The Protease Inhibitor CI2c Gene Induced by Bird Cherry-Oat Aphid in Barley Inhibits Green Peach Aphid Fecundity in Transgenic Arabidopsis

Abstract

Aphids are phloem feeders that cause large damage globally as pest insects. They induce a variety of responses in the host plant, but not much is known about which responses are promoting or inhibiting aphid performance. Here, we investigated whether one of the responses induced in barley by the cereal aphid, bird cherry-oat aphid (Rhopalosiphum padi L.) affects aphid performance in the model plant Arabidopsis thaliana L. A barley cDNA encoding the protease inhibitor CI2c was expressed in A. thaliana and aphid performance was studied using the generalist green peach aphid (Myzus persicae Sulzer). There were no consistent effects on aphid settling or preference or on parameters of life span and long-term fecundity. However, short-term tests with apterous adult aphids showed lower fecundity on three of the transgenic lines, as compared to on control plants. This effect was transient, observed on days 5 to 7, but not later. The results suggest that the protease inhibitor is taken up from the tissue during probing and weakly inhibits fecundity by an unknown mechanism. The study shows that a protease inhibitor induced in barley by an essentially monocot specialist aphid can inhibit a generalist aphid in transgenic Arabidopsis.

Transcriptome Profiling Revealed Potentially Critical Roles for Digestion and Defense-Related Genes in Insects’ Use of Resistant Host Plants: A Case Study with Sitobion Avenae

“…This explains the finding that the expression changes of β-glucosidase were specifically induced in S. avenae feeding on wheat in our study. Some proteases, like serine proteases and cysteine proteases, have both digestive and defensive functions in insects [56,57]. In this study, some cysteine proteases showed specific expression in S. avene on wheat, whereas some serine proteases were found to be specifically induced by barley.…”

“…Thus, the differential expression of these digestive enzymes may have significant implications in the adaptation of insect biotypes on different host plants with significant nutritional variation [52][53][54][55]. In addition to their nutritional implications, some proteases, such as the above-mentioned serine proteases, may also be involved in defensive adaptation against proteinase inhibitors of host plants for insects [56,57]. Indeed, proteinase inhibitors of wheat have been proved to have anti-metabolic effects on S. avenae midgut proteases [58].…”

Overexpression and Down-Regulation of Barley Lipoxygenase LOX2.2 Affects Jasmonate-Regulated Genes and Aphid Fecundity

“…In addition, THIO1567 was at a lower expression in the antisense line compared to the control line upon GPA infestation ( Figure 5 ), and both THIO1567 and CI2c were found at a higher transcript abundance in the resistant wild barley Hsp5 than in the other genotypes ( Figure 1 ). The proteinase inhibitor, CI2c , was previously shown to inhibit GPA reproduction when expressed in Arabidopsis [ 36 ]. Thionins are sulfur-rich small proteins with in vitro toxicity against plant fungal pathogens and bacteria [ 37 , 38 ].…”

Purification and characterization of Bowman-Birk and Kunitz isoinhibitors from the seeds of Rhynchosia sublobata (Schumach.) Meikle, a wild relative of pigeonpea

“…Many transgenic plants expressing PIs from non-host and wild relatives are reported to counteract the insect pests (Abdeen et al, 2005;Dunse et al, 2010;Hamza et al, 2018;Macedo et al, 2015;Rehman et al, 2017). Therefore, a continuous screening of non-hosts and wild relatives is essential to identify effective ecofriendly PIs to target economically important insect pests such as Helicoverpa armigera and Achaea janata (Jamal et al, 2013;Losvik et al, 2017). Controlling H. armigera (a polyphagous pest) and A. janata (a major pest on Ricinus communis) has been a major challenge since they are efficient in overcoming defense mechanisms of host plant and chemical pesticides due to their broad host range and voracious feeding behaviour.…”