大豆基因型中大豆疫病病原菌定殖的特征描述和量化。

Characterization and quantification of fungal colonization of Phakopsora pachyrhizi in soybean genotypes.

出版信息

Phytopathology. 2014 Jan;104(1):86-94. doi: 10.1094/PHYTO-12-12-0334-R.

Abstract

Soybean rust, caused by the fungus Phakopsora pachyrhizi, is an economically important disease of soybean with potential to cause severe epidemics resulting in significant yield losses. Host resistance is one of the management tools to control this disease. This study compared soybean genotypes exhibiting immunity, complete and incomplete resistance, and susceptibility to an isolate of P. pachyrhizi based on visual assessment of reaction type, other visual traits such as sporulation, quantitative measurements of the amount of fungal DNA (FDNA) present in leaf tissues, and data on infection and colonization levels. Soybean genotype UG5 (immune), and plant introduction (PI) 567102B and PI 567104B (complete resistance) had lower quantities of uredinia and FDNA than four other genotypes with incomplete resistance. Based on microscopic observations, early events of spore germination, appressorium formation, and fungal penetration of the epidermis occurred within 24 h postinoculation and were similar among the tested soybean genotypes. Differences in infection among the genotypes were evident once the hyphae penetrated into the intercellular spaces between the mesophyll cells. At 2 days after inoculation (dai), soybean genotype Williams 82 had a significantly (P < 0.05) higher percentage of hyphae in the mesophyll tissue than other soybean genotypes, with UG5 having significantly (P < 0.05) lower percentages than all of the other soybean genotypes at 3, 4, and 5 dai. The percentage of interaction sites with mesophyll cell death was significantly (P < 0.05) higher in UG5 than other genotypes at 3, 4, and 5 dai. There was a significant positive correlation (r = 0.30, P < 0.001) between quantities of hyphae in the mesophyll cells and FDNA. These results demonstrated that incompatible soybean-P. pachyrhizi interaction results in restricted hyphal development in mesophyll cell tissue, likely due to hypersensitive apoptosis.

摘要

大豆锈病是由真菌 Phakopsora pachyrhizi 引起的，是一种对大豆具有重要经济意义的疾病，有引发严重流行并导致显著产量损失的潜力。寄主抗性是控制这种疾病的管理工具之一。本研究基于发病类型的肉眼评估、产孢等其他肉眼特征、叶组织中真菌 DNA（FDNA）含量的定量测量以及感染和定殖水平的数据，比较了表现免疫、完全和不完全抗性以及易感性的大豆基因型对 P. pachyrhizi 分离株的反应。与其他 4 个具有不完全抗性的基因型相比，UG5（免疫）和植物引种（PI）567102B 和 PI 567104B（完全抗性）的夏孢子堆和 FDNA 数量较低。基于显微镜观察，孢子萌发、附着胞形成和真菌穿透表皮的早期事件在接种后 24 小时内发生，并且在测试的大豆基因型中相似。在菌丝穿透到叶肉细胞之间的细胞间隙后，基因型之间的感染差异变得明显。接种后 2 天（dai），Williams 82 基因型的菌丝在叶肉组织中的百分比显著（P < 0.05）高于其他大豆基因型，而 UG5 在 3、4 和 5 dai 的菌丝百分比显著（P < 0.05）低于所有其他大豆基因型。与其他基因型相比，UG5 在 3、4 和 5 dai 的与叶肉细胞死亡相互作用的位点百分比显著（P < 0.05）更高。叶肉细胞中菌丝数量与 FDNA 之间存在显著正相关（r = 0.30，P < 0.001）。这些结果表明，不相容的大豆- P. pachyrhizi 相互作用导致叶肉细胞组织中菌丝发育受限，可能是由于过敏细胞凋亡所致。