Phytochrome B mediates dim-light-reduced insect resistance by promoting the ethylene pathway in rice.

Increasing planting density is one of the most effective ways to improve crop yield. However, one major factor that limits crop planting density is the weakened immunity of plants to pathogens and insects caused by dim light (DL) under shade conditions. The molecular mechanism underlying how DL compromises plant immunity remains unclear. Here, we report that DL reduces rice (Oryza sativa) resistance against brown planthopper (BPH; Nilaparvata lugens) by elevating ethylene (ET) biosynthesis and signaling in a Phytochrome B (OsPHYB)-dependent manner. The DL-reduced BPH resistance is relieved in osphyB mutants, but aggravated in OsPHYB overexpressing plants. Further, we found that DL reduces the nuclear accumulation of OsphyB, thus alleviating Phytochrome Interacting Factor Like14 (OsPIL14) degradation, consequently leading to the up-regulation of 1-Aminocyclopropane-1-Carboxylate Oxidase1 (OsACO1) and an increase in ET levels. In addition, we found that nuclear OsphyB stabilizes Ethylene Insensitive Like2 (OsEIL2) by competitively interacting with EIN3 Binding F-Box Protein (OsEBF1) to enhance ET signaling in rice, which contrasts with previous findings that phyB blocks ET signaling by facilitating Ethylene Insensitive3 (EIN3) degradation in other plant species. Thus, enhanced ET biosynthesis and signaling reduces BPH resistance under DL conditions. Our findings provide insights into the molecular mechanism of the light-regulated ET pathway and host-insect interactions and potential strategies for sustainable insect management.

[Study on the identification of standard and false Gancao by Fourier transform infrared spectroscopy].

Standard Gancao (Glycyrrhiza uralensis Fisch) and false Ciguogancao (Glycyrrhiza pallidiflata Batal) were identified fast, nondestructively by Fourier transform infrared spectroscopy (FTIR) combined with derivative spectra and two-dimensional correlation spectroscopy (2D) in the present article. The result shows that although the two kinds of Gancao belong to one genus, there are some certain differences in their chemical components that are reflected in the IR spectra, but with some similarity and dissimilarity in the IR spectra. The two kinds of Gancao are quite different from each other in second derivative spectra and 2D spectra. Based on the differences reflected in the IR and 2D IR, the standard gancao can be identified from the false easily and clearly. The result also proved that there is a relationship between the IR spectra and the chemical components of the herbs. This method is fast, accurate and nondestructive, and the wastage of sample is less. The fast, accurate property of 2D spectroscopy makes it a powerful and new approach to evaluating medicinal herbs impersonally.