Cheng Zejun, Pu Haoshuai, Zheng Wei, Miao Pu, Wei Jiaming, Zhao Zhe, Zhang Xiaomei, Cheng Xianghan, Toyota Koki, Xu Jian-Qiang, Huang Xiaobo, Hou Wenbang
College of Horticulture and Plant Protection, Henan University of Science and Technology, Luoyang, Henan Province, China.
Henan Province Engineering Technology Research Center of Green Plant Protection, Luoyang 471023, Henan Province, China.
Plant Dis. 2025 Aug;109(8):1640-1647. doi: 10.1094/PDIS-07-24-1514-RE. Epub 2025 Aug 21.
Sweetpotato stem rot nematode () causes the most devastating disease affecting sweetpotato production in China. The objectives of this study were to (i) establish a quantification method using real-time PCR for of sweetpotato; (ii) analyze the effect of density at harvest on the percentage of disease incidence in sweetpotatoes; and (iii) evaluate the effect of soil physical properties on disease incidence. Populations of isolated from 28 different production areas in Henan Province exhibited identical sequences, and then real-time PCR-specific primers (PRNf and PRNr) were designed. The primer set demonstrated a 100% match with the sequences of from three regions in China but did not align perfectly with different species within the genus isolated from nine other countries. There were two and thirteen base mismatches with the closely related species and , respectively. The log-transformed number of inoculated nematodes () to soil was highly correlated with the corresponding Ct value (), resulting in the quantification curve ( = -1.0859 + 32.025, = 0.9866, 0.01). This quantification curve was utilized to evaluate the densities of in wheat fields that were not cultivated with sweetpotato and in fields under continuous sweetpotato cultivation. The results showed no detection in the wheat fields, and the densities ranged from 0 to 13,300 ± 1,020 individuals per 20 g of dry soil. At harvest, the density established a negative correlation with soil pH ( = -1.7431 + 12.568, = 0.6028, < 0.05). When soil pH values were between 5.6 and 6.8, and the density of at harvest was less than 160 ± 30 per 20 g of soil, the percentage of disease incidence at harvest was 0. A significant correlation was established between density and the severity of sweetpotato disease. The results indicate that the specific primer set developed in this study allows for the accurate and rapid quantification of density in the soil, as well as the prediction of disease incidence in sweetpotato.
甘薯茎腐线虫（）引发了影响中国甘薯生产的最具毁灭性的病害。本研究的目的是：（i）建立一种使用实时荧光定量PCR对甘薯中的进行定量的方法；（ii）分析收获时的密度对甘薯发病率的影响；（iii）评估土壤物理性质对发病率的影响。从河南省28个不同产区分离得到的种群表现出相同的序列，随后设计了实时荧光定量PCR特异性引物（PRNf和PRNr）。该引物对与来自中国三个地区的序列100%匹配，但与从其他九个国家分离得到的属内不同物种不完全对齐。与近缘物种和分别有两个和十三个碱基错配。接种到土壤中的线虫（）的对数转换数量（）与相应的Ct值（）高度相关，得出定量曲线（ = -1.0859 + 32.025， = 0.9866， 0.01）。该定量曲线用于评估未种植甘薯的麦田以及连续种植甘薯的田块中的密度。结果表明在麦田中未检测到，密度范围为每20克干土0至13300 ± 1020个个体。收获时，密度与土壤pH呈负相关（ = -1.7431 + 12.568， = 0.6028， < 0.05）。当土壤pH值在5.6至6.8之间且收获时密度小于每20克土壤160 ± 30个时，收获时的发病率为0。密度与甘薯病害严重程度之间建立了显著相关性。结果表明，本研究开发的特异性引物对能够准确、快速地定量土壤中的密度，并预测甘薯的发病率。
