Russell Dylan, Rajabal Vaheesan, Alfonzetti Matthew, van der Merwe Marlien M, Gallagher Rachael V, Tetu Sasha G
School of Natural Sciences, Macquarie University, Sydney, NSW, Australia.
ARC Centre of Excellence for Synthetic Biology, Macquarie University, Sydney, NSW, Australia.
Environ Microbiome. 2025 Jan 13;20(1):4. doi: 10.1186/s40793-024-00657-3.
Seed banks are a vital resource for preserving plant species diversity globally. However, seedling establishment and survival rates from banked seeds can be poor. Despite a growing appreciation for the role of seed-associated microbiota in supporting seed quality and plant health, our understanding of the effects of conventional seed banking processes on seed microbiomes remains limited. In this study we investigated the composition and functional potential of seed-associated bacterial epiphytes associated with stored and freshly collected seeds of a native plant, Acacia ulicifolia, using both 16S rRNA gene sequencing and culture-based approaches.
Seeds obtained from seed banking facilities were found to host significantly less diverse bacterial populations, with substantial reductions in both low-abundance taxa and in community members commonly identified in freshly collected A. ulicifolia seeds. Bacteria with key plant growth promoting traits including IAA production, ACC deaminase activity, phosphate solubilisation, siderophore activity, and nitrogen fixation were identified in seed epiphytic communities, but these beneficial traits were less prevalent in stored seed compared to fresh seeds.
Overall, these results suggest that epiphytic seed microbiomes may undergo significant changes during the storage process, selecting for bacteria tolerant to storage conditions, and potentially reducing the population of plant-growth promoting bacteria on seeds.
种子库是全球保护植物物种多样性的重要资源。然而，种子库中的种子的成苗率和存活率可能较低。尽管人们越来越认识到种子相关微生物群在维持种子质量和植物健康方面的作用，但我们对传统种子库流程对种子微生物组的影响的了解仍然有限。在本研究中，我们使用16S rRNA基因测序和基于培养的方法，研究了与本地植物澳洲相思（Acacia ulicifolia）的储存种子和新鲜采集种子相关的种子附生细菌的组成和功能潜力。
从种子库设施获得的种子被发现携带的细菌种群多样性显著较低，低丰度分类群和新鲜采集的澳洲相思种子中常见的群落成员均大幅减少。在种子附生群落中鉴定出具有关键植物生长促进特性的细菌，包括吲哚乙酸（IAA）产生、1-氨基环丙烷-1-羧酸（ACC）脱氨酶活性、磷溶解、铁载体活性和固氮，但与新鲜种子相比，这些有益特性在储存种子中不太普遍。
总体而言，这些结果表明，附生种子微生物组在储存过程中可能会发生显著变化，选择出耐储存条件的细菌，并可能减少种子上促进植物生长的细菌数量。
