Mathematically modeling photosynthesis helps to interpret gas exchange in a plant and estimate the photosynthetic rate as affected by environmental factors. Notably, the photosynthetic rate varies among leaf vertical positions within a single plant. The objective of this study was to measure the distinct photosynthetic rate of lily (Lilium Oriental Hybrid ‘Casa Blanca’) at the upper, medium, and basal leaf positions. Subsequently, the FvCB (Farquhar-von Caemmerer-Berry) photosynthesis model was employed to determine the parameters of the model and compared it with a rectangular hyperbola photosynthesis model. The photosynthetic rates were measured at different intracellular CO2 concentrations () and photosynthetic photon flux density (PPFD) levels. SPAD values significantly decreased with lowered leaf position. The photosynthetic rates at the medium and basal leaves were lower compared with the upper leaves. FvCB model parameters,  and   , showed no significant difference between the medium and basal leaves. Estimated photosynthetic rates from derived parameters by the FvCB model demonstrated over 0.86 of R2 compared with measured data. The rectangular hyperbola model tended to overestimate or underestimate photosynthetic rates at high  with high PPFD levels or low  with high PPFD levels, respectively, at each leaf position. These results indicated that the parameters of the FvCB model with different leaf positions can be used to estimate the photosynthetic rate of lily.

Salinity stress is a major threat to plant growth and development, affecting crop yield and quality. This study investigated the effects of different salinity levels on photosynthetic responses and bulb growth of Lilium LA hybrid “‘Serrada’.” Plants were irrigated with 1 L of 0, 200, and 400 mM NaCl solutions every two weeks for 14 weeks in a greenhouse. At the end of the cultivation period, the substrate pH decreased, and electrical conductivity increased with increasing salinity. Regardless of salinity levels, the days to flowering and number of flowers were similar among treatments. In contrast, the flower width, plant height, number of leaves, and leaf area decreased with increasing NaCl concentrations. Although there were no differences in the photosystem II (PSII) operating efficiency and maximum quantum yield of PSII, net CO2 assimilation rates (An) and stomatal conductance (gs) were significantly reduced at 200 and 400 mM NaCl solutions compared to the control. At 400 mM NaCl solution, bulb diameter and weight significantly decreased at the end of the experiment. These results suggest that bulb growth inhibition could be attributed to limiting photosynthetic rate and stem growth. This finding suggests that salinity mitigation is necessary to maintain plant growth and photosynthetic capacity in lily cultivation on salt-affected soils.

Biological properties of antimicrobial peptides (AMPs) of hemimetabolous insect are poorly characterized in innate immunity field. To investigate the biochemical properties of hemimetabolous insect’s AMPs, we purified the pyrrhocoricin-like AMP from the hemolymph of Riptortus pedestris and then named as riptocin. We successfully determined the primary protein structure and its cDNA sequence. Interestingly, the determined cDNA revealed that riptocin precursor is composed of 12 repeating units of active riptocins, which implied that riptocin precursor might require to be processed to generate active riptocins by several unidentified processing enzymes. In order to characterize the bio-processing mechanisms of riptocin precursor, we generated the antibody against active riptocin. Using quantitative PCR and Western blot analyses, we showed that gene of riptocin was started to express from the fatbody after three hours post bacterial infection. To address our hypothesis that active riptocin is generated from riptocin precursor by several processing enzymes, we need to obtain the riptocin precursor. Currently, we are expressing the recombinant riptocin precursor using in vitro translation system. Meanwhile, we investigated whether naive hemolymph (naive HL), which may contain precursor riptocin, can generate active riptocin when riptocin precursor was co-incubation with bacteria-challenged hemolymph (active HL), which may contain all processing enzymes. Actually, when naive HL was incubated with active HL, antimicrobial activity was dramatically increased, suggesting that processing enzymes in active HL may induce processing of riptocin precursor to generate active riptocins.

The four genetically distinct isolates have been identified previously from Bombyx mori nucleopolyhedroviruses (BmNPVs) isolated in Korea. To further understand the complex of viruses infecting Bombyx mori, the genome of BmNPV-K1 and K4 strains was completely sequenced and analyzed in comparison with the genome of other sequenced baculoviruses including previously reported BmNPV. BmNPV-K1 consisted of 127,542 bp and 133 open reading frames (ORFs) of 150 nucleotides or longer with minimal overlap have been identified. In contrast, BmNPV-K4 consisted of 128,615 bp and 134 open reading frames (ORFs). Although gene arrangement is virtually identical, the genome of BmNPV-K4 is 1,073 bp longer than BmNPV-K1. This was related to the more existence of bro genes in BmNPV-K4. To investigate the relationship between BmNPV-K1 and K4, phylogenetic analysis with each member of the paired ORFs was performed. The sequence data suggest that BmNPVK1 and BmNPV-K4 are closely related but have diverged and evolved into two separate strains. This was study to identify highly related but separately evolving viruses in the same insect host and geographic location. We are currently comparing the differences of these BmNPV genomes to elucidate characteristics of each virus.

Mamestra brassicae nucleopolyhedrovirus-K1 (MabrNPV-K1) was isolated from naturally infected Mamestra brassicae (Lepidoptera: Noctuidae) larvae in Korea. Restriction endonuclease fragment analysis using EcoRI, PstI, and BamHI estimated that the total genome size of MabrNPV-K1 is about 150 Kb. The full genome sequences of MabrNPV-K1 were determined, analyzed and compared to those of other baculoviruses. The MabrNPV-K1 genome consisted of 152,471 bp and had an overall G + C contents of 39.90 %. Computer-assisted analysis predicted 159 open reading frames (ORFs) of 150 nucleotides or greater that showed minimal overlap. The gene content and arrangement in MabrNPV-K1 were most similar to those of Mamestra configurata nucleopolyhedrovirus-B (MacoNPV-B), including three polh, p10 and lef-8 gene homologues. The MabrNPV-K1 genome contains four homologous repeat regions (hr1,hr2,hr3,hr4) that account for 3.1% of the genome. The genomic positions of MabrNPV-K1 regions hr1– hr4 are conserved with the genomic positions of MacoNPV-B hr1–hr4. This indicates that the position of MabrNPV–K1 hrs is conserved with regard to both the upstream and downstream genes. Given that hrs share higher similarity within a virus strain than any hrs between species, this evidence further indicates that hrs play a fundamental role in viral life cycle and replication process appears to be tightly linked to functional conservation. The dot plot analysis, percent identity of the gene homologues and a phylogenetic analysis suggested that MabrNPV-K1 is a Group II NPV that is closely related to MacoNPV but with a distinct genomic organization.