During a survey for the cyst nematodes (Heterodera elachista) from May to June of 2011, cyst nematodes were detected in hilly rice fields in five counties (Changsha, Pingjiang, Hengdong, Shaoyang, and Xiangxiang) of Hunan Province, China. Cyst nematodes obtained from soil samples and harvested rice root samples at these five locations had uniform morphological and molecular characteristics. Cysts (n = 20) had the following characteristics: spherical to lemon shaped, vulval cone ambifenestrate, vulval bridge narrow, medium sized underbridge, with a few dark brown bullae, body length (not including the neck) ranging from 354 to 586 μm (mean = 438.9 μm, st. dev. = 63.7); body width ranged from 283 to 495 μm (354.5, 60.1); fenestrate length of 30 to 50 μm (37.4, 5.0) and width of 25 to 47.5 μm (35.1, 7.1); underbridge length from 70 to 95 μm (83.4, 8.2); and vulval slit length from 30.3 to 55.5 μm (40.3, 9.1). J2 (n = 20) had the following characteristics: body length ranging from 404 to 525 μm (mean of 461.6 μm, st. dev. = 34.5); stylet length from 20 to 25 μm (22.5, 1.1) with rounded knob; tail length of 60 to 87.5 μm (67.3, 6.9); and hyaline terminal tail ranged from 30 to 50 μm (37.5, 6.4); lateral field with three lines. The mean and range of J2 were longer than those reported for H. elachista by Nobbs et al. (1) and Tanha et al. (4), but other morphological character values were within the range of those reported (4). DNA from a single cyst was extracted, the rDNA-internal transcribed spacer (ITS) and D2/D3 fragments of the 28S RNA were amplified with universal primers TW81 and AB28, D2A and D3B, respectively. Five ITS sequences (JN202913, JN202914, JN202915, JN202916, and JN202917) and five D2/D3 sequences (JN202918, JN202919, JN202920, JN202921, and JN202922) from nematode samples collected in Changsha, Hengdong, Shaoyang, Pingjiang, and Xiangxiang, respectively, were submitted to GenBank. These ITS sequences were remarkably similar to each other and exhibited 98.6 to 99.3% similarity with that of H. elachista isolate from Iran (AF498391), and 98.8 to 99.4% similarity with that of H. elachista isolates from Ningxia Province, China (HM560778 and HM560779). The D2/D3 sequences exhibited 99.7 to 100% similarity with that of H. elachista isolates from Ningxia Province, China (HM560842 and HM560843). These characteristics indicated that the five populations were H. elachista belonging to the ‘cyperi’ group (1,2). In glasshouse evaluations of the pathogenicity of these isolates, 500 second-stage juveniles were inoculated onto five 20-day-old seedlings of rice (Weiyou No.227) in 4.5-cm diameter 30-cm high tubes with six replicates. After 8 weeks, stunting and reduction of leaf length were observed and cysts were extracted from dried soil of each tube using sieves. Brown cysts (92 to 204) and white females (14 to 40) were obtained from inoculated rice from each tube. H. elachista can decrease yield by 7 to 19% and has the most severe impact during the later stages of plant growth (3). H. elachista has been previously identified from rice fields in Japan and Iran (3). To our knowledge, this is the first report of H. elachista on rice in Hunan Province, China. References: (1) J. M. Nobbs et al. Fundam. Appl. Nematol. 15:551, 1992. (2) S. A. Subbotin et al. Mol. Phylogenet. Evol. 21:1, 2001. (3) S. A. Subbotin et al. Systematics of Cyst Nematodes (Nematoda: Heteroderinae). Volume 8 Part B. Brill, Leiden, the Netherlands, 2010. (4) M. Z. Tanha et al. Nematology 5:99, 2003.
Yams (Dioscorea spp.) are widely cultivated in China, with many landraces maintained by local farmers. However, little is known about their diversity or species identity. In this study, inter-simple sequence repeats (ISSRs) were used to determine genetic diversity within 64 yam landraces from 12 provinces of China. A total of 45 bands were amplified with five ISSR primers, of which 40 (88.89%) were polymorphic, suggesting a high level of polymorphism. Moreover, genetic diversity, estimated using Shannon' index, was 0.3702, indicating relatively high genetic variation. A dendrogram of within-group linkage subsequently divided the 64 cultivars into three main clusters. Overall, the results suggest that these Chinese yam landraces are a valuable source of genes for future yam breeding programs.
During 2015, marginal scorch symptoms were detected in the production base of indigowoad rootin Hubei, China. On the basis of morphological features and 18S rDNA sequences, the pathogen was identified as Cladosporium sp. Koch's postulates were fulfilled by pathogenicity tests on potted indigowoad root seedlings. To our knowledge, this report is the first of marginal scorch on indigowoad root caused by Cladosporium sp. We propose the name "marginal scorch" for the new disease. KeywordsIndigowoad Root, Marginal Scorch, Cladosporium sp.Indigowoad root (Isatis tinctoria) is one of the most well-konwn approved prescription remedies and is frequently used as an anti-leukemia, antipyretic, anti-inflammatory and anti-virus agent [1]. In addition, a compound from indigowoad root granules has been accredited as antiviral agent against influenza virus [2]. Moreover, the fresh leaves are used as a vegetable. As there is more demand for healthy and nutritional life style, the medial role of indigowoad root will get more attention in future. As an important medical vegetable, the planting area of indigowoad roothassignificantly increased. However, the symptom of the marginal scorch for indigowoad root was observed in the Wuhan City andShennongjia Forestry District, Hubei Province, China (Figure 1(a)). First the margin of leaf became yellow, then gradually crispation and brown. The incidence of symptoms was almost 100%, seriously affecting thecommercial quality of the leaves from indigowoad root. Therefore, the pathogens were isolated by tissue segment method on potato dextrose agarmedium [3]. A suspension containing 10 5 conidiophores per ml collected from 7-day-old colonies grown on PDA was sprayed on the foliage of indigowoad root. The control plants were inoculated with sterile water. After inoculation, the plants * Corresponding author.
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