Pea aphids (Acyrthosiphon pisum) are one of the most important insect pests of alfalfa (Medicago sativa). Arbuscular mycorrhizal (AM) fungi are important microorganisms of the agroecosystem that promote plant growth and improve plant resistance to abiotic and biotic stress. Little information is available on AM fungi-regulated defense responses of alfalfa to pea aphids. To better understand how alfalfa responds and to evaluate the impact of an AM fungus on aphid infestation, transcriptome sequencing was done and physiological parameters were analyzed. Our experiments showed that Rhizophagus intraradices can regulate plant response to aphids by promoting growth and increasing plant peroxidase (POD) and catalase (CAT) activities and salicylic acid (SA) concentration after aphid infestation. Transcriptome analysis showed that R. intraradices increased the expression of resistance-related genes, such as “WRKY transcription factor” and “Kunitz trypsin inhibitor.” Additionally, GO terms “chitinase activity,” “peroxidase activity,” “defense response,” and “response to biotic stimulus,” and KEGG pathways “phenylpropanoid biosynthesis” and “phenylalanine metabolism” were significantly enriched in mycorrhizal fungus-inoculated plants and aphid-infested plants. These findings will improve our understanding about the impact of this AM fungus on alfalfa response to aphid feeding and will provide the basis for further research on plant defense against aphids.

中文翻译：

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RNA-Seq分析显示，根际内的根瘤菌能促进苜蓿（Medicago sativa）对豌豆蚜虫（Acyrthosiphon pisum）的防御。

豌豆蚜虫（Acyrthosiphon pisum）是苜蓿（紫花苜蓿）最重要的害虫之一。丛枝菌根（AM）真菌是农业生态系统中的重要微生物，可促进植物生长并提高植物对非生物和生物胁迫的抗性。关于苜蓿对苜蓿蚜虫的AM真菌调节防御反应的信息很少。为了更好地了解苜蓿如何做出反应并评估AM真菌对蚜虫侵染的影响，进行了转录组测序并分析了生理参数。我们的实验表明，根瘤菌内radi可以通过促进生长并增加蚜虫侵染后植物过氧化物酶（POD）和过氧化氢酶（CAT）的活性以及水杨酸（SA）的浓度来调节植物对蚜虫的反应。转录组分析表明，R。intraradices增加了抗性相关基因的表达，例如“ WRKY转录因子”和“ Kunitz胰蛋白酶抑制剂”。此外，GO术语“几丁质酶活性”，“过氧化物酶活性”，“防御反应”和“对生物刺激的反应”以及KEGG途径“苯丙烷类生物合成”和“苯丙氨酸代谢”在菌根真菌接种的植物和蚜虫中明显丰富。 -出没的植物。这些发现将增进我们对这种AM真菌对苜蓿对蚜虫摄食反应的影响的了解，并将为进一步研究植物对蚜虫的防御作用提供基础。