摘要：We recently isolated a novel adenylyl cyclase/cAMP phosphodiesterase gene from the liverwort,
Marchantia polymorpha. The protein encoded by this gene has a class III adenylyl cyclase (AC) in the C-terminal domain and class I phosphodiesterase (PDE) in the N-terminal domain; therefore, we named it CAPE (COMBINED AC with PDE). CAPE protein is likely involved in spermatogenesis and sperm motility due to its tissue-specific expression pattern in
M. polymorpha and the distribution of
CAPE genes in streptophytes. However, little is known about the distribution of
CAPE in gymnosperms that use motile sperm for fertilization, such as cycads and ginkgo. The present study aimed to isolate
CAPE genes from the cycad,
Cycas revoluta, the ginkgo,
Ginkgo biloba, and the hornwort,
Anthoceros agerestis. Sequences with high homology to
CAPE were obtained from these species. Our analyses revealed that all plant taxonomic groups reproducing via motile sperm possessed
CAPE, whereas those that do not produce motile sperm did not possess
CAPE, with one exception in gymnosperm Cupressales. The phylogenic distribution of
CAPE almost corresponds to the evolutionary history of motile sperm production and further suggests that
CAPE may be involved in sexual reproduction process using motile sperm in streptophytes.
