Primary Root Excision Induces ERF071 Which Mediates the Development of Lateral Roots in Makapuno Coconut (Cocos nucifera)

Abstract

Coconut (Cocos nucifera L.) is widely recognized as one of nature抯 most beneficial plants. Makapuno a special type of coconut with a soft jelly-like endosperm is a high-value commercial coconut and an expensive delicacy with a high cost of planting material. The embryo rescue technique is a very useful tool to support mass propagation of makapuno coconut. Nevertheless transplanting the seedlings is a challenge due to poor root development which results in the inability of the plant to acclimatize. In this study primary root excision was used in makapuno to observe the effects of primary root excision on lateral root development. The overall results showed that seedlings with roots excised had a significantly higher number of lateral roots and shoot length also increased significantly. Using de novo transcriptome assembly and differential gene expression analysis we identified 512 differentially expressed genes in the excised and intact root samples. ERF071 encoding an ethylene-responsive transcription factor was identified as a highly expressed gene in excised roots compared to intact roots and was considered a candidate gene associated with lateral root formation induced by root excision in makapuno coconut. This study provides insight into the mechanism and candidate genes involved in the development of lateral roots in coconut which may be useful for the future breeding and mass propagation of makapuno coconut through tissue culture. ? 2022 by the authors.