Chymotrypsin-like proteases contribute to Phthorimaea absoluta (Meyrick) susceptibility to Bacillus thuringiensis

IF 2.5 2区农林科学 Q1 AGRONOMY

Crop Protection Pub Date : 2025-03-26 DOI:10.1016/j.cropro.2025.107217

Andresa C.B. Oliveira , Valéria Wanderley-Teixeira , Teófilo P. Langa , José V.C. R. Dantas , Herbert A.A. de Siqueira

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引用次数: 0

Abstract

Phthorimaea absoluta (Meyrick) is a globally significant pest of tomato crops, capable of causing up to 100 % yield losses under high infestation levels. The continuous use of chemical insecticides has led to the evolution of resistant P. absoluta populations, resulting in frequent control failures in the field. This scenario extends to the entomopathogenic bacterium Bacillus thuringiensis (Berliner), raising concerns about resistance development due to increased usage as an alternative to chemical control. This study tested the hypothesis that Brazilian populations of P. absoluta have developed resistance to Bt formulations and investigated the role of serine proteases in this process. We conducted concentration-response assays for eight P. absoluta populations. Resistance variation was observed, with a 2.93-fold increase for Dipel® and a 5.83-fold increase for XenTari®. The LC80 values for XenTari® exceeded the recommended dose, indicating potential field control failures. Serine protease activities, specifically chymotrypsin and elastase, were inversely proportional to the LC50 values for Dipel®, suggesting their involvement in toxin activation. However, no correlation was found between serine protease activity and LC50 values for XenTari®, implying that these enzymes do not contribute to resistance against this formulation. The differential toxin composition of the two products likely explains the higher efficacy of B. thuringiensis var. kurstaki (Dipel®) compared to B. thuringiensis var. aizawai (XenTari®) against P. absoluta. The presence of the Cry1Ac toxin in Dipel® appears to enhance its efficiency in controlling P. absoluta while exerting selective pressure on the insect's humoral defenses.

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乳糜蛋白酶样蛋白酶有助于绝对Phthorimaea （Meyrick）对苏云金芽孢杆菌的敏感性

绝对灰霉（Meyrick）是全球番茄作物的重要害虫，在高水平侵染下能够造成高达100%的产量损失。化学杀虫剂的持续使用导致了抗药性绝对白蝇种群的进化，导致田间防治屡屡失败。这种情况延伸到昆虫致病细菌苏云金芽孢杆菌（Berliner），引起了人们对其耐药性发展的担忧，因为作为化学控制的替代品，苏云金芽孢杆菌的使用越来越多。本研究验证了巴西绝对p.a absoluta种群对Bt配方产生抗性的假设，并研究了丝氨酸蛋白酶在这一过程中的作用。我们对8个绝对白蝇种群进行了浓度-响应分析。观察到耐药性变化，Dipel®增加2.93倍，XenTari®增加5.83倍。XenTari®的LC80值超过推荐剂量，表明潜在的场控制失败。丝氨酸蛋白酶活性，特别是凝乳胰蛋白酶和弹性蛋白酶，与Dipel®的LC50值成反比，表明它们参与毒素激活。然而，没有发现丝氨酸蛋白酶活性与XenTari®LC50值之间的相关性，这意味着这些酶不会对该制剂产生抗性。这两种产品的不同毒素成分可能解释了为什么与苏云金芽孢杆菌（B. thuringiensis var. kurstaki）（Dipel®）相比，苏云金芽孢杆菌（B. thuringiensis var. aizawai）（XenTari®）对绝对p.a absoluta的疗效更高。Dipel®中Cry1Ac毒素的存在似乎增强了其控制绝对假单胞虫的效率，同时对昆虫的体液防御施加选择性压力。

本文章由计算机程序翻译，如有差异，请以英文原文为准。

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来源期刊

Crop Protection 农林科学-农艺学

CiteScore

6.10

自引率

3.60%

发文量

200

审稿时长

29 days

期刊介绍： The Editors of Crop Protection especially welcome papers describing an interdisciplinary approach showing how different control strategies can be integrated into practical pest management programs, covering high and low input agricultural systems worldwide. Crop Protection particularly emphasizes the practical aspects of control in the field and for protected crops, and includes work which may lead in the near future to more effective control. The journal does not duplicate the many existing excellent biological science journals, which deal mainly with the more fundamental aspects of plant pathology, applied zoology and weed science. Crop Protection covers all practical aspects of pest, disease and weed control, including the following topics: -Abiotic damage- Agronomic control methods- Assessment of pest and disease damage- Molecular methods for the detection and assessment of pests and diseases- Biological control- Biorational pesticides- Control of animal pests of world crops- Control of diseases of crop plants caused by microorganisms- Control of weeds and integrated management- Economic considerations- Effects of plant growth regulators- Environmental benefits of reduced pesticide use- Environmental effects of pesticides- Epidemiology of pests and diseases in relation to control- GM Crops, and genetic engineering applications- Importance and control of postharvest crop losses- Integrated control- Interrelationships and compatibility among different control strategies- Invasive species as they relate to implications for crop protection- Pesticide application methods- Pest management- Phytobiomes for pest and disease control- Resistance management- Sampling and monitoring schemes for diseases, nematodes, pests and weeds.