Transcriptome analysis reveals the effects of sugar metabolism and auxin and cytokinin signaling pathways on root growth and development of grafted apple

Abstract

BackgroundThe root architecture of grafted apple (Malus spp.) is affected by various characteristics of the scions. To provide information on the molecular mechanisms underlying this influence, we examined root transcriptomes of M. robusta rootstock grafted with scions of wild-type (WT) apple (M. spectabilis) and a more-branching (MB) mutant at the branching stage.ResultsThe growth rate of rootstock grafted MB was repressed significantly, especially the primary root length and diameter, and root weight. Biological function categories of differentially expressed genes were significantly enriched in processes associated with hormone signal transduction and intracellular activity, with processes related to the cell cycle especially down-regulated. Roots of rootstock grafted with MB scions displayed elevated auxin and cytokinin contents and reduced expression of MrPIN1, MrARF, MrAHP, most MrCRE1 genes, and cell growth-related genes MrGH3, MrSAUR and MrTCH4. Although auxin accumulation and transcription of MrPIN3, MrALF1 and MrALF4 tended to induce lateral root formation in MB-grafted rootstock, the number of lateral roots was not significantly changed. Sucrose, fructose and glucose contents were not decreased in MB-grafted roots compared with those bearing WT scions, but glycolysis and tricarboxylic acid cycle metabolic activities were repressed. Root resistance and nitrogen metabolism were reduced in MB-grafted roots as well.ConclusionsOur findings suggest that root growth and development of rootstock are mainly influenced by sugar metabolism and auxin and cytokinin signaling pathways. This study provides a basis that the characteristics of scions are related to root growth and development, resistance and activity of rootstocks.Electronic supplementary materialThe online version of this article (doi:10.1186/s12864-016-2484-x) contains supplementary material, which is available to authorized users.

Comprehensive transcriptome profiling and phenotyping of rootstock and scion in a tomato/potato heterografting system

“…Grafting-induced differences in the transcriptome profile of grafted parents have also been reported in other plants (Kumari et al 2015, Li et al 2016, Liu et al 2016). This study employed RNA-Seq to identify DEGs between Sl/St and self-grafted tomatoes.…”

Inhibition of adventitious root development in apple rootstocks by cytokinin is based on its suppression of adventitious root primordia formation

“…RT‐qPCR assays were performed according to the methods of Li et al (). An apple ACTIN gene was used for normalization.…”

Microstructural Observation and Transcriptome Analysis of Pistil Abortion in ‘Li Guang’ Apricot

“…Moreover, these two genes function in different organs to promote the transition from closed buds to mature normal flowers. At low auxin levels, AUX/IAA proteins bind to ARFs and suppress ARF function [49]. In the current study, AUX1(DN68818), AUX/IAA (DN70853, DN68398), ARF (DN71836) and SAURs (DN71004, DN69270, DN69226, DN50721), which were significantly up-regulated in NF compared with AF, were considered to be able to promote cell enlargement and plant growth and development.…”