馬鈴薯青枯病菌（Ralstonia solanacearum phylotype II/race 3/biovar 2）於雲林縣斗南地區田間之族群密度與馬鈴薯罹病率調查

Population Density of Ralstonia solanacearum Potato Strain, Phylotype II/Race 3/biovar 2, and Incidence of Potato Bacterial Wilt in Fields in Dounan, Yunlin County

吳雅芳(Y. F. Wu) ； 林志鴻(C. H. Lin) ； 王肇芬(J. F. Wang) ； 鄭安秀(A. S. Cheng)

《植物病理學會刊》 20卷3&4期 (2011/12) Pp. 68-77

https://doi.org/10.6649/PPB.201112_20(3_4).0002

摘要

2006年冬作於雲林縣斗南地區之馬鈴薯栽培田發現萎凋病株，分離純化之病原菌經鑑別培養基、菸草過敏性反應、病原性測定、生化型測定、及專一性聚合酶鏈鎖反應（PCR），證實該地區分離之病原菌為馬鈴薯青枯病菌，屬於第二演化型（phylotype II）與第二生化型（biovar 2）之第三生理小種（race 3）菌系。利用選擇性培養基與增量PCR偵測土壤樣品，經2007至2009年三期作偵測與調查結果，顯示2007年期作之10處調查田區，除田區一與田區二之罹病率高低與土壤含菌量多寡相符外，在其他田區並不一致，而爾後兩期作此倆田區皆未發生青枯病，亦偵測不到病原菌。在非馬鈴薯產期之土壤則偵測不到病原菌，但隔年期作有某些田區發生青枯病且罹病率極低。田區四前兩期作皆未發生青枯病，且土壤中偵測不到病原菌，但2009年期作之罹病率為40%，土壤含菌量每克乾土達10^5 CFU；由此推測該地區馬鈴薯青枯病的主要初次感染源為帶菌種薯而非土壤。人為混菌接種馬鈴薯結果，發現泥炭土含菌量多寡不影響種薯分芽之發芽率，但會影響青枯病的罹病率。病勢進展及罹病率皆隨著病原菌菌量增加而升高，但泥炭土中病原菌含量每克泥炭土低於10^5 CFU時則不發病；故降低田間土壤中的病原菌密度，應能有效降低罹病率。在雲林縣斗南地區的馬鈴薯栽培慣與水稻輪作，依據本研究調查結果，病菌在田土中存活機率低，故主要感染源最可能為帶菌種薯而非土壤，因此使用健康種薯是防治該地區馬鈴薯青枯病的重要關鍵。

關鍵字

馬鈴薯青枯病 ； 青枯病菌 ； 演化型 ； 生理小種 ； 生化型 ； 殘存

並列摘要

Potato plants showing wilting symptoms were found in potato production areas of Dounan, Yunlin in winter 2006. Isolates collected from wilted potato stems or tubers were identified using differential medium, tobacco hypersensitive reaction, pathogenicity test, biovar test, race 3/biovar 2-specific polymerase chain reaction (PCR), and phylotype-specific multiplex PCR. Results of identification showed that the pathogen belongs to potato strain of Ralstonia solanacearum phylotype II/race 3/biovar 2. The presence and density of the pathogen were monitored in 10 fields from 2007 to 2009 using selective medium and Bio-PCR. Results showed that soil pathogen density from all surveyed fields did not correlate with disease incidence except for Field #1 and #2. However, the pathogen was not detected in these two fields and no disease incidence was observed after 2007. The pathogen was not detected between two potato crops, but bacterial wilt was found in a few fields even though disease incidence was very low in 2008. Although bacterial wilt was not observed in 2007 and 2008 in Field #4, 40% of disease incidence and 10^5 CFU/g of dry soil of pathogen density were found in the 2009 crop. Germination of seed tubers in infested peat moss was as high as that in non-infested peat moss. Disease progress and incidence increased with the increase of pathogen density in the peat moss. But the disease did not occur when pathogen density of peat moss was less than 10^5 CFU/g of peat moss. Thus reducing inoculum density in the soil could reduce disease incidence. Potato is regularly rotated with paddy rice in Dounan, Yunlin. The chance of survival in soil is low for R. solanacearum phylotype II/race 3/biovar 2 strains. Based on our results, the primary inoculum source of potato bacterial wilt is most probably contaminated seed tubers, but not soil. Thus, using healthy seed tubers is the key to control potato bacterial wilt in the area.

並列關鍵字

bacterial wilt of potato ； Ralstonia solanacearum ； phylotype ； race ； biovar ； survival