio-active compounds. Changes in phenotypic characteristics of the isolates of C. militaris during subculturing can also be studied in relation to fruiting nature or production of bio-active compounds.…”

Cultural Characteristics and Fruiting Body Production inCordyceps bassiana

“…In wild, the color of C. bassiana is yellow. White colonies have also been reported, though much less in numbers, in C. militaris [11, 12], but it is quite common in C. bassiana . Crossings between white isolates EFCC 12511a × b 1 × 6 and 1 × 9 produced only mycelial growth or synnemata, but not perithecial stromata, while the crossing 3 × 9 produced perithecial fruiting bodies (Fig.…”

“…Also, it has been shown that colony pigmentation has no correlation with mating type in C. militaris [12]. C. bassiana isolates produce synnemata very profusely from both single isolates and their combinations, although perithecial stromata are also produced, usually from crossings of mating-compatible isolates [5].…”

Selection of Superior Strains ofCordyceps militariswith Enhanced Fruiting Body Productivity

“…For single ascospore isolation, stromata were detached from rice pupae medium and attached to the innerside of lids of Petri dishes containing WA. Single ascospores were picked up following the method of Shrestha et al (2004a, 2005a, b) and inoculated on fresh SDAY agar plates.…”

“…But, unstable fruiting body production poses a serious problem for large scale extraction of bio-active compounds from stromata of C. militaris (Shrestha et al, 2004b; Sung, 1996). More recently, bipolar heterothallism was shown during fruiting body production of C. militaris by inoculating single spore strains in pair-wise combinations in rice pupae medium (Shrestha, 2003; Shrestha et al, 2004a, 2005a, b). Relationship between colony pigmentation and mating type was also investigated by crossing strains with different pigmentation types (Shrestha et al, 2005a).…”