The first transcriptome analysis of sugar beet in compatible and incompatible interactions with Heterodera schachtii. The first transcriptome analysis of sugar beet in compatible and incompatible interactions with Heterodera schachtii

Sugar beet (Beta vulgaris subsp. vulgaris) is an economically important crop and provides nearly one third of the global sugar production annually. The beet cyst nematode (BCN), Heterodera schachtii, causes major yield losses in sugar beet worldwide. The most effective and economic approach to control this nematode is growing tolerant or resistant cultivars. To identify candidate genes involved in susceptibility and resistance, the transcriptome of sugar beet and BCN in compatible and incompatible interactions at two time points, was studied using mRNA-seq. In total, 16 cDNA libraries were constructed and 442 691 707raw reads were obtained. In the compatible interaction, many alterations in phytohormone-related genes were detected. The effect of exogenous application of methyl jasmonate and ethephon was therefore investigated and the results revealed significant reduction of J2s infection and female development rates in treated susceptible plants. Our results revealed candidate genes putatively involved in the Hs1pro1-induced resistance, such as genes related to phenylpropanoid pathway, putative R genes and genes encoding F-box proteins, zinc finger and NAC transcription factors, ABC transporters, BURP and CYSTM proteins. Also, the transcriptome of BCN in the infected root samples was analyzed and several nematode effector genes were found. Our study is the first investigation of the transcriptome profile in the compatible and incompatible interactions between sugar beet and BCN. Overall design: Two cultivars of sugar beet, a susceptible and a resistant variety, were infected with Heterodera schachtii. On two time points, 4 days after infection and 10 days after infection, plants were sampled. For each combination of sugar beet type and time point a corresponding non-infected control was sampled as well.

甜菜（Beta vulgaris subsp. vulgaris）是一种具有重要经济价值的作物，年产量约占全球食糖总产量的三分之一。甜菜胞囊线虫（BCN，Heterodera schachtii）会在全球范围内造成甜菜产量的大幅损失。防治该线虫最有效且经济的手段是种植耐病或抗病品种。为鉴定参与甜菜抗、感病性调控的候选基因，本研究采用mRNA测序（mRNA-seq）技术，对两个时间点下甜菜与BCN之间的亲和互作及非亲和互作样本的转录组进行了分析。本研究共构建16个cDNA文库，获得442,691,707条原始测序读段。在亲和互作样本中，研究人员检测到大量与植物激素相关的基因表达发生显著变化。为此，本研究对茉莉酸甲酯（methyl jasmonate）与乙烯利（ethephon）的外源施用效果展开了探究，结果表明，经处理的感病植株的线虫二龄幼虫（J2s）侵染率与雌虫发育率均显著下降。本研究鉴定出一批参与Hs1pro1介导的抗病反应的候选基因，例如苯丙烷途径（phenylpropanoid pathway）相关基因、推定的抗病基因（R genes），以及编码F-box蛋白（F-box proteins）、锌指蛋白与NAC转录因子（NAC transcription factors）的基因、ABC转运蛋白（ABC transporters）、BURP家族蛋白及CYSTM家族蛋白。此外，本研究还对侵染根系样本中的BCN转录组进行了分析，鉴定出多个线虫效应蛋白基因。本研究是首个针对甜菜与BCN之间亲和及非亲和互作转录组特征的系统性分析。整体实验设计：供试甜菜分为感病品种与抗病品种两个栽培种，均接种Heterodera schachtii；分别于接种后4天与接种后10天两个时间点采集植株样本；针对每种甜菜品种与每个时间点的组合，同步采集对应的未接种对照样本。