Epigenetic changes detected in micropropagated hop plants

Area of Science:

• Plant Biotechnology
• Molecular Biology
• Horticulture

Background:

• Micropropagation is a key technique for propagating hops (Humulus lupulus L.).
• Assessing the genetic and epigenetic stability of micropropagated plants is crucial for crop improvement.
• Previous studies have not evaluated the long-term stability of hop microplants.

Purpose of the Study:

• To investigate the genetic and epigenetic stability of hop (Humulus lupulus L.) plants during prolonged in vitro micropropagation.
• To determine if micropropagation induces genetic mutations or epigenetic modifications in hop plants.
• To compare epigenetic profiles between field-grown and in vitro-propagated hop plants.

Main Methods:

• Micropropagation of two hop accessions over two years (12 subcultures).
• Analysis of genetic stability using Random Amplified DNA Polymorphism (RAPD).
• Assessment of genetic and epigenetic variation using Retrotransposon Microsatellite Amplified Polymorphism (REMAP) and Methylation-Sensitive Amplification Polymorphism (MSAP).

Main Results:

• No genetic variation was detected among hop plants, irrespective of the number of micropropagation cycles.
• Significant epigenetic variation was observed when comparing field-grown and in vitro-propagated hop plants.
• A consistent pattern of epigenetic alterations was found in approximately 30% of fragments across all in vitro-propagated plants.
• Lower levels of epigenetic variation were detected among different subcultures, suggesting accumulation over time.

Conclusions:

• Micropropagation of hops (Humulus lupulus L.) maintains high genetic stability over extended periods.
• Epigenetic modifications occur during hop micropropagation, differentiating in vitro plants from field-grown counterparts.
• The detected epigenetic variations may accumulate with successive subcultures, warranting further investigation for long-term propagation strategies.