Embryonic development of parthenogenetic and sexual eggs in lower
termites Running title Differences of parthenogenetic ability in two
termite species
Abstract
Termites are ancient social insects worldwide. In this research,
developmental stages of embryos in the sexual and parthenogenetic eggs
of Reticulitermes chinensis and R. aculabialis were observed and
categorized. The embryonic development eggs was decteted by DAPI
staining, single transcriptome sequencing analysis and RT-PCR . The
ovarian development of FF and FM groups in R. flaviceps occurred in the
early developmental stages, whilst in R. aculabialis, this occurred
mainly in the late developmental stage. The difference was significant
in micropyle number between the R. flaviceps FF colony type and the
R.aculabialis FF colony type. There were no significant differences in
the number of micropyles between other groups. In R. flaviceps, 86% of
unfertilized eggs stopped development during the formation of the
blastoderm, with the yolk cell gathering extensively at the egg center.
Single-cell transcriptome sequencing analysis were annotated many genes
in this two species termite. According this answer we analyzed the
egg-to-larvae genes expression, and found that the expression levels of
PKA, MAP2K1, MAPK1/3, HGK, MKP and Pax6 gene in RaFF were significantly
higher than RfFF (P<0.05). We found a significantly lower
oocyte cleavage rate in R. flaviceps than in R. aculabialis, resulting
in fewer developed oocytes in R. flaviceps. In both species, activation
and one or two cleavage events of oocytes occurred during ovulation, but
in R. flaviceps the development of unfertilized eggs stopped. We suggest
that genes with significant expression differences may play an important
role in oocyte and embryonic development in termites.