Suqing Zhu

The tea geometrid (Ectropis grisescens) is a significant pest in Chinese tea plantations. Although Metarhizium anisopliae serves as an environmentally friendly biocontrol agent against E. grisescens, the molecular mechanisms underlying the insect’s immune response remain unclear. This study investigates changes in immunity-related genes and metabolites in E. grisescens larvae infected with a virulent strain of M. anisopliae through transcriptome sequencing and metabolome analysis. We identified 2409 differentially expressed genes (DEGs) at 48 h post-infection, with 1611 genes up-regulated. GO analysis revealed that 119 DEGs were significantly enriched in immune-related processes. Additionally, 1860 differentially accumulated metabolites (DAMs) were detected, including 652 up-regulated and 1208 down-regulated metabolites, with 236 significantly enriched in 82 KEGG pathways. These findings indicate the activation of immunity-related and detoxifying enzyme-related genes, providing new insights into the physiological and biochemical responses of insects to biopesticides and potential targets for controlling tea geometrid.

Phenylalanine ammonia-lyase (PAL) is the core branch-point enzyme connecting plant primary aromatic amino acid metabolism to the phenylpropanoid pathway, which determines carbon flux redistribution between growth and defense and is essential for plant adaptation to various environments. Extensive research has clarified PAL’s conserved homotetrameric structure, MIO cofactor-dependent catalytic mechanism, and its roles in plant growth, development, and stress responses. However, there is a lack of comprehensive review studies focusing on PAL-mediated carbon metabolic flux redistribution, specifically covering its structural and evolutionary foundations, the links between this flux regulation and plant growth/development, its multi-layered regulatory network, and its roles in stress adaptation, limiting a comprehensive understanding of its evolutionary and functional diversity. This review systematically covers four core aspects: first, the molecular foundation, encompassing PAL’s structural features and catalytic specificity governed by the MIO cofactor; second, evolutionary diversity spanning from algae to angiosperms, with emphasis on unique regulatory mechanisms and evolutionary significance across lineages; third, the multi-layered regulatory network, integrating transcriptional control, post-translational modifications, epigenetic regulation, and functional crosstalk with phytohormones; and fourth, functional dynamics, which elaborate PAL’s roles in organ development, including root lignification, stem mechanical strength, leaf photoprotection, flower and fruit quality formation, and lifecycle-wide dynamic expression, as well as its mediated stress adaptations and regulatory networks under combined stresses. These insights provide a theoretical basis for targeted manipulation of PAL to optimize crop carbon allocation, thus improving growth performance, enhance stress resilience, and promote sustainable agriculture.