Effects Of Feeding With Different Mouthpart Insects On Defense Substances Of Tobacco And Insects Following Feeders

Tobacco is an important agricultural cash crop in China.It is usually harmed by pests such as M.persicae,S.litura and H.armigera.Using plant-induction borer-resistance to prevent and cure pests is a new-type green and effective prevention and control technology.This study takes tobacco?MS K326?,which is largely planted as testing article.This study focuses on the effect to the activity of the defensive signal molecule in tobacco,including signaling molecules NO,JA,H₂S,and defense enzymes PAL,LOX,PPO,POD in tobacco after it is bitten by Helicoverpa armigera Hubner,Spodoptera litura Fabricius?Masticatory mouthparts?and Myzus persicae Sulzer?Piercing-sucking mouthparts?.At the same time,we will observe that after these three insects bite the tabacco,what effect will have on the S.litura,who bites later and also test the activity of MFO,Car E,GST and Ach E in the larva of S.litura.This article intends to explore the plant-mediated interaction mechanism between species of insects,to demonstrate the differences of plant-defense from biting induction of insects with different mouth parts and its effect on insects who bite later and to provide theoretical proof for green prevention and control technology of tobacco insects.The main research results of this article are as follows:1.Effect of feeding with different mouthpart insects on signaling molecules of tobaccoIn this study,the contents of JA,NO and H₂S in different treatments of tobacco were determined by enzymatic labeling method in 6,12,24,48 and 72 h,including S.litura feeding,H.armigera feeding,M.persicae feeding,mechanical damage and control group The results showed that the contents of tobacco leaf JA and NO were significantly increased by bollworm feeding with masticatory mouthpiece;JA and NO contents in tobacco leaf did not change significantly after feeding with S.litura or M.persicae,and H₂S contents in all treated tobacco leaf were increased after feeding.2.Effect of feeding with different mouthpart insects on defense enzymes of tobaccoThis experiment,the chewing mouthparts?S.litura or H.armigera?and the sucking mouthparts?M.persicae?insects for feeding,mechanical perforating and mechanical pricks,control 6 types treat,The enzyme activities of PAL,LOX,PPO,POD of the tobacco leaves under different treatments were changed at 6,12,24,48and 72 h.The results showed that after feeding by H.armigera and S.litura,the activity of PAL in tobacco leaves increased,LOX activity decreased,and PPO activity increased?S.litura feeding significantly increased?,The former POD activity decreases close to CK,the latter POD activity increased;After feeding on M.persicae,PAL activity was inhibited at 12 h and increased at 48 h.LOX,PPO,and POD activities were significantly increased at 6 h after feeding,and were subsequently inhibited to varying degrees.POD activity was 24 h inhibition was most pronounced.The activity of most of the defense enzymes in tobacco leaves increased the most after S.litura chewing.3.Effect of feeding with different mouthpart insects on feeding behavior of following feeder S.litura in tobaccoIn the study,chewing mouthparts?S.litura or H.armigera?and sucking mouthparts?M.persicae?insects were used for feeding,mechanical perforating and mechanical pricks,control.After processing tobacco for 12 h,tobacco picking the leaves make leaf discs with a diameter of 2 cm,and 20 S.litura 1st instar or 1 3-4instar larvae were hatched within 12 h,and put into differently treated leaves?worms body leaves,mechanically damaged leaves,and control leaves?in a petri dish with a diameter of 14 cm,add an appropriate amount of water to the filter paper to moisturize,cover it with a black cloth,and record after taking 12 hours.The results showed that after different mouth insects pre-feeded tobacco leaves,S.litura?first hatched larvae?tended to choose tobacco aphids as harmful leaves and refused to feed on S.litura;The 4th instar larvae feed the most perforated pieces,the largest feeding area is needles leaves,and the lowest is S.litura feeding leaves.4.Effect of feeding with different mouthpart insects on detoxifying enzyme activity of following feeder S.litura in tobaccoThis experiment using chewing mouthparts?S.litura or H.armigera?and sucking mouthparts?M.persicae?insects were used for feeding,mechanical perforating and mechanical pricks,control.After treating tobacco for 12 hours,pick up various types of tobacco leaves and place them flat in clean insect culture boxes.Bundle the petioles with moist cotton to keep leaves fresh.Pick 5 3-4 instar S.litura larvae of the same size and put them into the.In the box,the changes of enzyme activities such as Ach E,Car E,GST,and MFO in the body after 6 insect culture,12,24,and 48 hours after feeding were detected.The experiments showed that different mouthsinsects,H.armigera or S.litura,and M.persicae after eating tobacco,and the late-feeder S.litura had a greater effect on tobacco leaves treated by chewing insects,H.armigera and S.litura Strong adaptability.The detoxification enzymes Ach E,Car E,GST and MFO in the two leaf tobacco insects increased in different degrees.After eating M.persicae,the peaks of Ach E and MFO enzyme activity were lower than others.In the treatment group,Car E and GST activities increased.To sum up,feeding by different mouthparts insects can induce tobacco to have a relevant defense response,resulting in changes in the defense physiology of tobacco leaves and affecting the feeding and physiological changes of the post-eaters.There was a tendency to avoid food,and the activity of a part detoxifying enzymes in the body after ingestion of the same species was not significant.