Data underlying the publication: Spinach seed microbiota associated with Globisporangium ultimum disease suppression are culturable and highly prevalent

Four microbial genera associated with spinach (<em>Spinacia oleracea</em>) seeds were recently described as indicators of suppressiveness against <em>Globisporangium ultimum </em>(previously known as <em>Pythium ultimum</em>) damping-off using amplicon sequencing. These were the bacterial genus <em>Massilia</em> as well as the basidiomycetous dimorphic yeasts <em>Vishniacozyma</em>, <em>Filobasidium </em>and<em> Papiliotrema</em>. Here, we examined the culturability of spinach seed microbiota using two spinach seed lots. Seeds were split into true seed and pericarp compartments and these were used to prepare suspensions that were plated on R2A and PDA plates to culture bacteria and fungi, respectively. We found that 49 % of bacterial and 52 % of fungal genera were culturable, including all four genera correlating with suppressiveness and most high-prevalence genera, while this was not the case for most low-prevalence genera. Most high-prevalence genera were found in both seed compartments (true seed and pericarp) with little variation between seed compartment communities, while more than 65 % of microbial composition variation was explained by the factor whole seed sample, indicating high intraspecific seed microbiota variability. Given the culturability and ubiquity of indicator genera, our results are a stepping stone towards the use of seed microbiota for disease suppression.<br>

近期通过扩增子测序（amplicon sequencing）技术，研究人员鉴定出4种与菠菜（Spinacia oleracea）种子相关的微生物类群，它们可作为抵御终极球状孢囊霉（Globisporangium ultimum，曾被归类为终极腐霉Pythium ultimum）引发的猝倒病的生物指示因子。上述类群包括细菌属马赛利亚菌属（Massilia），以及担子菌门双态酵母维什尼亚科酵母属（Vishniacozyma）、菲洛巴斯蒂德酵母属（Filobasidium）与帕皮利特雷玛酵母属（Papiliotrema）。本研究利用两批菠菜种子样本，探究了菠菜种子微生物组的可培养性：将种子分为种仁（true seed）与果皮（pericarp）两个组分，分别制备悬浮液后接种于R2A培养基与PDA培养基，以分别培养细菌与真菌。研究结果显示，49%的细菌属与52%的真菌属具备可培养性，其中涵盖全部4种与病害抑制效应相关的类群以及多数高检出率属；而多数低检出率属则未被成功培养。多数高检出率属同时存在于种仁与果皮两个组分中，两组分的微生物群落组成差异极小；但超过65%的微生物组组成变异可由完整种子样本这一因素解释，这表明种内种子微生物组存在较高的变异性。鉴于上述指示类群具备可培养性且分布广泛，本研究结果为利用种子微生物组开展病害生物防治迈出了关键一步。