Evolution analysis and expression divergence of the chitinase gene family against Leptosphaeria maculans and Sclerotinia sclerotiorum infection in Brassica napus

Abstract

AbstractBlackleg 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 abiotic stress 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. The recent release of assembled genome sequence of rapeseed allowed us to perform a genome-wide identification of the chitinase gene family. 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 profiling 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 exhibit distinct expression in response to L. maculans and S. sclerotiorum infection. This study presents a comprehensive survey of the chitinase gene family in B. napus and provides valuable information for further understanding the functions of the chitinase gene family.