Tomato Below Ground–Above Ground Interactions: Trichoderma longibrachiatum Affects the Performance of Macrosiphum euphorbiae and Its Natural Antagonists

Abstract

Below ground and above ground plant-insect-microorganism interactions are complex and regulate most of the developmental responses of important crop plants such as tomato. We investigated the influence of root colonization by a nonmycorrhizal plant-growth-promoting fungus on direct and indirect defenses of tomato plant against aphids. The multitrophic system included the plant Solanum lycopersicum ('San Marzano nano'), the root-associated biocontrol fungus Trichoderma longibrachiatum strain MK1, the aphid Macrosiphum euphorbiae (a tomato pest), the aphid parasitoid Aphidius ervi, and the aphid predator Macrolophus pygmaeus. Laboratory bioassays were performed to assess the effect of T. longibrachiatum MK1, interacting with the tomato plant, on quantity and quality of volatile organic compounds (VOC) released by tomato plant, aphid development and reproduction, parasitoid behavior, and predator behavior and development. When compared with the uncolonized controls, plants whose roots were colonized by T. longibrachiatum MK1 showed quantitative differences in the release of specific VOC, better aphid population growth indices, a higher attractiveness toward the aphid parasitoid and the aphid predator, and a quicker development of aphid predator. These findings support the development of novel strategies of integrated control of aphid pests. The species-specific or strain-specific characteristics of these below ground-above ground interactions remain to be assessed.

Oviposition induced volatiles in tomato plants

“…Volatiles emitted from herbivore infested tomato plants had quantitative and qualitative differences from undamaged plants. Even below-ground infestation by a microbe has been found to cause changes in the headspace volatile profile of tomato plants (Battaglia et al, 2013). Here we show that egg deposition per se is adequate to evoke indirect defense mechanisms in tomato plants.…”

Improving the efficiency of Trichogramma achaeae to control Tuta absoluta

“…S. cerealella and E. kuehniella eggs) alter parasitism rate (Makee 2005;Kölliker-Ott et al 2003;Grenier et al 2001;Brotodjojo and Walter 2006). Similarly, nutritious quality of the prey/host affects predator/parasitoid performance which has been confirmed for generalist arthropod predators (reviewed by Toft 2013;Jensen et al 2012;Mayntz et al 2005;Battaglia et al 2013), but less so for parasitoids. It is therefore a challenge to find ways to enhance the parasitoid's preference for the target host.…”

Trichoderma harzianum enhances tomato indirect defense against aphids

“…PGPFs (Plant Growth Promoting Fungi) belonging to the genus Trichoderma are among the most widespread soil microbes, which are effective biocontrol agents of plant pathogens (Lorito et al ., ; Lorito & Woo, ). Moreover, the possibility that these beneficial agents could have a positive impact on plant response to insect pests is attractive but poorly understood (e.g., Battaglia et al ., ; Pineda et al ., ). Indeed, the currently available information indicates that both plant resistance and growth promotion can be induced under different environmental conditions, with contrasting effects on insect growth and survival (Pieterse et al ., ).…”