Pawar N V, Patil V B, Kamble S S, Dixit G B
Department of Botany, Shivaji University, Kolhapur-416 004, (M.S.) India.
Plant Dis. 2008 Sep;92(9):1368. doi: 10.1094/PDIS-92-9-1368C.
Zingiber officinale Rosc., belonging to the Zingiberaceae family, is medicinally important. It is commonly known as ginger and has been extensively cultivated for many centuries for use as a spice and traditional medicine in India. During a survey in September of 2007, leaves of Z. officinale showed a necrotic leaf spot disease on a plant growing in Kolhapur, India. Symptoms of the disease appeared as small (10 to 15 mm), rectangular to irregular, yellow spots on the leaves that covered a major area of the leaf when severe. The infection caused defoliation. Symptomatic leaves were collected and isolations from infected leaves were made on Czapek's Dox agar supplemented with streptomycin sulfate (30 mg/l). Plates were incubated at 28 to 30°C for 6 to 7 days. The fungal colonies were colorless to pale on the reverse side and covered with a dense layer of dark brown-to-black conidial heads. Conidia were globose to subglobose (3.5 to 5.0 μm in diameter), dark brown to black, and rough walled. 16S rRNA of isolates was amplified and sequenced (EMBL Accession No. AM941157) and compared with sequences of known Aspergillus species obtained from GenBank. The closest matches (99% identity) were with A. niger. On the basis of morphological and molecular approaches, the pathogen was confirmed as A. niger. Of five isolates, AN-5 was used for pathogenicity study. Koch's postulates were satisfied after reisolating the fungus from leaves inoculated with a conidial suspension that showed symptoms (6 days after inoculation) similar to the lesions observed on the leaves collected from Z. officinale. The tests were repeated three times in the greenhouse. Healthy, potted Z. officinale plants were grown in isolation after artificial inoculation with a suspension of spores (10,000 conidia per ml), which was prepared in 100 ml of sterile distilled water and then sprayed on the abaxial and adaxial surface of leaves. Noninoculated plants served as controls. These results confirmed the pathogenicity of A. niger on Z. officinale. To our knowledge, this is the first report of A. niger causing a disease on ginger (1). Reference: (1) G. N. Dake. J. Spices Aromatic Crops. 4:40, 1995.
姜（Zingiber officinale Rosc.）属于姜科，具有重要的药用价值。它通常被称为生姜，在印度作为香料和传统药物已有数百年的广泛种植历史。在2007年9月的一次调查中，印度科尔哈普尔一株生长的姜的叶片上出现了坏死叶斑病。该病症状表现为叶片上出现小的（10至15毫米）、长方形至不规则形的黄色斑点，严重时覆盖叶片的大部分区域。感染导致落叶。采集有症状的叶片，并在添加硫酸链霉素（30毫克/升）的察氏琼脂上从感染叶片进行分离培养。平板在28至30°C下培养6至7天。真菌菌落背面无色至浅色，覆盖着一层密集的深褐色至黑色分生孢子头。分生孢子球形至近球形（直径3.5至5.0微米），深褐色至黑色，壁粗糙。对分离物的16S rRNA进行扩增和测序（EMBL登录号AM941157），并与从GenBank获得的已知曲霉属物种的序列进行比较。最接近的匹配（99%同一性）是黑曲霉。基于形态学和分子方法，确认病原菌为黑曲霉。在五个分离物中，AN - 5用于致病性研究。在用分生孢子悬浮液接种叶片后（接种6天后），从表现出与从姜上采集的叶片上观察到的病斑相似症状的叶片中重新分离出真菌，从而满足了科赫法则。这些试验在温室中重复进行了三次。在人工接种孢子悬浮液（每毫升10000个分生孢子）后，将健康的盆栽姜单独种植，该悬浮液在100毫升无菌蒸馏水中制备，然后喷洒在叶片的正面和背面。未接种的植物作为对照。这些结果证实了黑曲霉对姜的致病性。据我们所知，这是关于黑曲霉引起姜病害的首次报道(1)。参考文献：(1) G. N. Dake. J. Spices Aromatic Crops. 4:40, 1995.
