Transcriptome Analysis of Age-Related Gain of Callus-Forming Capacity in Arabidopsis Hypocotyls

Abstract

Callus-forming capacity is enhanced with hypocotyl maturity in Arabidopsis. However, the genetic regulation of age-related gain in capacity for callus formation is unclear. We used a gene expression microarray assay to characterize the underlying mechanisms during callus formation in young and mature hypocotyl explants of Arabidopsis. As expected, genes involved in photosynthesis and cell wall thickening showed altered expression during hypocotyl maturation. In addition, genes involved in cytokinin perception were enriched in mature hypocotyl tissues. Phytohormone-induced callus formation in hypocotyl explants was accompanied by increased expression of genes mainly related to the cell cycle, histones and epigenetics. The induction level of these genes was higher in mature hypocotyl explants than young explants during callus formation. We identified a number of genes, including those with unknown function, potentially involved in age-related gain in callus formation. Our results provide insight into the effect of hypocotyl age on callus formation. Altered cytokinin signaling components, cell cycle regulation and epigenetics may work in concert to lead to gain of callus-forming capacity in hypocotyls with age.

Analysis of Papaya Cell Wall-Related Genes during Fruit Ripening Indicates a Central Role of Polygalacturonases during Pulp Softening

“…In addition to a previous observation of the similarities between ripening papayas and Arabidopsis hypocotyl gene expression [10], new data from Arabidopsis development (young and mature plants – [13] – Table S1 in File S1 ) indicate similar co-expression patterns for several cell wall-related papaya genes. In this regard, the cpPG1 orthologue from Arabidopsis ( AT3G59850 ) appears to play a central role in cell wall disassembly because the transgenic expression of this gene and the co-expression of expansin ( EXP2 - AT2G39700 - [25]) markedly changed the pulp firmness and increased the tomato susceptibility to Botrytis cinerea [26].…”

“…The PGs were positively correlated to galactanases, xylanases and, to a lesser degree, expansins and negatively correlated to a second group of genes encompassing PMEs, PLs and ARF. Because the expression of papaya cell wall disassembling genes was similar to Arabidopsis from 5 to 11-day-old hypocotyls growth [9], [10], a new comparison of papaya data was done with newly Arabidopsis data [13]. The comparison ( Table S1 in File S1 ) showed changes in the expression of 11 out of 16 genes, which were similar between the ripening fruit and the growing plant.…”

iTRAQ-Based Protein Profiling Provides Insights into the Mechanism of Light-Induced Anthocyanin Biosynthesis in Chrysanthemum (Chrysanthemum × morifolium)

“…In Arabidopsis and rice (Oryza sativa), 108 [62] and 114 [63] members are included in the GDSL esterase family, respectively. GDSL esterases regulate multiple metabolic processes in plants, e.g., plant growth and development such as pollen formation and development [64], root growth [65] and floral development [66] as well as stress tolerance such as water stress [67].…”

Direct reprogramming of adult somatic cells toward adventitious root formation in forest tree species: the effect of the juvenile–adult transition

“…The mechanisms of induction and repression of callus formation are unknown. Several key regulators of auxin and cytokinin signaling pathways, as well as the involvement of intrinsic programs of cell development, and their interaction, function during callus formation (Chen et al, 2012; Ikeuchi et al, 2013). …”

“…Epigenetic regulation of vegetative phase change, dedifferentiation, and adventitious root formation has been described (Wang et al, 2011; Vining et al, 2013; You et al, 2014). In addition, epigenetically repressed embryonic programs could be presumably involved in callus repression and regeneration in post-embryonic tissues (Chen et al, 2012; Ikeuchi et al, 2013). The large-scale transcript profiles of plantlets and dedifferentiated protoplast-derived cells from Arabidopsis indicate that the epigenetic status of protoplast-derived cells differs from the well-established cultures, with protoplast-derived cells exhibiting changes in transposon reactivation and chromatin-associated genes (Chupeau et al, 2013).…”