印度梨形孢菌應用於褐根病防治之探討

Abstract

Phellinus noxius 引起的褐根病會導致樹木根基部腐朽，容易倒伏，影響公共安全。防治褐根病的眾多方法之中，生物防治法對環境生態較為友善，且不會使病原菌產生抗藥性，值得進一步發展。印度梨形孢菌 Serendipita indica 為可人工培養的植物內共生真菌，具有促進植物生長的功能並可協助植物抵抗生物及非生物逆境。本研究首先針對印度梨形孢菌之培養及接種方式進行測試，發現使用馬鈴薯葡萄糖液態培養基震盪培養後打碎，再將接種源調整至 106 spores/ml，以 50 ml 混拌至 650 g土壤中進行接種 (約 7.7 × 104 spores/g soil)，可透過台盼藍染色法在根部觀察到印度梨形孢菌厚膜胞子。為了解印度梨形孢菌能否運用於褐根病防治及生長促進效果，使用茄苳苗進行接種試驗，發現先接種印度梨形孢菌後兩週再接種褐根病菌的組別，相較於僅接種褐根病菌的組別，具有較低的植物萎凋率與褐根病菌分離率，且茄苳苗之濕重與根系投影面積顯著增加。為了進一步瞭解印度梨形孢菌與殺菌劑共同施用的可行性，也作為未來開發印度梨形孢菌選擇性培養基之參考，測試其在含有 100 ppm (mg a.i./L)、10 ppm、1 ppm、0.1 ppm 的滅達樂、殺紋寧、免賴得、白克列、百克敏、嘉賜黴素、撲滅寧、大克爛、得克利、鋅錳乃浦、蓋普丹、克熱淨 (烷苯磺酸鹽) 及腐絕快得寧共 13 種藥劑之馬鈴薯葡萄糖瓊脂培養基上菌絲生長情形，結果顯示印度梨形孢菌對得克利、克熱淨 (烷苯磺酸鹽)、腐絕快得寧呈現敏感性；對免賴得、白克列、百克敏、嘉賜黴素、鋅錳乃浦呈現低敏感性；對大克爛、蓋普丹呈現中度抗性；對滅達樂、殺紋寧、撲滅寧呈現高度抗性。本研究成果可作為未來印度梨形孢菌應用於木本植物之參考，達到預防病害與促進生長之效果。

Brown root rot disease caused by Phellinus noxius can cause root decay of trees, making them prone to collapse and endanger public safety. Among many strategies to control brown root rot disease, biological control is worthy of development because it is environmentally friendly and will not cause the emergence of fungicide-resistant pathogens. Serendipita indica is a culturable endophytic fungus that promotes plant growth and assists in its resistance to abiotic and biotic stresses. This research first tested different culture and inoculation methods. The S. indica inoculum was prepared by shaking culturing in potato dextrose broth and then homogenized. By mixing 50 ml of the inoculum (106 chlamydospores/ml) with the planting substrate (about 7.7 × 104 spores/g substrate), successful root colonization of S. indica could be observed by trypan blue staining. To understand whether S. indica can be used to prevent and control brown root rot disease, an inoculation test was conducted using Bischofia javanica seedlings. Compared to P. noxius-inoculated plants, plants pre-treated with S. indica and then inoculated with P. noxius two weeks later showed lower wilting rate, lower P noxius reisolation rate, and increased wet weight and root projected area. To understand the potential of integrating S. indica with chemical control and also serve as a reference for future development of selective culture media for S. indica, the sensitivity of S. indica to 13 fungicides was tested on potato dextrose agar containing 100 ppm (mg a.i./L), 10 ppm, 1 ppm, and 0.1 ppm of the fungicides. S. indica was sensitive to tebuconazole, iminoctadine tris (albesilate), and thiabendazole + oxine-copper; less sensitivity to benomyl, boscalid, pyraclostrobin, kasugamycin, and mancozeb; intermediately resistant to dicloran and captan; and highly resistant to metalaxyl, hymexazol, and procymidone. The outcomes of this study can provide a reference for applying S. indica for the integrated health management of woody plants.