State Key Laboratory of Agricultural Microbiology and Key Laboratory of Plant Pathology of Hubei Province, Huazhong Agricultural University, Wuhan 430070, China.
United States Department of Agriculture, Agricultural Research Service, Washington State University, Pullman, WA 99164, U.S.A.
Plant Dis. 2024 Aug;108(8):2399-2409. doi: 10.1094/PDIS-09-23-1921-RE. Epub 2024 Jul 22.
P2 was isolated from rapeseed (), and it is an endophyte of rapeseed and an antagonist of three rapeseed pathogens, , , and . However, whether P2 has a suppressive effect on infection of rapeseed by the clubroot pathogen remains unknown. This study was conducted to detect production of antimicrobials by P2 and to determine the efficacy of the antimicrobials and P2 pycnidiospores in suppression of rapeseed clubroot. The results showed that cultural filtrates (CFs) of P2 in potato dextrose broth and the substances in pycnidiospore mucilages exuded from P2 pycnidia were inhibitory to . In the indoor experiment, seeds of the susceptible rapeseed cultivar Zhongshuang No. 9 treated with P2 CF and the P2 pycnidiospore suspension (P2 SS, 1 × 10 spores/ml) reduced clubroot severity by 31 to 70% on the 30-day-old seedlings compared with the control (seeds treated with water). P2 was reisolated from the roots of the seedlings in the treatment of P2 SS; the average isolation frequency in the healthy roots (26%) was much higher than that (5%) in the diseased roots. In the field experiment, seeds of another susceptible rapeseed cultivar, Huayouza 50 (HYZ50), treated with P2 CF, P2 CE (chloroform extract of P2 CF, 30 μg/ml), and P2 SS reduced clubroot severity by 29 to 48% on 60-day-old seedlings and by 28 to 59% on adult plants (220 days old) compared with the control treatment. The three P2 treatments on HYZ50 produced significantly ( < 0.05) higher seed yield than the control treatment on this rapeseed cultivar, and they even generated seed yield similar to that produced by the resistant rapeseed cultivar Shengguang 165R in one of the two seasons. These results suggest that P2 is an effective biocontrol agent against rapeseed clubroot.
P2 是从油菜中分离出来的，它是油菜的内生菌，也是三种油菜病原菌、、和的拮抗物。然而，P2 是否对油菜菌核病病原菌的侵染有抑制作用尚不清楚。本研究旨在检测 P2 产生的抗微生物物质，并确定这些抗微生物物质和 P2 分生孢子在抑制油菜菌核病中的效果。结果表明，P2 在马铃薯葡萄糖肉汤中的培养滤液（CFs）和从 P2 分生孢子囊中渗出的分生孢子粘液中的物质对有抑制作用。在室内试验中，与对照（用无菌水处理的种子）相比，用 P2 CF 和 P2 分生孢子悬浮液（P2 SS，1×10 个孢子/ml）处理的易感油菜品种中双 9 号种子在 30 日龄幼苗上的菌核病严重度降低了 31%至 70%。在 P2 SS 处理的幼苗根部重新分离到 P2；健康根（26%）的平均分离频率远高于患病根（5%）。在田间试验中，用 P2 CF、P2 CE（P2 CF 的氯仿提取物，30μg/ml）和 P2 SS 处理的另一个易感油菜品种华优 50（HYZ50）种子在 60 日龄幼苗上的菌核病严重度降低了 29%至 48%，在 220 日龄成株上降低了 28%至 59%，与对照处理相比。在 HYZ50 上的三种 P2 处理方法显著（<0.05）提高了该油菜品种的种子产量，在两个季节中的一个季节中，甚至产生了与抗病油菜品种圣光 165R 相当的种子产量。这些结果表明，P2 是一种有效的油菜菌核病生物防治剂。
