Transcriptome‐wide identification of R2R3 ‐ MYB protein family and functional analysis of CpMYB44 in Cyclocarya paliurus during Colletotrichum fructicola infection

BACKGROUND: Wheel wingnut (Cyclocarya paliurus) is a multifunctional specie in China, and anthracnose induced by Colletotrichum fructicola is a disastrous disease that restricts the development of C. paliurus. R2R3-MYB proteins are involved in metabolism, developmental processes and the responses to diverse stresses. However, the functions of R2R3-MYB proteins in C. paliurus, particularly regarding anthracnose resistance remain poorly understood. The study aimed to identify R2R3-MYB family from the resistant cultivar, characterize the expression profiles under infection of C. fructicola and find potential genes for plant resistance. RESULTS: Fifty-five R2R3-MYB genes were identified from transcriptome data of C. paliurus infected by C. fructicola. These genes were categorized into 19 subgroups and a total of 5, 24 and 44 R2R3-MYB genes from C. paliurus shows homology to Zea mays, Nicotiana benthamiana and Juglans regia, respectively. Transient expression in C. paliurus leaves and stable transformation of N. benthamiana further confirmed that CpMYB44 enhances resistance against C. fructicola. Moreover, the expression level of CHI and flavonoid content were elevated in overexpression leaves and transgenic tobacco. CONCLUSION: The study identified and characterized R2R3-MYB family genes associated with responses to C. fructicola in the resistant C. paliurus. CpMYB44 shows potential for application in enhancing flavonoid accumulation and improving plant resistance to C. fructicola. These findings provide critical insights into the molecular mechanisms underlying resistance to anthracnose and offer promising targets for resistance breeding.