‘Beta’ is a hybrid of Vitis riparia L. and V. labrusca and has a strong ability to adapt to adverse growth environments and is mainly cultivated and used as a resistant rootstock. At present, the most extensively studied MYB TFs are R2R3-type, which have been found to be involved in plant growth, development, and stress response processes. In the present research, VhMYB15, a key transcription factor for abiotic stress tolerance, was screened by bioinformatics in ‘Beta’ rootstock, and its function under salinity and drought stresses was investigated. VhMYB15 was highly expressed in roots and mature leave under salinity and drought stresses. Observing the phenotype and calculating the survival rate of plants, it was found that VhMYB15-overexpressing plants exhibited relatively less yellowing and wilting of leaves and a higher survival rate under salinity and drought stresses. Consistent with the above results, through the determination of stress-related physiological indicators and the expression analysis of stress-related genes (AtSOS2, AtSOS3, AtSOS1, AtNHX1, AtSnRK2.6, AtNCED3, AtP5CS1, and AtCAT1), it was found that transgenic Arabidopsis showed better stress tolerance and stronger adaptability under salinity and drought stresses. Based on the above data, it was preliminarily indicated that VhMYB15 may be a key factor in salinity and drought regulation networks, enhancing the adaptability of ‘Beta’ to adverse environments.

‘Beta’ (Vitisriparia × V. labrusca) is a vine fruit tree of the genus Vitis which is a cross between American and riparian grapes. In the current situation of grape production in northern regions, cold, drought, and salinity are important bottlenecks restricting its development, while some grape rootstocks with excellent traits show the disadvantage of poor resilience. ‘Beta’ (Vitis riparia × V. labrusca), one of the most extensively utilized rootstocks in viticulture, has demonstrated remarkable resilience to adverse conditions. However, the mechanisms by which ‘Beta’ rootstocks resist abiotic stresses are unknown and need to be further investigated. In this study, we successfully isolated and cloned a novel MYB transcription factor, VhMYB60, from the ‘Beta’ grapevine. This factor spans 972 base pairs and encodes a protein comprising 323 amino acids. Subcellular localization studies revealed that VhMYB60 is predominantly expressed within the nucleus. Furthermore, tissue-specific expression analysis demonstrated that VhMYB60 is more abundantly expressed in the mature leaves and roots of the grape plant. Further studies showed that salt and cold stress notably increased VhMYB60 gene expression in both mature leaves and grape roots. Compared with the control, Arabidopsis thaliana (Arabidopsis) plants molecularly modified to overexpress VhMYB60 exhibited enhanced salt and cold resistance and improved survival rates. Moreover, notable changes were detected in chlorophyll, malondialdehyde (MDA), proline, peroxidase (POD), catalase (CAT), and superoxide dismutase (SOD) levels. Concurrently, the expression levels of structural genes that are positively correlated with resistance to adversity stress were markedly elevated in Arabidopsis plants that overexpress VhMYB60. Consequently, VhMYB60 may serve as a pivotal transcription factor in the regulation of ‘Beta’ resistance.

Fragaria vesca L., a widely distributed model species, serves as a key resource for studying the evolution and genetics of the Fragaria genus. Research has shown that R2R3-MYB transcription factors are crucial for plant growth and development. However, their specific role in cold resistance in F. vesca is not well understood. In this study, we used the latest genome data for the strawberry (F. vesca v6.0). We performed a genome-wide identification of the R2R3-MYB gene family in F. vesca. We identified a total of 106 R2R3-FvMYBs. Based on their predicted functions in plants, we classified these genes into 25 distinct subfamilies. We then conducted a comprehensive bioinformatics analysis of this family. We performed a detailed examination of the R2R3-FvMYBs structures and physicochemical properties. This analysis provided five key parameters for each protein: molecular weight, the number of amino acids, theoretical isoelectric point, grand average of hydropathicity (GRAVY), and instability index. Gene duplication analysis suggested that segmental duplications were a primary driver of the proliferation of this gene family. Promoter cis-acting element prediction revealed that a large proportion of R2R3-FvMYBs possess elements predominantly associated with phytohormone responsiveness and biotic/abiotic stress responses. Quantitative real-time reverse transcription PCR (qRT-PCR) results confirmed that the expression levels of several R2R3-FvMYBs were upregulated under cold stress. Furthermore, compared to wild-type controls, the overexpression of FvMYB103 in Arabidopsis thaliana enhanced cold tolerance, accompanied by increases in the relevant physiological indices. Collectively, these findings support further investigation into R2R3-MYB gene family to directly assess their contribution to cold resistance.