白及根腐病病原菌的鉴定及抑制效应研究

Identification and inhibiting effect of pathogens that caused tuber rot of Bletilla striata

关键词:  白及, 根腐病, 病原菌分离和鉴定, 高粱附球菌, 中草药提取物

Key words:  Bletilla striata, tuber rot, pathogen isolation and identification, Epicoccum sorghinum, Chinese herbal extracts

摘要:

为明确鉴定白及块茎腐烂病(根腐病)的病原菌,并筛选能够抑制病原菌的中药材提取物。该研究利用常规组织分离法对病原菌进行分离,通过形态学和分子生物学技术对致病菌株进行鉴定,同时观察了7种中药材提取物对病原菌的抑菌效果。结果表明:(1)从感病叶片、叶鞘及块茎中共分离得到 14 株真菌和 4株细菌,病原菌室内和室外回接表明菌株 GF-1致病症状与田间一致,致病率均达到100%。(2)经形态学鉴定,菌株GF-1为附球菌属(Epicoccum)病原菌,菌落白色绒絮状,圆形; 菌丝匍匐向外、向上生长,气生,无色,有隔膜,有分枝,具有分生孢子和厚垣孢子。(3)菌株GF-1的ITS 序列(全长522 bp)与 GenBank 中已登录的甘蔗的高粱附球菌(E. sorghinum,MN493119.1)序列一致性最高,达99.62%,与已报道的白及叶斑病致病菌高粱附球菌(E. sorghinum, MF948994.1)的一致性为98.88%。(4)培养基中含有0.1～0.2 g·mL^-1的青钱柳等7种中药材提取物,能够完全抑制GF-1菌落的生长; 当培养基中含有0.05 g·mL^-1的提取物时,肉桂和丁香提取物仍然能够完全抑制菌落的生长。综上认为,引起白及根腐病的致病菌为附球菌属高粱附球菌(E. sorghinum),培养基中分别含有0.1～0.2 g·mL^-1的青钱柳、白及、厚朴、八角、肉桂、蛇床子和丁香7种中药材提取物且均能完全抑制致病菌的生长。该研究结果为白及根腐病的防治提供了理论指导。

Abstract:

In order to identify the pathogens that caused tuber rot in Bletilla striata and study the inhibiting effects of herbal extracts on pathogens, the pathogens that caused tuber rot of B. striata were isolated using usual tissue isolation the strains were identified by morphological and molecular biological techniques, and inhibiting effects of seven traditional Chinese medicine extracts on pathogen were observed. The results were as follows:(1)A total of fourteen fungi and four bacteria were isolated from diseased leaves, leaf sheaths and tubers. But only strain GF-1 caused disease, whose symptoms consistent with those in the field. The incidences of GF-1 disease reinoculated in the field and laboratory were both 100%.(2)GF-1 was identified as a member of Epicoccum, and its colonial morphology was a circular form, with white mycelium, prostrate on the medium, aerial, diaphragms and branches. There were conidia and chlamydospores.(3)At last, the sequence of internal transcribed spacer(ITS)region of GF-1 were analyzed, the length was 522 bp. The sequence was compared with other species in the GenBank and reached 99.62% similarity to Epicoccum sorghinum (MN493119.1)isolated form Sorghum, which was closer than others, including Epicoccum sorghinum(MF948994.1)isolated form leaves of Bletilla striata.(4)GF-1 could be fully inhibited when the medium contained 0.1-0.2 g·mL^-1 extracts that extracted from seven traditional Chinese medicines, respectively. It also could be fully inhibited by 0.05 g·mL^-1 of Cinnamomum cassia or Syringa oblate. In summary, the pathogen that caused tuber rot in Bletilla striata was identified as Epicoccum sorghinum. And GF-1 could be fully inhibited cultivated on the medium which contained 0.1-0.2 g·mL^-1 herbal extracts, e.g.: Cinnamomum cassia, Syringa oblate, Cyclocarya paliurus, Bletilla striata, Houpoea officinalis, Illicium verum or Cnidium monnieri. The results provide theoretical references for the control of tuber rot of Bletilla striata.