Abstract
A Nipponbare Tos17 mutant XC20 showed decreased field resistance against bacterial blight disease, and a putatively responsible gene xc20, was identified by the Tos17 tagging method. The field resistance of the XC20 was recovered after the reintroduction of the native the xc20 gene. The other five Nipponbare mutants in which the Tos17 was inserted in their xc20 gene showed the decreased field resistance as XC20. We concluded that xc20 is one of the responsible genes for field resistance against bacterial blight.
The amino acid sequences deduced from the xc20 gene had a similarity to the sequence of SAUR family protein. The SAUR proteins are induced by auxin accumulation after the infection of pathogens and considered to act as one of the negative regulators for auxin synthesis. Therefore, the xc20 gene might be involved a field resistance mechanism against bacterial blight disease by suppressing the auxin accumulation.
The XC20 has distinctive yellow-green leaves. However, because the other five mutants mentioned above have wild type leaves and showed decreased resistance, the change of leaf color in XC20 might not affects its field resistance against bacterial blight.
