The OVATE family proteins (OFPs) are plant-specific proteins that modulate diverse aspects of plant growth and development.  In tomato, OFP20 has been shown to interact with TONNEAU1 Recruiting Motif (TRM) proteins to regulate fruit shape.  In this study, we demonstrated that the mutation of StOFP20 caused a shift from round to oval shaped tubers in a diploid accession C151, supporting the role of StOFP20 in controlling tuber shape.  Its expression reached a maximum in the tuber initiation stage and then decreased as the tuber develops.  To help elucidate the mechanism of tuber shape regulation by StOFP20, 27 TONNEAU1 Recruiting Motif (TRM) proteins were identified and 23 of them were successfully amplified in C151.  A yeast two-hybrid assay identified three TRM proteins that interacted with StOFP20, which was confirmed by firefly luciferase complementation in tobacco leaves.  The OVATE domain was indispensable for the interactions, while the necessity of the M10 motif in TRM proteins varied among the interactions between StOFP20 and the three TRMs.  In summary, both StOFP20 and SlOFP20 directed interactions with TRM proteins, but the corresponding interactants were not completely consistent, implying that they exert regulatory roles through mechanisms that are only partially overlapping.  

Selection of quantitative characteristics, division of their expression ranges, and selection of example varieties are key issues on developing DUS Test Guidelines, which are more crucial for quantitative characteristics since their expressions vary in different degrees. Taking the development of DUS Test Guideline of Ranunculus asiaticus L. as an example, this paper applied statistic-based approaches for the analyses of quantitative characteristics. We selected 9 quantitative characteristics from 18 pre-selected characteristics, based on within-variety uniformity, stability between different growing cycles, and correlation among characteristics, by the analyses of coefficient of variation, paired-samples t-test and partial correlation. The expression ranges of the 9 selected quantitative characteristics were divided into different states using descriptive statistics and distribution frequency of varieties. Eight of the 9 selected quantitative characteristics were categorized as standard characteristics as they showed one peak in distribution frequency of 120 varieties in various expressions of the characteristics, whereas, plant height can be categorized as grouping characteristic since it gave two peaks, and can group the varieties into pot and cut varieties. Finally, box-plot was applied to visually select the example varieties, and varieties 7, 12, and 28 were determined as the example varieties for plant height. The methods described in this paper are effective for the selection of quantitative characteristics, division of expression ranges, and selection of example varieties in Ranunculus asiaticus L. for DUS test, and may also be interest for other plant genera.