摘要
携带抗白粉病基因Pm21的小麦材料对白粉病免疫,叶片可见坏死斑。苗期人工接种小麦白粉菌(Blumeria graminis f.sp. tritici)和病原侵染初期的细胞学观察表明,在互作位点,携带Pm21基因的抗病材料上表皮细胞乳突形成时间与感病对照差异不明显,但乳突的大小、致密度、持续时间及乳突中H2O2染色较对照有明显差异,并由此显著降低白粉菌的侵入频率。抗病材料上发生多次侵染未成功导致白粉菌附着胞畸形。对于少数成功侵入并形成吸器的白粉菌,抗病材料表皮细胞发生过敏性反应,限制白粉菌吸器和二级菌丝的发展。因此,Pm21调控的白粉病抗病反应在细胞水平上表现为细胞壁加固和过敏性反应的发生。
Pm21 is a wide-spectrum resistance gene to powdery mildew（Blumeria graminis f.sp.tritici,Bgt） in wheat（Triticum aestivum L.）,which originates from Haynaldia villosa.To reveal the mechanism of Pm21-mediated Bgt resistance in wheat at early infection stage,we carried out the cytological observations using wheat line 92R137,carrying Pm21 gene and presenting immunity（but with visible spots on leaves） to Bgt after artificial inoculation with the prevalent Bgt race 15.Chinese Spring（CS） was used as the susceptible control.In wheat–Bgt interaction sites on leaves,papillae formed at a similar time in challenged epi-dermal cells in both 92R137 and CS.However,the papillae were larger and more compact and persisted in longer time in 92R137 than in CS,resulting in effectively blocking the penetration of Bgt.Accumulation of H2O2 was observed in the papillae of 92R137 by DAB staining.Appressorium malformation occurred in 92R137,which was probably caused by the failure of multiple penetra-tion attempts of Bgt.For the small number of Bgt that successfully penetrated the epidermal cells of 92R137,hausto-rium-dependent hypersensitive reactions were induced to suppress further development of haustoria and secondary hyphae,ar-resting onset of powdery mildew.Therefore,the major mechanism of Pm21-mediated Bgt resistance involves challenged host cell wall reinforcement and hypersensitive reaction.
出处
《作物学报》
CAS
CSCD
北大核心
2011年第1期67-73,共7页
Acta Agronomica Sinica
基金
天津市自然科学基金项目(08JCYBJC05000)
天津市高等学校科技发展基金项目(20070916)资助
关键词
小麦白粉病
PM21
细胞壁加固
过敏性反应
Wheat powdery mildew
Pm21 gene
Cell wall reinforcement
Hypersensitive reaction
