Plant growth-promoting fungi belonging to genus Trichoderma are known to help plants when dealing with biotic stressors by enhancing plant defenses. While beneficial effects of Trichoderma spp. against plant pathogens have long been documented, fewer studies have investigated their effect on insect pests. Here, we studied the impact of Trichoderma root colonization on the plant defense responses against stink bug feeding attack. For this purpose, a model system consisting of tomato plant, Solanum lycopersicum cv Dwarf San Marzano, Trichoderma harzianum strain T22 and the southern green stink bug, Nezara viridula, was used. We firstly determined stink bug performance in terms of relative growth rate and survival on tomato plants inoculated by T. harzianum T22. Then, we evaluated relative expression of plant defense-related genes on inoculated plants induced by stink bug feeding. We found evidence that T. harzianum T22 affects tomato defense responses against N. viridula nymphs leading to reduction of growth rate. Our results also showed that T. harzianum T22 enhances plant direct defenses by an early increase of transcript levels of jasmonic acid marker genes. Yet this effect was time-dependent and only detected 8 h after herbivore induction. Taken together, our findings provide better understanding on the mechanisms underlying tomato induced resistance against herbivorous stink bugs.

已知木霉属的植物促生长真菌通过增强植物防御来帮助植物应对生物胁迫。虽然木霉属的有益作用。对抗植物病原体的研究早已被记录在案，但很少有研究调查它们对害虫的影响。在这里，我们研究了木霉根系定植对植物抵御臭虫进食攻击的防御反应的影响。为此，一个模型系统由番茄植物、Solanum lycopersicum cv Dwarf San Marzano、Trichoderma harzianum T22 和南方绿色臭虫Nezara viridula 组成，被使用。我们首先根据哈茨木霉T22接种的番茄植株的相对生长率和存活率来确定臭虫的表现。然后，我们评估了由臭虫喂养诱导的接种植物上植物防御相关基因的相对表达。我们发现有证据表明T. harzianum T22 影响番茄针对N. viridula若虫的防御反应，导致生长速度降低。我们的结果还表明，T. harzianumT22 通过早期增加茉莉酸标记基因的转录水平来增强植物的直接防御。然而，这种效应是时间依赖性的，并且仅在食草动物诱导后 8 小时检测到。综上所述，我们的研究结果提供了对番茄诱导对草食性臭虫产生抗性的潜在机制的更好理解。