Construction Of Engineered Endophyte With Pinellia Ternate Agglutinin And The Effect Of Anti-Homoptera

In this paper,66 and 63 strains were isolated from rice and rape, respectively. The separation results showed that the bacillus, gram-positive bacteria, spores were in the majority. SJ-10, and YY-23, isolated from rice and rape, were identified as Enterobacter sp. and Bacillus thuringiensi, respectively, based on the basic properties tests,16SrRNA and 16SrRNA phylogenetic tree. WB800 was Bacillus subtilis. The three strains were able to colonize in rice and rape by dipping the seeds, watering the roots, and inoculating aseptic seedlings. The inoculation treatment had been proved that they could live in many plants, such as wheat, maize, rape, chinese kale, navet. After three mothes, SJ-10 and WB800 could be colonized from the plants mentioned above. After two mothes, YY-23 also could be colonized. Rape seeds were dipped for 24h with YY-23 and SJ-10, then sowed. After 20 days, the fresh weight of rape plants was increased by 113.5% and 52.5% respectively. Rice seeds were dipped like rape with WB800, and after 30 days, the fresh weight of rice was increased by 62.16%.A shuttle and secreting expression vector including Pinellia ternate agglutinin (PTA) gene was constructed and introduced into endophytic SJ-10 and WB800. SDS-PAGE and Western Bloting analysis showed that PTA protein could be detected in recombinant SJ-10 and WB800. After inoculated rice seedlings with the recombinant endophytic bacteria, insecticidal activity against white backed planthopper was detected. The results showed that the PTA protein expressed by the recombinant SJ-10 and WB800 could obviously decrease the survival and fecundity of white backed planthopper. The insect number on rice seedlings in control group was 3.38 times of that inoculated with recombinant SJ-10, and 98.7 times of that inoculated with recombinant WB800 at day 19. At the end, rice seedlings in the control group and SJ-10 all died, but seedlings inoculated with WB800, the recombinant WB800 and SJ-10 grown very well.Cotton aphid was fed with artificial diets adding bacteria, result showed that the survival rate of aphid in SJ-10 group was lower than CK on the sixth day, the difference was very distinctive (p<0.05). However, YY-23 expressed no resistance to aphid.In a word, the results showed that the three strains could colonize stably and promote growth in plants. The rice seedlings inoculated with the recombinant endophytic bacteria expressing PTA protein were endowed with the anti-pest activity, and could reduce damages caused by white backed planthopper. Wild SJ-10 had insecticidal effect on cotton aphid. Therefore, the endophytic bacteria could be used as a living vector for expressing anti-pest proteins to control sap-sucking Homoptera insects in the future.