Green leaf volatiles (GLVs), volatile organic compounds released by plants upon tissue damage, are key signaling molecules in plant immunity. The ability of exogenous GLV application to trigger an induced resistance (IR) phenotype against arthropod pests has been widely reported, but its effectiveness against plant pathogens is less well-understood. In this study, we combined mRNA sequencing-based transcriptomics and phytohormone measurements with multispectral imaging-based precision phenotyping to gain insights into the molecular basis of Z-3-hexenyl acetate induced resistance (Z-3-HAC-IR) in rice. Furthermore, we evaluated the efficacy of Z-3-HAC-IR against a panel of economically significant rice pathogens: Pyricularia oryzae, Rhizoctonia solani, Xanthomonas oryzae pv. oryzae, Cochliobolus miyabeanus and Meloidogyne graminicola. Our data revealed rapid induction of jasmonate metabolism and systemic induction of plant immune responses upon Z-3-HAC exposure, as well as a transient allocation cost due to accelerated chlorophyll degradation and nutrient remobilization. Z-3-HAC-IR proved effective against all tested pathogens except for C. miyabeanus, including against the (hemi)biotrophs M. graminicola, X. oryzae pv. oryzae and P. oryzae. The Z-3-HAC-IR phenotype was lost in the jasmonate-deficient hebiba mutant, which confirms the causal role of JA in Z-3-HAC-IR. Together, our results show that GLV exposure in rice induces broad-spectrum, JA-mediated disease resistance with limited allocation costs, and may thus be a promising alternative crop protection approach.

Rice synthesises diterpenoid phytoalexins (DPs) which are known to operate in defence against foliar microbial pathogens and the root‐knot nematode Meloidogyne graminicola . Here, we examined the role of DPs in shaping rice‐associated root microbiomes in nematode‐infested field soil. Further, we assessed how DPs affect interactions between the root microbiomes and M. graminicola . We used 16S and ITS2 rRNA gene amplicon analysis to characterise the root‐ and rhizosphere‐associated microbiomes of DP knock‐out rice mutants and their wild‐type parental line, at an early (17 days) and late (28 days) stage of plant development in field soil. Disruption of DP synthesis resulted in distinct changes in the composition and structure of microbial communities both relative to the parental/wild‐type line but also between individual mutants, indicating specificity in DP‐microbe interactions. Moreover, the abundance of nematode‐suppressive microbial taxa, including Streptomyces , Stenotrophomonas and Enterobacter was negatively correlated with that of Meloidogyne . Differential enrichment of microbial taxa in the roots of rice DP knock‐out mutants versus wild‐type suggests that DPs modulate specific taxa in the rice root microbiome. These findings indicate a role for DPs in plant‐microbiome assembly and nematode interactions, further underscoring the potential of leveraging phytoalexins for sustainable management of crop diseases.

On a global scale, pesticide use has almost doubled since 1990, with the world market expected to reach $130 billion by the end of 2023. With a rapidly growing world population, the use of pesticides, also called plant protection products (PPP), has played an important role in increasing crop yields to ensure adequate food availability. In the early 1960s, growing concern and awareness about the potential for PPP to non-specifically affect the surrounding ecosystem led to a growing field of resistance. Governmental and intergovernmental bodies have since placed sustainable agricultural practices at the top of their agendas, leading to the use of PPP becoming an increasingly controversial topic of discussion. This policy analysis broadly describes PPP regulation systems in the US and the EU by providing historic accounts of key policy developments of PPP use and their regulations. A direct comparison between regulatory systems for PPP in the US and in the EU is then explored. Washington State and Belgium were chosen as case studies in order to provide a more detailed look into the complexities of such systems and allow for a comparative approach to examine the opportunities and challenges for policy changes. Additionally, suggestions as to what the EU and the US entities can learn from one another to improve the respective PPP regulation systems are investigated. Finally, the analysis explores the potential of strengthening transatlantic cooperation through the establishment of an intergovernmental framework that deals with collection of scientific evidence on PPP and their use. As a result, this analysis acts as a tool for policymakers to better comprehend the different approaches to PPP regulation in the US and the EU as the need to feed the growing world population becomes more urgent, all while safeguarding human and ecosystem health through well-informed policies on PPP use.

While organophosphorus chemistry is gaining attention in a variety of fields, the synthesis of the phosphorus derivatives of amino acids remains a challenging task. Previously reported methods require the deprotonation of the nucleophile, complex reagents or hydrolysis of the phosphonate ester. In this paper, we demonstrate how to avoid these issues by employing phosphonylaminium salts for the synthesis of novel mixed n-alkylphosphonate diesters or amino acid-derived n-alkylphosphonamidates. We successfully applied this methodology for the synthesis of novel N-acyl homoserine lactone analogues with varying alkyl chains and ester groups in the phosphorus moiety. Finally, we developed a rapid, quantitative and high-throughput bioassay to screen a selection of these compounds for their herbicidal activity. Together, these results will aid future research in phosphorus chemistry, agrochemistry and the synthesis of bioactive targets.