小麦miR9778基因家族的泛基因组鉴定与表达模式分析

MicroRNAs (miRNAs), as critical regulatory factors, play essential roles in plant growth, development, and stress responses. In this study, we employed bioinformatics approaches to identify members of the miR9778 gene family across 22 wheat cultivars and analyzed their sequence characteristics, expression patterns, and target genes. The results demonstrated that wheat harbors three miR9778 genes (Tae-miR9778a, Tae-miR9778b, and Tae-miR9778c), located on chromosomes 7A, 7B, and 7D, respectively. These genes encode 21-bp mature miRNAs derived from 79-bp precursor sequences, all forming stable stem-loop secondary structures. The mature Pan-genome identification and expression pattern analysis of the wheat miR9778 gene familysequences of the three Tae-miR9778 genes were identical across all 22 cultivars. The precursor sequences of Tae-miR9778a and Tae-miR9778c were highly conserved among all cultivars, whereas variations were observed in the precursor sequence of Tae-miR9778b in Jinmai47, Mazhamai, and Beijing8, with polymorphisms at positions 10 (T/G) and 60 (A/G).Expression analysis revealed that Tae-miR9778 genes were most highly expressed in seedlings and least expressed in spikes. Under low-potassium stress, their expression was downregulated in potassium-efficient cultivars but showed no significant changes in potassium-inefficient cultivars, suggesting that Tae-miR9778 participates in the low-potassium stress response in tolerant genotypes. Promoter analysis identified 27 types of cis-acting regulatory elements in the Tae-miR9778a/b/c promoters, primarily including light-responsive elements, phytohormone-responsive elements, stress-responsive elements, growth/development-related elements, and secondary metabolite biosynthesis-associated elements.This study systematically elucidates the members, expression dynamics, and target networks of Tae-miR9778 in wheat, laying a foundation for further investigation into the molecular mechanisms underlying its role in low-potassium stress adaptation.