Search

Abstract The adaptability of insects to hosts has long been a focal point in the study of insect-plant interactions. The pea aphid (Acythosiphon pisum), a significant pest of numerous leguminous crops, not only inflicts direct economic losses but also disseminates various plant viruses. To understand how pea aphids adapt to diverse alfalfa varieties. We analyzed the differentially expressed genes (DEGs) of pea aphids in distinct alfalfa varieties using transcriptome sequencing, and subsequently conducted functional validation of these genes. Comparative analysis between pea aphids feeding on susceptible and resistant strains revealed that DEGs in aphids feeding on resistant strains were primarily associated with transcriptional enrichment in the sugar, amino acid, protein, and lipid metabolism pathways. Fourteen DEGs related to adaptation of the pea aphid to alfalfa were chosen, including five carboxylesterases (CarE), four cytochrome P450s, three glutathione S-transferases, and two peroxidases (POD). RT-qPCR results indicated significant up-regulation of two carboxylesterase genes and two peroxidase genes after 24 h of feeding resistant alfalfa (Gannong 5, GN5) compared to the susceptible varieties (Hunter River, LRH), particularly highlighting the high expression levels of ApCarE4 and ApPOD3. Simultaneously, RNAi-induced knockdown of ApCarE4 and ApPOD3 led to a higher mortality of pea aphids in the alfalfa Hunter River. These results indicate that ApPOD3 and ApCarE4 are involved in the detoxification of metabolic functions in the adaptation of pea aphids to host switching. These findings contribute to the understanding of pea aphid adaptation to host plants and lay a foundation for further exploration of the physiological roles of carboxylesterase and peroxidase genes in pea aphids.

By adopting gradient analysis combining with the analysis of urban land use degree, this paper studied the spatial layout characteristics of residential and industrial lands in new Yinzhou Town, and explored the location characters of various urban land use by selecting public green land, public facilities, and road as the location advantage factors. Gradient analysis could effectively connect with the spatial layout of urban land use, and quantitatively depict the spatial character of urban land use. In the new town, there was a new urban spatial center mostly within the radius of 2 km, namely, the urban core area had obvious location advantage in the cross-shaft direction urban development. On the south of Yinzhou Avenue, the urban hinterland would be constructed soon. In the future land use of the new town, the focus would be the reasonable vicissitude of industrial land after the adjustment of industrial structure, the high-efficient intensive use of the commercial land restricted by the compulsive condition of urban core area, and the agricultural land protection in the southeastern urban-rural fringe. [ABSTRACT FROM AUTHOR]

By adopting gradient analysis combining with the analysis of urban land use degree, this paper studied the spatial layout characteristics of residential and industrial lands in new Yinzhou Town, and explored the location characters of various urban land use by selecting public green land, public facilities, and road as the location advantage factors. Gradient analysis could effectively connect with the spatial layout of urban land use, and quantitatively depict the spatial character of urban land use. In the new town, there was a new urban spatial center mostly within the radius of 2 km, namely, the urban core area had obvious location advantage in the cross-shaft direction urban development. On the south of Yinzhou Avenue, the urban hinterland would be constructed soon. In the future land use of the new town, the focus would be the reasonable vicissitude of industrial land after the adjustment of industrial structure, the high-efficient intensive use of the commercial land restricted by the compulsive condition of urban core area, and the agricultural land protection in the southeastern urban-rural fringe.