Auxin-Cytokinin Cross Talk in Somatic Embryogenesis of Coffea canephora

Abstract

Cytokinins (CK) are plant growth regulators involved in multiple physiological processes in plants. One less studied aspect is CK homeostasis (HM). The primary genes related to HM are involved in biosynthesis (IPT), degradation (CKX), and signaling (ARR). This paper demonstrates the effect of auxin (Aux) and CK and their cross talk in a Coffea canephora embryogenic system. The transcriptome and RT-qPCR suggest that Aux in pre-treatment represses biosynthesis, degradation, and signal CK genes. However, in the induction, there is an increase of genes implicated in the CK perception/signal, indicating perhaps, as in other species, Aux is repressing CK, and CK are inducing per se genes involved in its HM. This is reflected in the endogenous concentration of CK; pharmacology experiments helped study the effect of each plant growth regulator in our SE system. We conclude that the Aux–CK balance is crucial to directing somatic embryogenesis in C. canephora.

Global transcriptome profiling reveals differential regulatory, metabolic and hormonal networks during somatic embryogenesis in Coffea arabica

“…Many authors have focused on the complex gene networks involved in the response to growth regulators, mainly auxin and cytokinin, to understand the expression of cell totipotency in Arabidopsis and in cotton [8,71,72]. The genes identified in these model plants were also found in coffee [68] and showed similar patterns during the developmental stages we studied, indicating conserved pathways of cell totipotency between species. We believe that coffee SE could be used as a reference system to better understand fundamental mechanisms behind the response of woody plants to growth regulators.…”

“…According to Sugimoto et al [ 67 ], the prime characteristic of plant regeneration is cell fate reprogramming induced by wounding, stress, and hormones, in agreement with our results. Auxins and cytokinins are widely known to play essential roles in the induction of embryogenic culture [ 22 , 57 , 58 , 68 , 69 ]. Additionally, many authors have reported the involvement of certain transcription factors (TFs) in the induction of somatic embryos in different species.…”

Comparative Transcriptome Analysis of High- and Low- Embryogenic Hevea brasiliensis Genotypes Reveals Involvement of Phytohormones in Somatic Embryogenesis

“…Auxins and CKs are known for their key roles as regulators of both cell division and differentiation in plants [74]. The signi cant increase in tZ levels in YT-y (Fig.…”