建立番石榴立枯病菌之病原性快速檢測技術

Establishment of rapid method for detection pathogenicity of Nalanthamala psidii from guava

王照仁(C. J. Wang) ； 顏志恒(J. H. Yen) ； 吳志恩(C. E. Wu) ； 鍾文全(W. C. Chung) ； 林永建(Y. C. Lin) ； 鍾文鑫(W. H. Chung)

《植物病理學會刊》 24卷3&4期 (2015/12) Pp. 211-223

https://doi.org/10.6649/PPB.201512_24(3_4).0004

摘要

由Nalanthamala psidii所引起之立枯病為番石榴（Psidium guajava L.）栽培產業的重要限制因子。目前立枯病菌的接種測試主要以一年生以上之嫁接苗或實生苗為主，接種後需歷時數月才能確認所測試菌株是否具病原性，此過程十分耗時，導致相關研究進步緩慢。本研究嘗試建立快速檢測立枯病菌毒性強弱之接種方法，並比較接種嫁接苗或實生苗後的表現。結果顯示，接種病原之一年生嫁接苗植株，從發病到死亡約需4-6個月；而接種於去頂芽製造傷口之番石榴實生苗（2-3片真葉，苗齡約5-6週）植株發病最快，7天即可產生病徵；另無傷口之頂芽接種則需2週才可觀察到病徵。反之，莖基部與剪根部位接種法，不會使植株產生病徵。進一步將接種後罹病植株進行組織分離，在有外部病徵處皆可分離到病原菌，而無外部病徵植株之分離率亦有59.1%與75.0%，顯示田間只將植株發病部位砍除，可能無法有效達到清園的效果。為瞭解最適接種濃度，將孢子懸浮液濃度配製成10^0-10^7 conidia/ml，接種於去頂芽番石榴實生苗，結果顯示當濃度高於10^5 conidia/ml 時才可產生病徵；而高於10^6 conidia/ml時，植株則會出現萎凋死亡的現象。進一步以去頂芽實生幼苗接種法測試12株供試菌株之病原性，結果顯示所有菌株於第4週之發病度介於38.9- 72.2%間，顯示去頂芽實生苗接種法可用於快速檢測病原菌的致病能力，且結果亦顯示田間可能存在不同毒力菌株。

關鍵字

番石榴 ； 立枯病 ； 番石榴立枯病菌 ； 產孢

並列摘要

The wilting disease caused by Nalanthamala psidii of guava is the limitation factor in guava (Psidium guajava L.) production. The one-year-old grafted/non-grafted guava plant had been used to examine the pathogenicity of N. psidii. However, the wilting symptom showed after several months' inoculation. Thus, the inoculation of N. psidii on one-year-old guava plant is time consuming and interrupts the study on N. psidii. The objectives of this study were to develop a rapid, efficient inoculation method for examining the pathogenicity of N. psidii from natural field. The results showed that the one-year-old grafted guava plants were died within 4 to 6 months after inoculation. The other side, the apical bud with wound of guava seedling showed symptom 7 days after inoculation, and the apical bud without wound showed symptom 2 weeks after inoculation. However, the basal stem and cutting-root did not have any symptom after inoculation. The reisolation rates of the N. psidii from the tissue with or without symptom were 59.1% and 75%, respectively. Thus, removing the parts showed symptom could not take off the source of N. psidii completely in the field. Several conidia concentrations (range from 10^1-10^7 conidia/ml) were used for the pathogenicity test. Result revealed that the 10^5 conidia/ml is limitation on showing symptom in guava seedling, and the guava seedlings were die after inoculation at a concentration of 10^6 conidia/ml. In this study, twelve isolates of N. psidii were inoculated on apical bud with wound of guava seedling and the symptoms could be showed 2 weeks after inoculation. Moreover, the disease severities of guava seedling inoculated by 12 isolates were ranged from 38.9 % to 72.2 %. Consequently, the apical bud with wound of guava seedling can use as material to examine the pathogenicity of N. psidii from field, and the result demonstrates that the virulent variations exist in isolates of N. psidii.

並列關鍵字

Psidium guajava ； wilting disease ； Nalanthamala psidii ； sporulation