RESUMEN
Introduction: The research on plant leaf morphology is of great significance for understanding the development and evolution of plant organ morphology. As a relict plant, the G. biloba leaf morphology typically exhibits bifoliate and peltate forms. However, throughout its long evolutionary history, Ginkgo leaves have undergone diverse changes. Methods: This study focuses on the distinct "trumpet" leaves and normal fan-shaped leaves of G. biloba for analysis of their phenotypes, photosynthetic activity, anatomical observations, as well as transcriptomic and metabolomic analyses. Results: The results showed that trumpet-shaped G. biloba leaves have fewer cells, significant morphological differences between dorsal and abaxial epidermal cells, leading to a significantly lower net photosynthetic rate. Additionally, this study found that endogenous plant hormones such as GA, auxin, and JA as well as metabolites such as flavonoids and phenolic acids play roles in the formation of trumpet-shaped G. biloba leaves. Moreover, the experiments revealed the regulatory mechanisms of various key biological processes and gene expressions in the trumpet-shaped leaves of G. biloba. Discussion: Differences in the dorsal and abdominal cells of G. biloba leaves can cause the leaf to curl, thus reducing the overall photosynthetic efficiency of the leaves. However, the morphology of plant leaves is determined during the primordia leaf stage. In the early stages of leaf development, the shoot apical meristem (SAM) determines the developmental morphology of dicotyledonous plant leaves. This process involves the activity of multiple gene families and small RNAs. The establishment of leaf morphology is complexly regulated by various endogenous hormones, including the effect of auxin on cell walls. Additionally, changes in intracellular ion concentrations, such as fluctuations in Ca2+ concentration, also affect cell wall rigidity, thereby influencing leaf growth morphology.
RESUMEN
Fall armyworm, Spodoptera frugiperda (J. E. Smith), is a widely recognized global agricultural pest that has significantly reduced crop yields all over the world. S. frugiperda has developed resistance to various insecticides. Insect cytochrome P450 monooxygenases (CYPs or P450s) play an important role in detoxifying insecticides, leading to increased resistance in insect populations. However, the function of the specific P450 gene for lambda-cyhalothrin resistance in S. frugiperda was unclear. Herein, the expression patterns of 40 P450 genes in the susceptible and lambda-cyhalothrin-resistant populations were analyzed. Among them, CYP321A7 was found to be overexpressed in the resistant population, specifically LRS (resistance ratio = 25.38-fold) derived from a lambda-cyhalothrin-susceptible (SS) population and FLRS (a population caught from a field, resistance ratio = 63.80-fold). Elevated enzyme activity of cytochrome P450 monooxygenases (P450s) was observed for LRS (2.76-fold) and the FLRS (4.88-fold) as compared to SS, while no significant differences were observed in the activities of glutathione S-transferases and esterases. Furthermore, the knockdown of CYP321A7 gene by RNA interference significantly increased the susceptibility to lambda-cyhalothrin. Remarkably, the knockdown of CYP321A7 reduced the enzymatic activity of P450 by 43.7%, 31.9%, and 22.5% in SS, LRS, and FLRS populations, respectively. Interestingly, fourth-instar larvae treated with lambda-cyhalothrin at the LC30 dosage had a greater mortality rate due to RNA interference-induced suppression of CYP321A7 (with increases of 61.1%, 50.0%, and 45.6% for SS, LRS, and FLRS populations, respectively). These findings suggest a link between lambda-cyhalothrin resistance and continual overexpression of CYP321A7 in S. frugiperda larvae, emphasizing the possible importance of CYP321A7 in lambda-cyhalothrin detoxification in S. frugiperda.
