Sundararajan Poorva, Ghosh Samrat, Kelbessa Bekele Gelena, Whisson Stephen C, Dubey Mukesh, Chawade Aakash, Vetukuri Ramesh Raju
Department of Plant Breeding, Swedish University of Agricultural Sciences, Alnarp, Sweden.
Cell and Molecular Sciences, The James Hutton Institute, Invergowrie, Dundee, UK.
Environ Microbiome. 2025 Jan 8;20(1):1. doi: 10.1186/s40793-024-00660-8.
Fusarium head blight (FHB) is a major disease affecting cereal crops including wheat, barley, rye, oats and maize. Its predominant causal agent is the ascomycete fungus Fusarium graminearum, which infects the spikes and thereby reduces grain yield and quality. The frequency and severity of FHB epidemics has increased in recent years, threatening global food security. Spray-induced gene silencing (SIGS) is an alternative technique for tackling this devastating disease through foliar spraying with exogenous double-stranded RNA (dsRNA) to silence specific pathogen genes via RNA interference. This has the advantage of avoiding transgenic approaches, but several aspects of the technology require further development to make it a viable field-level management tool. One such existing knowledge gap is how dsRNA spraying affects the microbiota of the host plants.
We found that the diversity, structure and composition of the bacterial microbiota are subject to changes depending on dsRNA targeted and host studied, while the fungal microbiota in the phyllosphere remained relatively unchanged upon spraying with dsRNA. Analyses of fungal co-occurrence patterns also showed that F. graminearum established itself among the fungal communities through negative interactions with neighbouring fungi. Through these analyses, we have also found bacterial and fungal genera ubiquitous in the phyllosphere, irrespective of dsRNA treatment. These results suggest that although rarer and less abundant microbial species change upon dsRNA spray, the ubiquitous bacterial and fungal components of the phyllosphere in wheat and barley remain unchanged.
We show for the first time the effects of exogenous dsRNA spraying on bacterial and fungal communities in the wheat and barley phyllospheres using a high-throughput amplicon sequencing approach. The results obtained further validate the safety and target-specificity of SIGS and emphasize its potential as an environmentally friendly option for managing Fusarium head blight in wheat and barley.
小麦赤霉病是一种影响包括小麦、大麦、黑麦、燕麦和玉米在内的谷类作物的主要病害。其主要致病因子是子囊菌禾谷镰刀菌，该菌感染穗部，从而降低谷物产量和品质。近年来，小麦赤霉病流行的频率和严重程度有所增加，威胁着全球粮食安全。喷雾诱导基因沉默（SIGS）是一种通过叶面喷施外源双链RNA（dsRNA）以通过RNA干扰使特定病原体基因沉默来应对这种毁灭性病害的替代技术。这具有避免转基因方法的优点，但该技术的几个方面需要进一步发展才能使其成为一种可行的田间管理工具。一个现有的知识空白是dsRNA喷施如何影响寄主植物的微生物群。
我们发现，细菌微生物群的多样性、结构和组成会因靶向的dsRNA和所研究的寄主不同而发生变化，而叶际真菌微生物群在用dsRNA喷施后保持相对不变。对真菌共现模式的分析还表明，禾谷镰刀菌通过与邻近真菌的负相互作用在真菌群落中立足。通过这些分析，我们还发现了叶际中普遍存在的细菌和真菌属，无论是否进行dsRNA处理。这些结果表明，虽然dsRNA喷施后较罕见和丰度较低的微生物物种会发生变化，但小麦和大麦叶际中普遍存在的细菌和真菌成分保持不变。
我们首次使用高通量扩增子测序方法展示了外源dsRNA喷施对小麦和大麦叶际细菌和真菌群落的影响。所获得的结果进一步验证了SIGS的安全性和靶向特异性，并强调了其作为管理小麦和大麦赤霉病的环境友好选择的潜力。
