Please use this identifier to cite or link to this item: http://hdl.handle.net/11455/31738
標題: 辣椒種原PBC81(Capsicum baccatum)及PBC932(C.chinense)對辣椒炭疽病菌(Colletotrichum acutatum)之抗病性初探
Preliminary studies on the resistance of hot pepper accessions PBC81 (Capsicum baccatum) and PBC932 (C. chinense) to anthracnose caused by Colletotrichum acutatum
作者: 陳盈如
Chen, Ying-Ru
關鍵字: 辣椒
hot pepper
炭疽病
炭疽病菌
抗病性
水楊酸
病程相關基因
防禦相關基因
chili pepper
Capsicum spp.
anthracnose
Colletotrichum spp.
disease resistance
salicylic acid
pathogenesis-related genes
defense-related genes
出版社: 植物病理學系所
摘要: 辣椒 (Capsicum annuum) 為國內主要香辛作物之一。目前台灣地區之辣椒栽培受到炭疽病 (Anthracnose) 之危害嚴重,它是由 Colletotrichum acutatum 、 Co. gloeosporioides 、 Co. capsici 及 Co. coccodes 所引起,其中又以 Co. acutatum 發生頻率最高。本病害為辣椒生產的重要病害之一,至今尚無經濟、有效的方法來防治此病害,也無抗病的商業品種可供利用。世界蔬菜中心 [The World Vegetable Center,原亞洲蔬菜研究及發展中心 (Asian Vegetable Research and Development Center, AVRDC)] 經由三種辣椒炭疽病菌 Co. acutatum 、 Co. gloeosporioides 、 Co. capsici 之接種測試篩選出PBC81 (Ca. baccatum) 及 PBC932 (Ca. chinense) 兩個抗病種原,而為釐清這兩個種原抗炭疽病之機制,以裨益未來辣椒抗病品種選育工作之進行。本研究利用感病之辣椒品種-群香 (Ca. annuum) 與上述兩個抗病性野生辣椒種原為材料,建立 Co. acutatum與辣椒果實間交互作用之系統,來探討辣椒抗炭疽病之防禦相關機制。首先分析辣椒果實汁液對炭疽病菌菌落生長及孢子發芽之影響之情形,結果顯示抗、感病辣椒果實汁液對於炭疽病菌菌絲生長並無抑制之現象,反而發現果實汁液能促進孢子發芽,初步推測抗病辣椒果實之抗病反應並非由先天既存的水溶性物質所造成,而可能是其他因子所造成。接下來進行分子層次分析,由於在植物體內持續表現各種「病程相關」 (pathogenesis-related, PRs) 或「 NPR1 之作用因子 (NPR1-interacting factor, NIF1) 」 等其他防禦相關基因 (defense-related genes) ,可增進植物對各種病原菌之抗性或耐性,因此本研究分析對炭疽病具不同抗(PBC932)、感(群香)性之辣椒於接種前後,植物體內上述不同防禦相關基因之表現情形,首先針對基因庫中已發表的茄科植物中各 PRs 及 NIF1 基因之高度保留性區域設計各別之專一性引子對,並以 RT-PCR 技術自 SA 處理之群香品種 cDNA 中增幅且選殖出 PR1 、 PR5 與 NIF1 等防禦相關基因之部分序列,經核酸序列比對後,確定各選殖片段為辣椒中之 PR-1 (CaPR1) 、PR-5 (CaPR5) 或 NIF1 (CaNIF1) 基因片段無誤。接下來利用北方雜合法 (northern hybridization analysis) 分別以辣椒之各個防禦相關基因 CaPR1、CaPR5 與 CaNIF1 及番茄防禦相關基因 PR2、 PR3 與 PAL 等片段分析不同防禦相關基因之表現情形。而由本研究之北方雜合分析結果顯示在抗病辣椒 PBC932 健康果實中 PR3 與 PAL 基因表現量維持一定,雖然在綠果中 PR3 因接種而表現減少,但在 PBC932 紅果中兩者皆因病原菌接種而誘導產生較高之表現。而由抗病辣椒 PBC932 的接種結果亦顯示, PBC932 即使以傷口接種亦不發病,其為本研究中最抗病之辣椒種原,因此推測其抗病因子可能與防禦相關基因表現有關。另外,在所有供試辣椒果實中, PR5 基因表現較為明顯,但 PR5 基因在抗、感病辣椒果實中之表現情況不同,故目前尚無法推斷在辣椒果實中PR5基因之表現是否與抗病機制有關,但可推測抗、感病辣椒材料對於炭疽病菌有不同反應,其抗病機制可能也有差異。
Hot pepper (Capsicum annuum L.) is one of the important spice crops in Taiwan. Pepper anthracnose, which is one of the most damaging diseases in hot pepper production, can be incited by Colletotrichum acutatum, Co. gloeosporioides, Co. capsici and Co. coccodes. So far, no resistant cultivar is introduced against pepper anthracnose and no effective and economic strategy is available for the control of anthracnose. In this study, two anthracnose-resistant pepper accessions PBC81 (Ca. baccatum) and PBC932 (Ca. chinense), provided by AVRDC (Asian Vegetable Research and Development Center, The World Vegetable Center) together with a susceptible cultivar Chiun-Shiang (Ca. annuum) were used to investigate the resistance mechanism of hot pepper fruits to Co. acutatum. Analysis of antifungal activity of both lines (Chiun-Shiang, PBC81 and PBC932) indicated that the conidia germination in pepper fruits juice increased in contrast to the control conidia in water. In addition, no difference was found on the growth of pathogen on PDA (less sugar), water, and fruit juice treatments. We hence suggest that the resistance mechanism maybe not due to the preformed water-soluble compounds, but the other compounds. Many defense-related genes play important roles in plant defense response. For this reason, we have isolated the partial sequences of some defense-related genes, namely CaPR (pathogenesis-related) 1, CaPR5, and CaNIF1 (NPR1-interacting factor) from hot pepper. The expression of these genes together with the PR2, PR3, and PAL (Phenylalanine ammonia lyase) genes in fruits of the control and Co. acutatum-inoculated resistant (PBC932) and susceptible (Chiun-Shiang) hot pepper has been analyzed by northern hybridization analysis to help elucidating the factors affecting anthracnose resistance. The results showed that the expression level of these genes in fruits of hot pepper increased or decreased to some extent individually after inoculation with the pathogen. PR5 was strongly expressed during Co. acutatum-infection in ripe pepper fruits. Furthermore, the expression of PR3 and PAL in PBC932, the most anthracnose-resistant accession tested in this study, is higher than that in another pepper entry. These results suggest that these genes play important roles in disease resistance. Because the expression of these defense-related genes in the fruits of resistant and susceptible hot pepper was slightly different, it suggests that the resistance mechanism to Co. acutatum in the resistant hot pepper entries are different.
URI: http://hdl.handle.net/11455/31738
Appears in Collections:植物病理學系

文件中的檔案:

取得全文請前往華藝線上圖書館



Items in DSpace are protected by copyright, with all rights reserved, unless otherwise indicated.