Coppola Mariangela, Diretto Gianfranco, Digilio Maria Cristina, Woo Sheridan Lois, Giuliano Giovanni, Molisso Donata, Pennacchio Francesco, Lorito Matteo, Rao Rosa
Department of Agricultural Sciences, Portici, Italy.
ENEA, Rome, Italy.
Front Physiol. 2019 Jun 21;10:745. doi: 10.3389/fphys.2019.00745. eCollection 2019.
Beneficial fungi in the genus are among the most widespread biocontrol agents of plant pathogens. Their role in triggering plant defenses against pathogens has been intensely investigated, while, in contrast, very limited information is available on induced barriers active against insects. The growing experimental evidence on this latter topic looks promising, and paves the way toward the development of strains and/or consortia active against multiple targets. However, the predictability and reproducibility of the effects that these beneficial fungi is still somewhat limited by the lack of an in-depth understanding of the molecular mechanisms underlying the specificity of their interaction with different crop varieties, and on how the environmental factors modulate this interaction. To fill this research gap, here we studied the transcriptome changes in tomato plants (cultivar "Dwarf San Marzano") induced by (strain T22) colonization and subsequent infestation by the aphid . A wide transcriptome reprogramming, related to metabolic processes, regulation of gene expression and defense responses, was induced both by separate experimental treatments, which showed a synergistic interaction when concurrently applied. The most evident expression changes of defense genes were associated with the multitrophic interaction -tomato-aphid. Early and late genes involved in direct defense against insects were induced (i.e., ), along with indirect defense genes, such as and . Targeted and untargeted semi-polar metabolome analysis revealed a wide metabolome alteration showing an increased accumulation of isoprenoids in treated plants. The wide array of transcriptomic and metabolomics changes nicely fit with the higher mortality of aphids when feeding on treated plants, herein reported, and with the previously observed attractiveness of these latter toward the aphid parasitoid . Moreover, treated plants showed the over-expression of transcripts coding for several families of defense-related transcription factors (bZIP, MYB, NAC, AP2-ERF, WRKY), suggesting that the fungus contributes to the priming of plant responses against pest insects. Collectively, our data indicate that treatment of tomato plants induces transcriptomic and metabolomic changes, which underpin both direct and indirect defense responses.
该属中的有益真菌是植物病原体最广泛的生物防治剂之一。它们在触发植物对病原体的防御方面的作用已得到深入研究，而相比之下，关于对昆虫有活性的诱导屏障的信息却非常有限。关于后一个主题越来越多的实验证据看起来很有前景，并为开发针对多个目标有活性的菌株和/或菌群铺平了道路。然而，这些有益真菌所产生效果的可预测性和可重复性仍然受到一定限制，因为缺乏对其与不同作物品种相互作用特异性背后分子机制的深入理解，以及环境因素如何调节这种相互作用。为了填补这一研究空白，我们在此研究了番茄植株（品种“矮生圣马扎诺”）在被木霉菌（菌株T22）定殖以及随后被蚜虫侵染后转录组的变化。单独的实验处理均诱导了与代谢过程、基因表达调控和防御反应相关的广泛转录组重编程，当同时应用时显示出协同相互作用。防御基因最明显的表达变化与多营养相互作用——番茄 - 蚜虫相关。参与对昆虫直接防御的早期和晚期基因（即 ）以及间接防御基因（如 和 ）都被诱导。靶向和非靶向半极性代谢组分析揭示了广泛的代谢组改变，显示在木霉菌处理的植株中类异戊二烯积累增加。本文报道，大量的转录组和代谢组变化很好地符合了蚜虫取食木霉菌处理植株时更高的死亡率，以及之前观察到的这些植株对蚜虫寄生蜂的吸引力。此外，木霉菌处理的植株显示出编码几个防御相关转录因子家族（bZIP、MYB、NAC、AP2 - ERF,、WRKY）的转录本的过表达，表明该真菌有助于引发植物对害虫的反应。总体而言，我们的数据表明木霉菌处理番茄植株会诱导转录组和代谢组变化，这些变化是直接和间接防御反应的基础。
