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ARS Home » Northeast Area » Beltsville, Maryland (BARC) » Beltsville Agricultural Research Center » Molecular Plant Pathology Laboratory » Research » Publications at this Location » Publication #320399
Title: Co-expression of cystatin inhibitors OCI and OCII in transgenic potato plants alters Colorado potato beetle development

Author
item CINGEL, ALEKSANDAR - University Of Belgrade
item SAVIC, JALENA - University Of Belgrade
item LAZAREVIC, JELICA - University Of Belgrade
item RASPOR, MARTIN - University Of Belgrade
item COSIC, TATJANA - University Of Belgrade
item Smigocki, Anna
item NINKOVIC, SLAVICA - University Of Belgrade

Submitted to: Insect Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 4/28/2016
Publication Date: 6/6/2016
Citation: Cingel, A., Savic, J., Lazarevic, J., Raspor, M., Cosic, T., Smigocki, A.C., Ninkovic, S. 2016. Co-expression of cystatin inhibitors OCI and OCII in transgenic potato plants alters Colorado potato beetle development. Insect Science. doi: 10.1111/1744-7917.12364.

Interpretive Summary: Potato cultivars with excellent growth, yield, cooking and nutritional quality are highly susceptible to attack by herbivours insect pests, particularly the Colorado potato beetle (CPB). To improve insect resistance in potato, several potato varieties were modified with two beneficial insect resistance traits (OCI and OCII genes) isolated from rice. Early stage larvae fed on the genetically modified potato leaves exhibited altered growth and development. During the early stages, larvae fed on transformed potato leaves tended to molt earlier, gained weight faster and consumed leaf material more quickly than larvae fed on normal plants. Consequently, these larvae reached their maximum weights three days earlier in preparation for subsequent early onset of pupation. When larvae in the later stage of development were fed similar plant materials, their maximum weight gain and leaf consumption were reduced. A more than 50-60% decrease in digestive activity was observed in the guts of early stage larvae. However, continued feeding by the older larvae restored the digestive activity back to levels that were observed in the control larvae. This suggests that the older larvae adapted their digestive system to compensate for the new inhibitory products in their diet.

Technical Abstract: Oryzacystatins I and II (OCI and OCII) show potential for controlling pests that utilize cysteine proteinases for protein digestion. To strengthen individual inhibitory range and achieve an additive effect in the overall efficiency of these proteins against pests, both cystatin genes were co-expressed in three potato cultivars. In the absence of significant mortality, feeding of Colorado potato beetle (Leptinotarsa decemlineata Say) larvae on OCI/OCII-expressing leaves had an impact on various aspects of larval growth and development. During early L2 and L3 developmental stages, larvae fed on transformed potato leaves tended to molt earlier, gained weight up to 30% faster and consumed leaf material up to 29% faster than larvae fed on nontransformed leaves. Consequently, larvae on OCI/OCII foliage reached their maximum weights three days earlier and slowed their feeding in preparation for pupation. During the later L4 stage, maximum larval weight gained and amount of leaves consumed was up to 19% less on OCI/OCII potato. An initial decrease of up to 56% in the total digestive proteinase activity was observed for the L3 larvae, of which up to 62% was specific for cysteine proteinase inhibition. However, with continued feeding on the OCI/OCII potato foliage, total and cysteine proteinase activities were similar to the controls, suggesting that the larvae adapted their proteinase digestive system to compensate for the recombinant oryzacystatins in the diet.