發展鏈黴菌Streptomyces griseobrunneus SGS3可濕性粉劑以防治青椒疫病Phytophthora capsici
Development of a wettable powder formulation of Streptomyces griseobrunneus SGS3 for the control of pepper blight caused by Phytophthora capsici
鏈黴菌 ； 青椒疫病 ； 可濕性粉劑 ； 儲架壽命 ； 商品化 ； Streptomyces ； pepper blight ； wettable powder formulation ； shelf life ； commercial product
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青椒疫病是栽培青椒過程中重要的病害之一，常在台灣的颱風或雨季過後病害發生尤為嚴重，該病由青椒疫病菌Phytophthora capsici 所引起的；而供試鏈黴菌Streptomyces griseobrunneus SGS3為賴氏 (2003) 於台中太平的柑桔根圈土壤分離所得，已證實其對卵菌綱病原菌及部分土壤傳播性真菌所造成的病害具優異的防治潛力，包括造成甜椒根腐及猝倒的立枯絲核菌 (Rhizoctonia solani AG4)、以及甜椒炭疽病菌 (Colletotrichum gloeosporioides)。經750 L發酵槽所製程的發酵液量產技術也已建立，主要型態以氣生孢子為主，其菌量可達2 x 1011 CFU/mL。本研究目的為開發SGS3可濕性粉劑劑型，並探討其應用防治策略。首先，以膨潤土、二氧化矽及微晶纖維作為擔體材料，並以流體造粒機所製成的可濕性粉劑劑型 (SGS3 WP)，可維持粉體菌量在2.91 x 1010 CFU/g。在為期一年的儲架壽命測試上，SGS3發酵液存放在6℃的菌量為4.62 x 105 CFU/mL，但在室溫環境下則菌量快速減少。粉劑在6℃及室溫下的菌量分別為1.1 x 109和7.7 x 108 CFU /g，顯示粉劑之儲架壽命優於發酵液，且在青椒葉片菌量殘存能力上表現亦較發酵液為佳。在青椒離葉及果實之接種防治上，處理發酵液稀釋100倍與粉劑100倍皆能有效防治病害發生，且發酵液稀釋100倍亦可有效抑制P. capsici孢囊及游走孢子發芽，進一步混合卵菌綱推薦用藥，證實殺菌劑賽座滅、亞托敏、依得利及普拔克依其推薦濃度使用並混合SGS3發酵液 100倍處理除了對抑制孢囊發芽及菌絲生長具有加成作用之外，亦可有效防治青椒幼苗及果實上病害的發生，且SGS3亦具有促進青椒植株生長的效果，其中又以SGS3發酵液稀釋100倍對青椒植株之株高、株徑、地上部及地下部之鮮重及乾重之生長促進效果最為顯著。在溫室青椒幼苗接種試驗上，SGS3發酵液之防治效果以同時接種病原菌和處理菌液100倍時效果最佳，發病率為15.4%；而粉劑則以先處理再接種粉劑100倍時效果最佳，發病率為8.1%。在以建立的疫病菌帶病土之接種系統中，證實混合粉劑1% (v/v)及0.5% (v/v) 皆能有效防治病害發生，可將發病率分別降至7.07及9.07%；而將粉劑應用於青椒種子之種衣披覆，以50及100% 粉劑製成之種衣披覆之種子可有效增加青椒幼苗之存活率，並於種植後一周澆灌SGS3發酵液100倍更能有效防治青椒疫病的發生。在田間試驗中，亦證實SGS3發酵液稀釋100倍對青椒疫病具有防治效果，且添加SGS3粉劑混拌後的介質以及將SGS3發酵液搭配依得利進行混合防治確實可以增加對青椒疫病的防治效果。綜合上述試驗結果，顯示Streptomyces griseobrunneus SGS3之發酵液與所開發之可濕性粉劑皆具有針對青椒疫病之防治效果及商品化之潛力。
Phytophthora blight of pepper caused by Phytophthora capsici is one of the most important diseases in pepper cultivation. Severe damage was usually observed during typhoon or raining seasons in Taiwan. The antagonistic Streptomyces griseobrunneus SGS3 isolated from Taichung was shown of great potential as a microbial bio-agent for the control of plant diseases caused by Oomycetes and some soil-borne true fungi, including pepper root rot or damping-off caused by Rhizoctonia solani AG4 and anthracnose caused by Colletotrichum gloeosporioides. And a standard operation protocol for mass production of anthrospore formulation of the bacteria was established by a 750 L fermenter. The spore yield reached approximately 2 x 1011 CFU/mL. This research was aimed to develope a wettable powder (WP) formulation for the control of pepper Phytophthora blight. Using bentonite, silica and microcrystalline cellulose as the carriers, a wettable powder (SGS3 WP) with 2.91 x 1010 CFU /g without contamination was prepared by a Fluid Bed Dryer. Examination of the shelf life of the attempted formulation after one year storage indicated a better performance of SGS3 WP comparing to that of liquid culture broth. For broth culture kept at 6℃, the survival count was 4.62 x 105 CFU/mL. Whereas for those kept at room temperature, a rapid decline of the bacterial propagule was detected. As for the compared SGS3 WP formulation, the survival count detected after stored for one year at 6℃ and at room temperature, respectively, was 1.1 x 109 CFU /g and 7.7 x 108 CFU /g. The SGS3 WP formulation also gave a better survival of the applied bacteria on pepper leaves. On a detached pepper leaves and fruits system artificially inoculated with P. capsici, the application of SGS3 broth culture and WP formulation each at 100-fold dilution both showed significant effectiveness in reducing the fungal infection. As for inhibition of sporangium and zoospore germination, a better performance of SGS3 at 100-fold dilution was detected. Augmentation of SGS3 broth culture supplementation with the selected oomycete fungicides including cyazofamid, azoxystrobin, etridiazole and propamocarb each at recommended concentration was significant not only on the inhibitory effectiveness of sporangial germination and hyphal growth, but also on the disease control of pepper seedlings and fruits. Effect of growth promotion was also shown on the plant height, plant stem diameter, aboveground and underground fresh weight and dry weight of the pepper seedlings treated with 100X diluted SGS3 broth culture. In greenhouse trial, application of 100X diluted SGS3 broth culture and inoculating with the pathogen simultaneously effectively controlled the infection of P. capsici on pepper seedlings. The disease incidence was 15.4%. Whereas the application of 100X diluted SGS3 WP formulation 1 day before inoculating with the pathogen showed an even better effectiveness. The disease incidence was 8.1%. And for the pathogen-infested soil system, amendment of 1% (v/v) and 0.5% (v/v) WP formulation respectively, was also effective in controlling the fungal infection. Each disease incidence was 7.07% and 9.07%. Application of seed coating with 50% (v/v) and 100% (v/v) WP formulation respectively, also showed great survival abilities on pepper seedlings. Moreover, with another treatment of SGS3 broth culture at 100-fold dilution by spraying 1 week after seeds plantation, better survival abilities were confirmed. In the field trail, treatment of SGS3 broth culture at 100-fold dilution was also shown great effectiveness for disease control. With the amendment of SGS3 WP mix with the cultivation medium, or the combined-treatment of SGS3 broth culture and the fungicide, etridiazole, better disease control were also confirmed. The evidence accumulated so far indicated clearly the usefulness of both liquid broth culture and the developed WP formulation for controlling Phytophthora blight on pepper, and the potential to develop the WP formulation as a commercial product.
生物農學 > 植物學