Previously, we cloned a putative osmosensing histidine kinase gene (BcOS1) and revealed that a single amino acid substitution, isoleucine to serine at codon 365, conferred dicarboximide resistance in field isolates of Botrytis cinerea. This point mutation (type I) occurred within the restriction enzyme TaqI site of the wild-type BcOS1 gene. Thus, a procedure was developed for detecting the type I mutation of the BcOS1 gene using a polymerase chain reaction (PCR) in combination with restriction fragment-length polymorphism (RFLP). Diagnosis by PCR-RFLP was conducted on the 105 isolates isolated from 26 fields in Japan. All dicarboximide-sensitive isolates (49 isolates) had the wild-type BcOS1 gene, and the 43 isolates with the type I mutation were resistant to dicarboximides without exception. These data indicate that dicarboximide-resistant isolates with type I mutation are widespread throughout Japan. However, other types of dicarboximide resistance were detected among isolates from Osaka; among the 24 resistant isolates from Osaka, 12 had the BcOS1 gene without the type I mutation. BcOS1 gene sequencing of these resistant isolates classified them into two groups, type II and type III. The type II isolates have three amino acid substitutions within BcOS1p ( 368 Val to Phe, 369 Gln to His, and 447 Thr to Ser). The type III isolates have two amino acid substitutions within BcOS1p ( 369 Gln to Pro and 373 Asn to Ser). These amino acid changes are located on the amino acid repeat domain in BcOS1p. The three types of resistant isolates were all moderately resistant to dicarboximides without significant osmotic sensitivity, and their pathogenicity on cucumber leaves was also very similar to that of the wild-type isolate.

Distribution and seasonal fluctuation of the bacteria which inhibit the growth of a red tide marine dinoflagellate Gymnodinium mikimotoi, were surveyed in Tanabe Bay (Wakayama Pref., Japan), us ing the newly developed MPN method with an axenic culture of G. mikimotoi. G. mikimotoi's growth inhibiting bacteria (Gm-GIB) were detected at 103-104 cells/ ml before occurrences of huge red tides by G. mikimotoi at the beginning of August in 1990 and from the end of August to the beginning of Sep tember in 1991. The number of Gm-GIB fell by about two orders of magnitude at the blooming periods of G. mikimotoi, and then increased again after the blooms declined. These results suggest that the fluc tuation of Gm-GIB counts in seawater is significantly related to the development and decline process of G. mikimotoi red tide. Forty strains of Gm-GIB isolated in this study all acted as killers against this dinoflagellate rather than as suppressers on the algal growth under laboratory conditions. The precise causes of the fluctuation of Gm-GIB in seawater environments remain unknown.

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Tomato leaf mold caused by Passalora fulva was found on two tomato varieties carrying the Cf-9 gene in Japan, in 2007. The isolates obtained from Chiba and Fukushima were identified as race 4.9.11, and those from Gunma were races 4.9 or 4.9.11. This is the first report in Japan of tomato leaf mold caused by P. fulva strains that can overcome the Cf-9 gene.

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