Flower power and the mustard bomb: Comparative analysis of gene and genome duplications in glucosinolate biosynthetic pathway evolution in Cleomaceae and Brassicaceae.
Glucosinolates (GS) are a class of plant secondary metabolites that provide defense against herbivores and may play an important role in pollinator attraction. Through coevolution with plant-interacting organisms, glucosinolates have diversified into a variety of chemotypes through gene sub- and neofunctionalization. Polyploidy has been of major importance in the evolutionary history of these gene families and the development of chemically separate GS types. Here we study the effects of polyploidy in Tarenaya hassleriana (Cleomaceae) on the genes underlying GS biosynthesis.



We established putative orthologs of all gene families involved in GS biosynthesis through sequence comparison and their duplication method through calculation of synonymous substitution ratios, phylogenetic gene trees, and synteny comparison. We drew expression data from previously published work of the identified genes and compared expression in several tissues.



We show that the majority of gene family expansion in T. hassleriana has taken place through the retention of polyploid duplicates, together with tandem and transpositional duplicates. We also show that the large majority (>75%) is actively expressed either globally or in specific tissues. We show that MAM and CYP83 gene families, which are crucial to GS diversification in Brassicaceae, are also recruited into specific tissue expression pathways in Cleomaceae.



Many GS genes have expanded through polyploidy, gene transposition duplication, and tandem duplication in Cleomaceae. Duplicate retention through these mechanisms is similar to A. thaliana, but based on the expression of GS genes, Cleomaceae-specific diversification of GS genes has taken place.
Biosystematics Group, Wageningen University & Research Center, Droevendaalsesteeg 1, 6708PB, Wageningen, The Netherlands The Genome Analysis Centre, Norwich Research Park, Norwich, NR4 7UH, UK.
Erik
E
van den Bergh
Biosystematics Group, Wageningen University & Research Center, Droevendaalsesteeg 1, 6708PB, Wageningen, The Netherlands Big Data Analytics, Detecon Co., Ltd., 100600 Beijing, PR China.
Johannes A
JA
Hofberger
Biosystematics Group, Wageningen University & Research Center, Droevendaalsesteeg 1, 6708PB, Wageningen, The Netherlands Eric.Schranz@wur.nl.
M Eric
ME
Schranz
D017360:Arabidopsis / Q000235:genetics; D005075:Biological Evolution; D053898:Biosynthetic Pathways; D019607:Brassicaceae / Q000235:genetics*; D035264:Flowers / Q000235:genetics*; D020440:Gene Duplication; D018745:Genome, Plant / Q000235:genetics*; D005961:Glucosinolates / Q000235:genetics*; D019684:Magnoliopsida / Q000235:genetics*; D011123:Polyploidy
D005961:Glucosinolates
Arabidopsis thaliana; Brassicaceae; Cleomaceae; Tarenaya hassleriana; gene duplication; gene family evolution; glucosinolates; polyploidy