Inter-species mRNA transfer among green peach aphids,dodder parasites,and cucumber host plants

mRNAs are transported within a plant through phloem.Aphids are phloem feeders and dodders(Cuscuta spp.)are parasites which establish phloem connections with host plants.When aphids feed on dodders,whether there is trafficking of mRNAs among aphids,dodders,and host plants and if aphid feeding a匚fects the mRNA transfer between dodders and hosts are unclear.We constructed a green peach aphid(GPA,Myzus persicae)-dodder(Cuscuta austra/is)-cucumber(Cucumis sativus)tritrophic system by infesting GPAs on C.australis,which parasitized cucumber hosts.We found that GPA feeding activated defense-related phytohormonal and transcriptomic responses in both C.australis and cucumbers and large numbers of mRNAs were found to be transferred between C.australis and cucumbers and between C.australis and GPAs;importantly,GPA feeding on C.australis greatly altered inter-species mobile mRNA profiles.Furthermore,three cucumber mRNAs and three GPA mRNAs could be respectively detected in GPAs and cucumbers.Moreover,our statistical analysis indicated that mRNAs with high abundances and long transcript lengths are likely to be mobile.This study reveals the existence of inter-species and even inter-kingdom mRNA movement among insects,parasitic plants,and parasite hosts,and suggests complex regulation of mRNA trafficking.

Identification of Early Peach Aphid Infestation Based on Hyperspectral Imaging Technology

Peach aphid is a common pest and hard to detect.This study employs hyperspectral imaging technology to identify early damage in green cabbage caused by peach aphid.Through principal component transformation and multiple linear regression analysis,the correlation relation between spectral characteristics and infestation stage is analyzed.Then,four characteristic wavelength selection methods are compared and optimal characteristic wavelengths subset is determined to be input for modelling.One linear algorithm and two nonlinear modelling algorithms are compared.Finally,support vector machine(SVM)model based on the characteristic wavelengths selected by multi-cluster feature selection(MCFS)acquires the highest identification accuracy,which is 98.97%.These results indicate that hyperspectral imaging technology have the ability to identify early peach aphid infestation stages on green cabbages.

The Control Efficiency of Plant Alcohol Extracts on the Laboratory Populations of Myzus persicae(Sulzer)and Lipaphis erysimi (Kaltenbach)

The effects of semiochemicals extracted from 63 species of plants, on peach aphid (Myzus per-sicae) and mustard aphid (Lipaphis erysimi), were studied in laboratory. The deterrent rate, reproduction deterrent index and the interferential index of population control (IIPC) was used to evaluate the efficiency of semiochemicals on population control of the two target aphids. The results showed that the extracts of 34 species of common plants have noticeable effect on both aphid populations, especially, Xanthium sibiricum Petr. Et Widd. and Syngonium podophyllum Schott. These plant extracts could be used to construct the plant pro-tectant to protect crops.

Response of Solanum tuberosum to Myzus persicae infestation at different stages of foliage maturity

Young leaves of the potato Solanum tuberosum L. cultivar Kardal contain resistance factors to the green peach aphid Myzuspersicae （Sulzer） （Hemiptera： Aphididae） and normal probing behavior is impeded. However, M. persicae can survive and reproduce on mature and senescent leaves of the cv. Kardal plant without problems. We compared the settling ofM. persicae on young and old leaves and analyzed the impact of aphids settling on the plant in terms of gene expression. Settling, as measured by aphid numbers staying on young or old leaves, showed that after 21 h significantly fewer aphids were found on the young leaves. At earlier time points there were no difference between young and old leaves, suggesting that the young leaf resistance factors are not located at the surface level but deeper in the tissue. Gene expression was measured in plants at 96 h postinfestation, which is at a late stage in the interaction and in compatible interactions this is long enough for host plant acceptance to occur. In old leaves of cv. Kardal （compatible interaction）, M. persicae infestation elicited a higher number of differentially regulated genes than in young leaves. The plant response to aphid infestation included a larger number of genes induced than repressed, and the proportion of induced versus repressed genes was larger in young than in old leaves. Several genes changing expression seem to be involved in changing the metabolic state of the leaf from source to sink.