A genome-wide view of transcriptional responses during Aphis glycines Matsumura infestation in soybean

Soybean aphid is one of the major limiting factors for soybean production. However, the mechanism for aphid resistance in soybean is remain enigmatic, very little information is available about the different mechanisms between antibiosis and antixenosis genotypes. Here we dissected aphid infestation into three stages and used genome-wide gene expression profiling to investigate the underlying aphid-plant interaction mechanisms. Approximately 990 million raw reads in total were obtained, the high expression correlation in each genotype between infestation and non-infestation indicated that the response to aphid was controlled by a small subset of important genes. Moreover, plant response to aphid infestation was more rapid in resistant genotypes. Among the differentially expressed genes (DEGs), a total of 901 transcription factor (TF) genes categorized to 40 families were identified with distinct expression patterns, of which AP2/ERF, MYB and WRKY families were proposed to playing dominated roles. Gene expression profiling demonstrated that these genes had either similar or distinct expression patterns in genotypes. Besides, JA-responsive pathway was domination in aphid-soybean interaction compared to SA pathway, which was not involved plant response to aphid in susceptible and antixenotic genotypes but played an important role in antibiosis one. Throughout, callose were deposited in all genotypes but it was more rapidly and efficiently in antibiotic one. However, reactive oxygen species were not involved in response to aphid attack in resistant genotypes during aphid infestation. Our study helps uncover important genes associated with aphid-attack response in antibiosis and antixenotic genotypes of soybean. Overall design: mRNA profiles of aphid-susceptible, antibiotic and antixenotic soybean genotypes in 24h, 48h and 96h after infestation generated using Illumina HiSeq 4000 platform, in triplicate

大豆蚜是制约大豆生产的主要限制因子之一。然而，大豆抗蚜机制仍不甚明晰，目前针对抗生性（antibiosis）与排趋性（antixenosis）基因型间的差异抗性机制的相关研究尚且匮乏。本研究将蚜虫侵染过程划分为三个阶段，采用全基因组基因表达谱分析，以解析蚜虫-植物互作的潜在机制。本研究共获得约9.9亿条原始测序读段（raw reads）。各基因型在蚜虫侵染与未侵染条件下的基因表达相关性较高，表明大豆对蚜虫的响应由少数关键基因调控。此外，抗蚜基因型对蚜虫侵染的响应更为迅速。在差异表达基因（differentially expressed genes, DEGs）中，共鉴定得到901个转录因子（transcription factor, TF）基因，分属40个基因家族，且呈现出独特的表达模式；其中AP2/ERF、MYB与WRKY家族被推测发挥主导调控作用。基因表达谱分析显示，这些基因在不同基因型中呈现相似或迥异的表达模式。此外，相较于水杨酸（salicylic acid, SA）信号通路，茉莉酸（jasmonic acid, JA）信号通路在蚜虫-大豆互作中占据主导地位：SA信号通路未参与感蚜与排趋性基因型的蚜虫响应，但在抗生性基因型中发挥重要作用。全程观测到所有基因型均有胼胝质（callose）沉积，但在抗生性基因型中，胼胝质沉积更为迅速且高效。然而，在蚜虫侵染过程中，抗蚜基因型的活性氧（reactive oxygen species, ROS）并未参与蚜虫攻击响应。本研究有助于揭示大豆抗生性与排趋性基因型中与蚜虫侵染响应相关的关键基因。实验设计：采用Illumina HiSeq 4000测序平台，对感蚜、抗生性及排趋性大豆基因型在蚜虫侵染后24h、48h及96h的mRNA表达谱进行检测，每组设置三次生物学重复。