Applications of Cytokinins in Horticultural Fruit Crops: Trends and Future Prospects

Abstract

Cytokinins (CKs) are a chemically diverse class of plant growth regulators, exhibiting wide-ranging actions on plant growth and development, hence their exploitation in agriculture for crop improvement and management. Their coordinated regulatory effects and cross-talk interactions with other phytohormones and signaling networks are highly sophisticated, eliciting and controlling varied biological processes at the cellular to organismal levels. In this review, we briefly introduce the mode of action and general molecular biological effects of naturally occurring CKs before highlighting the great variability in the response of fruit crops to CK-based innovations. We present a comprehensive compilation of research linked to the application of CKs in non-model crop species in different phases of fruit production and management. By doing so, it is clear that the effects of CKs on fruit set, development, maturation, and ripening are not necessarily generic, even for cultivars within the same species, illustrating the magnitude of yet unknown intricate biochemical and genetic mechanisms regulating these processes in different fruit crops. Current approaches using genomic-to-metabolomic analysis are providing new insights into the in planta mechanisms of CKs, pinpointing the underlying CK-derived actions that may serve as potential targets for improving crop-specific traits and the development of new solutions for the preharvest and postharvest management of fruit crops. Where information is available, CK molecular biology is discussed in the context of its present and future implications in the applications of CKs to fruits of horticultural significance.

Establishment of an Efficient In Vitro Culture System in Dicentra × hybrida

“…These findings suggest that D. × hybrida is a good model organism for further studies related to in vitro cultures. Increasing the concentration of KIN or the addition of an auxin could increase the proliferation rate even more, as described with other plant species [11].…”

Importance of paclobutrazol in out-of-season citrus production

“…Hormones were discovered in the early 20th century, and have been used as an agronomic instrument, mainly in fruticulture (Lal et al, 2017). Phytohormones act at the cellular level, and occur at low concentrations (Kumar et al, 2021), and currently 5 groups of phytohormones are known (Aremu et al, 2020). These include: Abscisic acid, gibberellic acid, indoleacetic acid, cytokines and ethylene (Kwon et al, 2020).…”

Endogenous Hormones in Habanero Pepper Seeds

“…The use of exogenous cytokinins provoked promotion in seed germination and fruit growth in jalapeño and habanero pepper [3,21,22]. Aremu et al [23], reported the beneficial effects in yield and fruit quality when exogenous cytokinins are applied to several fruit crops. There is also some evidence that cytokinins could be a key driver force for seed yield [24], or may act as a fruit growth promotor when deficiency of seed physiological function is present [25].…”