Knowledge Network Node

Defense Mechanisms of Different Drought-tolerant Potato Cultivars against Green Peach Aphids under Drought StressEN



Abstract:Availability of water is critical for plant growth and their resistance to insect pests,and thus understanding plant responses to simultaneous stressors,such as drought and insect pests,is necessary.Potato(Solanum tuberosum L.)is a vegetable crop that plays a major role in global food security.However,its production and sustainability is adversely affected due to aphid infestation.Other researchers reported that drought severity could result in the outbreak of insect pests such as aphids.Therefore,the identification of drought-tolerant cultivars as well as cultivars that possess some resistance to insect pests has become an important area of research.The first experiment was conducted to determine the effect of drought and aphid(Myzus persicae Sulzer)infestation on three potato(Solanum tuberosum L)cultivars under greenhouse conditions.In the second experiment,the root system architecture and biochemical responses of three potato(Solanum tuberosum L.)cultivars to drought and aphid(Myzus persicae Sulzer)infestation under greenhouse conditions was conducted.In the third experiment,the cross-talk of phytohormones in potato glycoalcaloids defense against green peach aphids under greenhouse conditions was examined.In the fourth experiment,the effect of three concentrations of the leaf extract(100,75,and 50% potato extract),synthetic pesticide and distilled water(control)treatments on green peach aphids was assessed.All the four experiments were conducted under greenhouse condition.The results of the first experiment show aphid survival rate on plants under no drought(87.7%)and those under drought(67.2%)were highest on QS9 and least on DXY(41.3% and31.2%,respectively).Colonization success of aphids on plants under no drought and on those exposed to drought was highest on QS9(24.2 and 19.5%,respectively)and least on DXY plants(13.7 and 10.9%,respectively).The drought-sensitive cultivar,DXY,exhibited greater tolerance to peach aphid under drought or no drought conditions.This was demonstrated by poor aphid performance and higher biomass accumulation of this cultivar.However,the drought-tolerant cultivar,QS9,was highly susceptible to the peach aphid.This was shown by the high aphid performance and low biomass accumulation.Furthermore,the extreme water loss of the sensitive cultivar,DXY,dramatically decreased the performance of the green peach aphid under drought stress.The drought-tolerant cultivar exhibited high water content on which the green peach aphid is able to absorb from the xylem sap,thereby improving the performance of the green peach aphid.Resistance of the DXY cultivar to peach aphid may also be due to the presence of toxic compounds in the plants,since it exhibited poor host acceptance.Thus,the DXY cultivar can be considered to increase potato yield in areas where peach aphids are a major constraint.This study demonstrates that the biochemical and morphological traits that confer drought tolerance in potato do not necessarily confer aphid tolerance.Further studies to ascertain the presence and levels of compounds that could inhibit feeding by peach aphid could advance our knowledge on the response of these cultivars to peach aphid.In the second experiment,the results demonstrate that the number of green peach aphids at 28 d post-infestation associated with QS9,L3,and DXY was increased by 71.2,68.7,and43.3%,respectively,under well-watered conditions,and by 64.2,60.2,and 35.8% under drought stress.Moreover,green peach aphids reared on DXY plants exhibited a 53.1 and44.4% decrease in population compared with those reared on QS9 and L3 plants,respectively,under well-watered and drought-stressed conditions,at 32 d post-infestation.DXY cultivar,which possesses a root system sensitive to drought,showed greater resistant to the peach aphid under both water treatments.This cultivar also exhibited poor aphid population abundance,high mortality rate,and higher biomass accumulation under aphid stress.Moreover,QS9,which possesses root system tolerant to drought,was extremely susceptible to the aphid and demonstrated high aphid population abundance,low aphid mortality rate,and low biomass accumulation under aphid stress.Moreover,dehydration of the DXY cultivar decreased the population abundance of the aphid under drought stress.The QS9 cultivar,which had enhanced root system,probably improved water uptake and led to greater availability of sap on which the aphid survived and increased its population.The resistance of DXY to the peach aphid under both water treatments may also be due to the presence of secondary metabolites in the cultivar.Thus,the DXY cultivar can be considered to protect against losses in potato yield in areas where peach aphids are a major pest of potato.This study indicates that the root architecture and biochemical trait that enhances potato tolerance to drought do not necessarily correlate to a plant’s tolerance to aphids.In the third experiment,the results show that under drought stress,leaf α-chaconine content of QS9,L3,and DXY increased by 24.6,33.6,and 43.6%,respectively,and by 6.4,11.8,and 17.4% under aphid stress.Drought stress also increased leaf α-solanine content of QS9,L3,and DXY by 31.1,31.5,and 49.8%,respectively,and by 6.7,9.4,and 12.1% under aphid stress.Moreover,under drought stress,green peach aphids thrive well on host plants,which contain relatively high water content.The QS9 plants,which exhibited greater water use efficiency,also demonstrated poor resistance to green peach aphid,compared with the other cultivars.Under drought condition,the cross-talk of phytohormones such as JA,SA,ABA,and OPDA do not only function as signal hormones,but also modify host plant secondary metabolites to defend against sap-sucking insects.Many potato cultivars may activate phytohormones under drought stress;however,only host plants with a greater level of secondary metabolites may be able to defend against aphid attack.The greater α-chaconine and α-solanine contents in the DXY plants inhibited aphid performance under both water treatments.Most importantly,the DXY cultivar,which demonstrated high resistance to green peach aphid,can be considered in areas where green peach aphid is a major challenge to potato cultivation.In the fourth experiment,the results show that aphid survival rate was highest in 50%extract(53.4%),followed by 70% extract(53.3%)and 100% extract(14.0%),and was least in synthetic(6.9%).Comparatively,the synthetic pesticide,which was used as a standard check,demonstrated the greatest aphicidal effect on green peach aphid.However,100% potato leaf extract also exhibited similar greater deleterious effects on green peach aphid,compared with the other levels of botanical control.This botanical treatment also had a significant effect on the reproductive potential of green peach aphid.We therefore conclude that the lowest dilution of potato(DXY)leaf extract(100% extract)could be used as appropriate dosage of application for green peach aphid control.This can greatly reduce the use of synthetic insecticides,which are continuously used and endanger the health of farm operators,animals,and food consumers.Over all,this research work has provided more insight into the mechanisms of aphid’s survival and potato tolerance to drought stress and aphid infestation.This study has also identify a potato leaf extract which has the potential to control green peach aphid.This innovation can be developed for commercial or industrial use to help increase potato production in areas where aphids’ poses as a major constrain to potato production.
  • Series:

    (D) Agriculture

  • Subject:

    Plant Protection

  • DOI:


  • Classification Code:




Download the mobile appuse the app to scan this coderead the article.

Download:77 Page:101 Size:6748K

Related Literature
  • Similar Article
  • Reader Recommendationr
  • Related Funding Articles
  • Citation Network
  • Study Results