Genome-wide identification and characterization of polygalacturonase gene family in linseed (Linum usitatissimum L.) and comparative expression in its wild relative (Linum bienne) upon bud fly infestation.

backgroundLinseed is an important minor oilseed crop, which is well known for food, feed, oil, fiber, and pharmaceutical industries. The higher concentrations of omega-3 fatty acid augment their importance. Among the several productivity constraints, the linseed bud fly is a major pest that leads to severe yield loss. Limited donors are available for bud fly resistance, but deeper insight into its characterization at the gene or transcript level is not well studied.

resultsIdentification, characterization, and expression of polygalacturonase encoding genes have been done in the present investigation. A total of 42 LusPG genes were identified in the linseed genome and grouped into two major clades and six subclades. All the genes comprise the Gluco_Hydro_28 domain, whereas two candidates consist of the LRR domain. Three domains, such as "SPNTDG", "GDDC", and "CGPGHG", were found as conserved signatures. The comparative expression in linseed cultivar and one of its wild relatives demonstrated the differential layer of transcriptional regulation modulating bud fly resistance. The gene expression analysis demonstrated that the genes such as Lus10041051, Lus10043087, Lus10013025, and Lus10002727 were found to be significantly regulated upon bud fly infestation. Two candidates, namely Lus10042371 and Lus10026299, had R-gene domain along with GH28 domain, suggesting their cell wall modification and inhibitor activity.

conclusionsThe present study identified 42 genes in linseed, with four key genes showing potential for inhibiting bud fly feeding by altering cell walls. These findings provide a foundation for future breeding programs to enhance pest resistance in linseed crops.