College of Natural Resources and Environment, South China Agricultural University, Guangzhou 510642, China.
Institute of Tropical and Subtropical Ecology, South China Agricultural University, Guangzhou 510642, China.
Int J Mol Sci. 2019 Feb 11;20(3):761. doi: 10.3390/ijms20030761.
Bacterial wilt is a devastating disease of tomato caused by soilborne pathogenic bacterium . Previous studies found that silicon (Si) can increase tomato resistance against , but the exact molecular mechanism remains unclear. RNA sequencing (RNA-Seq) technology was used to investigate the dynamic changes of root transcriptome profiles between Si-treated (+Si) and untreated (-Si) tomato plants at 1, 3, and 7 days post-inoculation with . The contents of salicylic acid (SA), ethylene (ET), and jasmonic acid (JA) and the activity of defense-related enzymes in roots of tomato in different treatments were also determined. The burst of ET production in roots was delayed, and SA and JA contents were altered in Si treatment. The transcriptional response to infection of the +Si plants was quicker than that of the untreated plants. The expression levels of differentially-expressed genes involved in pathogen-associated molecular pattern-triggered immunity (PTI), oxidation resistance, and water-deficit stress tolerance were upregulated in the Si-treated plants. Multiple hormone-related genes were differentially expressed in the Si-treated plants. Si-mediated resistance involves mechanisms other than SA- and JA/ET-mediated stress responses. We propose that Si-mediated tomato resistance to is associated with activated PTI-related responses and enhanced disease resistance and tolerance via several signaling pathways. Such pathways are mediated by multiple hormones (e.g., SA, JA, ET, and auxin), leading to diminished adverse effects (e.g., senescence, water-deficit, salinity and oxidative stress) normally caused by infection. This finding will provide an important basis to further characterize the role of Si in enhancing plant resistance against biotic stress.
细菌性萎蔫病是一种由土壤病原菌引起的毁灭性番茄病害。先前的研究发现，硅（Si）可以提高番茄对病害的抗性，但确切的分子机制尚不清楚。本研究采用 RNA 测序（RNA-Seq）技术，研究了硅处理（+Si）和未处理（-Si）番茄植株在接种病原菌后 1、3 和 7 天根转录组图谱的动态变化。还测定了不同处理条件下番茄根中水杨酸（SA）、乙烯（ET）和茉莉酸（JA）的含量以及防御相关酶的活性。Si 处理延迟了 ET 在根部的爆发，改变了 SA 和 JA 的含量。+Si 植株对病原菌感染的转录反应比未处理植株更快。与未处理植株相比，参与病原菌相关分子模式触发免疫（PTI）、氧化抗性和水分胁迫耐受的差异表达基因的表达水平在 Si 处理植株中上调。在 Si 处理植株中，多个激素相关基因表达存在差异。Si 介导的抗性涉及到不同于 SA 和 JA/ET 介导的应激反应的机制。我们提出，Si 介导的番茄对病害的抗性与激活的 PTI 相关反应有关，并通过多种信号通路增强了对疾病的抗性和耐受性。这些途径是由多种激素（如 SA、JA、ET 和生长素）介导的，从而减轻了病原菌感染通常引起的不利影响（如衰老、水分胁迫、盐度和氧化胁迫）。这一发现将为进一步表征 Si 增强植物对生物胁迫抗性的作用提供重要依据。
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