Cowpea bruchid Callosobruchus maculatus uses a three‐component strategy to overcome a plant defensive cysteine protease inhibitor

Abstract

The soybean cysteine protease inhibitor, soyacystatin N (scN), negatively impacts growth and development of the cowpea bruchid, Callosobruchus maculatus[Koiwa et al. (1998) Plant J 14: 371-379]. However, the developmental delay and feeding inhibition caused by dietary scN occurred only during the early developmental stages (the 1st, 2nd and 3rd instars) of the cowpea bruchid. The 4th instar larvae reared on scN diet (adapted) exhibited rates of feeding and development which were comparable to those feeding on an scN-free diet (unadapted) prior to pupation. Total gut proteolytic capacity at this larval stage significantly increased in the scN-adapted insects. The elevated enzymatic activity was attributed to a differential expression of insect gut cysteine proteases (representing the major digestive enzymes), and of aspartic proteases. scN degradation by the gut extract was observed only in adapted bruchids, and this activity appeared to be a combined effect of scN-induced cysteine and aspartic proteases. Thirty cDNAs encoding cathepsin L-like cysteine proteases were isolated from insect guts, and they were differentially regulated by dietary scN. Our results suggest that the cowpea bruchid adapts to the challenge of scN by qualitative and quantitative remodelling of its digestive protease complement, and by activating scN-degrading protease activity.

Tailoring the Specificity of a Plant Cystatin toward Herbivorous Insect Digestive Cysteine Proteases by Single Mutations at Positively Selected Amino Acid Sites

“…Insect herbivores have developed over time effective strategies to elude the inhibitory effects of plant protease inhibitors (Broadway, 2000), including: (1) the use of complex digestive protease systems with proteases from different mechanistic classes acting in a complementary, coordinated manner (Terra and Ferreira, 1994;Brunelle et al, 1999Brunelle et al, , 2004; (2) the production of alternative, insensitive protease forms following ingestion of protease inhibitors (Jongsma et al, 1995;Bown et al, 1997;Cloutier et al, 1999Cloutier et al, , 2000Broadway, 2001a, 2001b;Zhu-Salzman et al, 2003;Brunelle et al, 2004); and (3) the degradation of defensive protease inhibitors using nontarget, insensitive digestive proteases (Michaud et al, 1995a;Michaud, 1997;Girard et al, 1998a;Giri et al, 1998;Gruden et al, 2003;ZhuSalzman et al, 2003). It is now generally recognized that protease/inhibitor interactions in plant-insect systems are the result of a long, coevolutive process triggering the continuous diversification of proteolytic and protease inhibitory functions in the competing organisms (Lopes et al, 2004;Valueva and Mosolov, 2004;Christeller, 2005;Kiggundu et al, 2006;Girard et al, 2007).…”

Deleterious effects of plant cystatins against the banana weevil Cosmopolites sordidus

“…These insects have developed over time effective strategies to elude the inhibitory effects of plant protease inhibitors, involving the use of complex digestive protease systems with proteases from different mechanistic classes acting in a complementary, coordinated manner (Brunelle et al, 1999;Hernandez et al, 2003;Gruden et al, 2003;Vinokurov et al, 2006a,b;Prabhakar et al, 2007); the over-expression of target proteases following cystatin ingestion to outnumber the inhibitory proteins (Cloutier et al, 2000;Ahn et al, 2004); the constitutive or diet-induced expression of cysteine cathepsins weakly sensitive to the ingested cystatin, the so-called 'cystatin-insensitive proteases' (Michaud et al, 1993(Michaud et al, , 1995aGirard et al, 1998a;Cloutier et al, 1999Cloutier et al, , 2000ZhuSalzman et al, 2003;Brunelle et al, 2004;Gruden et al, 2004;Liu et al, 2004;Koo et al, 2008); the over-expression of proteases from alternative mechanistic classes following cystatin ingestion (Zhu-Salzman et al, 2003;Brunelle et al, 2004;Rivard et al, 2004;Oppert et al, 2005); and the degradation of defensive protease inhibitors using non-target, insensitive proteases (Michaud et al, 1995b;Girard et al, 1998b;Giri et al, 1998;Gruden et al, 2003;Zhu-Salzman et al, 2003).…”

“…The negative effects of E-64 on growth and fecundity of several coleopteran species, including cystatin-resistant insects such as the Colorado potato beetle Leptinotarsa decemlineata (Bolter and Latoszek-Green, 1997) and the cowpea weevil Callosobruchus maculatus (Murdock et al, 1988), were systematically associated with a broadspectrum inhibition of cysteine proteases in midgut extracts (Michaud et al, 1993;Fabrick et al, 2002;Kim and Mullin, 2003). By contrast, the reported inefficiency of plant cystatins against a number of Coleoptera was typically associated with the presence of cystatin-insensitive cysteine proteases, thought to help the target insects compensating for the loss of sensitive protease activities following cystatin intake (Cloutier et al, , 2000Zhu-Salzman et al, 2003;Gruden et al, 2003Gruden et al, , 2004. In line with previous studies reporting detrimental effects for cystatins or other plant cysteine-type inhibitors against some coleopteran species (Zhao et al, 1996;Koiwa et al, 2000;Fabrick et al, 2002), the negative effects of OsCYS1 and CpCYS1 against the banana Plant cystatins against the banana weevil Page 16 weevil were correlated with a broad inhibitory spectrum of the two cystatins against Z-FR-MCA-(cathepsin L-like) and Z-RR-MCA-hydrolyzing (cathepsin B-like) cysteine proteases in midgut extracts, comparable to the overall inhibitory effect of E-64 against the same enzymes.…”

“…Several papers have been published assessing the effectiveness of plant cystatins against herbivorous Coleoptera, with conclusive results in some cases (Leplé et al, 1995;Kuroda et al, 1996;Lecardonnel et al, 1999;Koiwa et al, 2000;Alvarez-Alfageme et al 2007;Ninkovic et al, 2007) but disappointing results in other cases owing to the ability of the target insects to readily elude or even counteract the antidigestive effects of natural or recombinant inhibitors (e.g. Girard et al, 1998a,b;Cloutier et al, 1999Cloutier et al, , 2000Zhu-Salzman et al, 2003;Gruden et al, 2003Gruden et al, , 2004Ahn et al, 2004Ahn et al, , 2007Oppert et al, 2005;Koo et al, 2008). Here we document the broad inhibitory effects of plant cystatins against midgut cysteine cathepsins of the banana weevil, and the detrimental effects of these proteins on larval growth using a novel bioassay set-up with cystatin-infiltrated banana tissues.…”

Quantitative genetics of preference and performance on chickpeas in the noctuid moth, Helicoverpa armigera

“…This could result in differing selection pressures at different life stages. Moreover, levels of additive genetic variation can also vary with age or life stage as genes may be differentially expressed, both qualitatively and quantitatively during development (Zhu-Salzman et al, 2003). If the levels of additive genetic variation in performance differ between young and old larvae, then the population-level response to selection could depend more strongly on responses in one life stage over another.…”