The phosphatidylethanolamine-binding protein (PEBP) family plays an important role in plant growth and development, flowering, seed formation, and dormancy. In this study, we searched for candidate genes for FLOWERING LOCUS T (FT) orthologs in the indigo plant, Polygonum tinctorium, using a leaf RNA-seq database. We identified nine PEBP family sequences, including five FT-like genes (PtFT1―5) in P. tinctorium. In the expression analysis under two different conditions, a 12 h photoperiod as a short-day condition and a 24 h photoperiod as a long-day condition, PtFT2 and PtFT4 were significantly upregulated under short-day conditions than under long-day conditions. In the photoperiodic response under short-day conditions with monochromatic blue LED light, PtFT2, PtFT4 and PtFT5 significantly increased during the light period of the day, peaking toward the middle or end of the light period. In addition, PtFT2 expression significantly increased in a time-dependent manner in leaves grown under short-day blue LED light conditions, whereas PtFT4 and PtFT5 levels gradually decreased. These results suggest that blue light-induced expression of PtFT2 in leaves under floral-inductive conditions may be involved in promoting flower bud formation in P. tinctorium.

　Ralstonia pseudosolanacearum is a soilborne bacterium causing bacterial wilt. The wild-type strain undergoes phenotypic conversion (PC) to its avirulent form, and PC mutants function as biocontrols for plant diseases. However, the underlying mechanisms of PC is unclear. In this study, we investigated the effect on induction of PC in wild-type strains by addition of iron chloride (IC), citric acid (CA) and ferric ammonium citrate (FAC) in minimal medium (MM) broth. PC frequently occurred in MM broth supplemented with IC or CA, alone or in combination, under static culture conditions. However, PC was not induced by shaking culture. We investigated PC induction in five strains (phylotype I) of different classifications. Strains 8238, 8216, and 8232 were likely to induce PC by adding 1% CA and 0.1–1% FAC; however, 8214 and 8357 strains were less likely to undergo PC. The frequency of PC by FAC varied depending on the bacterial strain and pH 5–8 conditions; strains 8238 and 8216 frequently induced PC, but strain 8214 did not induce PC. This study clarified the culture conditions and bacterial strains likely to induce PC by application of IC, CA, and FAC, and will be useful for elucidating the mechanism of PC.

　The application of circadian clock technology to agriculture (“Chronoculture”) is gaining attention. The circadian clock responds to environmental stimuli and the response is represented by a phase response curve (PRC). When multiple inputs, such as light and temperature, are applied, the combined PRC becomes more complex, particularly when there is a time lag between the stimuli. This response arises from the clock cells that function as coupled oscillator systems. To analyze these dynamic and complex interactions, we developed a simulator using the Unity game engine to model the environmental stimulus response of a population of circadian clock cells. We introduce the Condensed Unit of Biological Environment (CUBE), a digital object that represents complex environmental inputs. Using CUBE in the simulation, we analyzed the synchronization response of oscillators in a minimal plant model represented as a phytomer. Applying CUBE could alter oscillator synchronization. Pre-constructed CUBEs could locally form distinct spatiotemporal patterns corresponding to each CUBE. This Unity based simulator offers real-time visualization and a new spatiotemporal analysis method to ensure the reproducibility of complex biological environments.

　This study aimed to non-destructively identify the maturity level of Tongar avocado fruit using thermal imaging method. Thermal images of Tongar avocados at four maturity stages, based on harvest times of 150, 180, 210, and 240 days after flowering (DAF), were captured using a FLIR C3-X thermal camera. The images were then processed using software developed in MATLAB to extract hue, saturation, intensity (HSI) values and surface temperature. The results showed that changes in fruit skin color values (HSI) were observed; however, these differences were not consistently significant across all maturity stages. There were significant differences in surface temperature across maturity stages. These results indicate that color parameters cannot serve as dependable indicators, while surface temperature can be used as quantitative indicators in determining Tongar avocado maturity. Thermal imaging has great potential as a non-destructive method for accurate and efficient classification and prediction of avocado maturity.

　For strawberry (Fragaria×ananassa Duch.) production in a plant factory with artificial lighting and a growth shelf with a fixed height, we noted that a cultivar with a greater plant height (tall cultivar) had a higher photosynthetic rate and yield than those of a cultivar with a lesser plant height (dwarf cultivar) due to the variation in light intensity induced by different distances from the light source to the plant. We hypothesized that the dwarf cultivar could have the same yield level in the same light intensity as that of the tall cultivar by positioning the light source close to the plant. Here, gas exchange, growth, and yield were measured in three treatments (a tall cultivar, a dwarf cultivar with a closer, and that with a conventional distance from the plant to the light). The photosynthetic rate and yield of the dwarf cultivar positioned closer to the light source were almost the same as those of the tall cultivar and higher than those of the dwarf cultivar placed a conventional distance from the light source. This demonstrates that improved productivity should be possible by adjusting the position of the light source according to the plant height for each cultivar.