Structure of a Gelasinospora linear plasmid closely related to the kalilo plasmid of Neurospora intermedia

Abstract

We have determined the complete nucleotide sequence of a linear mitochondrial plasmid from a natural isolate of a homothallic species of Gelasinospora. The plasmid genome is 8231 bp long. It carries terminal inverted repeats of 1137 bp. Extending inwards from the terminal repeats are two long open reading frames coding for putative proteins with similarity to DNA and RNA polymerases. These are separated by a short intergenic region. The plasmid sequence shows remarkable similarity to that of the Neurospora intermedia senescence-plasmid kalilo. Overall the two plasmids have a similar genetic organization and are clearly homologous at the sequence level. The main differences are in the intergenic region and in the terminal repeats.

Detection and distribution of six linear mitochondrial plasmids in the shiitake mushroom, Lentinula edodes

“…This suggests the independent replication of these plasmids, and relates to their very high frequency of distribution in natural populations. The widespread incidence of L. edodes plasmids suggests that they may be neutral genetic elements for their hosts, in contrast to the exceptional case of the kalilo plasmid of Neurospora species, which reduces its incidence in populations through its destructive effect on hosts (Arganoza et al, 1994;Debets et al, 1995;Yuewang et al, 1996). The finding that two L. edodes reciprocal dikaryons with the same nuclei but different plasmid types showed similar morphological properties also supports this idea.…”

Polymorphism for pKALILO based senescence in Hawaiian populations of Neurospora intermedia and Neurospora tetrasperma

“…The latter authors did not report whether this particular isolate showed senescence or not. Several homologues of pKALILO were found in a range of diVerent hosts, including Neurospora discreta, N. crassa, and even in the related genus Gelasinospora (He et al, 2000;Marcinko-Kuehn et al, 1994;Yuewang et al, 1996), but all of these plasmids were substantially diVerent from pKALILO at the DNA sequence level and, in contrast to the prototypic plasmid from N. intermedia, those tested neither integrated into the mitochondrial genome nor showed a convincing correlation with senescence. Thus, Kalilo itself has formally never been described in natural populations of Neurospora outside the Hawaiian one of N. intermedia.…”

Neurospora from Natural Populations: A Global Study

“…Three of these subtypes were present in strains belonging to four Neurospora species from Hawaii, Tahiti, Thailand, Ivory Coast, Haiti, and Louisiana (He et al, 1997(He et al, , 2000. The fourth was from a strain of Gelasinospora, a genus closely related to Neurospora (Yuewang et al, 1996). Introgression and subsequent heterokaryosis have been used to transfer pKALILO in both directions between N. crassa and N. tetrasperma (Bok et al, 1999).…”