State Key Laboratory of Rice Biology and Breeding, Ministry of Agriculture Key Lab of Molecular Biology of Crop Pathogens and Insects, Zhejiang Key Laboratory of Biology and Ecological Regulation of Crop Pathogens and Insects, Institute of Insect Sciences, Zhejiang University, Hangzhou 310058, China.
Int J Mol Sci. 2024 Nov 10;25(22):12076. doi: 10.3390/ijms252212076.
The molecular mechanisms of plant responses to phytophagous insect eggs are poorly understood, despite their importance in insect-plant interactions. This study investigates the plant defense mechanisms triggered by the eggs of whitefly , a globally significant agricultural pest. A transcriptome comparison of tobacco plants with and without eggs revealed that whitefly eggs may activate the response of defense-related genes, including those involved in the salicylic acid (SA) signaling pathway. SA levels are induced by eggs, resulting in a reduction in egg hatching, which suggests that SA plays a key role in plant resistance to whitefly eggs. Employing -mediated transient expression, virus-induced gene silencing assays, DNA-protein interaction studies, and bioassays, we elucidate the regulatory mechanisms involved. Pathogenesis-related proteins NtPR1-L1 and NtPR5-L2, downstream of the SA pathway, also affect whitefly egg hatching. The SA-regulated transcription factor NtWRKY70a directly binds to the promoter, enhancing its expression. Moreover, NtPR1-L1 promotes callose deposition, which may impede the eggs' access to water and nutrients. This study establishes the SA-WRKY70-PR-callose axis as a key mechanism linking plant responses and defenses against whitefly eggs, providing new insights into the molecular interactions between plants and insect eggs.
尽管植食性昆虫卵在昆虫-植物相互作用中具有重要意义，但植物对其反应的分子机制仍知之甚少。本研究调查了烟粉虱卵引发的植物防御机制，烟粉虱是一种具有全球重要意义的农业害虫。对有卵和无卵的烟草植物进行转录组比较后发现，烟粉虱卵可能激活了与防御相关基因的反应，包括参与水杨酸（SA）信号通路的基因。卵诱导 SA 水平升高，导致卵孵化减少，表明 SA 在植物抵御烟粉虱卵中发挥关键作用。通过介导的瞬时表达、病毒诱导的基因沉默测定、DNA-蛋白相互作用研究和生物测定，我们阐明了所涉及的调控机制。SA 途径下游的病程相关蛋白 NtPR1-L1 和 NtPR5-L2 也影响烟粉虱卵孵化。SA 调节的转录因子 NtWRKY70a 直接结合到 启动子上，增强其表达。此外，NtPR1-L1 促进胼胝质沉积，这可能阻碍卵获得水和营养。本研究确立了 SA-WRKY70-PR-胼胝质轴作为连接植物对烟粉虱卵反应和防御的关键机制，为植物与昆虫卵之间的分子相互作用提供了新的见解。
