Key Laboratory of Plant Functional Genomics of the Ministry of Education/Jiangsu, Key Laboratory of Crop Genomics and Molecular Breeding/Collaborative Innovation of Modern Crops and Food Crops in Jiangsu/Jiangsu Key Laboratory of Crop Genetics and Physiology, College of Agriculture, Yangzhou University, Yangzhou, 225009, China.
BMC Plant Biol. 2022 Jan 3;22(1):3. doi: 10.1186/s12870-021-03393-9.
Fusarium head blight (FHB) caused by Fusarium graminearum is a devastating fungal disease of wheat. The mechanism underlying F. graminearum-wheat interaction remains largely unknown. tRNA-derived fragments (tRFs) are RNase-dependent small RNAs derived from tRNAs, and they have not been reported in wheat yet, and whether tRFs are involved in wheat-F. graminearum interactions remains unknown.
Herein, small RNAs from the spikelets inoculated with F. graminearum and mock from an FHB-susceptible variety Chinese Spring (CS) and an FHB-resistant variety Sumai3 (SM) were sequenced respectively. A total of 1249 putative tRFs were identified, in which 15 tRFs was CS-specific and 12 SM-specific. Compared with mock inoculation, 39 tRFs were significantly up-regulated across both wheat varieties after F. graminearum challenge and only nine tRFs were significantly down-regulated. tRF, tRF and tRF were dramatically induced by F. graminearum infection, with significantly higher fold changes in CS than those in SM. The expression patterns of the three highly induced tRFs were further validated by stem-loop qRT-PCR. The accumulation of tRFs were closely related to ribonucleases T2 family members, which were induced by F. graminearum challenge. The tRFs' targets in host were predicted and were validated by RNA sequencing.
Integrative analysis of the differentially expressed tRFs and their candidate targets indicated that tRF, tRF and tRF might negatively regulate wheat resistance to FHB. Our results unvealed the potential roles of tRFs in wheat-F. graminearum interactions.
由镰刀菌（Fusarium graminearum）引起的小麦赤霉病（FHB）是一种破坏性的真菌病害。F. graminearum-小麦互作的机制在很大程度上尚不清楚。tRNA 衍生片段（tRFs）是一类由 tRNA 产生的依赖于 RNA 酶的小 RNA，它们在小麦中尚未被报道，并且 tRFs 是否参与小麦与 F. graminearum 的相互作用也尚不清楚。
本文分别从小麦品种中国春（CS）和苏麦 3 号（SM）接种镰刀菌和模拟接种的小穗中进行了测序。共鉴定出 1249 个假定的 tRFs，其中 15 个 tRFs是 CS 特异性的，12 个 tRFs是 SM 特异性的。与模拟接种相比，在 F. graminearum 挑战后，两种小麦品种均有 39 个 tRFs显著上调，仅有 9 个 tRFs显著下调。tRF、tRF 和 tRF 在 F. graminearum 感染后被显著诱导，在 CS 中的丰度变化倍数明显高于 SM。通过茎环 qRT-PCR 进一步验证了这三个高度诱导的 tRF 的表达模式。tRFs 的积累与被 F. graminearum 挑战诱导的核糖核酸酶 T2 家族成员密切相关。预测了 tRFs 的宿主靶标，并通过 RNA 测序进行了验证。
差异表达的 tRFs 及其候选靶标的综合分析表明，tRF、tRF 和 tRF 可能负调控小麦对 FHB 的抗性。我们的研究结果揭示了 tRFs 在小麦与 F. graminearum 互作中的潜在作用。
