Abstract:
R2R3-MYB transcription factors (TFs) are key regulators of secondary metabolism
and abiotic stress responses across plant species. However, limited information
is available on the functional roles of R2R3-MYB TFs in rice in the context
of sustainable agriculture. This study aimed to identify and functionally predict
rice MYB transcription factors associated with anthocyanin biosynthesis and
stress resilience using a comprehensive in-silico approach. Thirty-one MYB gene
sequences linked to pigmentation and stress responses were retrieved from the
Plant Transcription Factor Database. Conserved motif analysis confirmed the
presence of the R2R3 domain and identified potential repressors. Phylogenetic
analysis distinguished MYBs involved in anthocyanin biosynthesis, while the detection
of EAR motifs in StMYB44 and PhMYB4 suggested repressor activity.
Gene interaction network analysis revealed associations with stress-related pathways,
including lignin biosynthesis, reactive oxygen species scavenging, stomatal
regulation, and hormone signaling. Six novel rice orthologs, OsMYB52,
OsMYB14, OsMYB26, OsMYB56, OsMYB64, and OsMYB80 were identified,
showing close evolutionary relationships with functionally characterized MYBs
from Arabidopsis thaliana, Capsicum annuum, Zea mays, Triticum aestivum, and
Vitis vinifera. Cis-regulatory analysis revealed key promoter elements such as
CAAT-box, TATA-box, ABRE, ARE, and G-box motifs, indicating responsiveness
to environmental and hormonal cues. Experimental validation will be necessary
to confirm the functional roles of the identified MYB candidates in stress
resilience and anthocyanin accumulation.
