Abstract: Based on conservd protein sequence of Lectin-LegB（Pfam：PF00139），Pkinase（Pfam：PF00069）domain，the L-LEC-RLKs of apple（Malus × domestica Borkh.）were identified at a genome-wide level. For all members，physicochemical parameters，evolutionary characteristics，subcellular localization，chromosomal position and expressional patterns were investigated. In total，41 L-LEC-RLKs were identified in the apple genome，with amino acid size，the molecular weight，and isoelectric point varying from 423 to 1 291 aa，47.12–143.27 kD and 5.50 to 8.91，respectively. Among these，28 members were predicted on plasma membrane. Evolutionary analysis showed that L-LEC-RLKs from Arabidopsis，rice，potato，Populus and apple could be divided into 8 sub-groups，the members from apple were distributed in sub-groupⅠ，Ⅱ，Ⅲ，Ⅴ，Ⅵ and Ⅷ. Apple L-LEC-RLKs showed diverse expression patterns in different tissues. Twenty-seven members were differentially expressed when apple trees were infected with Valsa mili（Vm）or Alternaria alternata apple pathotype（AAAP）. Strikingly，the expression levels of MD15G1226500 and MD14G1055200 were dramatically altered in apple infected with either pathogen. These differentially expressed genes could be used as candidate genes for disease resistance and further functional investigation.

Key words: apple, L-LEC-RLK, bioinformatic analysis, valsa canker of apple, alternaria blotch of apple