Diversification in flowering time due to tandem FT-like gene duplication, generating novel Mendelian factors in wild and cultivated rice

The complex structure of a single Mendelian factor widespread in the Asian cultivated rice ( Oryza sativa ) and its wild progenitor ( Oryza rufipogon ) that caused diverse phenotypes in the timing of flowering under natural field conditions was investigated in near isogenic lines. These near isogenic lines showed differences in flowering time despite all eight accessions collected from tropical regions possessing a recessive gene allelic to the se-pat gene. Fine mapping in two of these near-isogenic lines revealed that cultivated (Patpaku) and wild (W593) accessions had three and two linked quantitative trait loci (QTL) in the candidate regions, respectively, showing that Patpaku and W593 possessed linked QTLs with different effects in addition to the commonly-observed recessive gene ( se-pat ). Molecular dissection suggested that the tandemly duplicated FT-like genes ( Hd3a and RFT1 ) could be the candidate genes for these QTLs. Interestingly, the linked QTLs differed in their epistases, degree of dominance, and genotype × environment interactions. The nucleotide sequences showed that RFT1 has diverged more rapidly than Hd3a during rice evolution, suggesting phenotypic diversification of the two genes. Phylogenetic analysis implied that the se-pat ⁺ alleles might have emerged in different lineages within O. sativa . The present results strongly suggest that nucleotide divergence and shuffling of the linked QTLs by recombination might have created novel Mendelian factors that probably contribute to responding to local environments.     

Prothoracicotropic Hormone Bioassay: Pupal-Adult Bombyx Assay

Blockage of adult development by brain removal and its resumption by application of the prothoracicotropic hormone (PTTH) were studied using pupae of a racial hybrid J-122 × C-115 of Bombyx mori . A log-linear dose-response relationship was obrained after injection of a PTTH solution. The Bombyx -unit of PTTH has been defined from this dose-response curve.     

Fungus gnats of the genera Anatella,Allodia and Cordyla in Japan (Diptera: Mycetophilidae)†

Six new mycetophilid species from three genera belonging to the tribe Exechiini are described: Anatella prominens on a fungus of the Polyporaceae, Allodia bipexa and Allodia conifera on fungi of the Russulaceae, Allodia quadrata on fungi of the Hygrophoraceae, Tricholomataceae, Rhodophyllaceae, Russulaceae and Fistulinaceae, Allodia laccariae on a fungus of the Tricholomataceae, and Cordyla bidenticulata on a fungus of the Boletaceae. Their characteristic male genitalia are illustrated. Cordyla flaviceps Staeger, Cordyla fusca Meigen and Cordyla pusilla Edwards are newly recorded from Japan.     

Species Specificity of the Insect Prothoracicotropic Hormone (PITH): the Presence of Bombyx-and Samia-Specific PTTHs in the Brain of Bombyx mori

Crude extracts of Bombyx mori brains can provoke adult development when injected into brain-removed dormant pupae of Bombyx mori and Samia Cynthia ricini. From this fact the prothoracicotropic hormone (PTTH) of Bombyx has long been thought to be species-nonspecifically active on Samia. Chemical fractionation of Bombyx brain or head extracts by fractional precipitation with acetone, Sephadex G-50 gel-filtration, and DEAE-Sepharose CL-6B chromatography, however, separated the fractions which activated Bombyx brainless pupae from those which activated Samia. Those results reveal the existence of two species-specific PTTHs.     

CHANGES IN TITER OF THE BRAIN HORMONE DURING DEVELOPMENT OF THE SILKWORM, BOMBYX MORI

Changes in titer of brain hormone (BH) extracted from the brain, head, and thorax and abdomen during the development of Bombyx mori from the 4th larval molting up to 6 days after adult emergence were investigated. The hypothesis is presented that high secretory activity of the brain is not reflected in a corresponding change in its BH titer, while low secretory activity brings about an accumulation of BH in the brain. An interesting finding is that extremely high titers of BH were found in the thorax and abdomen, from 4 days after pupation to adult emergence, of females only. This sexual difference was, however, not found in all of the races examined.     

Pteromalid parasitoids (Hymenoptera) of Oulema oryzae (Kuwayama) (Coleoptera: Chrysomelidae) from Japan, with notes on Pteromalus bifoveolatus

The present paper discusses three Japanese species of Pteromalidae reared from cocoons of the rice beetle Oulema oryzae (Kuwayama, 1929) (Coleoptera, Chrysomelidae). Pteromalus cyclostomus Ishizaki sp. nov. is described. Spaniopus monospilus (Thomson, 1878) and Usubaia liparae Kamijo, 1983 are newly recognized as parasitoid wasps of O. oryzae , and the former is also recorded from Japan for the first time. Pteromalus bifoveolatus Förster, 1861 is also newly recorded from Japan, with a new host record from Samia cynthia pryeri (Lepidoptera: Saturniidae).     

Intra-guild predation and variation in egg defence between sympatric and allopatric populations of two species of ladybird beetles

Abstract.  1. Ladybird eggs are defended chemically against intra-guild predation, and are unsuitable to varying degrees as food for other ladybirds.
2. Ladybird eggs [ Coccinella septempunctata (Cs) and Harmonia axyridis (Ha); Coleoptera: Coccinellidae] from local Japanese versus North American populations were compared as food for two ladybirds (Cs and Ha) co-occurring in Japan.
3. Larvae of Cs exhibited high mortality, slow development, and reduced egg consumption and weight gain when they fed on Ha versus conspecific eggs, especially when Ha eggs were from the local (Japanese) population versus a distant (North American) population of Ha.
4. Larvae of Ha survived equally well on a diet of Cs or conspecific eggs, but developed more slowly and gained less weight on Cs eggs. Ha larvae were more reluctant to eat eggs from the local (Japanese) population of Cs than eggs from the distant (North American) population of Cs; however, other measures of performance did not differ significantly.
5. These results indicate greater egg chemical defence of Ha eggs against Cs larvae than vice versa, as expected from field observations of greater temporal overlap between Cs larvae and Ha eggs than between Ha larvae and Cs eggs. Furthermore, results also indicate that local populations of eggs are better defended than eggs from elsewhere against locally occurring intra-guild predators. Thus, it appears that the effectiveness of chemical defence of ladybird eggs reflects the degree to which specific pairings of ladybirds have the potential to interact in nature through egg predation.     

Cold‐induced organelle relocation in the liverwort Marchantia polymorpha L.

Organelles change their subcellular positions in response to various environmental conditions. Recently, we reported that cold treatments alter the intracellular position of chloroplasts and nuclei (cold positioning) in the fern Adiantum capillus‐veneris; chloroplasts and nuclei localized to the periclinal cell wall relocated to anticlinal cell wall after cold treatments. To further understand organelle positioning under cold conditions, we studied cold‐induced organelle relocation in the liverwort Marchantia polymorpha L. When sporelings and gemmmalings were treated under low temperature (5 °C), chloroplast cold positioning response was successfully induced both in the sporelings and the gemmmalings of M. polymorpha. Using a genetic transformation, nuclei, mitochondria or peroxisomes were visualized with a fluorescent protein, and the transgenic gemmmalings were incubated under the cold condition. Nuclei and peroxisomes, but not mitochondria, clearly relocated from the periclinal cell wall to the anticlinal cell wall after cold treatments. Our findings suggest that several organelles concurrently change their positions in the liverwort cell to cope with cold temperature.     

Further Evidence for the Presence of a Circadian Clock in the Prothoracic Glands of the Saturniid Moth Samia cynthia ricini: Decapitated Larvae Can Respond to Light-Dark Changes

A small peak of haemolymph ecdysteroid titre precedes the gut purge that characterizes larval-prepupal transition of the saturniid moth Samia cynthia ricini. This peak shifts its phase in parallel with the phase shifts of gut purge according to the changes in light-dark conditions preceding gut purge. Decapitated larvae responded to these light-dark changes as intact larvae did, as assessed by the phase shifts of the haemolymph ecdysteroid peak. This indicates that the brain-centred PTTH clock is not prerequisite for realization of the circadian-clock-controlled timing in the initiation of prepupal development, and supports indirectly our previous notion that the prothoracic glands of Samia possess a circadian clock dictating gut purge timing.