Root Transcriptome of the Pachycereus pringlei, a Sonoran Desert Cactus with Determinate Growth of the Primary Root

The primary root of the Sonoran Desert cactus Pachycereus pringlei exhibits a determinate growth, i.e. the root apical meristem (RAM) undergoes exhaustion after a few cell divisions and then the root tip cells become differentiated. This growth pattern of the primary root is present in many species of the Cactaceae family but is unique among angiosperms; however the mechanisms underlying meristem exhaustion and determinate root growth are not known. To get an insight into the molecular mechanisms of the RAM maintenance and determinate root growth in Cactaceae, we used the Illumina HiSeq platform for transcriptome RNA-seq and CLC workbench for de novo assembly, contig annotation and analysis of differential gene expression. We estimated the differential gene expression in root tips during primary root development. Our gene expression analysis shows that many stress-related genes of P. pringlei are induced in the primary root tips when the RAM is ehxausted, and suggest the involvement of some transcription factors and hormone-related genes in the RAM maintenance. Together, these results provide a starting point to further study gene regulatory networks involved in RAM maintenance and exhaustion.

This work was supported by UNAM-DGAPA-PAPIIT (IN204912).