Strigolactones (SLs) are plant secondary metabolites derived from carotenoids. SLs play important roles in the regulation of plant growth and development in planta and coordinate interactions between plants and other organisms including root parasitic plants, and symbiotic and pathogenic microbes in the rhizosphere. In the 50 years since the discovery of the first SL, strigol, our knowledge about the chemistry and biochemistry of SLs has advanced explosively, especially over the last two decades. In this review, recent advances in the chemistry and biology of SLs are summarized and possible future outcomes are discussed.

General trends and strategies for novel pesticides are summarized. Global pesticide sales and pesticide discovery research are also briefly reviewed. At least 105 chemical pesticides have been launched during the past decade or are under development: 43 fungicides, 34 insecticides/acaricides, 6 nematicides, 21 herbicides, and 1 herbicide safener. Most of them are safe to humans and environmentally friendly. The most developed fungicides are SDHI (succinate dehydrogenase inhibitors), DMI (demethylation inhibitors), QoI (quinone outside inhibitors), and QiI (quinone inside inhibitors). Due to the development of resistance to fungicides with existing modes of action, many fungicides possessing various novel modes of action have been launched or are under development. The trend of insecticide development is changing from organophosphorus, carbamate, and synthetic pyrethroids to nicotinic and diamide insecticides. During the past decade, compounds possessing a variety of novel modes of action have also been launched or are under development. Flupyradifurone and flupyrimin, exhibiting extremely low honeybee toxicity, have been developed and subjected to practical use. Herbicides possessing varied modes of action, such as acetolactate synthase, p-hydroxyphenylpyruvate dioxygenase, protoporphyrinogen oxidase, and very-long-chain fatty acid elongase inhibition, have been developed, but no herbicides possessing a novel mode action have commercialized in nearly 30 years. It is of interest that cyclopyrimorate, which was recently launched, and tetflupyrolimet, which is under development, have novel modes action: homogentisate solanesyltransferase (HST) and dihydroorotate dehydrogenase (DHODH) inhibition, respectively. The development of useful acaricides and nematicides is also progressing. Some natural product origin pesticides are getting attention.

Cucurbitaceae family members are accumulators of hydrophobic pollutants. Such pollutants have been detected in cucurbits at levels above the maximum residue limit. Since major latex-like proteins (MLPs) are involved in hydrophobic pollutant uptake, changes in MLP expression can increase or decrease contamination. MLP expression levels were altered in the roots of Cucurbita pepo ‘Magda,’ and MLP-PG1 was detected in the xylem sap of Magda when cultivated at a high temperature (35°C). Day length also influenced MLP expression levels but only induced minor changes in the amount of MLPs. The concentration of pyrene, a hydrophobic pollutant, significantly increased with increasing MLP levels in the xylem sap of Magda when cultivated at 35°C. Thus, high temperatures promote the pollution of cucurbits by hydrophobic pollutants. These results can be used to develop novel techniques to reduce crop contamination and establish efficient phytoremediation.

A new asteltoxin analog, named asteltoxin H (1), was isolated by the solid-state fermentation of the fungus Pochonia suchlasporia var. suchlasporia TAMA 87. The chemical structure of 1 was deduced by spectroscopic methods, including 1D and 2D NMR, HRESIMS, and UV-Vis analyses. Compound 1 showed insecticidal activity against prepupae of the blowfly, Lucilia sericata, with an LD₅₀ value of 0.94 µg/mg prepupal body weight.

We investigated the dissipation of 27 pesticides in five Japanese soils at three temperatures and the variability of activation energies (E_a). The dissipation of total pesticides extracted sequentially using water and acetone was fitted to a single first-order (SFO) model. The E_a values calculated from the dissipation rate constants of the SFO model showed a normal distribution with a median of 61.1 kJ mol⁻¹. The dissipation of water-extractable pesticides (i.e., phytoavailable pesticides) was fitted to a double first-order in parallel model with two dissipation rate constants: k₁ and k₂. The E_a values calculated from k₁ and k₂ showed normal or lognormal distribution, and the medians of the normal distribution calculated from k₁ and k₂ were 62.8 and 45.2 kJ mol⁻¹, respectively. Furthermore, the method for estimating the biphasic dissipation of phytoavailable pesticides at different temperatures by using the median E_a values of the laboratory experiment was demonstrated in a field experiment.

Arabidopsis bHLH-type transcription factors—BRASSINOSTEROID INSENSITIVE 1-EMS-SUPPRESSOR 1 (BES1) and BRASSINAZOLE RESISTANT 1 (BZR1)—play key roles in brassinosteroid (BR) signaling. By contrast, the functions of the other four BES1/BZR1 homologs (BEH1–4) remain unknown. Here, we describe the detailed expression profiles of the BES1/BZR1 family genes. Their expressions were distinct regarding growth-stage dependence and organ specificity but exhibited some overlaps as well. Furthermore, their mRNA levels mostly remained unchanged responding to seven non-BR phytohormones. However, BEH1 and BEH2 were downregulated by brassinolide, suggesting a close association with the BR function. Additionally, BEH4 was ubiquitously expressed throughout the life of the plant but displayed some expression preference. For instance, BEH4 expression was limited to guard cells and the adjacent pavement cells in the leaf epidermis and was induced during growth progression in very young seedlings, suggesting that BEH4 is specifically regulated in certain contexts, although it is almost constitutively controlled.

Flutianil was discovered as a novel fungicide chemically characterized as a cyano-methylene thiazolidine. This chemical showed particularly high fungicidal activities against powdery mildew on various crops. Optimization of the fungicidal performance of the series of synthesized chemicals finally led to the identification of flutianil, which could control powdery mildew diseases. In this report, details of the structure–activity relationships from the lead compound to flutianil are described.

Glyphosate is often tank-mixed with auxinic herbicide 2,4-D for grass and broadleaf weed control. Here we examined the possible interaction of 2,4-D and glyphosate in barnyard grass, Echinochloa colona (L.) Link. The results showed that 2,4-D antagonizes glyphosate remarkably in glyphosate-resistant populations but only marginally in susceptible populations. This antagonism is related to reduced glyphosate uptake and (to a lesser extent) translocation. As 2,4-D has multiple, unpredictable effects on other herbicides, care must be taken when tank-mixing herbicides with 2,4-D.

This study examined changes in the proportions of ryanodine receptor mutations (G4946E and I4790K) for Plutella xylostella populations in the field. Results show that the proportion of G4946E decreased during the survey years without diamide application and that insects with I4790K were observed less frequently during the survey period. This study also examined the biotic performances of diamide-resistant P. xylostella strains. The results show that the diamide-resistant strains exhibited hatchability, larval development, and fecundity equivalent to those of diamide-susceptible strains.

The use of organochlorine pesticides, such as dichlorodiphenyltrichloroethane (DDT) and benzene hexachloride (BHC), have contributed substantially to the increase and stable supply of food production post-World War II. However, they have also become a major source of pollution on a global scale due to their persistence in the environment, high bioconcentration, toxicity, and their long-distance mobility. Although the use and production of these pesticides were banned over 45 years ago, they still present a risk to human health and ecosystems, and pose a threat to food safety. These pesticides were designated as persistent organic pollutants (POPs) by the Stockholm Convention in 2001, which urged the industry to reduce or eliminate them globally. The authors of this study have been involved in the research and development of bioaugmentation soil remediation technology to reduce the risk of environmental and crop contamination originating from POPs. In this paper, these studies are summarized, from basic studies (1, 2, 3) to an applied study (4), as follows: (1) use of the soil–charcoal perfusion method to explore POP-degrading bacteria, (2) bacteriological characteristics, metabolic pathways and dechlorination genes of the hexaclorobenzene (HCB)-mineralizing bacterial strain PD653, (3) characteristics and metabolic pathways of the dieldrin-degrading bacterial strain KSF27, and (4) application of these degrading bacteria for remediation of POPs-contaminated soil.