Amorphophallus konjac is an important economic crop widely cultivated in Southeast Asia and Africa. However, A. konjac is seriously infected by soft rot pathogen. The endocellular acyl homoserine lactonase (AiiA) which is generated by Bacillus species has inhibitory effect on soft rot pathogen through disrupting the signal molecules (N-acylhomoserine lactones, AHL) of their Quorum Sensing system. The aim of our study is to obtain recombinant yeast which produces AiiA protein. The recombinant yeast Pichia pastoris GS115 was constructed to constitutive expression of the AiiA gene. The results of reverse transcript PCR analysis showed that the AiiA gene was expressed successfully in the yeast. Proteins extracted from YPDS showed the highest inhibition efficacy to E. carotovora compared with the other two mediums (YPD and LB) under tested conditions.

2% NaCl (3). Indirect ELISA analysis (NEOGEN, Lansing, MI) was conducted using antibodies specific for Xanthomonas fragariae. Conventional PCR assay using the primer pairs 241A/241B was performed (2). The ELISA test was positive. The expected 300-and 550-bp bands were observed in the PCR analysis. The bacteria was identified as X. fragariae Kennedy and King. Pathogenicity tests were conducted twice in a greenhouse (24 ± 4°C) on a total of five strawberry cv. Aromas plants. The main vein of each of three leaves per plant were punctured using sterile needles. Pathogen inoculum was obtained from 6-to B-day-old NA cultures. Bacteria were applied onto the wounds with a sterile cotton swab dipped into the bacterial suspension (10' CFU/ml). Inoculated plants were covered with plastic bags for 48 h. Symptoms resembling those seen in the field developed on all inoculated plants after 9 days. X. fragariae was re-isolated from the necrotic lesions and identified by PCR. Control plants were similarly inoculated with water but did not develop symptoms. To our knowledge, this is the first report of X. fragariae causing angular leaf spot in strawberry in Michoacán, México.

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.

In the springs of 2020 and 2021, with a temperature of 15°C, root rot on garlic were widespread in Enshi, Hubei Province, China. Based on micro-morphological and cultural characteristics, the pathogen was identified as a Fusarium sp. Further, based on multilocus (ITS, EF-1α) phylogenic data, the strains were identified as Fusarium oxysporum. Koch's postulates were thus fulfilled by pathogenicity tests on garlic seedlings cultured in vitro.