黑胫病和菌核病是造成世界油菜产量下降的2种主要病害，分别由油菜茎基溃疡病菌和核盘菌引起。几丁质酶基因家族被认为是一类病害相关蛋白质，在植物抵抗病菌和非生物胁迫应答过程中发挥着重要作用。然而，甘蓝型油菜中关于几丁质酶基因家族进化及其应答黑胫病和菌核病的表达研究尚未有报道。本研究在甘蓝型油菜基因组中共鉴定了68个几丁质酶基因，分为5个不同的类，分布在15条染色体上。进化分析表明，甘蓝型油菜中几丁质酶基因家族成员的扩张主要是由片段复制和串联重复所致。此外，利用转录组测序数据分析了甘蓝型油菜几丁质酶基因家族应答2种病菌胁迫的表达谱。结果表明，在2种病菌侵染下，几丁质酶基因家族中有一些成员的表达均被诱导，也存在一些几丁质酶基因家族成员被特异地诱导表达。由此可见，甘蓝型油菜中几丁质酶基因家族不同成员的功能在长期进化过程中发生了分化，在应答不同病害胁迫中发挥特异的作用。

Blackleg and sclerotinia stem rot caused by Leptosphaeria maculans and Sclerotinia sclerotiorum respectively are two major diseases in rapeseed worldwide,which cause serious yield losses. Chitinases are pathogenesis-related proteins and play important roles in host resistance to various pathogens and abioticstress responses.However,a systematic investigation of the chitinase gene family and its expression profile against L.maculans and S.sclerotiorum infection in rapeseed remains elusive. In this study,68 chitinase genes were identified in Brassica napus genome.These genes were divided into five different classes and distributed among 15 chromosomes.Evolutionary analysis indicated that the expansion of the chitinase gene family was mainly attributed to segmental and tandem duplication.Moreover,the expression profile of the chitinase gene family was investigated using RNA sequencing (RNA-Seq) and the results revealed that some chitinase genes were both induced while the other members exhibited distinct expression in response to L.maculans and S.sclerotiorum infection.Thus,the functions of different chitinase gene family members have diverged during long-term evolution and might exhibit different roles against different disease stresses in Brassica napus.