Diagnostic kit for rice blight resistance

First author: Joon-Seob Eom; Affiliations: Heinrich Heine University of Düsseldorf (杜塞尔多夫大学): Düsseldorf, Germany

Corresponding author: Wolf B. Frommer 

Blight-resistant rice lines are the most effective solution for bacterial blight, caused by Xanthomonas oryzae pv. oryzae (Xoo). Key resistance mechanisms involve SWEET genes as susceptibility factors. Bacterial transcription activator-like (TAL) effectors bind to effector-binding elements (EBEs) in SWEET gene promoters and induce SWEET genes. EBE variants that cannot be recognized by TAL effectors abrogate induction, causing resistance. Here we describe a diagnostic kit to enable analysis of bacterial blight in the field and identification of suitable resistant lines. Specifically, we include a SWEET promoter database, RT–PCR primers for detecting SWEET induction, engineered reporter rice lines to visualize SWEET protein accumulation and knock-out rice lines to identify virulence mechanisms in bacterial isolates. We also developed CRISPR–Cas9 genome-edited Kitaake rice to evaluate the efficacy of EBE mutations in resistance, software to predict the optimal resistance gene set for a specific geographic region, and two resistant ‘mega’ rice lines that will empower farmers to plant lines that are most likely to resist rice blight.

抗白叶枯病的水稻品系是解决由水稻黄单胞菌水稻致病变种Xoo引起的细菌性枯萎病最有效的方案。该过程最为核心的抗性机制涉及到SWEET基因作为易感性因子。细菌类转录激活因子TAL效应物会结合到SWEET基因启动子中的效应子结合元件EBE上，并诱导SWEET基因的表达。 某些水稻含有不能被TAL效应物识别的EBE变体，SWEET基因不会在致病菌侵染时诱导表达，从而获得抗性。本文中，作者报道了一种诊断试剂盒，可用于在大田环境下检测细菌性枯萎病，并鉴定合适的抗性系水稻。具体来说，该套工具包括了一个SWEET启动子数据库，用于检测SWEET诱导表达的RT-PCR引物，人工构建的水稻报告系以可视化SWEET蛋白的积累，以及水稻敲除系以鉴定细菌分离株中的毒力机制。作者还开发了CRISPR–Cas9基因组编辑的Kitaake水稻系，以评估EBE突变后对致病菌抗性的有效性，预测特定地理区域的最佳抗性基因集的软件，以及两个Mega水稻系，将有利于帮助农民种植最有可能抗枯萎病的水稻系。

通讯：Wolf B. Frommer (http://www.molecular-physiology.hhu.de/en/our-team/curriculum-vitae.html)

研究方向：植物的营养成分转运过程，主要涉及作物正常生长状态下的产量以及受到病原物侵染时的产量。

doi: https://doi.org/10.1038/s41587-019-0268-y

Journal: Nature Biotechnology

Published date: October 28, 2019