Genome-wide analysis of the cellulose toolbox of Primulina eburnea, a calcium-rich vegetable

Background Human-guided crop domestication has lasted for more than 10,000 years. In terms of the  domestication and breeding of vegetables, cellulose content in edible tissues is one of the most important traits.  Primulina eburnea is a recently developed calcium-rich vegetable with a high soluble and bioavailable calcium  content in its leaves. However, the high cellulose content in the leaves hampers the taste, and no research has been  reported on the genetic basis of cellulose biosynthesis in this calcium-rich vegetable. 

Results We identified 36 cellulose biosynthesis-involved genes belonging to eight gene families in the P. eburnea genome. The cellulose accumulated decreasingly throughout leaf development. Nineteen genes were considered  core genes in cellulose biosynthesis, which were highly expressed in buds but lowly expressed in mature leaves.  In the nitrogen fertilization experiment, exogenous nitrogen decreased the cellulose content in the buds. The  expressing pattern of 14 genes were consistent with phenotypic variation in the nitrogen fertilization experiment, and  thus they were proposed as cellulose toolbox genes. 

Conclusions The present study provides a strong basis for the subsequent functional research of cellulose  biosynthesis-involved genes in P. eburnea, and provides a reference for breeding and/or engineering this calcium-rich  vegetable with decreased leaf cellulose content to improve the taste.