Analysis of Cytology and Expression of Resistance Genes in Maize Infected with Sporisorium reilianum
Analysis of Cytology and Expression of Resistance Genes in Maize Infected with Sporisorium reilianum
复制标题
玉米孢子虫感染的细胞学及抗性基因表达分析
DOI：
10.1094/pdis-09-18-1687-re
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发表时间：
2019-08-01
期刊：
影响因子：
4.5
通讯作者：
Zhou, Yu
中科院分区：
文献类型：
--
作者：
Qi, Fengkun;Zhang, Lin;Zhou, Yu
玉米丝黑穗病是由玉米孢子菌引起的一种毁灭性的全球性病害。本研究通过中胚轴针接种(NIM)和胚根浸泡接种(SIR)两种方法，将亲和交配型菌株人工接种玉米幼苗。NIM或SIR处理后，黄早4号的胚轴损伤严重，褐变、坏死，而Mo17的胚轴几乎没有损伤。荧光和电子显微镜观察表明，Reilianum在SIR后0.5d内侵染玉米，主要定殖在韧皮部。随着培养时间的延长，维管束内菌丝密度增加，主要集中在韧皮部。在Mo17中，感染细胞呈现凋亡样特征，菌丝被隔离在死亡细胞内。相反，在黄早4号中，病原菌入侵导致自噬，但未能阻止菌丝扩散。菌丝生长在接种后6d开始减弱，此时R基因ZmWAK和ZmNL的表达达到高峰。因此，接种SIR后6d可能是抑制玉米雷氏链霉菌侵染进展的重要时期。本研究结果将为进一步分析玉米对青枯病的抗性机制提供依据。
Head smut, caused by the fungus Sporisorium reilianum, is a devastating global disease of maize (Zea mays). In the present study, maize seedlings were artificially inoculated with compatible mating-type strains of S. reilianum by needle inoculation of mesocotyls (NIM) or by soaking inoculation of radicles (SIR). After NIM or SIR, Huangzao4 mesocotyls exhibited severe damage with brownish discoloration and necrosis, whereas Mo17 mesocotyls exhibited few lesions. Fluorescence and electron microscopy showed that S. reilianum infected maize within 0.5 day after SIR and mainly colonized the phloem. With longer incubation, the density of S. reilianum hyphae increased in the vascular bundles, concentrated mainly in the phloem. In Mo17, infected cells exhibited apoptosis-like features, and hyphae became sequestered within dead cells. In contrast, in Huangzao4, pathogen invasion resulted in autophagy that failed to prevent hyphal spreading. The growth of S. reilianum hyphae diminished at 6 days after inoculation when expression of the R genes ZmWAK and ZmNL peaked. Thus, 6 days after SIR inoculation might be an important time for inhibiting the progress of S. reilianum infection in maize. The results of this study will provide a basis for further analysis of the mechanisms of maize resistance to S. reilianum.