Sieve element occlusion provides resistance against Aphis gossypii in TGR-1551 melons  

作　　者：Hsuan-Chieh Peng Gregory P.Walker 

机构地区：[1]Department of Microbiology and Plant Pathology,University of California,Riverside,California,USA [2]Department of Entomology,University of California,Riverside,California,USA

出　　处：《Insect Science》2020年第1期33-48,共16页昆虫科学（英文版）

基　　金：supported in part by a grant from the National Science Foundation,Division of Integrative Organismal Systems(award number IOS-1052589).

摘　　要：Feeding behavior and plant response to feeding were studied for the aphid Aphis gossypii Glover on susceptible and resistant melons(cv.Iroquois and TGR-1551,respectively).Average phloem phase bout duration on TGR-1551 was<7% of the duration on Iroquois.Sixty-seven percent of aphids on TGR-1551 never produced a phloem phase that attained ingestion(EPG waveform E2)in contrast to only 7% of aphids on Iroquois.Average bout duration of waveform E2(scored as zero if phloem phase did not attain E2)on TGR-1551 was<3% of the duration on Iroquois.Conversely,average bout duration of EPG waveform El(sieve element salivation)was 2.8 times greater on TGR-1551 than on Iroquois.In a second experiment,liquid nitrogen was used to rapidly cryofix leaves and aphids within a few minutes after the aphids penetrated a sieve element.Phloem near the penetration site was then examined by confocal laser scanning microscopy.Ninety-six percent of penetrated sieve elements were occluded by protein in TGR-1551 in contrast to only 28% in Iroquois.Usually in TGR-1551,occlusion was also observed in nearby nonpenetrated sieve elements.Next,a calcium channel blocker,trivalent lanthanum,was used to prevent phloem occlusion in TGR-1551,and A.gossypii feeding behavior and the plants phloem response were compared between lanthanum-treated and control TGR-1551.Lanthanum treatment eliminated the sieve element protein occlusion response and the aphids readily ingested phloem sap from treated plants.This study provides strong evidence that phloem occlusion is a mechanism for resistance against A.gossypii in TGR-1551.

关 键 词：aphid feeding behavior Aphis gossypii Cucumis melo insect-plant resistance phloem occlusion sieve element occlusion proteins 

分 类 号：Q96[生物学—昆虫学]