Page 132 - 《广西植物》2024年第2期
P. 132

3 3 4                                  广  西  植  物                                         44 卷
                 Abstract: Konjac (Amorphophallus konjac) is a horticultural plant with high nutritional and medicinal values. Soft rot is
                 a severe disease in production of konjac and it is also the main factor restricting the development of the konjac
                 industry. It has been reported that the soft rot of konjac is mainly caused by pathogenic bacteria (mainly including
                 Pectobacterium aroidearumꎬ P. carotovorum subsp. carotovorumꎬ P. chrysanthemi and Enterobacter sp.)ꎬ and there is rare
                 reports on pathogenic fungi that cause konjac soft rot. In order to clarify the pathogenic types and infection characteristics
                 of the soft rot in Qujing Cityꎬ Yunnan Provinceꎬ the diseased corms were collected for fungal isolation by tissue isolation
                 methods. The isolated fungi were identified by morphological and molecular identification methods based on ITS and LSU
                 sequence analysesꎬ and pathogenicity was determined according to Kochs rule. The infection characteristic was analyzed
                 by mixed inoculation using the identified pathogenic fungi and the pathogenic bacteria of konjac soft rot. The results were
                 as follows: (1) Three species of Fusarium spp. (Fusarium concentricumꎬ F. oxysporum and F. ambrosium)ꎬ one species
                 of Mucor sp.ꎬ one species of Rhizopus sp.ꎬ one species of Penicillium sp. and one species of Clonostachys sp. were
                 identified. (2) Statistics analysis found that Fusarium concentricum had the highest relative abundance (45.45%). (3)
                 Koch postulates tests showed that inoculation with F. concentricum caused obvious soft rot symptoms of konjac corms
                 within three days. (4) In additionꎬ mixed Pectobacterium aroidearum and Fusarium concentricum together inoculation
                 promoted the disease developmentꎬ and the weight of rotten tissue was significantly higher than that of single inoculation
                 using F. concentricum or Pectobacterium aroidearum. Overallꎬ these results indicate that konjac soft rot may be caused by
                 a combination of fungus and bacterium infection. The results provide a theoretical reference for the prevention and
                 management of konjac soft rot.
                 Key words: Amorphophallus konjacꎬ soft rotꎬ pathogenic fungusꎬ phylogenetic analysisꎬ pathogenicity




                  魔 芋 属 ( Amorphophallus) 植 物 是 天 南 星 科        产业威胁最大的毁灭性病害ꎬ在魔芋生长期和贮
            (Araceae)多年生草本植物ꎬ主要生长在高海拔山区                        藏期均可能发生ꎮ 生长期魔芋软腐病的发病特征
            (邱凌和仇农学ꎬ 1995)ꎮ 全世界大约有 170 种ꎬ主                     是植株的茎秆、球茎部位会由硬变软ꎬ叶片萎蔫ꎬ
            要分布在越南、缅甸、中国、日本等国家ꎬ其中我国                            随后球茎发黑腐烂ꎬ有臭味散发出ꎬ并会出现倒苗

            约有 17 种ꎬ主要集中分布在广东、四川、云南等地ꎮ                         的现象(Wei et al.ꎬ 2020ꎻ王敏珍等ꎬ2021)ꎮ 在贮
            魔芋球茎的蛋白质含量高于马铃薯和甘薯ꎬ并且富                             藏期及播种期ꎬ如果种芋染上软腐病ꎬ球茎在发病
            含膳食纤维ꎮ 魔芋制品热量低ꎬ营养价值和药用价                            的初期ꎬ其表皮会出现水渍状的褐色斑纹ꎬ并不断
            值高ꎬ食用魔芋具有减肥、降血压和血糖、改善肠道                            地向内扩展ꎬ球茎的白色组织逐渐变成灰色乃至

            菌群结构和防癌等功效(Zhang et al.ꎬ 2005ꎻChua et              黄褐色ꎬ渗出大量浓稠的菌液ꎬ致使球茎腐烂( 王
            al.ꎬ 2010ꎻSrzednicki & Borompichaichartkulꎬ 2020)ꎮ  敏珍等ꎬ2021)ꎮ 软腐病在魔芋种植区广泛传播严
            魔芋葡甘聚糖(konjac glucomannanꎬKGM)作为魔芋                 重阻碍了我国魔芋产业的发展ꎮ
            粉的主要成分( Li et al.ꎬ 2010)ꎬ是一种水溶性多                       目前ꎬ有报道魔芋软腐病主要由胡萝卜果胶杆
            糖ꎬ在食品科学、营养保健、生物技术、药理学和精                            菌(Pectobacterium aroidearum)、胡萝卜果胶杆菌胡

            细化工等领域具有多种用途( Zhang et al.ꎬ 2005ꎻ                  萝卜软腐亚种 [ P. carotovorum subsp. carotovorum
            Chua et al.ꎬ 2010ꎻBehera & Rayꎬ 2016ꎻZhuꎬ 2018ꎻ    (Pcc)]、菊果胶杆菌(P. chrysanthemi) 和肠杆菌属
            Srzednicki et al.ꎬ 2020)ꎮ 花 魔 芋 ( Amorphophallus   (Enterobacter sp.) 等引起的细菌性软腐病 ( Wu et
            konjac)作为葡甘聚糖含量最高的魔芋种类之一ꎬ是                         al.ꎬ 2011ꎻ 徐 炜ꎬ 2011ꎻ 黄 露 等ꎬ 2014ꎻ Wu et al.ꎬ
            我国主要的栽培种(Gao et al.ꎬ 2022)ꎮ 作为重要经                  2015ꎻ Sunꎬ 2019ꎻ Wei et al.ꎬ 2020ꎻ Zhang et al.ꎬ
            济作物ꎬ魔芋已成为云、贵、川等地区农业经济发展                            2022)ꎬ而关于 魔 芋 软 腐 病 病 原 真 菌 的 报 道 比 较
            中最具潜力与竞争优势的特色资源产业之一ꎬ也是                             少ꎮ 何斐等(2016) 研究发现ꎬ导致魔芋病株的根
            乡村振兴重点推广种植的作物ꎮ                                     区、根表土壤和根系腐烂的病原真菌是腐皮镰刀
                 软腐病是魔芋病害中影响最为严重的病害ꎮ                           菌 ( Fusarium solani ) 和 尖 孢 镰 刀 菌 ( F.
            由于缺乏持续有效的防控措施ꎬ被认为是对魔芋                              oxysporum)ꎻ李迎宾等(2017)通过用离体菌丝块接
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