Comparison of central repeat units within the deduced amino acid sequences of avrBs3/pthA family members from strain KC21 of X. axonopodis pv. citri (A). Each central repeat unit is displayed as a distinctive capital letter as seen in B. The 1st to the 6th repeats of hssB3.0 were identical to the 1st to the 6th repeats of pB3.1, while the 7th to the 12th repeats were identical to the 2nd to the 7th repeats of pB3.7. The 13th to the last repeat was also identical to the 14th to the last repeat of pB3.1. The central region of pthA-KC21 was similar in arrangement to that of pthA, although displacements were observed at the 6th, 13th, and 15th repeats. GenBank accession numbers are as follows: pthA, U28802; hssB3.0, AB175482; pB3.1, AB206387; pthA-KC21, AB206388; pB3.7, AB206389.