PlantView 230F Support Rose Drought Tolerance Research: RrMYB2 Regulates Drought Stress via RrJMJ12-Dependent Epigenetic Modification in Rosa rugosa

New progress has been made in the study of drought tolerance mechanisms in rose.

Professor Liguo Feng's research group from the College of Horticulture and Landscape Architecture, Yangzhou University, in collaboration with Professor Changquan Wang's research group from Nanjing Agricultural University, published their findings in Plant Biotechnology Journal (IF = 10.5, top-tier journal).

This study revealed that RrMYB2 regulates drought stress responses in rose through RrJMJ12-dependent epigenetic modification, providing new insights into the transcriptional and epigenetic regulatory mechanisms underlying drought tolerance in woody ornamental plants.

Rose (Rosa rugosa) is an economically important crop widely cultivated in the fragrance and pharmaceutical industries due to its aromatic compounds and bioactive metabolites, such as anthocyanins and flavonoids, particularly contributing significant economic value in East Asia. However, roses are predominantly grown under open-field conditions, making them highly susceptible to drought stress under changing climate conditions. Drought causes leaf wilting, reduced photosynthetic efficiency, and even plant death, resulting in yield losses of up to 30% and posing a serious threat to sustainable production. Although the vulnerability of rose to drought has long been recognized, the molecular pathways governing drought tolerance remain largely unclear, limiting the development of effective genetic improvement strategies.

Plants have evolved complex molecular cascades to cope with drought stress, involving physiological regulation, such as stomatal closure and enhanced antioxidant enzyme activity, as well as multiple signaling pathways. At the core of this regulatory network are transcription factors, among which the R2R3-MYB family plays a key role in the ABA signaling pathway by activating stress-responsive genes, including ABF, thereby promoting osmotic adjustment and the accumulation of protective metabolites. Meanwhile, epigenetic modifications, such as histone methylation, dynamically regulate stress-responsive gene expression by altering chromatin accessibility. Members of the JMJ histone demethylase family can remove the repressive H3K27me3 mark to activate gene expression. In Arabidopsis, the cooperative action of MYB2 and JMJ12 has been shown to enhance drought tolerance, but whether a similar mechanism exists in woody economic crops remains largely unexplored.

In rose, the functional roles of MYB transcription factors and epigenetic regulators in drought tolerance remain largely unknown. Previous studies have suggested that the ABA signaling pathway plays a central role in the drought response of rose, yet the specific functions of R2R3-MYB genes and their interactions with epigenetic modifiers have not been elucidated. Therefore, this study aimed to fill this knowledge gap by systematically identifying R2R3-MYB family members in the rose genome and investigating whether RrMYB2 suppresses ABA receptor inhibitors (PP2Cs) through JMJ12-mediated epigenetic reprogramming. This work establishes a novel transcriptional–epigenetic regulatory axis and provides promising molecular targets for breeding drought-tolerant rose varieties.

Experiments using PlantView

To investigate the functional role of RrMYB2 in the drought stress response of rose, researchers subjected transgenic plants overexpressing RrMYB2 (35S:RrMYB2), RrMYB2 RNA interference (RrMYB2-RNAi) plants, and empty vector controls to natural drought treatment using six-week-old plants. When leaf wilting, a characteristic symptom of drought stress, became apparent, chlorophyll fluorescence parameters were measured using the PlantView 230F Modulated Chlorophyll Fluorescence In Vivo Imaging System developed by Guangzhou Biolight Biotechnology. The results showed that the overexpression lines exhibited significantly less wilting and maintained substantially higher Y(II) (effective quantum yield of photosystem II) values than the control plants, indicating reduced damage to the photosynthetic apparatus. In contrast, the RNAi lines displayed a sharp decline in Y(II) accompanied by more severe wilting symptoms (Figure 1). These findings demonstrate that RrMYB2 positively regulates drought tolerance in rose, likely by maintaining photochemical efficiency and alleviating the inhibitory effects of drought stress on photosynthesis.

DOI: org/10.1111/pbi.70432