Mung bean is an important food legume and a useful model for studying early plant growth, yet many of the small RNAs that regulate its development have remained poorly understood. MicroRNAs are short regulatory molecules that fine-tune gene expression and influence organ formation, hormone responses, and adaptation to changing environments. In crop species, however, identifying biologically meaningful, species-specific microRNAs is still difficult, and validating them often depends on labor-intensive techniques such as qRT-PCR or northern blotting. These limits have slowed efforts to connect RNA discovery with practical agricultural use. Based on these challenges, deeper research is needed on rapid discovery and validation of development-related microRNAs in mung bean.
Researchers from Yonsei University, Xenohelix Research Institute, and Pohang University of Science and Technology reported (DOI: 10.1093/hr/uhaf312) in Horticulture Research that they identified tissue-specific microRNAs active during early mung bean development and validated them using a DNA/AgNC nanosensor platform capable of rapid, tissue-sensitive detection.
The team profiled small RNAs from 7-day-old mung bean seedlings and compared leaf, stem, and root tissues with an early developmental control. Their analysis identified 1,016 predicted miRNAs, including 470 conserved miRNAs and 546 mung bean-specific candidates. Among these, 129 novel tissue-specific miRNAs were highlighted, and 17 high-confidence candidates were selected after additional structural screening. Many of the strongest signals appeared in leaves, pointing to an especially active miRNA network during early aerial growth.
To validate these candidates more efficiently, the researchers used Tailed-Hoogsteen triplex DNA-encapsulated silver nanocluster sensors. The nanosensors detected selected miRNAs within about 30 minutes and produced tissue-specific fluorescence signals that matched sequencing-based expression trends. Several of the newly identified miRNAs were predicted to regulate PME1, a gene involved in pectin modification and cell wall remodeling during organ expansion. Others were linked to genes associated with auxin biosynthesis, photosynthesis, and cell growth, including IAMH2, GPDH, MSMO1-2, and FNR. Gene ontology analysis further connected the targets to hormone signaling, transcriptional control, root and embryo development, and RNA metabolism.
The team then tested whether one candidate, Vr.miR N.045, could be properly processed and function in plant cells. In a tobacco transient-expression system, the precursor RNA was successfully converted into a mature miRNA, and co-expression experiments showed reduced PME1 transcript levels, confirming its gene-silencing activity.
This study is compelling because it combines biological discovery with a usable detection strategy. Rather than stopping at sequencing, the researchers showed that crop-specific microRNAs can be quickly measured and linked to real developmental functions. That matters for non-model crops, where regulatory signals are often understudied and difficult to verify. By coupling discovery with rapid validation, the work moves plant RNA research closer to tools that breeders and crop scientists may actually use.
The findings broaden the known microRNA catalog of mung bean and clarify how early seedling growth may be fine-tuned through RNA-guided regulation of genes involved in cell expansion, hormone pathways, and photosynthetic development. Just as importantly, the nanosensor platform offers a faster route from RNA discovery to practical application. Because it detects target miRNAs directly from purified small RNAs with relatively simple handling, it may support future crop diagnostics, developmental screening, and stress monitoring in mung bean and other non-model species. In that sense, the study does more than reveal hidden growth signals—it helps build a bridge between plant molecular biology and real-world agriculture.
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References
DOI
10.1093/hr/uhaf312
Original Source URL
https://doi.org/10.1093/hr/uhaf312
Funding information
This research was supported by the Basic Science Research Program through the National Research Foundation of Korea (NRF), funded by the Ministry of Science, ICT, and Future Planning NRF-RS-2023-NR077248 to S.W.Y. and supported in part by the NRF-RS-2022-NR074880 to H.J.J. This research was supported in part by the Brain Korea 21 (BK21) FOUR (Fostering Outstanding Universities for Research) program from the Ministry of Education (MOE, South Korea).
About Horticulture Research
Horticulture Research is an open access journal of Nanjing Agricultural University and ranked number one in the Horticulture category of the Journal Citation Reports ™ from Clarivate, 2023. The journal is committed to publishing original research articles, reviews, perspectives, comments, correspondence articles and letters to the editor related to all major horticultural plants and disciplines, including biotechnology, breeding, cellular and molecular biology, evolution, genetics, inter-species interactions, physiology, and the origination and domestication of crops.