台灣新紀錄真菌Gilbertella persicaria引起之紅龍果濕腐病

Flower and Fruit Wet Rot of Pitaya (Hylocereus spp.) Caused by Gilbertella persicaria, a New Disease Record in Taiwan

林筑蘋(J. P. Lin) ； 安寶貞(P. J. Ann) ； 蔡志濃(J. N. Tsai) ； 徐子惠(Z. H. Hsu) ； 張捷婷(J. T. Chang)

《植物病理學會刊》 23卷2期 (2014/06) Pp. 109-124

https://doi.org/10.6649/PPB.201406_23(2).0003

摘要

紅龍果(Hylocereus spp.)為台灣重要新興作物之一，2009年8月開始，發現紅龍果果實在採收後常自切口處出現水浸狀病徵，偶而自果實表皮或鱗片開始發病，病斑迅速擴展，3-5天內感染整顆果實，致果實軟化腐敗；在罹病果園中可發現花苞、花瓣及幼果產生褐黑色凹陷、水浸狀潰爛病徵，或是幼果發育不良情形。這些罹病組織在潮濕環境下皆會產生黑色長柄孢囊，經組織分離可分離到相同的真菌。如以該菌之孢子懸浮液接種花器與果實，花器組織在無傷痍處理下即會出現與田間觀察到的相同病徵，而果實組織則是在有傷口下會出現與市場上觀察到的相同病徵，而無傷痍處理之組織則偶而發病，表示傷口為果實發病重要因子之一。由於此類型病害在潮溼環境下較易發生，且病組織常呈現水浸狀腐爛病徵，因此命名為「紅龍果濕腐病」。藉由形態特徵與ITS DNA序列比對結果，確定引起紅龍果果實濕腐病的為病原菌為Gibertella persicaria。除紅龍果外，田間調查結果顯示，在秋葵(Abelmoschus esculentus)之枯萎花瓣與水蜜桃(Prunus persica)之罹病果實病組織上都曾分離到G. persicaria，其中秋葵分離株對紅龍果果實具強烈致病力，然而水蜜桃分離株引起的病斑較小且病斑顏色較褐色，而其ITS序列與紅龍果分離株之序列具1.63%差異度。藉人工接種孢子懸浮液，本菌可以感染無論有無傷痍處理的水蜜桃、有傷痍處理之硬柿、梨子、李子、蘋果、芒果、及番茄，而奇異果與香蕉則沒有明顯病徵。本研究為G. persicaria在台灣引起作物病害之首度報導。

關鍵字

紅龍果 ； 濕腐病 ； 寄主範圍 ； 儲藏期病害

並列摘要

Pitaya (Hylocereus spp.) is one of the important emerging fruit crops in Taiwan. Fruit wet rot, a severe postharvest disease of pitaya caused by Gilbertella persicaria, was first found in August 2009. Fruit infection occurred in the field during rainy season with a small water-soaked lesion around the stem-end, which developed into fruit soft rot within 3-5 days after harvest. Occasionally, fruit soft rot initiated from lesions on fruit skin or scales were also observed. Results of survey of pitaya orchards in 2010 showed that infection of G. persicaria on young fruits or on flower buds and petals resulted in the development of symptoms similar to that observed in 2009. Most of the infected fruits in the orchard failed to develop normally and dropped prematurely. Brown to black sporangia of G. persicaria were formed on the surface of infected tissues, especially under humid conditions. Young pitaya fruits and flowers collected from the field were inoculated by G. persicaria resulted in the development of soft rot symptoms identical to that observed in the orchards and tissue wounding was an important factor affecting the disease severity. In addition to morphological characteristics, identity of G. persicaria from pitaya was also confirmed by ITS1-5.8S rDNA-ITS2 sequence analysis. Results of artificial inoculations also showed that isolates of G. persicaira from pitaya were pathogenic on fruits of peach and wounded fruits of apple, mango, persimmon, plum and tomato, but they were non-pathogenic on banana and kiwifruits. Gilbertella persicaria is a new record fungal pathogen causing wet rot of pitaya in Taiwan.

並列關鍵字

Gilbertella persicaria ； postharvest disease ； host range ； Hylocereus spp. ； pitaya ； wet rot.